A-Level Chemistry Exam Questions

Page 02 SECTION 1 — 30 marks Attempt ALL questions 1. Which of the following lists electromagnetic radiation bands in order of increasing wavelength? A X-ray, infrared, ultraviolet, radio B Infrared, ultraviolet, X-ray, gamma C Ultraviolet, visible, infrared, radio D Radio, infrared, visible, gamma 2. Which of the following states that electrons fill orbitals in order of increasing energy? A Hund’s rule B The aufbau principle C The Pauli exclusion principle D The valence shell electron pair repulsion theory 3. X In the periodic table outlined above, one area is marked X. Moving across area X, from one element to the next, the extra electron usually occupies an orbital of type A s B p C d D f. 4. Which of the following molecules contains three atoms in a straight line? A BF3 B CH4 C H2O D SF6

Page 03 5. The complex ion [Cu(CN)6]4− is called A hexacyanocopper(II) B hexacyanocopper(IV) C hexacyanocuprate(II) D hexacyanocuprate(IV). 6. HCN(aq) + H2O(ℓ) Ý H3O+(aq) + CN−(aq) In the above equation HCN(aq) is acting as A an acid B a conjugate acid C a base D a conjugate base. 7. The use of an indicator is not appropriate in titrations involving A hydrochloric acid solution and methylamine solution B nitric acid solution and potassium hydroxide solution C methanoic acid solution and ammonia solution D propanoic acid solution and sodium hydroxide solution. 8. Which of the following can produce a buffer solution when added to aqueous NH4Cl? A Ammonia B Ethanoic acid C Potassium chloride D Ammonium sulfate 9. Which of the following reactions cannot be described as an enthalpy of formation? A Si(s) + 4Cl(g) → SiCl4(ℓ) B Mg(s) + ½O2(g) → MgO(s) C C(s) + 2H2(g) + ½O2(g) → CH3OH(ℓ) D 2C(s) + 3H2(g) → C2H6(g) [Turn over

Page 04 10. Which of the following is likely to have the lowest standard entropy at 100 ºC? A Neon B Mercury C Sulfur D Phosphorus 11. For the reaction 2A + 2B ↓ C the rate equation is rate = k[A][B]2. Which of the following could be a possible mechanism for this reaction? A A + B ↓ X (fast) X + A + B ↓ C (slow) B A + 2B ↓ X (slow) X + A ↓ C (fast) C 2A + B ↓ X (slow) X + B ↓ C (fast) D 2A + B ↓ X (fast) X + B ↓ C (slow) 12. Which line in the table has the correct number and type of bonds in the structure shown? H C H H C C H C H H H C H C C H H H H Number of σ-bonds Number of π-bonds A 2 18 B 4 16 C 16 4 D 18 2

Page 05 13. 5-Methylhept-3-ene-2-one is an aroma molecule found in some types of tea. Which of the following shows a structural formula for the trans-isomer of 5-methylhept-3-ene-2-one? O O O O A B C D 14. Which of the following does not exhibit hydrogen bonding between its molecules? A Ethanol B Ethylamine C Ethanoic acid D Ethoxyethane 15. In the homologous series of amines, an increase in chain length is accompanied by Volatility Solubility in water A increased increased B decreased decreased C increased decreased D decreased increased [Turn over

Page 06 16. Which of the following will react together to produce 2-ethoxypropane? A CH3CH2OH and CH3CH2COONa B CH3CH2ONa and CH3CH2CH2Br C CH3CH(OH)CH3 and CH3COONa D CH3CH2ONa and CH3CHBrCH3 17. Aldehydes can be converted into alcohols by the reaction shown R' C H O C R' H3C OH H (i) CH3MgBr (ii) H+ Which of the following aldehydes would produce a primary alcohol? A Methanal B Ethanal C Propanal D Butanal 18. CH3CHO + NH2NH2 ↓ CH3CH = NNH2 + H2O This reaction is an example of A hydration B hydrolysis C dehydration D condensation. 19. When but-1-ene reacts with hydrogen chloride, 1-chlorobutane and 2-chlorobutane are formed. According to Markovnikov’s rule A there will be more 2-chlorobutane than 1-chlorobutane B there will be more 1-chlorobutane than 2-chlorobutane C there will be equal proportions of both products D it is impossible to tell the relative proportion of each product.

Page 07 20. When 2-bromobutane reacts with ethanolic potassium cyanide and the compound formed is hydrolysed with dilute acid, the final product is A butanoic acid B pentanoic acid C 2-methylbutanoic acid D 2-methylpentanoic acid. 21. H C C C H H H H H Cl H 1 H C C C H H H H H OH H 2 H C C C H H H H H O 3 H C C C H H H H H 4 Which line in the table correctly identifies W, X, Y and Z in the reaction sequence? reduction dehydration addition W X Y Z W X Y Z A 1 4 2 3 B 3 2 1 4 C 3 2 4 1 D 4 1 2 3 22. Which of the following statements about benzene is not true? A It is planar. B It is susceptible to attack by electrophilic reagents. C Its carbon to carbon bonds are equal in length. D It is readily attacked by bromine. [Turn over

Page 08 23. (CH3)3CBr + OH− ↓ (CH3)3COH + Br− The above reaction proceeds via an SN1 mechanism. What effect will doubling the concentration of hydroxide ions have on the reaction rate? A It will have no effect. B The reaction rate will halve. C The reaction rate will double. D The reaction rate will increase by a factor of four. 24. H C H H C H H C O O H Which of the following shows the splitting pattern for the circled H atom above, in a high resolution proton NMR spectrum? A B C D Page 09 25. HO OH C H OH C H H N H H OH C H OH C H H N CH3 H C H OH C H CH3 N H H Noradrenaline Phenylephrine Amphetamine Noradrenaline and phenylephrine stimulate receptors in the body resulting in increased blood pressure. Amphetamine has the same effect but works indirectly in the body by stimulating production of noradrenaline. The structural fragment acting directly on the receptor is OH C H C H H N H OH C H C H H N H H C H OH C H N H OH C H OH C H H N H A B C D [Turn over

Page 10 26. In a UK workplace, the maximum short-term exposure limit for carbon monoxide is 200 ppm in a 15 minute period. If a person breathes in 134 g of air in a 15 minute period, what is the mass of carbon monoxide breathed in at the maximum short-term exposure limit? A 1·49 mg B 26·8 mg C 1·49 g D 26·8 g 27. Sodium hydroxide is unsuitable for use as a primary standard because it A is corrosive B is readily soluble in water C is available in a high degree of purity D readily absorbs water from the atmosphere. 28. What volume of 0·25 mol l−1 calcium nitrate is required to make, by dilution with water, 500 cm3 of a solution with a nitrate ion concentration of 0·1 mol l−1? A 50 cm3 B 100 cm3 C 200 cm3 D 400 cm3 29. 1·60 g of an anhydrous metal sulfate were dissolved in water. Addition of excess barium chloride solution resulted in the precipitation of 2·33 g of barium sulfate. The original substance was A copper(II) sulfate B magnesium sulfate C sodium sulfate D calcium sulfate.

Page 11 30. 0·020 moles of the salt Pt(NH3)xCl2 required 20·0 cm3 of 4·0 mol l−1 nitric acid to react completely with the NH3 ligands. The value of x is A 2 B 4 C 6 D 8. [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET] Page 12 [BLANK PAGE] DO NOT WRITE ON THIS PAGE AH FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2016 Reference may be made to the Chemistry Higher and Advanced Higher Data Booklet. Total marks — 100 SECTION 1 —30 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on Page 02. SECTION 2 —70 marks Attempt ALL questions. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/77/01 WEDNESDAY, 18 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer Grid and Section 2 Page 02 SECTION 1 — 30 marks The questions for Section 1 are contained in the question paper X713/77/02. Read these and record your answers on the answer grid on Page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample Question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D Page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 A B C D 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SECTION 1 — Answer Grid [Turn over Page 04 [BLANK PAGE] do not write on this page Page 05 [Turn over for next question do not write on this page Page 06 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 70 marks Attempt ALL questions 1. Ethene can be hydrated to produce ethanol. C2H4(g) + H2O(ℓ) → C2H5OH(ℓ) Compound Standard free energy of formation, ΔG° (kJ mol−1) Standard enthalpy of formation, ΔH°f (kJ mol−1) Ethene 68 52 Water −237 −286 Ethanol −175 −278 (a) For the hydration of ethene, use the data in the table to calculate: (i) the standard enthalpy change, ΔH°, in kJ mol−1; (ii) the standard entropy change, ΔS°, in J K−1 mol−1. (b) Calculate the temperature, in K, at which this reaction just becomes feasible. 1 3 2 Page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. In the periodic table, period 2 is comprised of the elements lithium to neon. The following table shows two of the quantum numbers for all ten electrons in a neon atom. Electron Principal quantum number, n Angular momentum quantum number, l 1 1 0 2 1 0 3 2 0 4 2 0 5 2 1 6 2 1 7 2 1 8 2 1 9 2 1 10 2 1 (a) Write the electronic configuration for neon in terms of s and p orbitals. (b) The angular momentum quantum number, l, is related to the shape of an orbital. Draw the shape of an orbital when l has a value of 1. (c) The magnetic quantum number, m, is related to the orientation of an orbital in space. State the values of m for the orbital which contains the tenth electron. 1 1 1 [Turn over Page 08 [BLANK PAGE] do not write on this page Page 09 MARKS DO NOT WRITE IN THIS MARGIN 3. Iron can form a variety of complexes with different ligands. Each complex has different properties. (a) Some iron complex ions are paramagnetic. Paramagnetic substances are substances that are weakly attracted by a magnetic field. Paramagnetism is caused by the presence of unpaired electrons. In both [Fe(H2O)6]2+ and [Fe(CN)6]4−, the Fe2+ ion has six d-electrons, but only [Fe(H2O)6]2+ is paramagnetic. (i) Complete the d-orbital box diagram for the complex ion [Fe(CN)6]4−. Energy ∆ (An additional diagram, if required, can be found on Page 28) (ii) The relative ability of a ligand to split the d-orbitals when forming a complex ion is given by the spectrochemical series. The spectrochemical series for some ligands is shown below. CN− > NH3 > H2O The [Fe(H2O)6]2+ ion has unpaired electrons and is therefore paramagnetic. Explain how unpaired electrons can arise in this complex ion. (iii) Explain why all of the complex ions formed by the Fe3+ ion are paramagnetic. 1 2 1 [Turn over Page 10 MArKS DO NOT WRITE IN THIS MARGIN 3. (continued) (b) Human blood is red due to the presence of haemoglobin bonded to oxygen. Other animals have different coloured blood due to the presence of different complex ions bonded to oxygen. Human Haemoglobin Oxyhaemocyanin RED Animal Complex ion Colour of blood N N N N H3C CH2 CH3 CH2 H3C O OH CH3 OH O Fe2+ Leech GREEN Spider BLUE Chlorocruorin N N N N O O OH OH O Fe2+ H3C CH3 CH2 H3C CH3 O O Cu Cu N N N NH N N N HN HN NH NH HN CH3 CH3 CH3 H3C H3C H3C 2+ 2+ (i) State the co-ordination number of the Fe2+ ion in haemoglobin. 1 Page 11 MARKS DO NOT WRITE IN THIS MARGIN 3. (b) (continued) (ii) Spiders’ blood contains the oxyhaemocyanin complex ion. Oxyhaemocyanin contains copper ions. Suggest an analytical technique that could be used to determine the presence of copper ions in spiders’ blood. (iii) Using your knowledge of chemistry, comment on why these animals have different coloured blood. [Turn over 1 3 Page 12 MARKS DO NOT WRITE IN THIS MARGIN 4. As part of an Advanced Higher Chemistry project, a student determined the chloride ion concentration of seawater by two different methods. Volumetric method A sample of seawater was titrated with standard silver nitrate solution. Gravimetric method A sample of seawater was reacted with standard silver nitrate solution to form a precipitate. The precipitate was collected by filtration and weighed. (a) For the volumetric method, a 0∙1 mol l−1 standard solution of silver nitrate was prepared by following the instructions below. 1. Dry 5 g of silver nitrate for 2 hours at 100 °C and allow to cool. 2. Weigh accurately approximately 4∙25 g of solid silver nitrate. 3. Use this sample to prepare 250 cm3 of standard silver nitrate solution. (i) State what is meant by “weigh accurately approximately” 4∙25 g of solid silver nitrate. (ii) Outline how the student would have prepared the standard silver nitrate solution. (iii) Samples of the diluted seawater were titrated and the average titre was found to be 3∙9 cm3. Suggest an improvement the student could make to reduce the uncertainty in the titre value. 1 2 1 Page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (b) For the gravimetric method, standard silver nitrate solution was added to a seawater sample to form a precipitate of silver chloride. (i) Describe how the filtration should have been carried out to ensure a fast means of separating the precipitate from the reaction mixture. (ii) After the precipitate was filtered, the filtrate was tested with a few drops of silver nitrate solution. Suggest why the student tested the filtrate in this way. (c) The student also planned to carry out an analysis of chloride ion concentration in fresh river water. Explain why the volumetric method, rather than the gravimetric method, would be more appropriate for the analysis of chloride ion concentration in fresh river water. [Turn over 1 1 1 Page 14 MArKS DO NOT WRITE IN THIS MARGIN 5. Mandelic acid, 2-hydroxy-2-phenylethanoic acid, is a component of skin care products. mandelic acid OH OH O (a) Mandelic acid is a weak acid. C6H5CH(OH)COOH(aq) + H2O(ℓ) Ý C6H5CH(OH)COO−(aq) + H3O+(aq) Write the expression for the dissociation constant, Ka, for mandelic acid. (b) A 100 cm3 sample of skin care product contained 10∙0 g of mandelic acid. The Ka of mandelic acid is 1∙78 × 10−4. (i) Calculate the concentration of the mandelic acid, in mol l−1, present in the skin care product. (ii) Using your answer to (b)(i), calculate the pH of a solution of mandelic acid of this concentration. 1 2 3 Page 15 [Turn over for next question do not write on this page Page 16 MARKS DO NOT WRITE IN THIS MARGIN 6. Chlorine is a versatile element which forms a wide range of compounds. (a) One example of a compound containing chlorine is vanadium(IV) chloride. It reacts vigorously with water forming a blue solution. The blue solution absorbs light of wavelength 610 nm. Calculate the energy, in kJ mol−1, associated with this wavelength. (b) Chlorine dioxide, ClO2, is used in water sterilisation. An experiment was carried out to determine the kinetics for the reaction between chlorine dioxide and hydroxide ions. 2ClO2(aq) + 2OH−(aq) → ClO2 −(aq) + ClO3 −(aq) + H2O(ℓ) Under certain conditions the following results were obtained. [ClO2] (mol l−1) [OH−] (mol l−1) Initial rate (mol l−1s−1) 6·00 × 10−2 3·00 × 10−2 2·48 × 10−2 1·20 × 10−1 3·00 × 10−2 9·92 × 10−2 1·20 × 10−1 9·00 × 10−2 2·98 × 10−1 (i) Determine the order of reaction with respect to: (A) ClO2 (B) OH− 2 1 1 Page 17 MARKS DO NOT WRITE IN THIS MARGIN 6. (b) (continued) (ii) Write the overall rate equation for the reaction. (iii) Calculate the value for the rate constant, k, including the appropriate units. 1 2 [Turn over Page 18 MArKS DO NOT WRITE IN THIS MARGIN 7. Aldehydes and ketones can exist in two forms, a keto form and an enol form. For example, the aldehyde ethanal exists in equilibrium with its enol form, ethenol. K = 3·0 × 10−7 ethanal (keto form) ethenol (enol form) H3C C O H H2C C H OH Ý These two different molecules are known as tautomers. (a) State which of the tautomers is the more abundant in this equilibrium. (b) 3-Methylpentan-2-one is optically active and exists in equilibrium with its enol tautomer. (i) Circle the chiral centre on 3-methylpentan-2-one. H3C CH3 H C C CH2 O H3C (ii) Suggest why the optical activity of 3-methylpentan-2-one decreases over time. 1 1 1 Page 19 MArKS DO NOT WRITE IN THIS MARGIN 7. (b) (continued) (iii) Draw the skeletal formula for 3-methylpentan-2-one. (c) A possible mechanism for acid-catalysed enolisation is shown below, where R, R' and R" are alkyl groups. C C R H H+ O .. .. .. R' R'' C C R H H O+ H+ .. R' R'' C C R H O .. R' R'' Ý Ý Using structural formulae and curly arrow notation, show a possible mechanism for the acid-catalysed enolisation of 3-methylpentan-2-one. 1 3 [Turn over Page 20 MARKS DO NOT WRITE IN THIS MARGIN 8. Aspirin can be used as a starting material for the synthesis of the drug, salbutamol, which is used in the treatment of asthma. Salbutamol acts as an agonist by stimulating receptors in the lungs. A possible synthetic route is shown. HO2C H3COCO HO2C HO O H3CO2C HO O H3CO2C HO O Br H3CO2C HO O N C H CH3 CH3 H3C HO OH N C H CH3 CH3 H3C HO AlCl3 CH3OH/H+ Br2 Step 1 Step 2 Step 3 Step 4 Step 5 (a) State what is meant by the term agonist. (b) Step ➀ is known as a Fries rearrangement. Suggest the role of AlCl3 in this rearrangement. 1 1 Page 21 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (c) Suggest a reaction condition required for Step ➂. (d) Identify the type of reaction taking place in Step ➃. (e) Step ➄ involves several reactions. Suggest a suitable reagent that could be used to convert the ketone carbonyl group to the hydroxyl group. [Turn over 1 1 1 Page 22 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (f) The purity of salbutamol can be determined using a variety of analytical techniques. Using your knowledge of chemistry, discuss how analytical techniques could be used to determine the purity of salbutamol. 3 Page 23 MARKS DO NOT WRITE IN THIS MARGIN 9. Parabens are used as preservatives in cosmetics, pharmaceutical products and foods. Parabens are esters of 4-hydroxybenzoic acid. One common paraben used as a food preservative is ethylparaben. O O OH ethylparaben (a) Ethylparaben is an aromatic compound containing both sigma and pi bonds. (i) Write the molecular formula for ethylparaben. (ii) State the type of hybridisation which is adopted by the carbon atoms in the aromatic ring. (iii) Describe how pi bonds form. [Turn over 1 1 1 Page 24 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (b) Another preservative is sodium 4-hydroxybenzoate. It can be prepared by refluxing ethylparaben with sodium hydroxide solution. O O OH O O−Na+ OH CH3CH2OH Na + + +OH− (i) Complete the diagram below to show how the reaction mixture is heated under reflux. Heating mantle (An additional diagram, if required, can be found on Page 28) (ii) At the start of the reaction, two layers were observed in the reaction mixture. Explain why only one layer was observed when the reaction was complete. 1 1 Page 25 MARKS DO NOT WRITE IN THIS MARGIN 9. (b) (continued) (iii) Explain fully why a solution of the salt sodium 4-hydroxybenzoate has a pH greater than 7. (iv) After refluxing, dilute hydrochloric acid was added to the reaction mixture and a white precipitate of 4-hydroxybenzoic acid was produced. The crude 4-hydroxybenzoic acid was recrystallised. 4-hydroxybenzoic acid is soluble in different solvents but only some of these solvents are suitable for recrystallisation. State two factors that should be considered when selecting an appropriate solvent for this recrystallisation. (v) In this experiment, the percentage yield of 4-hydroxybenzoic acid was 77·5%. Calculate the mass of ethylparaben (GFM = 166 g) required to produce 2·48 g of 4-hydroxybenzoic acid (GFM = 138 g). [Turn over 2 2 2 Page 26 MArKS DO NOT WRITE IN THIS MARGIN 10. Phenylbutazone is an anti-inflammatory drug used for the short-term treatment of pain and fever in animals. (a) Phenylbutazone can be synthesised, in a multi-step process, starting from compound A. Elemental microanalysis showed that compound A has a composition, by mass, of 50∙0% C; 5∙60% H; 44∙4% O Calculate the empirical formula of compound A. (b) An infra-red spectrum for compound A is shown below. 3500 50 100 3000 2500 2000 Wave number (cm−1) Transmittance (%) 1500 1000 Identify the functional group responsible for the peak at 1710 cm−1. 2 1 Page 27 MArKS DO NOT WRITE IN THIS MARGIN 10. (continued) (c) The mass spectrum for compound A is shown below. m/z % 100 80 60 40 20 0 10 70 90 50 30 25 43 45 55 27 72 (i) Write the molecular formula for compound A. (ii) Suggest a possible ion fragment that may be responsible for the peak at m/z 27. (d) Considering all the evidence, draw a structural formula for compound A. [END OF QUESTION PAPEr] 1 1 1 Page 28 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL DIAGRAM FOR USE IN QUESTION 3 (a) (i) Energy ∆ ADDITIONAL DIAGRAM FOR USE IN QUESTION 9 (b) (i) Heating mantle Page 29 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 30 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 31 [BLANK PAGE] do not write on this page Page 32 ACKNOWLEDGEMENT Section 2 Question 3(b) – Anna Rassadnikova/shutterstock.com RATOCA/shutterstock.com vladis.studio/shutterstock.com

Page 02 SECTION 1 — 20 marks Attempt ALL questions 1. Particles with the same electron arrangement are said to be isoelectronic. Which of the following compounds contains ions which are isoelectronic? A Na2S B MgCl2 C KBr D CaCl2 2. Which line in the table is correct for the polar covalent bond in hydrogen chloride? Relative position of bonding electrons Dipole notation A H Cl δ+ δ– H Cl B H Cl δ+ δ– H Cl C H Cl δ– δ+ H Cl D H Cl δ– δ+ H Cl 3. Which of the following compounds has the greatest ionic character? A Caesium fluoride B Caesium iodide C Sodium fluoride D Sodium iodide

Page 03 4. The diagram below shows the energy profiles for a reaction carried out with and without a catalyst. 250 200 150 100 50 0 Reaction path Potential energy (kJ mol−1) What is the enthalpy change, in kJ mol–1, for the catalysed reaction? A –100 B –50 C +50 D +100 5. Limonene is a terpene molecule present in lemons. H2C H2C CH CH2 CH C CH3 C H3C CH2 limonene How many isoprene units are joined together in a limonene molecule? A 1 B 2 C 3 D 4 [Turn over

Page 04 6. The following molecules give flavour to food. Which of the following flavour molecules would be most likely to be retained in the food when the food is cooked in water? O C H CH CH CH2 CH2 CH CH H2C CH3 C C CH O C H3C CH3 O O H C 3 S CH2 CH2 CH N C O O A B C D H H H H C C C C C C O H H C H O H O CH3 H 7. vegetable oil vegetable fat Which of the following reactions brings about the above change? A Hydrolysis B Condensation C Hydrogenation D Dehydrogenation

Page 05 8. The rate of hydrolysis of protein, using an enzyme, was studied at different temperatures. Which of the following graphs would be obtained? Reaction rate Reaction rate Reaction rate Reaction rate Temperature (°C) Temperature (°C) Temperature (°C) Temperature (°C) 0 0 0 0 40 40 40 40 80 80 80 80 A B C D [Turn over

Page 06 9. Which of the following is the salt of a long-chain fatty acid? A Fat B Oil C Soap D Glycerol 10. Emulsifiers for use in food are commonly made by reacting edible oils with A esters B glycerol C fatty acids D amino acids. 11. The equation for the reduction reaction taking place when ethanal reacts with Tollens’ reagent is A Cu2+(aq) + e− → Cu+(aq) B Ag+(aq) + e− → Ag(s) C Cr2O7 2−(aq) + 14H+(aq) + 6e− → 2Cr3+(aq) + 7H2O(ℓ) D MnO4 −(aq) + 8H+(aq) + 5e− → Mn2+(aq) + 4H2O(ℓ) 12. The name of the compound with structure: H3C CH CH3 CH CH3 C CH3 O is A 2,3-dimethylpentan-4-one B 2,3-dimethylpentan-2-al C 3,4-dimethylpentan-2-one D 3,4-dimethylpentan-2-al. Page 07 13. CaCO3(s) + 2HNO3(aq) → Ca(NO3)2 (aq) + CO2(g) + H2O(ℓ) Mass of 1 mol Mass of 1 mol = 100 g = 164 g 2·00 g of calcium carbonate (CaCO3) was reacted with 200 cm3 of 0·1 mol l−1 nitric acid (HNO3). Take the volume of 1 mole of carbon dioxide to be 24 litres. In the reaction A CaCO3 is the limiting reactant B an excess of 0·1 mol of nitric acid remains at the end of the reaction C 1·64 g of calcium nitrate is produced by the reaction D 480 cm3 of carbon dioxide is produced by the reaction. 14. The mean bond enthalpy of a C – F bond is 484 kJ mol−1. In which of the processes is DH approximately equal to +1936 kJ mol−1? A CF4(g) → C(s) + 2F2(g) B CF4(g) → C(g) + 4F(g) C CF4(g) → C(g) + 2F2(g) D CF4(g) → C(s) + 4F(g) 15. In a reversible reaction, equilibrium is reached when A molecules of reactants cease to change into molecules of products B the concentrations of reactants and products are equal C the concentrations of reactants and products are constant D the activation energy of the forward reaction is equal to that of the reverse reaction. 16. Which of the following equations represents the enthalpy of combustion of propane? A C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(ℓ) B C3H8(g) + 7 2 O2(g) → 3CO(g) + 4H2O(ℓ) C C3H8(g) + 3O2(g) → 3CO2(g) + 4H2(g) D C3H8(g) + 3 2 O2(g) → 3CO(g) + 4H2(g) [Turn over

Page 08 17. An oxidising agent A gains electrons and is oxidised B loses electrons and is oxidised C gains electrons and is reduced D loses electrons and is reduced. 18. During a redox process in acid solution, chlorate ions, ClO3 −(aq), are converted into chlorine, Cl2(g). ClO3 −(aq) → Cl2(g) The numbers of H+(aq) and H2O(ℓ) required to balance the ion-electron equation for the formation of 1 mol of Cl2(g) are, respectively A 3 and 6 B 6 and 3 C 6 and 12 D 12 and 6. 19. Which of the following ions could be used to oxidise iodide ions to iodine? 2I−(aq) → I2(s) + 2e− A SO4 2−(aq) B SO3 2−(aq) C Cr3+(aq) D Cr2O7 2−(aq) Page 09 20. iodine solution vitamin C solution + starch A student was carrying out a titration to establish the concentration of vitamin C using iodine solution. Which of the following would help the student achieve a precise end-point? A Placing a white tile underneath the conical flask B Using the bottom of the meniscus when reading the burette C Repeating titrations D Carrying out a rough titration first [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] Page 10 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 11 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 12 [BLANK PAGE] DO NOT WRITE ON THIS PAGE H FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2016 Total marks — 100 SECTION 1 — 20 marks Attempt ALL questions. Instructions for completion of Section 1 are given on Page 02. SECTION 2 — 80 marks Attempt ALL questions Reference may be made to the Chemistry Higher and Advanced Higher Data Booklet. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not you may lose all the marks for this paper. X713/76/01 WEDNESDAY, 18 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer Grid and Section 2 Page 02 SECTION 1 — 20 marks The questions for Section 1 are contained in the question paper X713/76/02. Read these and record your answers on the answer grid on Page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample Question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B—chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D Page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 SECTION 1 — Answer Grid [Turn over Page 04 [BLANK PAGE] do not write on this page Page 05 [Turn over for next question do not write on this page Page 06 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 80 marks Attempt ALL questions 1. Hydrogen peroxide gradually decomposes into water and oxygen, according to the following equation. 2H2O2(aq) → 2H2O(ℓ) + O2(g) (a) At room temperature, the reaction is very slow. It can be speeded up by heating the reaction mixture. State why increasing the temperature causes an increase in reaction rate. (b) (i) The reaction can also be speeded up by adding a catalyst, such as manganese dioxide. To determine the rate of the reaction, the volume of gas produced in a given time can be measured. Complete the diagram below to show how the gas produced can be collected and measured. (An additional diagram, if required, can be found on Page 38). hydrogen peroxide manganese dioxide 1 1 Page 07 MARKS DO NOT WRITE IN THIS MARGIN 1. (b) (continued) (ii) The concentration of hydrogen peroxide is often described as a volume strength. This relates to the volume of oxygen that can be produced from a hydrogen peroxide solution. volume of = volume × volume of hydrogen oxygen produced strength peroxide solution In an experiment, 74 cm3 of oxygen was produced from 20 cm3 of hydrogen peroxide solution. Calculate the volume strength of the hydrogen peroxide. (c) Hydrogen peroxide can react with potassium iodide to produce water and iodine. A student carried out an experiment to investigate the effect of changing the concentration of potassium iodide on reaction rate. The results are shown below. Relative rate (s−1) Concentration of potassium iodide (mol l−1) 0·25 0·20 0·15 0·10 0·05 0 0 0·2 0·4 0·6 0·8 1·0 1·2 Calculate the time taken, in s, for the reaction when the concentration of potassium iodide used was 0·6 mol l−1. 1 1 [Turn over Page 08 MARKS DO NOT WRITE IN THIS MARGIN 2. (a) Graph 1 shows the sizes of atoms and ions for elements in the third period of the Periodic Table. Graph 1 Na Mg Al Si P S Cl 300 250 200 150 100 50 0 covalent radius (pm) ionic radius (pm) Radius (pm) Element The covalent radius is a measure of the size of an atom. (i) Explain why covalent radius decreases across the period from sodium to chlorine. (ii) Explain fully why the covalent radius of sodium is larger than the ionic radius of sodium. 1 2 Page 09 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (b) Graph 2 shows the first and second ionisation energies of elements in Group 1 of the Periodic Table. First ionisation energy Second ionisation energy Graph 2 8000 6000 4000 2000 0 Li Na K Rb Cs Ionisation energy (kJ mol −1) Element (i) Explain why the first ionisation energy decreases going down Group 1. (ii) Explain fully why the second ionisation energy is much greater than the first ionisation energy for Group 1 elements. 1 2 [Turn over Page 10 MArKS DO NOT WRITE IN THIS MARGIN 2. (continued) (c) The lattice enthalpy is the energy needed to completely separate the ions in one mole of an ionic solid. + + + + + + + + + - - - - - - - - - - Table 1 shows the size of selected ions. Table 1 Ion Li+ Na+ K+ Rb+ F ‾ Cl ‾ Ionic radius (pm) 76 102 138 152 133 181 Table 2 shows the lattice enthalpies, in kJ mol−1, for some Group 1 halides. Table 2 Ions F ‾ Cl ‾ Li+ 1030 834 Na+ 910 769 K+ 808 701 rb+ 658 (i) Predict the lattice enthalpy, in kJ mol−1, for rubidium fluoride. (ii) Write a general statement linking lattice enthalpy to ionic radii. 1 1 Page 11 MARKS DO NOT WRITE IN THIS MARGIN 3. Phosphine (PH3) is used as an insecticide in the storage of grain. Phosphine can be produced by the reaction of water with aluminium phosphide AlP(s) + 3H2O(ℓ) PH3(g) + Al(OH)3(aq) (a) State the type of bonding and structure in phosphine. (b) 2·9 kg of aluminium phosphide were used in a phosphine generator. Calculate the volume of phosphine gas, in litres, that would have been produced. (Take the volume of 1 mole of phosphine to be 24 litres). (c) Carbon dioxide is fed into the phosphine generator to keep the phosphine concentration less than 2·6%. Above this level phosphine can ignite due to the presence of diphosphane, P2H4(g), as an impurity. Draw a structural formula for diphosphane. 1 2 1 [Turn over Page 12 MARKS DO NOT WRITE IN THIS MARGIN 4. The viscosity of alcohols depends on a number of factors: • the strength of intermolecular forces • the size of the molecule • temperature These factors can be investigated using alcohols and apparatus from the lists below. Alcohols Apparatus methanol beakers ethanol funnels propan-1-ol burettes ethane-1,2-diol measuring cylinders butan-1-ol plastic syringes propane-1,3-diol glass tubing pentan-1-ol stoppers propane-1,2,3-triol timer metre stick ball bearing clamp stands kettle thermometer Using your knowledge of chemistry, identify the alcohols and apparatus that you would select and describe how these could be used to investigate one, or more, of the factors affecting the viscosity of alcohols. 3 Page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) Answer space [Turn over Page 14 MARKS DO NOT WRITE IN THIS MARGIN 5. When fats and oils are hydrolysed, mixtures of fatty acids are obtained. (a) Name the other product obtained in this reaction. (b) The table below shows the percentage composition of the fatty acid mixtures obtained by hydrolysis of coconut oil and olive oil. Class of fatty acids produced on hydrolysis Name of oil Coconut oil Olive oil Saturated 91 14 Monounsaturated 6 72 Polyunsaturated 3 14 (i) One of the fatty acids produced by the hydrolysis of olive oil is linoleic acid, C17H31COOH. State the class of fatty acid to which linoleic acid belongs. (ii) Hydrolysed coconut oil contains the fatty acid, caprylic acid, with the formula CH3(CH2)6COOH. State the systematic name for caprylic acid. (c) The degree of unsaturation of oil can be tested by adding drops of bromine solution to the oil. Bromine adds across carbon to carbon double bonds in the fatty acid chains. C H C H + Br Br C Br H C H Br 1 1 1 Page 15 MARKS DO NOT WRITE IN THIS MARGIN 5. (c) (continued) The following apparatus can be used to compare the degree of unsaturation of different oils. burette filled with 0·02 mol l−1 bromine solution conical flask 0·5 cm3 oil to be tested, dissolved in hexane (i) Describe how this apparatus could be used to show that olive oil has a greater degree of unsaturation than coconut oil. (ii) Suggest why hexane is used as the solvent, rather than water. (iii) Coconut oil has a melting point of 25 °C. Olive oil has a melting point of −6 °C. Give two reasons why coconut oil has a higher melting point than olive oil. 2 1 2 [Turn over Page 16 MARKS DO NOT WRITE IN THIS MARGIN 6. Peptide molecules can be classified according to the number of amino acid units joined by peptide bonds in the molecule. Type of peptide Example of amino acid sequence dipeptide aspartic acid-phenylalanine tripeptide isoleucine-proline-proline tetrapeptide lysine-proline-proline-arginine pentapeptide serine-glycine-tyrosine-alanine-leucine alanine-glycine-valine-proline-tyrosine-serine polypeptide many amino acids (a) Complete the table to identify the type of peptide with the following amino acid sequence alanine-glycine-valine-proline-tyrosine-serine (b) Partial hydrolysis of another pentapeptide molecule gave a mixture of three smaller peptide molecules with the following amino acid sequences. leucine-glycine-valine isoleucine-leucine glycine-valine-serine Write the amino acid sequence for the original pentapeptide molecule. – – – – (c) Some amino acids needed to form polypeptides cannot be produced in the human body. State the term used to describe amino acids that the body cannot make. 1 1 1 Page 17 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (d) Paper chromatography is often used to analyse the mixtures of amino acids produced when peptides are broken down. On a chromatogram, the retention factor Rf, for a substance can be a useful method of identifying the substance. f distance moved by the substance maximum distance moved by the so R lvent = The structure of the pentapeptide methionine enkephalin was investigated. A sample of the pentapeptide was completely hydrolysed into its constituent amino acids and this amino acid mixture was applied to a piece of chromatography paper and placed in a solvent. The chromatogram obtained is shown below. lid chromatography tank maximum distance moved by solvent direction of movement of solvent amino acid mixture applied solvent (i) Suggest why only four spots were obtained on the chromatogram of the hydrolysed pentapeptide. (ii) It is known that this amino acid mixture contains the amino acid methionine. The Rf value for methionine in this solvent is 0·40. Draw a circle around the spot on the chromatogram that corresponds to methionine. 1 1 [Turn over Page 18 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (e) Over the last decade several families of extremely stable peptide molecules have been discovered, where the peptide chain forms a ring. (i) A simple cyclic dipeptide is shown. C N C C N C O H H CH3 O H H H Draw a structural formula for one of the amino acids that would be formed on complete hydrolysis of the above cyclic dipeptide. (ii) Alpha-amanitin is a highly toxic cyclic peptide found in death cap mushrooms. The lethal dose for humans is 100 mg per kg of body mass. 1·0 g of death cap mushrooms contains 250 mg of alpha-amanitin. Calculate the minimum mass of death cap mushrooms that would contain the lethal dose for a 75 kg adult. 1 2 Page 19 [Turn over for next question do not write on this page Page 20 MARKS DO NOT WRITE IN THIS MARGIN 7. Modern shellac nail varnishes are more durable and so last longer than traditional nail polish. The shellac nail varnish is applied in thin layers to the nails and then the fingers are placed under a UV lamp. (a) The Skin Care Foundation has recommended that a sun-block is applied to the fingers and hand before using the lamp. Suggest why the Skin Care Foundation makes this recommendation. (b) A free radical chain reaction takes place and the varnish hardens. (i) State what is meant by the term free radical. 1 1 Page 21 MARKS DO NOT WRITE IN THIS MARGIN 7. (b) (continued) (ii) The shellac nail varnish contains a mixture of ingredients that take part in the free radical chain reaction. One of the steps in the free radical chain reaction is: C C O CH2 CH2 H2C CH2 CH2 OH H2C CH2 CH2 C CH2 CH2 OH C O State the term used to describe this type of step in a free radical chain reaction. (iii) During the free radical chain reaction small molecules join to form large chain molecules. One example of a small molecule used is C C H2C CH3 OH O Name the functional group circled above. (iv) Alcohol wipes are used to finish the varnishing treatment. Alcohol wipes contain the alcohol propan-2-ol. State why propan-2-ol can be described as a secondary alcohol. 1 1 1 [Turn over Page 22 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (c) Traditional nail varnishes use ethyl ethanoate and butyl ethanoate as solvents. (i) Draw a structural formula for butyl ethanoate. (ii) Ethyl ethanoate can be made in the laboratory using the following apparatus. elastic band water bath paper towel soaked in cold water mixture of reactants + concentrated sulfuric acid Suggest why a wet paper towel is wrapped around the test tube. 1 1 Page 23 MARKS DO NOT WRITE IN THIS MARGIN 7. (c) (continued) (iii) A student used 2·5 g of ethanol and a slight excess of ethanoic acid to produce 2·9 g of ethyl ethanoate. ethanol + ethanoic acid ⇌ ethyl ethanoate + water mass of mass of one mole one mole = 46·0 g = 88·0 g (One mole of ethanol reacts with one mole of ethanoic acid to produce one mole of ethyl ethanoate.) Calculate the percentage yield of ethyl ethanoate. (iv) Name the type of reaction that takes place during the formation of ethyl ethanoate. [Turn over 2 1 Page 24 MARKS DO NOT WRITE IN THIS MARGIN 8. Methanol (CH3OH) is an important chemical in industry. (a) Methanol is produced from methane in a two-step process. In step 1, methane is reacted with steam as shown. Step 1: CH4(g) + H2O(g) ⇌ 3H2(g) + CO(g) ΔH = +210 kJ mol−1 In step 2, hydrogen reacts with carbon monoxide. Step 2: 2H2(g) + CO(g) ⇌ CH3OH(g) ∆H = −91 kJ mol−1 Complete the table to show the most favourable conditions to maximise the yield for each step. Temperature (High/Low) Pressure (High/Low) Step 1 Step 2 (b) Methanol reacts with compound X, in an addition reaction, to form methyl tertiary-butyl ether, an additive for petrol. CH3OH(g) + X H3C C OCH3 CH3 CH3 methyl tertiary-butyl ether (i) Suggest a structure for compound X. (ii) The atom economy of this reaction is 100%. Explain what this means. 2 1 1 Page 25 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (c) Methanol can be converted to methanal as shown. H C H H O H C O H H H H + Using bond enthalpy and mean bond enthalpy values from the data booklet, calculate the enthalpy change, in kJ mol−1, for the reaction. [Turn over 2 Page 26 DO NOT WRITE IN THIS MARGIN 9. A group of students carried out an investigation into the energy changes that take place when metal hydroxides dissolve in water. The following apparatus was used as a simple calorimeter to determine the change in temperature. digital thermometer polystyrene cup with lid water 20·0 °C The experiment was carried out as follows. Step 1: 100 cm3 of deionised water was added to the cup. Step 2: The stop-clock was started, the water stirred continuously and the temperature recorded every 20 seconds. Step 3: After 60 seconds, an accurately weighed mass of the metal hydroxide was added to the water and the temperature recorded every 20 seconds. Graph 1 shows the group’s results for lithium hydroxide. 30 29 28 27 26 25 24 23 22 21 20 0 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Time (s) Temperature (°C) ΔT = 28·4 − 20·4 = 8·0 28·4 cooling curve solute added 20·4 line extrapolated from cooling curve Graph 1 – Lithium hydroxide The heat energy transferred to the water can be calculated as shown. Eh = cmΔT = 4·18 × 0·10 × 8·0 = 3·3 kJ Page 27 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (a) The experiment was repeated using sodium hydroxide. Graph 2 shows the results of this experiment. 30 31 32 29 28 27 26 25 24 23 22 21 20 19 18 0 Temperature (°C) 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Time (s) Graph 2 – Sodium Hydroxide cooling curve solute added (i) Using Graph 2 calculate the heat energy transferred to the water, in kJ, when the sodium hydroxide dissolved. (ii) Suggest why the experiment was carried out in a polystyrene cup with a lid. 2 1 [Turn over Page 28 MARKS DO NOT WRITE IN THIS MARGIN 9. (a) (continued) (iii) In another experiment the students found that 5·61 g of potassium hydroxide (KOH) released 5·25 kJ of heat energy on dissolving. Use this information to calculate the energy released, in kJ mol−1, when one mole of potassium hydroxide dissolves in water. (b) Calcium hydroxide solution can be formed by adding calcium metal to excess water. Solid calcium hydroxide would form if the exact molar ratio of calcium to water is used. The equation for the reaction is Ca(s) + 2H2O(ℓ) → Ca(OH)2(s) + H2(g) Calculate the enthalpy change, in kJ mol−1, for the reaction above by using the data shown below. H2(g) + ½O2(g) → H2O(ℓ) ΔH = −286 kJ mol−1 Ca(s) + O2(g) + H2(g) → Ca(OH)2(s) ΔH = −986 kJ mol−1 1 2 Page 29 MARKS DO NOT WRITE IN THIS MARGIN 10. The chemical industry creates an immense variety of products which impact on virtually every aspect of our lives. Industrial scientists, including chemical engineers, production chemists and environmental chemists, carry out different roles to maximise the efficiency of industrial processes. Using your knowledge of chemistry, comment on what industrial scientists can do to maximise profit from industrial processes and minimise impact on the environment. 3 [Turn over Page 30 MARKS DO NOT WRITE IN THIS MARGIN 11. Soft drinks contain a variety of sugars. A student investigated the sugar content of a soft drink. (a) The density of the soft drink can be used to estimate its total sugar concentration. Solutions of different sugars, with the same concentration, have similar densities. The first experiment was to determine the total sugar concentration of the soft drink by comparing the density of the drink with the density of standard sucrose solutions. (i) This firstly involved producing standard sucrose solutions of different concentrations. The standard sucrose solutions were made up in volumetric flasks. Draw a diagram of a volumetric flask. (ii) The density of each standard sucrose solution was then determined. In order to determine the density of each solution, the student accurately measured the mass of 10·0 cm3 of each sucrose solution. Describe fully a method that the student could have used to accurately measure the mass of 10·0 cm3 of each sucrose solution. 1 2 Page 31 MARKS DO NOT WRITE IN THIS MARGIN [Turn over 11. (a) (continued) (iii) The results that the student obtained for the density of the standard solutions of sucrose are shown in the table. % Concentration of sucrose solution Density of sucrose solution (g cm−3) 0·0 1·00 5·0 1·10 10·0 1·19 15·0 1·31 20·0 1·41 Draw a line graph using the student’s results. (Additional graph paper, if required, can be found on Page 38.) 1·50 1·40 1·30 1·20 1·10 1·00 0·90 0·0 5·0 10·0 15·0 20·0 25·0 30·0 Density of sucrose solution (g cm−3) % Concentration of sucrose solution 2 Page 32 MARKS DO NOT WRITE IN THIS MARGIN 11. (a) (continued) (iv) The student used the line graph to obtain the relationship between the concentration of sugars in solution and the density of the solution. This equation shows the relationship. density of sugar in g cm−3 = (0·0204 × % concentration of sugars in solution ) + 1·00 The student then determined the density of a soft drink. In order to ensure that the drink was flat, all the gas had been allowed to escape. (A) Suggest a reason why the soft drink needed to be flat before its density was determined. (B) The soft drink tested had a density of 1·07 g cm−3. Using the equation, calculate the % concentration of sugars present in the soft drink. (v) A different soft drink is found to contain 10·6 grams of sugar in 100 cm3. Calculate the total mass of sugar present, in grams, in a 330 cm3 can of this soft drink. (b) The second experiment in the investigation was to determine the concentration of specific types of sugar called reducing sugars. This was carried out by titration with Fehling’s solution. (i) Reducing sugars contain an aldehyde functional group. Draw this functional group. 1 1 1 1 Page 33 MARKS DO NOT WRITE IN THIS MARGIN [Turn over 11. (b) (continued) (ii) The overall reaction that occurs with Fehling’s solution and a reducing sugar is shown. C6H12O6 + 2Cu2+ + H2O → C6H12O7 + 2Cu+ + 2H+ reducing Fehling’s sugar solution Write the ion-electron equation for the oxidation reaction. (iii) State the colour change that would be observed when reducing sugars are reacted with Fehling’s solution. (iv) For the titrations, the student diluted the soft drink to improve the accuracy of results. 25·0 cm3 samples of the diluted soft drink were titrated with Fehling’s solution which had a Cu2+ concentration of 0·0250 mol l−1. The average volume of Fehling’s solution used in the titrations was 19·8 cm3. C6H12O6 + 2Cu2+ + H2O → C6H12O7 + 2Cu+ + 2H+ reducing Fehling’s sugar solution Calculate the concentration, in mol l−1, of reducing sugars present in the diluted sample of the soft drink. 1 1 3 Page 34 DO NOT WRITE IN THIS MARGIN 12. (a) The table shows the boiling points and structures of some isomers with molecular formula C6H12O2. Isomer Structure Boiling point (°C) 1 H C H H C H H C H H C H H C H H C O OH 205 2 H C H H C H C H H H C H H C H H C OH O 201 3 H C H H C C H H H C H H C C H H H O OH 187 4 H C H H C H H C H H C H H C H H O C H O 132 5 H H C H C C H C H O C H O C H H H H H H 125 6 H C H H C C H H C H H H C H H H O C H O 119 7 H C H H C H H C H H C H H O C O C H H H 126 8 H C H H C C H H H C H H H O C O C H H H 98 Page 35 MARKS DO NOT WRITE IN THIS MARGIN 12. (a) (continued) (i) Name the intermolecular force which accounts for the higher boiling points of isomers 1, 2 and 3. (ii) Using the information in the table, describe two ways in which differences in structure affect the boiling points of isomeric esters 4–8. (iii) Predict the boiling point, in ºC, for the isomer shown below. H C H H C C C H H H H H H O C C H H H O [Turn over 1 2 1 Page 36 DO NOT WRITE IN THIS MARGIN 12. (continued) (b) Carbon-13 NMR spectroscopy is a technique that can be used in chemistry to determine the structure of organic molecules such as esters. In a carbon-13 NMR spectrum, a carbon atom in a molecule is identified by its chemical shift. This value depends on the other atoms bonded to the carbon atom, which is known as the “chemical environment” of the carbon-13 atom. Carbon-13 chemical shift values are shown in the table below. The carbon-13 atom in each chemical environment has been circled. Chemical environment Chemical shift (ppm) C H 25–35 H C H 16–25 H C O H 50–90 H C H H 10–15 H C H C H O 20–50 C O O 170–185 The number of peaks in a carbon-13 NMR spectrum corresponds to the number of carbon atoms in different chemical environments within the molecule. The position of a peak (the chemical shift) indicates the type of carbon atom. Page 37 MArKS DO NOT WRITE IN THIS MARGIN 12. (b) (continued) The spectrum for ethyl ethanoate is shown below. 200 180 160 140 120 100 80 60 40 20 0 Chemical shift (ppm) (i) Label each peak in the ethyl ethanoate spectrum with a number to match the carbon atom in ethyl ethanoate, shown below. H C H H C O O C H H C H H H 1 2 3 4 (ii) Determine the number of peaks that would be seen in the carbon-13 NMR spectrum for the ester shown below. H C C C C H H O C O C H H H H H H H H H Number of peaks in carbon-13 NMR spectrum = 1 1 [END OF QUESTION PAPEr] Page 38 MARKS DO NOT WRITE IN THIS MARGIN Additional DIAGRAM FOR USE IN QUESTION 1 (b) (i) hydrogen peroxide manganese dioxide Additional graph paper for Question 11 (a) (iii) 1·50 1·40 1·30 1·20 1·10 1·00 0·90 0·0 5·0 10·0 15·0 20·0 25·0 30·0 Density of sucrose solution (g cm−3) % Concentration of sucrose solution Page 39 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 40 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 41 ACKNOWLEDGEMENT Section 2 Question 7 - sima/shutterstock.com

6 (B410U10-1) Examiner only 10. Using ideas that you have studied in your Chemistry course comment on and explain the following observations. (a) In sodium chloride and caesium chloride the arrangements of the particles in the solids are different. [4] (b) Hydrogen sulfide, H2S, is a gas at room temperature and pressure but water, H2O, is a liquid under the same conditions. [4] © WJEC CBAC Ltd. (B410U10-1) Turn over. B 410 U101 07 7 Examiner only (c) The bond angles in the PCl4 + ion are greater than the bond angles in the PCl6 − ion. [4] © WJEC CBAC Ltd. 12

8 (B410U10-1) Examiner only 11. X and Y are metals that are in the same group of the Periodic Table. Aqueous solutions of a salt of each metal were added to three aqueous laboratory reagents. The observations made are shown in the table. (a) Suggest the identity of metal X and metal Y. Explain your reasoning. [3] X is ....................................................................................... Y is ....................................................................................... Explanation (b) (i) Using the symbol X for the metal, write the ionic equation for the reaction of the salt of X with dilute sulfuric acid. Include state symbols. [1] (ii) Using the symbol Y for the metal, write the ionic equation for the reaction of the salt of Y with aqueous sodium hydroxide. Include state symbols. [1] © WJEC CBAC Ltd. H2SO4(aq) NaOH(aq) Cl2(aq) Salt of X white precipitate no visible reaction orange/brown solution Salt of Y no visible reaction white precipitate orange/brown solution (B410U10-1) Turn over. B 410 U101 0 9 9 Examiner only (c) (i) Explain what happens when aqueous chlorine is added to solutions of the salts of X and Y. [3] You should include: • the identity of the orange/brown product • the nature of the reaction occurring • a suggested identity for the anion present in both salts (ii) Describe a test that you could carry out on the salt solutions to confirm the identity of this anion. Include the observation expected in the test. [2] © WJEC CBAC Ltd. 10

10 (B410U10-1) Examiner only 12. David said that sodium compounds give a yellow flame test because the heat makes the atoms move faster. He also said that the yellow flame was the sodium absorption spectrum consisting of one line because the atoms take in light of just one energy. (a) Discuss how far you agree with David’s statement and correct any errors which he has made. You should include the chemical principles involved. [6 QER] (b) A white solid is known to be either a magnesium or a potassium compound. Describe how you could carry out a flame test to identify the metal ion present. You should include the expected result for each compound. [2] © WJEC CBAC Ltd. Turn over. 11 Examiner only (c) (i) A line in a visible spectrum was observed at a wavelength of 500 nm. Calculate the energy involved in the formation of this line. Give your answer with its unit and in standard form. [3] Energy = ............................................... Unit = ............................................... (ii) A line in another spectrum was found to have a higher energy associated with its formation so that it was no longer visible. In which part of the electromagnetic spectrum would it be found? [1] © WJEC CBAC Ltd. 12 (B410U10-1)

12 (B410U10-1) Examiner only 13. (a) A student was told that a bottle of hydrochloric acid he was given was approximately of concentration 0.1 mol dm−3. He was asked to determine the accurate concentration of the acid using a titration method. He had access to solid anhydrous sodium carbonate, Na2CO3, and the apparatus normally found in a school or college laboratory. (i) Write the equation for the reaction between sodium carbonate and hydrochloric acid. [1] (ii) Describe how the student should carry out the determination of the concentration of the acid. You should include the apparatus required and the masses and volumes of any chemicals used. I. Outline the preparation of a solution of sodium carbonate suitable for use in a titration against the hydrochloric acid. [3] II. Describe how the student should carry out the titration to determine the concentration of the acid. You do not need to describe how the apparatus is cleaned or set up. [3] © WJEC CBAC Ltd. (B410U10-1) Turn over. 13 Examiner only (b) The student found in (a) that the hydrochloric acid had a concentration of 0.110 mol dm−3. Calculate the pH of this solution. [2] pH = ............................................... (c) Another student was given a sample of ore containing compounds of silver and was asked to find the percentage of silver in the ore. He dissolved 2.48 g of the silver ore in nitric acid and added excess of the hydrochloric acid to precipitate the silver as silver chloride. He filtered off the precipitate of silver chloride and found its mass. (i) State how the precipitate was treated in order to obtain the mass of the silver chloride. Explain why the precipitate was treated in this way. [2] (ii) Write the ionic equation for the formation of this precipitate. Include state symbols. [1] (iii) The mass of silver chloride obtained was 0.93 g. Calculate the percentage of silver in the ore. [2] Percentage = ............................................... % © WJEC CBAC Ltd. 14

14 (B410U10-1) Examiner only 14. Emily was investigating the reversible reaction between methanol and ethanoic acid. CH3OH(l) + CH3COOH(l) a CH3COOCH3(l) + H2O(l) Reaction 1 She followed these instructions. • Heat 16.0 g of methanol with 36.0 g of ethanoic acid under reflux for one hour so that the reaction reaches equilibrium. • Titrate the contents of the flask with aqueous sodium hydroxide. Complete this titration as quickly as possible. • Note the volume of alkali used. The equation for the reaction with sodium hydroxide is as follows. CH3COOH(l) + NaOH(aq) CH3COONa(aq) + H2O(l) (a) Write the expression for the equilibrium constant, Kc, for the reaction between methanol and ethanoic acid, Reaction 1. [1] (b) Emily calculated that she had used 0.220 mol of sodium hydroxide in her titration. How many moles of ethanoic acid were present in the flask at equilibrium? [1] Number of moles of acid = .............................................. © WJEC CBAC Ltd. (B410U10-1) Turn over. 15 Examiner only (c) Emily also calculated that there were 0.12 mol of methanol in the flask at equilibrium. Her teacher told her that the equilibrium constant, Kc, for this reaction is 5.47. Emily looks at the equation for the equilibrium and sees that the number of moles of ester, CH3COOCH3, and water at equilibrium would be the same. Use these data, and the value found in (b), to calculate the number of moles of ester present at equilibrium. In this reaction you should assume that the concentration, in mol dm−3, is equal to the number of moles of each substance present. [3] Number of moles of ester = .............................................. (d) Another student carried out a similar experiment to that above to determine the value of the equilibrium constant, Kc. However he refluxed the mixture for only 30 minutes. When he calculated the value of Kc he found it to have a significantly lower value than that found in data books. Give a possible explanation for the difference in the value of Kc. [1] (e) Explain why the heating should be carried out under reflux. [1] © WJEC CBAC Ltd. (B410U10-1) 16 Examiner only (f) (i) Explain why the instructions said that the titration should be completed as quickly as possible. [2] (ii) What would be the effect on the value of Kc that Emily calculated if she took a long time carrying out the titration? Explain your answer. [1] (g) The value of Kc for this reaction decreases if the temperature at which it is carried out increases. Deduce whether the forward reaction is exothermic or endothermic. Explain your reasoning. [2] END OF PAPER © WJEC CBAC Ltd. 12 (B410U10-1) 17 Examiner only © WJEC CBAC Ltd. For continuation only. BLANK PAGE (B410U10-1) 18 © WJEC CBAC Ltd. BLANK PAGE (B410U10-1) 19 © WJEC CBAC Ltd.

Page 02 SECTION 1 — 30 marks Attempt ALL questions 1. All noble gases are characterised by the completion of the outermost orbital. This orbital is A an s-orbital B a p-orbital C a d-orbital D an s or p-orbital. 2. The electronic configuration of an atom of X, in its ground state, is 1s22s22p63s23p63d14s2. X is an atom of A calcium B scandium C titanium D vanadium. 3. Which line in the table could represent the four quantum numbers of an outer electron in an Mg2+ ion? n l m s A 2 1 −2 −½ B 2 0 0 +½ C 2 1 −1 +½ D 3 0 0 −½

Page 03 4. The coordination number of an ionic lattice can be determined by using the following equation. radius ratio = radius of positive ion radius of negative ion Radius ratio Coordination number less than 0·23 3 0·23–0·42 4 0·42–0·73 6 greater than 0·73 8 What is the coordination number in zinc(II) sulfide? A 3 B 4 C 6 D 8 5. What is the formula for the diaquatetrachlorocobaltate(II) ion? A [CoCl4(H2O)2]2− B [CoCl2(H2O)4]2− C [CoCl4(H2O)2]2+ D [CoCl2(H2O)4]2+ 6. Which of the following indicators is most suitable to use in a titration of dilute hydrochloric acid solution with dilute ammonia solution? A Bromothymol blue B Phenolphthalein C Methyl orange D Phenol red 7. The pH of a solution of benzoic acid with concentration 0·01 mol l−1 is A 1·1 B 2·0 C 3·1 D 5·2. [Turn over

Page 04 8. A reaction must be exothermic if A both ∆G ° and ∆S ° are negative B both ∆G ° and ∆S ° are positive C ∆G ° is negative D ∆S ° is positive. 9. For the reaction A + B ↓ C the following data were obtained. Experiment Initial concentration of A (mol l−1) Initial concentration of B (mol l−1) Initial rate of formation of C (mol l−1 s−1) 1 0·1 0·1 0·05 2 0·2 0·1 0·05 3 0·1 0·2 X Given that the rate equation is Rate = k[B]2 the value of X will be A 0·05 B 0·10 C 0·15 D 0·20. 10. The rate equation for the reaction between nitrogen monoxide and chlorine is rate = k[NO]2[Cl2] The units for the rate constant, k, in this reaction are A s−1 B mol l−1 s−1 C l mol−1 s−1 D l2 mol−2 s−1.

Page 05 11. Which of the following describes the bonding in ethane? A sp2 hybridisation with sigma bonds only. B sp3 hybridisation with sigma bonds only. C sp2 hybridisation with sigma and pi bonds. D sp3 hybridisation with sigma and pi bonds. 12. Pyridine has the following structure. N The number of sigma bonds in a molecule of pyridine is A 3 B 6 C 11 D 12. 13. A racemic mixture is defined as A a mixture of two enantiomers B a pair of enantiomers mixed in equal proportions C a mixture of two geometric isomers D a pair of geometric isomers mixed in equal proportions. [Turn over

Page 06 14. CH3CH2Br + NH3 ↓ CH3CH2NH2 + HBr CH3Br + OH− ↓ CH3OH + Br− The nucleophiles in these two reactions are A CH3Br and NH3 B OH− and CH3CH2Br C CH3CH2Br and CH3Br D NH3 and OH−. 15. A compound X has a GFM of less than 100 g. Complete combustion of compound X produces carbon dioxide and water only. Reduction of compound X produces a secondary alcohol. Compound X is most likely to be A B C D H3C C C2H5 O H C C2H5 O H3C C CH2Cl O H3C C C6H5 O Page 07 16. Amine Boiling point (°C) C2H5N(CH3)2 37·5 (C2H5)2NH 56·3 C4H9NH2 77·8 Based on the information in the table, A the tertiary amine has the highest boiling point B the secondary amine has the lowest boiling point C the primary amine has a lower boiling point than the tertiary amine D the secondary amine has a lower boiling point than the primary amine. 17. Compound Y reacts with the product of its own oxidation to form an ester. Compound Y could be A propanal B propan-1-ol C propan-2-ol D propanoic acid. 18. Which of the following statements about benzene is correct? A The benzene molecule is planar. B Benzene does not react with electrophiles. C Benzene readily undergoes nucleophilic attack. D The benzene molecule contains carbon to carbon bonds of two different lengths. 19. Chlorine has two isotopes, 35Cl and 37Cl. These isotopes are present in a sample of 1,1,1-trichloroethane, C2H3Cl3. The number of molecular ion peaks expected in the mass spectrum of 1,1,1-trichloroethane is A 6 B 4 C 3 D 2. [Turn over

Page 08 20. The following substance was analysed using an infrared spectrometer. C C C C C C H H H H H H H H H NH2 O The spectrum produced would not have a significant peak in the wave number range A 1700–1680 cm−1 B 2962–2853 cm−1 C 3100–3000 cm−1 D 3500–3300 cm−1. 21. Antisense drugs are a group of medicines that act by binding to DNA to block the synthesis of some proteins. Which line in the table is correct for antisense drugs? Classification Receptor A antagonist DNA B antagonist protein C agonist DNA D agonist protein 22. Which of the following would be most suitable as a reagent in the gravimetric analysis of silver ions? A Sodium nitrate B Potassium sulfate C Barium carbonate D Ammonium chloride

Page 09 23. Using colorimetry, the most appropriate filter for determining the concentration of green nickel ions, Ni2+(aq), in a solution, would be A 390 nm B 490 nm C 540 nm D 680 nm. 24. The diagram shows a thin layer chromatogram for a mixture of amino acids. Distance moved by solvent and amino acids (cm) Solvent front Amino acid S Amino acid R Amino acid Q Amino acid P 9 8 7 6 5 4 3 2 1 0 Which amino acid has an Rf value of approximately 0∙75? A Amino acid S B Amino acid R C Amino acid Q D Amino acid P [Turn over

Page 10 25. Which line in the table shows the properties of the most suitable solvent to extract caffeine from an aqueous solution of tea? A Caffeine is more soluble in the solvent than it is in the tea solution. The solvent is immiscible in the tea solution. B Caffeine is more soluble in the solvent than it is in the tea solution. The solvent is miscible in the tea solution. C Caffeine is less soluble in the solvent than it is in the tea solution. The solvent is miscible in the tea solution. D Caffeine is less soluble in the solvent than it is in the tea solution. The solvent is immiscible in the tea solution. 26. A series of titrations was performed to determine the concentration of vitamin C in a brand of fruit juice. A standard solution of the fruit juice was prepared and titrated with iodine solution. Which of the following would be a suitable control experiment for this analysis? A Titrate more samples from the same carton of fruit juice. B Titrate a solution of pure vitamin C of known concentration. C Titrate more samples from the standard solution of fruit juice. D Titrate a sample from a different carton of the same brand of fruit juice. 27. Ba(OH)2(aq) + Na2SO4(aq) ↓ BaSO4(s) + 2NaOH(aq) 50 cm3 of 0·010 mol l−1 barium hydroxide solution were added to 50 cm3 of 0·010 mol l−1 sodium sulfate solution. The concentration of sodium hydroxide, in mol l−1, in the resulting solution is A 0·0010 B 0·010 C 0·020 D 0·10.

Page 11 28. 1·06 × 10−2 moles of phenylamine, C6H5NH2, react with 5·16 g of bromine. Which equation shows the correct stoichiometry for this reaction? A C6H5NH2 + Br2 ↓ C6H4BrNH2 + HBr B C6H5NH2 + 2Br2 ↓ C6H3Br2NH2 + 2HBr C C6H5NH2 + 3Br2 ↓ C6H2Br3NH2 + 3HBr D C6H5NH2 + 4Br2 ↓ C6HBr4NH2 + 4HBr 29. Ibuprofen is used for the relief of pain, fever and inflammation. A structural formula for ibuprofen is shown below. H3C CH C OH O CH2 CH H3C CH3 If one tablet contains 300 mg of ibuprofen, approximately how many tablets can be manufactured from 1 mole of ibuprofen? A 6·73 × 102 B 6·87 × 102 C 6·73 × 10−1 D 6·87 × 10−1 [Turn over for next question

Page 12 30. The term accuracy is used to describe how close an experimental result is to the theoretical value. The term precision is used to describe how close a set of duplicate results are to each other. Four students determined the percentage by mass of chlorine in BaCl2. 2H2O. Which of the following sets of results is both accurate and precise? A 29·0%, 29·0%, 29·1% B 29·1%, 28·2%, 29·9% C 34·0%, 34·1%, 34·0% D 34·0%, 34·3%, 33·8% [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET] AH FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2017 You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Total marks — 100 SECTION 1 — 30 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on Page 02. SECTION 2 — 70 marks Attempt ALL questions. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/77/01 MONDAY, 8 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer Grid and Section 2 Page 02 SECTION 1 — 30 marks The questions for Section 1 are contained in the question paper X713/77/02. Read these and record your answers on the answer grid on Page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample Question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D Page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 A B C D 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SECTION 1 — Answer Grid [Turn over Page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 05 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 70 marks Attempt ALL questions 1. Many of the paints used by artists contain cadmium compounds. The presence of cadmium in a paint sample can be detected by atomic emission spectroscopy. (a) (i) Explain how a line is produced in an emission spectrum. (ii) Explain why there is a series of lines at discrete wavelengths in the emission spectrum of cadmium. (b) The cadmium emission spectrum has a line at 644 nm. Calculate the energy, in kJ mol−1, associated with this wavelength. 2 1 2 [Turn over Page 06 MARKS DO NOT WRITE IN THIS MARGIN 2. Phosphorus forms different compounds with chlorine. (a) When heated, phosphorus pentachloride dissociates to form phosphorus trichloride and chlorine. PCl5(g) Ý PCl3(g) + Cl2(g) ΔH = +124 kJ mol−1 In an experiment to determine the equilibrium constant, K, 0∙100 mol of PCl5 was placed in a sealed 1∙00 litre flask and heated to 250 °C. At equilibrium 0∙0420 mol of PCl3 had been formed. (i) Calculate the equilibrium constant, K, for the reaction at 250 °C. (ii) The temperature of the equilibrium mixture was increased to 400 °C. Explain the effect of this change in temperature on the value of the equilibrium constant, K. 3 2 Page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (b) In the solid state, phosphorus pentachloride is ionic and has the formula [PCl4]+[PCl6]−. (i) The three-dimensional structure for the [PCl4]+ ion is shown. Complete the table for the [PCl6]− ion. Phosphorus species Three-dimensional structure [PCl4]+ P Cl Cl Cl Cl + [PCl6]− (ii) Phosphorus oxychloride, POCl3, has a similar three-dimensional structure to the [PCl4]+ ion as shown. P Cl Cl Cl Cl + 109º P Cl Cl Cl O 103º Suggest a reason why the bond angle in the POCl3 molecule is less than the bond angle in the [PCl4]+ ion. 1 1 [Turn over Page 08 MARKS DO NOT WRITE IN THIS MARGIN 3. Zinc is often found in nature together with lead in sulfide ores. Different industrial processes can be used for the production of zinc metal. One of these is an electrolytic process and another is a thermal process. (a) In the electrolytic process, zinc sulfide is converted into zinc oxide by roasting in a furnace at 1300 K. 2ZnS(s) + 3O2(g) ↓ 2ZnO(s) + 2SO2(g) The data in the table refers to this reaction. Substance ΔHf° (kJ mol−1) S ° (J K−1 mol−1) ZnS(s) −206 58 O2(g) 0 205 ZnO(s) −350 44 SO2(g) −297 248 (i) For the conversion of zinc sulfide into zinc oxide, use the data in the table to calculate: (A) ΔH °, in kJ mol−1; (B) ΔS °, in J K−1 mol−1. (ii) Calculate the theoretical temperature, in K, above which the reaction is no longer feasible. 1 1 2 Page 09 MARKS DO NOT WRITE IN THIS MARGIN 3. (continued) (b) In the thermal process, a mixture of zinc oxide and lead oxide is reacted with carbon in a furnace at a temperature of 1200 K. Data for the metals and metal oxides are shown in the table below. Substance Density (g cm−3) Melting point (K) Boiling point (K) Zn 7·1 693 1181 Pb 11·3 600 2024 ZnO 5·6 2248 2633 PbO 9·5 1161 1808 By considering all the information, suggest how a sample of zinc metal and a sample of lead metal could each be removed from the furnace. [Turn over 2 Page 10 MARKS DO NOT WRITE IN THIS MARGIN 4. Transition metals, such as vanadium and copper, can have variable oxidation states and a wide range of uses. (a) Vanadium dioxide, VO2, can be used to coat glass. (i) State the oxidation number of vanadium in VO2. (ii) Using orbital box notation, write the electronic configuration, in terms of s, p and d orbitals, for the vanadium ion in VO2. (b) Vanadium(III) ions can react with iron(III) ions in solution. V3+(aq) + Fe3+(aq) ↓ V4+(aq) + Fe2+(aq) (i) The reaction is first order with respect to both V3+(aq) and Fe3+(aq). Write the rate equation for this reaction. 1 1 1 Page 11 MARKS DO NOT WRITE IN THIS MARGIN 4. (b) (continued) (ii) In the presence of a Cu2+(aq) catalyst, the reaction mechanism is: Cu2+(aq) + V3+(aq) slow ↓ Cu+(aq) + V4+(aq) Cu+(aq) + Fe3+(aq) fast ↓ Cu2+(aq) + Fe2+(aq) (A) State the order of the reaction with respect to Fe3+(aq) when a Cu2+(aq) catalyst is present. Explain your answer. (B) Explain why Cu2+(aq) can be described as a homogeneous catalyst in this reaction. (c) In the Middle Ages, Damascus steel was used for making sword blades. The steel from a sword blade of mass 1300 g was found to have a vanadium concentration of 71 ppm. Calculate the total mass of vanadium present in the sword blade. [Turn over 2 1 2 Page 12 MARKS DO NOT WRITE IN THIS MARGIN 5. A simple model of an atom is shown. Nucleus Subatomic particles electron proton neutron This simplistic model can be useful to help explain bonding but it is also misleading, as the structure of the atom and bonding are more complicated. Using your knowledge of chemistry, discuss the strengths and weaknesses of this simple model compared to the concepts of atomic structure and bonding at Advanced Higher level. 3 Page 13 DO NOT WRITE IN THIS MARGIN 5. (continued) [Turn over Page 14 MARKS DO NOT WRITE IN THIS MARGIN 6. Wilson’s disease is a rare genetic disorder which results in a build-up of copper ions in the body. Unmetabolised copper ions are toxic, leading to health complications. Copper ions can be removed by reaction with trientine. H2N N H H N NH2 trientine (a) Trientine is a tetradentate ligand that reacts with copper(II) ions in a 1:1 ratio to form a complex ion which can then be removed from the body. (i) Ligands form dative covalent bonds with metal ions. State what is meant by a dative covalent bond. (ii) Draw a structural formula for the complex ion. 1 1 Page 15 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (b) Zinc ethanoate can also be used to treat Wilson’s disease. (i) Zinc ethanoate can be prepared from zinc hydroxide and ethanoic acid. Name this type of reaction. (ii) Zinc ethanoate is a salt of a weak acid. State what is meant by a weak acid. (iii) A student carried out an experiment to determine the value of y in hydrated zinc ethanoate, Zn(CH3COO)2.yH2O. A 5∙00 g sample was heated until all the water was removed and a constant mass of 4∙18 g was obtained. (A) Name the piece of apparatus that should be used to store the zinc ethanoate while cooling. (B) Calculate the value of y. (C) The student repeated the experiment with a second sample of hydrated zinc ethanoate. The student’s calculations were correct but the value of y was found to be different from the expected value. Suggest a reason for this difference. 1 1 1 2 1 [Turn over Page 16 MARKS DO NOT WRITE IN THIS MARGIN 7. Phenolphthalein is an indicator that can be prepared by the reaction of phenol with phthalic anhydride. (a) Phenolphthalein prepared by this method can have insoluble impurities present. It can be purified by recrystallisation from an aqueous ethanol solution. (i) Outline the steps that should be carried out to recrystallise phenolphthalein. (ii) Name a technique that could be used to determine if the recrystallised phenolphthalein is pure. (b) The equation for the reaction is given below. 2C6H6O + C8H4O3 C20H14O4 + H2O phenol phthalic phenolphthalein water anhydride (GFM = 94 g) (GFM = 148 g) (GFM = 318 g) (GFM = 18 g) 0∙96 g of phenol is reacted with 1∙05 g phthalic anhydride. In an experimental procedure, the percentage yield of phenolphthalein was 58%. Calculate the mass, in grams, of phenolphthalein produced. 2 1 3 Page 17 MARKS DO NOT WRITE IN THIS MARGIN 8. High levels of sugar in foods are associated with obesity. Sugars are also the basis of many medicines. (a) Glucose-fructose syrup is a type of sugar that is added to many foods. It is a mixture of glucose and fructose. The ring structures of glucose and fructose are shown below. O OH OH OH OH HO O HO OH OH HO HO glucose fructose (i) Write the molecular formula for fructose. (ii) Suggest, with reference to the structures, how 1H NMR spectroscopy could be used to distinguish between glucose and fructose. [Turn over 1 1 Page 18 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (b) A more accurate representation of the structure of glucose, and its geometric isomer galactose, is shown below. O OH OH HO HO HO OH O OH OH HO OH glucose galactose With reference to the structures shown, explain why sugars such as glucose and galactose have geometric isomers. (c) The ring structure of glucose exists in equilibrium with its open-chain structure. The diagram below shows the open-chain structure of one optical isomer of glucose called D-glucose. D-glucose CH OH H OH OH H OH H OH H H O 2 C C C C C (i) State the number of chiral centres in D-glucose. (ii) Draw an open-chain structural formula for an optical isomer of D-glucose. 1 1 1 Page 19 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (d) Relenza is a sugar-based medicine used to treat the flu virus. It acts by attaching to an enzyme active site on the virus. The structure of Relenza is shown. Relenza HO O OH O OH HN OH O N NH2 NH2 (i) Suggest how the functional groups circled on the Relenza molecule would bind with part of the enzyme active site. (ii) The structure of the natural active compound, sialic acid, is shown. sialic acid O HO OH O OH HN OH O OH OH Sialic acid binds to the same part of the enzyme active site as Relenza. Circle the functional groups on the sialic acid molecule which are most likely to bind with the enzyme active site. (An additional diagram, if required, can be found on Page 28) 1 1 [Turn over Page 20 MARKS DO NOT WRITE IN THIS MARGIN 9. A student devised the following reaction scheme starting with 1-methylcyclohexene. CH3 CH3 CH3 CH3 CH3 CH3 CH3 O OH NaOH(aq) compound Y 3 KCN in ethanol CN 2 COOH 1-methylcyclohexene compound X HBr 1 Br (a) In reaction 1 , 1-methylcyclohexene reacts with HBr to produce two compounds. (i) Draw a structural formula for compound X. (ii) Reaction 1 obeys Markovnikov’s rule. Explain, with reference to the carbocation intermediate, why compound X is the minor product in this reaction. 1 1 Page 21 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (b) Suggest a reagent that could be used in reaction 2 . (c) Reaction 3 is likely to undergo an SN1 mechanism. Using curly arrow notation, draw the mechanism for this reaction. (d) Name compound Y. [Turn over 1 2 1 Page 22 MARKS DO NOT WRITE IN THIS MARGIN 10. An active ingredient in many stain removing products is the oxidising agent hydrogen peroxide, H2O2. (a) In an experiment to determine the concentration of hydrogen peroxide present in a stain remover a student carried out a titration with acidified permanganate solution. 2MnO4 − + 5H2O2 + 6H+ ↓ 2Mn2+ + 5O2 + 8H2O 5·0 cm3 of stain remover was pipetted into a 100 cm3 standard flask and made up to the mark with distilled water. 20·0 cm3 samples were titrated with 0·030 mol l−1 permanganate solution until a permanent pink colour remained. The results are shown in the table. 1st titration 2nd titration 3rd titration Initial burette reading (cm3) 0·3 19·2 0·2 Final burette reading (cm3) 19·2 37·7 18·8 Volume used (cm3) 18·9 18·5 18·6 (i) Calculate the number of moles of hydrogen peroxide in 20·0 cm3 of the diluted solution of stain remover. (ii) Calculate the concentration, in mol l−1, of hydrogen peroxide in the undiluted stain remover. 2 2 Page 23 MARKS DO NOT WRITE IN THIS MARGIN 10. (a) (continued) (iii) The concentration of hydrogen peroxide determined by the student was less than the concentration stated on the label for the stain remover. One possible source of error could be an inaccurate concentration of the permanganate solution. Describe how the student would confirm the concentration of the permanganate solution. [Turn over 1 Page 24 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (b) Some of the molecules thought to be responsible for the colour of stains are shown. OH HO OH O OH O OH HO OH blackcurrant stain red wine stain tomato stain Using your knowledge of chemistry, suggest how the chemicals in a stain remover might work on these stains. 3 Page 25 MARKS DO NOT WRITE IN THIS MARGIN 10. (b) (continued) [Turn over Page 26 MARKS DO NOT WRITE IN THIS MARGIN 11. Nutmeg is a seed that is commonly used as a spice in cooking. The flavour of nutmeg is due to a number of different compounds. (a) The oil in nutmeg, trimyristin, can be easily extracted and purified. In an experiment to extract trimyristin, a student refluxed nutmeg powder in a suitable solvent. Removal of the solvent produced an impure sample of solid trimyristin. (i) Suggest why an ether could be a suitable solvent to extract trimyristin oil from nutmeg. (ii) Suggest why the mixture was heated under reflux. (b) Myristicin is another compound that can be isolated from nutmeg. 1H NMR analysis showed there to be seven proton environments and these are numbered on the skeletal formula shown. O O O 4 3 1 2 5 6 7 myristicin (i) Suggest a possible chemical shift for the peak arising due to proton environment 1. (ii) Identify a proton environment which would produce a doublet in the 1H NMR spectrum. 1 1 1 1 Page 27 MARKS DO NOT WRITE IN THIS MARGIN 11. (continued) (c) Myristicin can be converted into compound X in two steps. O O O O O O NH2 compound X myristicin Suggest the type of reaction occurring at each step. Step 1: Step 2: [END OF QUESTION PAPER] 2 Page 28 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL DIAGRAM FOR USE IN QUESTION 8 (d) (ii) sialic acid O HO OH O OH HN OH O OH OH Page 29 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 30 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 31 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 32 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

Page 02 SECTION 1 — 20 marks Attempt ALL questions 1. Which of the following bonds is the least polar? A C — I B C — F C C — Cl D C — Br 2. Which of the following compounds would be the most water soluble? A CH3 C HC CH2 CH2 H2C CH C H2C CH3 B CH3 CH CH2 CH OH H2C H2C CH CH H3C CH3 C CH2 C C C H3C H2C H2C CH3 CH3 CH CH CH CH CH3 CH H 3 C CH CH O C C D CH2 HO C O O OH H OH HO C C C CH

Page 03 3. Which of the following atoms has the greatest attraction for bonding electrons? A Sulfur B Silicon C Nitrogen D Hydrogen 4. Which type of structure is found in phosphorus? A Covalent network B Covalent molecular C Monatomic D Metallic lattice 5. The polarity of molecules can be investigated using a charged rod. The charged rod will attract a stream of polar liquid flowing from a burette. Beaker Charged rod Burette Which of the following liquids would not be attracted? A Water B Propanone C Propanol D Hexane [Turn over

Page 04 6. xP2H4 + yO2 ↓ P4O10 + zH2O The equation is balanced when A x = 1, y = 5, z = 4 B x = 4, y = 6, z = 2 C x = 2, y = 7, z = 4 D x = 2, y = 5, z = 2 7. What is the systematic name for the compound below? H H C H H H H H C C H H C H C H OH A 2,2,2-trimethylethanol B 2,2-dimethylpropan-1-ol C 2,2-dimethylpropan-3-ol D 2,2-dimethylpentan-1-ol 8. Which of the following fatty acids is the most unsaturated? A C15H29COOH B C15H31COOH C C17H31COOH D C17H35COOH

Page 05 9. Which of the following is not a step in a free radical chain reaction? A Activation B Initiation C Propagation D Termination 10. Which of the following is an isomer of ethyl propanoate (CH3CH2COOCH2CH3)? A Methyl propanoate B Pentan-2-one C Pentanoic acid D Pentane-1,2-diol 11. Essential oils are A non-water soluble, non-volatile compounds B non-water soluble, volatile compounds C water soluble, non-volatile compounds D water soluble, volatile compounds. 12. The enthalpy of combustion of a hydrocarbon is the enthalpy change when A one mole of a hydrocarbon burns to give one mole of water B one mole of a hydrocarbon burns to give one mole of carbon dioxide C one mole of a hydrocarbon burns completely in oxygen D one mole of a hydrocarbon burns in one mole of oxygen. 13. Which of the following is the strongest reducing agent? A Fluorine B Lithium C Calcium D Iodine [Turn over Page 06 14. TiCl4 + 2Mg ↓ 2MgCl2 + Ti mass of mass of mass of mass of one mole one mole one mole one mole = 189·9 g = 24·3 g = 95·3 g = 47·9 g The atom economy for the production of titanium in the above equation is equal to A 47 9 100 189 9 24 3 × + · · · B ( ) 47 9 100 189 9 2 24 3 × × + · · · C 95 3 47 9 100 189 9 24 3 + × + · · · · D ( ) 2 47 9 100 189 9 24 3 × × + · · · 15. The vitamin C content of a carton of orange juice was determined by four students. Each student carried out the experiment three times. Experiment 1 (mg/100 cm3) Experiment 2 (mg/100 cm3) Experiment 3 (mg/100 cm3) Student A 30·0 29·0 28·0 Student B 26·4 26·6 26·8 Student C 26·9 27·0 26·9 Student D 26·9 26·5 26·9 The most reproducible results were obtained by A Student A B Student B C Student C D Student D.

Page 07 16. Cyanohydrin compounds can be made from carbonyl compounds by reacting the carbonyl compound with hydrogen cyanide (HCN). H C H H H H H H H H H C C H O + HCN C C C H CN OH Which carbonyl compound would react with hydrogen cyanide (HCN) to form the following compound? H C C C C C H H OH H H H H CN H CH3 H A H C H H C O C H H H C C H H H CH3 B H C H H C C O C H H C H H H CH3 H C C C C H H C H H C H H H H H O C H H H D H C H H C H H C H H C H H C O H [Turn over

Page 08 17. Chemical reactions are in a state of dynamic equilibrium only when A the reaction involves no enthalpy change B the concentrations of reactants and products are equal C the activation energies of the forward and backward reactions are equal D the rate of the forward reaction equals that of the backward reaction. 18. Bromine and hydrogen react together to form hydrogen bromide. H2(g) + Br2(g) ↓ 2HBr(g) Bonds broken Bonds made Bond Bond enthalpy (kJ mol−1) H―H 2 × H―Br H―H 436 Br―Br Br―Br 194 H―Br 366 The enthalpy change for this reaction, in kJ mol−1, is A −102 B +102 C −264 D +264.

Page 09 19. Which of the following is a structural formula for glycerol? A CH2 CH2 OH CH2OH B CH2OH CH2OH C CH2OH CH2COOH CHOH D CH2 CHOH OH CH2OH 20. Which line in the table best describes the effect of adding a catalyst to the following reaction? 4NH3(g) + 5O2(g) Ý 4NO(g) + 6H2O(g) ΔH = −ve Position of equilibrium Rate of forward reaction A unchanged unchanged B unchanged increased C moves to right unchanged D moves to right increased [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] Page 10 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 11 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 12 [BLANK PAGE] DO NOT WRITE ON THIS PAGE H FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2017 Total marks — 100 SECTION 1 — 20 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on Page 02. SECTION 2 — 80 marks Attempt ALL questions. You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/76/01 MONDAY, 8 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer Grid and Section 2 Page 02 SECTION 1 — 20 marks The questions for Section 1 are contained in the question paper X713/76/02. Read these and record your answers on the answer grid on Page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample Question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D Page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 SECTION 1 — Answer Grid [Turn over Page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 05 [Turn over for next question DO NOT WRITE ON THIS PAGE Page 06 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 80 marks Attempt ALL questions 1. The elements sodium to argon make up the third period of the Periodic Table. Na Mg Al Si P S Cl Ar (a) Name the element from the third period that exists as a covalent network. (b) Ionisation energy changes across the period. (i) Explain why the first ionisation energy increases across the period. (ii) Write an equation, including state symbols, for the second ionisation energy of magnesium. (iii) The table shows the values for the first four ionisation energies of aluminium. Ionisation energies (kJ mol−1) First Second Third Fourth 578 1817 2745 11 577 Explain why there is a large difference between the third and fourth ionisation energies. 1 1 1 1 Page 07 MARKS DO NOT WRITE IN THIS MARGIN 1. (continued) (c) The boiling point of chlorine is much higher than that of argon. Explain fully, in terms of structure and the type of van der Waals forces present, why the boiling point of chlorine is higher than that of argon. 3 [Turn over Page 08 MARKS DO NOT WRITE IN THIS MARGIN 2. Reactions involving iodine are commonly used to investigate rates of reaction. (a) One reaction involves hydrogen and iodine reacting together to form hydrogen iodide. H2(g) + I2(g) Ý 2HI(g) (i) This reaction is thought to occur by initially breaking bonds in one of the reactants. Explain, using bond enthalpies, which bond is more likely to break first during this reaction. (ii) The graph shows the distribution of kinetic energies of reactant molecules in the gas mixture at 300 °C. Ea Kinetic energy Number of molecules Add a second curve to the graph to show the distribution of kinetic energies at 400 °C. (An additional graph, if required, can be found on Page 35) 1 1 Page 09 MARKS DO NOT WRITE IN THIS MARGIN 2. (a) (continued) (iii) The reaction to produce hydrogen iodide is exothermic. H2(g) + I2(g) Ý 2HI(g) (A) State the effect of increasing temperature on the position of equilibrium. (B) State why changing the pressure has no effect on this equilibrium reaction. 1 1 [Turn over Page 10 MARKS DO NOT WRITE IN THIS MARGIN 2. (a) (continued) (iv) The potential energy diagram for the reaction between hydrogen and iodine is shown. Potential energy (kJ) unstable arrangement of atoms Reaction progress 2HI Ea forward = 173·2 kJ Ea backward = 182·8 kJ H2 + I2 (A) State the term for the unstable arrangement of atoms. (B) Calculate the enthalpy change, in kJ, for the forward reaction. (C) Platinum can be used as a catalyst for this reaction. State the effect that platinum would have on the activation energy for the reaction. 1 1 1 Page 11 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (b) The reaction between iodide ions, I−(aq), and persulfate ions, S2O8 2−(aq), is used to investigate the effect of changing concentration on rate of reaction. The relative rate of the reaction is determined by mixing the reactants in a beaker and recording the time taken for the mixture to change colour. The results of the investigation are shown in the table. Experiment Concentration of I−(aq) (mol l−1) Concentration of S2O8 2−(aq) (mol l−1) Time (s) Relative rate (s−1) 1 0·04 0·05 241 0·00415 2 0·06 0·05 180 0·00556 3 0·08 0·05 0·00819 4 0·1 0·05 103 0·00971 (i) The instructions state that a dry beaker must be used for each experiment. Suggest a reason why the beaker should be dry. (ii) Calculate the time, in seconds, for the reaction in experiment 3. (iii) Explain why decreasing the concentration of iodide ions lowers the reaction rate. 1 1 1 [Turn over Page 12 MARKS DO NOT WRITE IN THIS MARGIN 3. The leaves of the rhubarb plant are considered poisonous because they contain high levels of oxalic acid. Oxalic acid is a white, water-soluble solid. It is a dicarboxylic acid that has the structural formula shown. C C O O O O H H Oxalic acid reacts with bases to form salts. It can also be oxidised by strong oxidising agents to form carbon dioxide gas. The oxidation equation for oxalic acid is shown. H2C2O4 ↓ 2CO2 + 2e− + 2H+ Using your knowledge of chemistry, comment on how the mass of oxalic acid in a rhubarb leaf could be determined. 3 Page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. Pentyl butanoate is responsible for some of the flavour in apricots and strawberries. H C C C C C O C C C C H H H H H H H H H H H H H H H H H O (a) Hydrolysis of pentyl butanoate using sodium hydroxide produces an alcohol and the salt of the carboxylic acid. (i) Name the alcohol that would be formed when pentyl butanoate is hydrolysed. (ii) Draw a structural formula for the sodium salt of the carboxylic acid that would be formed. (b) Fats and oils belong to the same class of compounds as pentyl butanoate. (i) Name this class of compounds. (ii) When a fat is hydrolysed using sodium hydroxide, sodium salts of fatty acids are produced. State a use for sodium salts of fatty acids. 1 1 1 1 [Turn over Page 14 MARKS DO NOT WRITE IN THIS MARGIN 4. (b) (continued) (iii) Hydrolysis of fats using hydrochloric acid produces fatty acids. Stearic acid is a fatty acid that can be made from hydrolysis of beef fat. It is a fuel sometimes found in fireworks. During combustion, stearic acid (C17H35COOH) produces 623 kJ of energy per mole of CO2 produced. C17H35COOH + 26O2 ↓ 18CO2 + 18H2O mass of one mole = 284 g Calculate the energy released, in kJ, by combustion of 10 grams of stearic acid. 2 Page 15 MARKS DO NOT WRITE IN THIS MARGIN 5. Sulfur dioxide is a colourless, toxic gas that is soluble in water and more dense than air. (a) One laboratory method for preparation of sulfur dioxide gas involves adding dilute hydrochloric acid to solid sodium sulfite. The sulfur dioxide gas produced is dried by bubbling the gas through concentrated sulfuric acid. The sulfur dioxide gas can then be collected. collecting gas drying gas sodium sulfite flask dilute hydrochloric acid tap funnel (i) Complete the diagram by drawing: in the first box, apparatus suitable for drying the sulfur dioxide gas; in the second box, apparatus suitable for collecting the gas. (An additional diagram, if required, can be found on Page 35) 2 [Turn over Page 16 MARKS DO NOT WRITE IN THIS MARGIN 5. (a) (continued) (ii) 0·40 g of sodium sulfite, Na2SO3, is reacted with 50 cm3 of dilute hydrochloric acid, concentration 1·0 mol l−1. Na2SO3(s) + 2HCl(aq) ↓ H2O(ℓ) + 2NaCl(aq) + SO2(g) mass of one mole = 126·1 g Show, by calculation, that sodium sulfite is the limiting reactant. (b) Another reaction that produces sulfur dioxide gas involves combustion of carbon disulfide in the reaction shown. CS2(ℓ) + 3O2(g) ↓ CO2(g) + 2SO2(g) Calculate the enthalpy change, in kJ mol−1, for this reaction using the following information. C(s) + O2(g) ↓ CO2(g) ΔH = −393·5 kJ mol−1 S(s) + O2(g) ↓ SO2(g) ΔH = −296·8 kJ mol−1 C(s) + 2S(s) ↓ CS2(ℓ) ΔH = +87·9 kJ mol−1 2 2 Page 17 MARKS DO NOT WRITE IN THIS MARGIN 5. (continued) (c) The graph shows results for an experiment to determine the solubility of sulfur dioxide in water. 15 20 Temperature (°C) 50 250 150 5 0 200 100 0 Solubility of SO2 (g l−1) 10 (i) Determine the solubility of sulfur dioxide, in g l−1, in water at 10 °C. (ii) Information about sulfur dioxide and carbon dioxide is shown in the table. Shape of molecule Electronegativity difference between elements Solubility in water at 25 °C (g l−1) carbon dioxide linear O C O 1·0 1·45 sulfur dioxide bent O S O 1·0 94 Explain fully why carbon dioxide is much less soluble in water than sulfur dioxide is in water. 1 2 [Turn over Page 18 MARKS DO NOT WRITE IN THIS MARGIN 6. A student was carrying out an investigation into alcohols, aldehydes and ketones. (a) The student was given three alcohols labelled as A, B and C. These alcohols were all isomers with the formula C4H9OH. (i) Draw a structural formula for the secondary alcohol with the formula C4H9OH. (ii) The student set up the following experiment. C B A Hot water bath 10 cm3 of acidified dichromate solution + 2 cm3 of alcohol Alcohol Observation A Colour change B No change C Colour change (A) Suggest why a water bath is an appropriate method of heating the reaction mixture. (B) Describe the colour change that would have been observed with alcohols A and C. (C) Alcohol B is not oxidised. State the type of alcohol which cannot be oxidised by acidified dichromate solution. 1 1 1 1 Page 19 MARKS DO NOT WRITE IN THIS MARGIN 6. (a) (continued) (iii) The student set up a second experiment with alcohol A. wet pH paper held in the vapour loose plug of ceramic wool copper(II) oxide heat alcohol and ceramic wool loose plug of ceramic wool Hot copper(II) oxide is an oxidising agent. (A) When alcohol A (C4H9OH) is oxidised the product turns the pH paper red. Suggest a name for the product. (B) Complete the ion-electron equation for the oxidation reaction. C4H9OH ↓ C4H8O2 1 1 [Turn over Page 20 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (b) The student found the following information about the boiling points of some aldehydes. Aldehyde Molecular formula Boiling point (°C) H C C C C C H H H H H H H H O H C5H10O 102 H C C C C C C H H H H H O H H H H H H C6H12O 130 H C C C C C C H H H H H O H H H C H H H H H C7H14O 153 H C C C C H H H H H CH3 O H C5H10O 95 H C C C H CH3 H CH3 O H C5H10O 75 H C C C C C H H H H H H H O H CH3 C6H12O 119 H C C C C H H CH3 H H CH3 O H C6H12O 111 (i) Name the aldehyde that has a boiling point of 119 °C. (ii) Predict the boiling point, in °C, of the following molecule. C C C C C C C H H H H H H H H H H H H O H C H H H 1 1 Page 21 MARKS DO NOT WRITE IN THIS MARGIN 6. (b) (continued) (iii) Using information from the table, describe one way in which differences in structure affect the boiling point of isomeric aldehydes. (iv) State what would be observed when an aldehyde is gently heated with Tollens’ reagent. (c) Ketones contain a carbonyl group. Name the type of intermolecular interaction between ketone molecules. 1 1 1 [Turn over Page 22 MARKS DO NOT WRITE IN THIS MARGIN 7. Some people take iron tablets as a dietary supplement. Iron tablets may contain iron(II) sulfate. (a) A student was investigating the iron(II) content of iron tablets. A work card gave the following instructions for preparing an iron tablet solution. 1. Add five iron tablets to about 50 cm3 of dilute sulfuric acid in a small beaker and stir to dissolve. 2. Transfer quantitatively to a 100 cm3 volumetric flask. 3. Make up the solution to the graduation mark on the volumetric flask. 4. Stopper the flask and then invert it to mix the solution. To ‘transfer quantitatively’ means that all of the iron tablet solution must be transferred into the volumetric flask. Describe how this is carried out in practice. (b) The concentration of iron(II) ions (Fe2+) in this iron tablet solution can be determined by a redox titration with permanganate (MnO4 −) solution. 5Fe2+(aq) + 8H+(aq) + MnO4 −(aq) ↓ 5Fe3+(aq) + Mn2+(aq) + 4H2O(ℓ) (i) Suggest why it is not necessary to add an indicator to this titration. 1 1 Page 23 MARKS DO NOT WRITE IN THIS MARGIN 7. (b) (continued) (ii) Suggest why the titration must be carried out under acidic conditions. (iii) Three 25·0 cm3 samples of the iron tablet solution were titrated with a standard solution of 0·020 mol l−1 permanganate (MnO4 −). The results are shown below. Sample Volume of permanganate (cm3) 1 14·9 2 14·5 3 14·6 (A) State why the volume of permanganate used in the calculation was taken to be 14·55 cm3, although this is not the average of the three titres in the table. (B) Calculate the concentration, in mol l−1, of iron(II) ions in the iron tablet solution. 5Fe2+(aq) + 8H+(aq) + MnO4 −(aq) ↓ 5Fe3+(aq) + Mn2+(aq) + 4H2O(ℓ) 1 1 3 [Turn over Page 24 MARKS DO NOT WRITE IN THIS MARGIN 7. (b) (iii) (continued) (C) State what is meant by the term standard solution. (D) Name an appropriate piece of apparatus which could be used to measure 25·0 cm3 samples of iron tablet solution. (c) In a different experiment, five iron tablets were found to contain 0·00126 moles of iron(II) ions. Calculate the average mass, in mg, of iron present in one tablet. (d) It is recommended an adult female takes in 14·8 mg of iron per day. 100 g of a breakfast cereal contains 12·0 mg of iron. Calculate the percentage of the recommended daily amount of iron provided for an adult female by a 30 g serving. 1 1 1 2 Page 25 MARKS DO NOT WRITE IN THIS MARGIN 8. Skin care products contain a mixture of polar covalent, non-polar covalent and ionic compounds. The compounds need to stay mixed within the product. Skin care products also need to spread easily and remain on the skin for a period of time, as well as provide physical and chemical protection from the sun. In order to do this, skin care products contain a range of chemicals including water, fats and oils, antioxidants, minerals and sun block. Using your knowledge of chemistry, explain the role of different chemicals in skin care products. 3 [Turn over Page 26 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 27 MARKS DO NOT WRITE IN THIS MARGIN 9. Dishwasher tablets contain chemicals which remove dirt from dishes. (a) Dishwasher tablets include detergents. These molecules act like soaps to allow mixing of fat-soluble dirt and water. (i) During the cleaning process, the detergent molecules combine with fat-soluble dirt. A simplified diagram of a detergent molecule is shown. covalent tail ionic head Complete the diagram below to show how detergent molecules combine with fat-soluble dirt. fat-soluble dirt (An additional diagram, if required, can be found on Page 36) (ii) State the term used to describe the non-polar, hydrocarbon tail of a detergent molecule. 1 1 [Turn over Page 28 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (b) Dishwasher tablets produce the bleach hydrogen peroxide, H2O2. One action of this oxidising agent is to oxidise food. (i) Suggest another action of the bleach produced by the dishwasher tablets. (ii) Hydrogen peroxide decomposes to form water and oxygen. 2H2O2(ℓ) ↓ 2H2O(ℓ) + O2(g) A dishwasher tablet produces 0·051 g of hydrogen peroxide (mass of one mole = 34 g). Calculate the volume of oxygen that would be produced when 0·051 g of hydrogen peroxide decomposes. Take the volume of 1 mole of oxygen gas to be 24 litres. (c) Enzymes are commonly added to dishwasher tablets. These are used to break down proteins. (i) The proteins are broken down into small, water-soluble molecules. Name the small, water-soluble molecules made when proteins are broken down completely. 1 3 1 Page 29 MARKS DO NOT WRITE IN THIS MARGIN 9. (c) (continued) (ii) The structure of a section of protein chain found in egg white is shown. C C N C C N C C N C C N O H H O H O H O H CH CH2 CH2 CH2 NH C H2N NH H H CH2 SH H H H3C CH2 CH3 (A) Name the functional group circled. (B) Draw a structural formula for one of the molecules that would be made when this section of egg white protein chain is completely broken down. (iii) As part of the program in the dishwasher, the conditions in the dishwasher change so that the enzyme molecules no longer work because they change shape. (A) State the term used to describe the change in shape of enzyme molecules. (B) Suggest a change in conditions which would cause the enzyme molecules to change shape. 1 1 1 1 [Turn over Page 30 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (d) A bleach activator is frequently added to dishwasher tablets to speed up the bleaching reaction. One common bleach activator is TAED. TAED could be produced in a process which involves a number of stages. (i) The first stage in producing TAED is shown below. N H H H O C O CH3 + (CH2)2 N H H N C H O CH3 + (CH2)2 N H H O C C O O H3C CH3 ethylene diamine acetic anhydride Suggest a name for this type of reaction. 1 Page 31 MARKS DO NOT WRITE IN THIS MARGIN 9. (d) (continued) (ii) The final stage in the process producing TAED is shown below. N C H H O TAED C O O O O CH3 CH3 + + (CH2)2 N C C O C C O O H3C H3C H3C CH3 Draw a structural formula for TAED. 1 [Turn over Page 32 MARKS DO NOT WRITE IN THIS MARGIN 10. Essential oils from the lavender plant are used in aromatherapy. (a) Gas chromatography can be used to separate and identify the organic compounds in lavender oils. Chromatogram 1 - Lavender oil A 24 20 22 18 Retention time (minutes) (6) (5) (3) (4) (2) (1) 16 14 Peak Component Component peak area 1 1,8-cineole 7432 2 linalool 31 909 3 camphor 7518 4 linalyl acetate 27 504 5 geranyl acetate 3585 6 farnesene 1362 Total peak area    =        79 310 The relative concentration of each component can be calculated using the following formula. Relative concentration = Component peak area 100 (%) Total peak area × (i) Calculate the relative concentration of linalool in lavender oil A. 1 Page 33 MARKS DO NOT WRITE IN THIS MARGIN 10. (a) (continued) (ii) Different varieties of lavender oils have different compositions. Chromatogram 2 – Lavender oil B Retention time (minutes) 24 22 20 18 16 14 Identify the component found in lavender oil A that is missing from lavender oil B. (b) A brand of mouthwash contains the component 1,8-cineole at a concentration of 0·92 mg per cm3. The cost of 1 kg of 1,8-cineole is £59·10. Calculate the cost, in pence, of 1,8-cineole that is present in a 500 cm3 bottle of this brand of mouthwash. 1 2 [Turn over for next question Page 34 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (c) The component molecules found in lavender oils are terpenes or terpenoids. (i) A chiral carbon is a carbon atom attached to four different atoms or groups of atoms. An example is shown below. H3C C H Cl C2H5 Chiral carbon atom A molecule of the terpenoid linalool has a chiral carbon. Linalool has the following structure. C C C C C H H CH3 H H O H H C C H3C H CH3 H H Circle the chiral carbon atom in the linalool structure. (An additional diagram, if required, can be found on Page 36) (ii) Farnesene is a terpene consisting of three isoprene units (2-methylbuta-1,3-diene) joined together. Write the molecular formula of farnesene. [END OF QUESTION PAPER] 1 1 Page 35 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK ADDITIONAL DIAGRAM FOR USE IN QUESTION 2 (a) (ii) Ea Kinetic energy Number of molecules ADDITIONAL DIAGRAM FOR USE IN QUESTION 5 (a) (i) collecting gas drying gas sodium sulfite flask dilute hydrochloric acid tap funnel Page 36 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK ADDITIONAL DIAGRAM FOR USE IN QUESTION 9 (a) (i) fat-soluble dirt ADDITIONAL DIAGRAM FOR USE IN QUESTION 10 (c) (i) C C C C C H H CH3 H H O H H C C H3C H CH3 H H Page 37 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 38 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Page 39 [BLANK PAGE] DO NOT WRITE ON THIS PAGE Page 40 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

6 (B410U10-1) Examiner only 10. (a) Some students were discussing ionisation energies. (i) State the meaning of the term standard molar first ionisation energy. [2] (ii) The graph below shows the logarithm of the first eight successive ionisation energies for element X. © WJEC CBAC Ltd. 0 0 2.0 3.0 4.0 5.0 2 4 6 1 3 5 7 8 Number of electron lost log10 (Ionisation energy) I. Explain why successive ionisation energies increase. [2] II. Use the graph to determine in which group of the Periodic Table element X is found. Explain your answer. [2] (B410U10-1) Turn over. B 410 U101 07 7 Examiner only (b) The students used a hydrogen discharge tube and observed some coloured lines. One said that these visible lines could be used to determine the value of the first ionisation energy of hydrogen. (i) Discuss whether you agree with this student’s suggestion. You should include an explanation of how spectral lines are produced and how they can be used to determine ionisation energy. [6 QER] (ii) A spectral line with a frequency of 3.28 × 1015 Hz was formed when an atom of hydrogen was ionised. Calculate the first ionisation energy of hydrogen in kJ mol−1. Give your answer to the appropriate number of significant figures. [3] Ionisation energy = ................................................ kJ mol−1 © WJEC CBAC Ltd. 15 8 (B410U10-1) Examiner only 11. (a) When acids are being used chemists often refer to the pH of the solution. (i) State what is meant by pH. [1] (ii) Calculate the pH of 0.50 mol dm−3 hydrochloric acid. [1] pH = ................................................ (iii) Explain the observation that the pH of 0.10 mol dm−3 ethanoic acid, CH3COOH, is higher than the pH of 0.10 mol dm−3 hydrochloric acid. [3] (b) Water is able to act as a base as it can accept H+ to form H3O+. (i) Draw a dot and cross diagram to show the arrangement of electrons in H3O+. Show outer electrons only. [2] (ii) Name the type of bond present between H2O and the H+ added to form H3O+. [1] ............................................................................................................................................. (iii) Suggest a value for the bond angle between the O—H bonds in H3O+. Explain your answer. [3] © WJEC CBAC Ltd. (B410U10-1) Turn over. 9 Examiner only (c) An equilibrium exists, in aqueous solution, between chromate(VI) ions, CrO4 2−, and dichromate(VI) ions, Cr2O7 2−. 2CrO4 2−(aq) + 2H+(aq) a Cr2O7 2−(aq) + H2O(l) yellow orange (i) State le Chatelier’s principle. [2] (ii) Describe what is seen when aqueous sodium hydroxide is added to an orange solution containing dichromate(VI) ions. Explain your answer. [2] © WJEC CBAC Ltd. 15

10 (B410U10-1) Examiner only 12. (a) Caroline was investigating the number of moles of water of crystallisation, x, in hydrated barium chloride, BaCl2.xH2O. She was told that x is a whole number. She followed an instruction sheet. • Weigh an empty crucible with its lid. • Add the hydrated salt to the crucible and weigh crucible, lid and salt. • Place the lid on the crucible and heat salt for 3 minutes. • Cool and reweigh the crucible, lid and contents. • Heat for another 2 minutes and cool and reweigh again. Caroline obtained the following results. © WJEC CBAC Ltd. Mass / g Crucible + lid 13.132 Crucible + lid + BaCl2.xH2O 15.051 Crucible + lid + contents (after 1st heating) 14.787 Crucible + lid + contents (after 2nd heating) 14.777 (i) Use the data to determine the value of x in the formula BaCl2.xH2O. You must show your working. [4] x = ............................... (ii) Why did the instructions say that the lid should be in place when the heating was carried out? [1] (B410U10-1) Turn over. 11 Examiner only (iii) Ethan said that Caroline’s method was inaccurate, even though she had carried out the experiment carefully and recorded all her results correctly. Suggest two ways in which Caroline could make her experiment more accurate. Explain your answers. [4] Suggestion 1 Suggestion 2 (iv) Caroline agreed that her experiment had been inaccurate but said that it gave the correct answer for x. Comment on why Caroline was correct and that accuracy need not be high in this experiment to determine the value of x. [1] © WJEC CBAC Ltd. 12 (B410U10-1) Examiner only (b) Caroline used the barium chloride as one of the reagents to identify the ions present in an aqueous solution W. Solution W contains only two ions. The reagents were added to small volumes of solution W and the following observations were made. © WJEC CBAC Ltd. Test Observation add aqueous sodium hydroxide no visible reaction add aqueous barium chloride white precipitate formed add dilute nitric acid vigorous effervescence seen (i) From these observations name one ion present in solution W. [1] ........................................................................................................ (ii) The observations allowed Caroline to eliminate some metal ions as being present in W. Suggest one metal ion that she eliminated. [1] ........................................................................................................ (iii) Write the ionic equation for the reaction between aqueous solutions of barium chloride and W. Include state symbols. [1] 13 (B410U10-1) Turn over. 13 Examiner only 13. A group of students was given a mineral sample that came from a region where both magnesite, MgCO3, and dolomite, CaMg(CO3)2, were known to exist. They decided to analyse the sample by titration. They added 4.77 g of the mineral to 100 cm3 of 2.06 mol dm−3 hydrochloric acid. They titrated 25.0 cm3 samples of the solution formed against 1.00 mol dm−3 sodium hydroxide. The results of these titrations are given in the table. © WJEC CBAC Ltd. Titration number 1 2 3 Final burette reading / cm3 23.20 24.50 23.00 Initial burette reading / cm3 0.10 1.10 0.00 Titre / cm3 .................................... .................................... .................................... (a) Explain why universal indicator is not used to show the end-point of a titration. [1] (b) Complete the table and use the data to calculate a mean titre suitable for use in the calculation involved in the analysis of the sample. [1] Mean titre = ................................................ cm3 (c) Calculate the number of moles of hydrochloric acid that reacted with the mineral sample. [4] n(HCl) = ................................................ mol 14 (B410U10-1) Examiner only (d) Complete the ionic equation for the reaction between carbonate ions and acid and hence calculate the number of moles of carbonate present in the mineral sample. [1] CO3 2– + ........... H+ CO2 + ................................................ n(CO3 2–) = ................................................ mol (e) Calculate the relative formula mass of the carbonate and hence state whether the mineral is magnesite or dolomite. Assume that the mineral is a pure compound. [1] Mr = ................................................ (f) A burette can be read to an accuracy of ± 0.05 cm3. Calculate the maximum percentage error in any of the titres in the table. [2] Percentage error = ................................................ % © WJEC CBAC Ltd. (B410U10-1) Turn over. 15 Examiner only (g) The students extended their investigation by measuring the volume of carbon dioxide released when a 4.59 g sample of the mineral reacted with an excess of acid. They collected 1.31 dm3 of gas measured at 25 °C and at 1.01 × 105 Pa. (i) Use the ideal gas equation, pV = nRT, to calculate the number of moles of carbon dioxide formed. Show your working. [3] n(CO2) = ................................................. mol (ii) Show whether or not this extension confirms the conclusion reached in part (e). [1] END OF PAPER © WJEC CBAC Ltd. 14 Examiner only (B410U10-1) 16 © WJEC CBAC Ltd. For continuation only.

(B410U20-1) 12 Examiner only 10. (a) A student was asked to calculate the enthalpy change, ΔrH, for the reaction of magnesium oxide and carbon dioxide to form magnesium carbonate. Since this is difficult to measure directly he decided to determine the enthalpy changes for the reactions of magnesium oxide and magnesium carbonate with excess dilute hydrochloric acid in two similar, separate experiments and apply Hess’s law to his results. (i) The first experiment was to find the molar enthalpy change, ΔH1, for the reaction MgO(s) + 2HCl(aq) MgCl2(aq) + H2O(l) ΔH1 was calculated to be –115 kJ mol–1. Give one assumption made when finding the value of ΔH1 from experimental results. [1] (ii) The second experiment was to find the molar enthalpy change, ΔH2, for the reaction MgCO3(s) + 2HCl(aq) MgCl2(aq) + H2O(l) + CO2(g) The following values were recorded during the experiment: Mass of magnesium carbonate 3.50 g Volume of hydrochloric acid 50.0 cm3 Initial temperature of hydrochloric acid 22.0 °C Final temperature of solution 30.8 °C I. Calculate the molar enthalpy change for this reaction, ΔH2, in kJ mol–1. Give your answer to an appropriate number of significant figures. [4] ΔH2 = ................................................. kJ mol–1 © WJEC CBAC Ltd. 13 (B410U20-1) Examiner only II. State and explain the effect, if any, on the calculated enthalpy change, ΔH2, if the experiment were repeated with the same mass of damp magnesium carbonate. [2] (iii) The hydrochloric acid used in these experiments could be measured using either a volumetric pipette or a measuring cylinder. Give one practical advantage of using each piece of apparatus. [2] Volumetric pipette Measuring cylinder (iv) Each reading on the thermometer is accurate to ± 0.1 °C. Calculate the percentage error in the temperature rise recorded. [1] Percentage error = ................................................. % © WJEC CBAC Ltd. Turn over. (B410U20-1) 14 Examiner only © WJEC CBAC Ltd. (v) A Hess cycle connecting ΔrH to ΔH1 and ΔH2 is shown below. ΔrH MgO(s) + CO2(g) MgCO3(s) 2HCl(aq) ΔH1 ΔH2 2HCl(aq) MgCl2(aq) + H2O(l) + CO2(g) Calculate the value of ΔrH in kJ mol–1. [2] ΔrH = ................................................. kJ mol–1 (B410U20-1) Turn over. © WJEC CBAC Ltd. (b) The equation for the reaction between hydrazine and nitrogen dioxide is as follows. 2N2H4(l) + 2NO2(g) 3N2(g) + 4H2O(l) ΔH = −1313 kJ mol–1 Using this value and the standard enthalpy changes of formation, ΔfHθ, given in the table below, calculate the standard enthalpy change of formation of NO2. [2] Substance ΔfHθ / kJ mol–1 N2H4(l) 50.4 N2(g) 0 H2O(l) −286 ΔfHθ = ................................................. kJ mol–1 14 15 Examiner only

16 (B410U20-1) Examiner only 11. Adam investigated how the initial rate of reaction between hydrochloric acid and magnesium carbonate at 20 °C is affected by the concentration of the acid. The equation for the reaction is as follows. MgCO3(s) + 2HCl(aq) MgCl2(aq) + CO2(g) + H2O(l) He used 0.50 g of magnesium carbonate and 40 cm3 of 0.20 mol dm–3 hydrochloric acid. He measured the volume of carbon dioxide produced at regular time intervals as the reaction proceeded. Part of the apparatus used for the experiment is shown below. The magnesium carbonate was placed in the small glass container which was tipped over to start the reaction and a stopwatch was started at the same time. © WJEC CBAC Ltd. hydrochloric acid magnesium carbonate (a) Name the apparatus used to collect and measure the volume of the gas produced. [1] (b) Suggest an experimental method other than measuring the volume of gas that would allow the rate of this reaction to be studied. [2] (c) Elinor told Adam that in this experiment the carbonate needed to be in excess. He replied that it was. Is he correct? Justify your answer. [2] gas collected directly (B410U20-1) 17 Examiner only (d) Adam plotted his results as follows. © WJEC CBAC Ltd. 0 0 10 20 30 40 50 60 70 80 90 100 1 2 3 4 5 6 7 8 9 10 Time (minutes) Volume of carbon dioxide (cm3) By drawing a tangent to the curve calculate the initial rate of this reaction. State the unit. [2] Rate = ................................................. Unit ................................................. Turn over. 18 (B410U20-1) Examiner only (e) He then repeated the experiment using 40 cm3 of 0.10 mol dm–3 hydrochloric acid. Sketch on the graph in (d) the curve he would expect to obtain. Explain any differences in the curves. [3] (f) State one condition, other than temperature and pressure, which would need to be kept constant in this investigation. [1] END OF PAPER © WJEC CBAC Ltd. 11 Examiner only (B410U20-1) 19 © WJEC CBAC Ltd. For continuation only.

10 (A410U10-1) Examiner only 12. In 2011 a tsunami damaged the Fukushima nuclear plant in Japan. The radioactive material that escaped consisted of many isotopes. Contaminated water from the site was analysed in the immediate aftermath of the incident, with the levels of radioactivity due to each isotope noted. (a) The main radioactivity detected was beta radiation. Give a reason why it is unlikely that alpha radiation would be detected from a solution contained in a sample tube. [1] (b) State what is meant by gamma radiation. [1] (c) Give a reason why radioactivity is harmful to living things. [1] (d) Arsenic-74 can decay either by emission of a beta particle or by emission of a positron. Identify the isotope formed by emission of a positron. [1] Element ................................................................... Mass number ................................................................... © WJEC CBAC Ltd. Isotope Half-life Radioactivity / Bq per cm3 of solution Type(s) of radioactivity emitted Product of decay chlorine-38 37 minutes 1.9 × 106 beta 38Ar arsenic-74 18 days 3.9 × 102 yttrium-91 59 days 5.2 × 104 beta 91Zr iodine-131 8 days 2.1 × 105 beta 131Xe caesium-134 2 years 1.6 × 105 beta 134Ba caesium-136 13 days 1.7 × 104 beta 136Ba caesium-137 30 years 1.8 × 106 beta and gamma 137Ba lanthanum-140 1.6 days 3.4 × 102 beta 140Ce (A410U10-1) Turn over. A 410 U101 11 11 Examiner only (e) The Becquerel (Bq) is a unit of radioactivity which is equivalent to the decay of 1 nucleus per second. (i) Calculate the mass of xenon-131 produced per minute from 1 cm3 of the solution. [3] Mass = ....................................................... g (ii) Identify which original isotope is present in the greatest concentration in the solution. Explain your answer. [2] (f) After studying the data, it was suggested that the affected area around the reactor would be safe after 60 years as this is twice the half-life of the longest lived isotope in the sample. Give two reasons why this suggestion is incorrect. [2] © WJEC CBAC Ltd. 11

12 (A410U10-1) Examiner only 13. A class of students is provided with a mixture of the strong base sodium hydroxide and the weak base sodium carbonate. They are asked to carry out an experiment to find the percentage by mass of each in the sample using the following method. • Prepare a standard solution of the solid mixture in a 250 cm3 volumetric flask. • Measure 25.00 cm3 of this mixture into a conical flask and add a small amount of an appropriate indicator. • Add 0.105 mol dm–3 hydrochloric acid from a burette whilst swirling the mixture until a permanent colour change occurs. At this point all the sodium hydroxide has reacted. • Record the results and calculate the volume required to reach the first end-point (volume A). • Add a few drops of a different indicator. • Add more of the hydrochloric acid from the burette whilst swirling the mixture until a permanent colour change occurs. At this point all the sodium carbonate has reacted. • Record the results and calculate the additional volume required to reach the second end- point (volume B). (a) The results of the titrations are shown below. © WJEC CBAC Ltd. 1 2 3 4 Initial burette reading / cm3 0.00 0.00 1.20 5.55 Burette reading at first end-point / cm3 22.35 22.00 23.25 27.55 Burette reading at second end-point / cm3 33.55 32.65 33.80 38.00 Volume required to reach first end-point (volume A) / cm3 22.35 Additional volume required to reach second end-point (volume B) / cm3 11.20 (A410U10-1) Turn over. 13 Examiner only © WJEC CBAC Ltd. (i) Complete the table and calculate the mean volume required to reach the first end- point, and the mean additional volume required to reach the second end-point. [3] Mean volume for first end-point = ...................................................................... cm3 Mean additional volume for second end-point = ...................................................................... cm3 (ii) The class teacher tells the students that the data show that the value for volume A is more reliable than the value for volume B. Give two reasons for this. [2] (iii) Calculate the mass of sodium carbonate present in the original solid mixture. [3] Na2CO3 + 2HCl 2NaCl + CO2 + H2O Mr 106.0 Mass = ....................................................... g 14 (A410U10-1) Examiner only © WJEC CBAC Ltd. (b) Explain how an indicator works and give reasons why two different indicators are used to identify the end-points for neutralisation of sodium hydroxide and sodium carbonate. Suggest how you would select appropriate indicators for this experiment. [6 QER] (A410U10-1) Turn over. 15 © WJEC CBAC Ltd. (c) One student suggests using 0.100 mol dm–3 ethanoic acid for this titration method, however his partner suggests that a different method would be needed. (i) Calculate the pH of 0.100 mol dm–3 ethanoic acid. [2] (Ka for ethanoic acid = 1.76 × 10−5 mol dm−3) pH = ....................................................... (ii) Suggest how the equivalence point for the titration of a weak acid and a weak base such as sodium carbonate can be found experimentally. [2] 18 Examiner only

16 (A410U10-1) Examiner only 14. (a) The usual method for measuring the standard electrode potential of a half-cell is to connect it to a standard hydrogen electrode using a high resistance voltmeter and a salt bridge. (i) State the function of the salt bridge. [1] (ii) Draw a labelled diagram of the standard hydrogen electrode. [3] (iii) When measuring the standard electrode potential for the Zn2+(aq) │ Zn(s) system a piece of zinc metal is placed in an aqueous solution containing Zn2+(aq). Explain why a similar method would not be appropriate for the Li+(aq) │ Li(s) system. [1] (b) The values for some standard electrode potentials are listed in the table below. © WJEC CBAC Ltd. Standard electrode potential, E θ / V Li+(aq) + e− s Li(s) –3.04 Na+(aq) + e− s Na(s) –2.71 Zn2+(aq) + 2e− s Zn(s) –0.76 Fe3+(aq) + 3e− s Fe(s) –0.04 I2(s) + 2e− s 2I− (aq) +0.54 Fe3+(aq) + e− s Fe2+ (aq) +0.77 Br2(l) + 2e− s 2Br − (aq) +1.09 Cl2(g) + 2e− s 2Cl− (aq) +1.36 (A410U10-1) Turn over. 17 Examiner only (i) Give the formula of the strongest reducing agent in the table. [1] (ii) Calculate the EMF of the cell formed when the Br2(l) │ Br −(aq) half-cell is connected to the Zn2+(aq) │ Zn(s) half-cell. [2] EMF = ...................................................... V (iii) Use the values in the table to explain why the reaction between gaseous iodine and heated iron wire produces iron(II) iodide whilst chlorine gas and iron wire produce iron(III) chloride. Your answer should include: • An explanation of the products formed in the two reactions using the standard electrode potentials listed. • Chemical equations for both reactions. • A prediction of the product that would be formed when bromine gas reacts with heated iron wire, including a reason. • An explanation of why the prediction made using the standard electrode potentials above may not be correct. [6 QER] © WJEC CBAC Ltd. 14

18 (A410U10-1) Examiner only 15. The wide range of mobile technology available to us today has relied on the development of ways to store and utilise energy efficiently. Many mobile devices use batteries based on lithium ions as they have a large charge density. (a) A lithium ion battery can sustain a current over an extended period of time so that a total charge of 1.2 × 104 C has flowed. Calculate the mass of lithium that has reacted in this time, giving your answer to an appropriate number of significant figures. [3] Mass = ...................................................... g (b) Many lithium ion batteries contain electrodes made of compounds of formula LiaMb(PO4)c where M can be one of a range of metals from the first row of the d-block elements. A university student undertook a series of experiments to analyse the compound used as an electrode in a given lithium ion battery. The relative formula mass of the compound was approximately 158. 2.70 g of the solid were dissolved in hot acid and a solution containing calcium ions was added. All the phosphate ions were precipitated from the hot mixture as calcium phosphate (Mr 310.3). The calcium phosphate was washed and heated to constant mass, with 2.66 g produced. A small amount of the original compound was dissolved in hot solvent to give a solution of concentration 1.90 × 10−6 mol dm−3. Atomic absorption spectroscopy was used to measure the concentration of lithium ions in this solution and it was found to be 13.2 µg dm−3. (i) Explain why the solid calcium phosphate precipitate must be heated to constant mass. [1] (ii) Find the value of c, the number of phosphate ions present in the molecular formula. You must show your working. [3] c = ...................................................... © WJEC CBAC Ltd. (A410U10-1) Turn over. 19 Examiner only (iii) Find the value of a, the number of lithium ions present in the molecular formula. [2] a = ...................................................... (iv) Identify the first row d-block element M, and the number of atoms of this present in the molecular formula, b, and hence write the molecular formula of the compound. [2] Molecular formula ............................................................................................... © WJEC CBAC Ltd. 11

20 (A410U10-1) Examiner only 16. The reaction between ethoxide ions (C2H5O−) and iodoethane produces ethoxyethane. The reaction was studied at various temperatures and the percentage of products formed every 10 s was measured for the first 50 s. (a) The initial rate of reaction can be calculated approximately using the formula: rate = percentage conversion time taken (i) One student chose to use the data at 50 s to calculate the rate at 40 °C. Suggest and explain why this will not give an appropriate value of initial rate. [2] (ii) A second student chose to use the data at 10 s to calculate the rate. Give a reason why the percentage error at lower temperatures may be more significant. [2] © WJEC CBAC Ltd. Temperature / °C Percentage conversion of reactants to products 10 s 20 s 30 s 40 s 50 s 10 2 % 3 % 5 % 6 % 7 % 20 5 % 10 % 15 % 19 % 24 % 30 16 % 30 % 41 % 50 % 58 % 40 41 % 65 % 79 % 88 % 93 % 50 77 % 95 % 99 % 100 % 100 % (A410U10-1) 21 Examiner only (b) The rate constant for the reaction in solution at 30 °C is 1.752 × 10−2 dm3 mol−1 s−1. (i) Give the overall order of the reaction. [1] (ii) Explain what information about the mechanism can be found from: • the overall order of reaction • the orders with respect to each reactant [3] (iii) State the Arrhenius equation. [1] (iv) The frequency factor for the reaction under these conditions is found to be 1.49 × 1011 dm3 mol−1 s−1. Use this value to calculate the activation energy of the reaction in kJ mol–1. [3] Activation energy = ..................................................... kJ mol–1 END OF PAPER © WJEC CBAC Ltd. 12 (A410U10-1) 22 Examiner only © WJEC CBAC Ltd. For continuation only. Examiner only (A410U10-1) 23 © WJEC CBAC Ltd.

12. (a) When ethene is passed into aqueous chlorine one of the products is 2-chloroethanol. (i) The presence of a C–Cl bond in this compound can be shown by a simple test tube reaction. Outline the practical steps that are used in this method. You can assume that 2-chloroethanol is soluble in water. [4] (ii) The oxidation of 2-chloroethanol (Mr 80.6) produces chloroethanoic acid together with a little chloroethanal. (A410U20-1) Turn over. 21 Examiner only © WJEC CBAC Ltd. C C OH Cl H H H H 5.80 g of chloroethanol were oxidised and the chloroethanoic acid in the resulting mixture reacted with 0.0600 mol of sodium hydroxide in a 1:1 stoichiometric ratio. Show that the percentage conversion to chloroethanoic acid was 83 %. [3] C O OH ClCH2 C H H OH ClCH2 Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl H 22 (A410U20-1) Examiner only © WJEC CBAC Ltd. (b) DDT is an effective insecticide but its use in recent years has become restricted because of its persistence in the environment. The DDT that is sold is a mixture of closely related compounds that includes DDT, DDE and DDD. (i) Suggest why DDT is largely insoluble in water. [1] (ii) Suggest suitable reagent(s) that can be used to convert DDE into DDD. [1] DDT DDE DDD (A410U20-1) Turn over. Examiner only © WJEC CBAC Ltd. 11.0 11.4 11.8 12.2 9 10 13 48 Relative abundance Retention time / minutes (iii) Many areas around former DDT manufacturing sites remain contaminated. The soil from one contaminated area was analysed by gas chromatography. Calibration of the chromatogram showed that the concentration of DDT in the sample (shown as the largest peak) was 0.018 mol kg−1. Calculate the total concentration of all the contaminants shown in the chromatogram in mol kg−1. [2] Total concentration = ...................................................................... mol kg−1 23 24 (A410U20-1) Examiner only (c) Over the last thirty years the production and use of CFCs has declined mainly because of their adverse environmental effects. Using fluorotrichloromethane as your example, outline how the compound causes a reduction in the amount of ozone present in the upper atmosphere and state two problems that can be caused by this reduction. [6 QER] © WJEC CBAC Ltd. C C Cl F F F F F State and explain what you would expect to see in the molecular ion region of its mass spectrum and in its 13C spectrum. [4] 21 (A410U20-1) Turn over. 25 © WJEC CBAC Ltd. (d) The formula of chloropentafluoroethane is shown below. Examiner only 26 (A410U20-1) Examiner only © WJEC CBAC Ltd. 13. (a) 2,3-Dihydroxypropanal (glyceraldehyde), HOCH2CH(OH)CHO, contains a chiral centre. (i) State what is meant by a chiral centre. [1] (ii) Draw the two mirror image forms of 2,3-dihydroxypropanal. [1] (b) Glucose, like 2,3-dihydroxypropanal, contains an aldehyde group. Fehling’s / Benedict’s solutions are used to show the presence of an aldehyde. Describe another simple test to show the presence of this group. You should include the reagent(s) used and any observations made. [2] (A410U20-1) Turn over. 27 Examiner only © WJEC CBAC Ltd. (c) Glucose occurs as two enantiomers. The concentration of an enantiomer can be found by using a polarimeter to measure the rotation of the plane of plane polarised light. In an experiment using an aqueous solution of D-glucose at a certain temperature, the initial rotation of the plane of plane polarised light was 20 ° using a cell of 1 dm length to hold the glucose solution. Use the formula below to calculate the concentration of glucose in the solution in g dm−3. [2] [αD] = r × v m where specific rotation at this temperature [αD] = 112 ° rotation of the plane of plane polarised light (r) = 20 ° volume of solution in 1 dm cell (v) = 15 cm3 m is the mass of glucose in 15 cm3 of solution Concentration = ...................................................................... g dm−3 (d) Butan-2-ol (Mr 74) can be dehydrated to but-1-ene and but-2-ene. CH3CH2CH(OH)CH3 CH3CH2CH=CH2 + CH3CH=CHCH3 around 30 % around 70 % (i) State a dehydrating agent for this reaction. [1] (ii) Both but-2-ene and penta-1,3-diene can exist as E-Z isomers. Explain why this type of isomerism occurs and give the displayed formula of E-penta-1,3-diene. [2] 28 (A410U20-1) © WJEC CBAC Ltd. (e) Compound R is a neutral saturated aliphatic compound that contains only carbon, hydrogen and oxygen. The percentage of oxygen by mass is 24.6. This compound is hydrolysed in acid solution to give two new organic compounds, S and T. Further information about R, S and T is given below. Compound R • The 13C NMR spectrum shows that there are five different carbon environments • The 1H NMR spectrum shows the following signals • The infrared absorption spectrum shows a peak at 1731 cm−1 but no peak at 2500–3550 cm−1 • It is not an aldehyde or a ketone Compound S • The 13C NMR spectrum shows that there are three different carbon environments • The 1H NMR spectrum shows the following signals Signal δ / ppm Relative peak area 1.20 singlet 9 1.25 triplet 3 4.11 quartet 2 Signal δ / ppm Relative peak area 1.20 singlet 9 around 11 1 • An aqueous solution is weakly acidic Compound T • The 13C NMR spectrum shows that there are two different carbon environments • The 1H NMR spectrum is shown below – relative peak areas 1, 2 and 3 δ / ppm 10 8 6 4 2 0 1 2 3 • The compound is neutral (A410U20-1) Turn over. 29 Examiner only © WJEC CBAC Ltd. Use this information to deduce the formulae of compounds S and T and hence the displayed formula of compound R. It is not necessary to name any of the compounds. [11] END OF PAPER 20 30 (A410U20-1) Examiner only © WJEC CBAC Ltd. For continuation only. Examiner only (A410U20-1) 31 © WJEC CBAC Ltd.

11440.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Thursday 26 April 2018. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before 26 April 2018. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while he/she is on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

11440.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger him/herself or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification need be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 11440.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Subsidiary Chemistry Practical Booklet A [SCH31] Tuesday 1 May 2018 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number © CCEA 2017 SYMBOLS OF SELECTED IONS SOLUBILITY IN COLD WATER OF COMMON SALTS, HYDROXIDES AND OXIDES Negative ions Soluble All sodium, potassium and ammonium salts All nitrates Most chlorides, bromides and iodides EXCEPT silver and lead chlorides, bromides and iodides Most sulfates EXCEPT lead and barium sulfates Calcium sulfate is slightly soluble Insoluble Most carbonates EXCEPT sodium, potassium and ammonium carbonates Most hydroxides EXCEPT sodium, potassium and ammonium hydroxides Most oxides EXCEPT sodium, potassium and calcium oxides which react with water Name Symbol Ammonium Chromium(III) Cr3+ Copper(II) Cu2+ Iron(II) Fe2+ Iron(III) Fe3+ Lead(II) Pb2+ Silver Ag+ Zinc Zn2+ Name Symbol Butanoate C3H7COO- Carbonate Dichromate Ethanoate CH3COO- Hydrogencarbonate Hydroxide OH– Methanoate HCOO– Nitrate NO Propanoate C2H5COO– Sulfate Sulfi te New Specifi cation Positive ions © CCEA 2017 For fi rst teaching from September 2017 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Science: Chemistry, Science: Double Award or Science: Single Award Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gcse examinations chemistry 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number THE PERIODIC TABLE OF ELEMENTS Group a bx * † 1 1 1 2 3 4 5 6 7 0 285 112 Copernicium (approx)

11589 12 Two standard electrode potentials are given below: (a) half-cell E  /V Zn2+(aq)  +  2e− ?  Zn -0.76 Cu2+(aq)  +  2e− ?  Cu +0.34 (i) Define standard electrode potential. [2] (ii) When the two half-cells are connected zinc will reduce Cu2+ ions to Cu atoms. Write the equation for the reaction. [2] (iii) Calculate the emf for this cell. [1] z 11589 [Turn over (b) Describe how you would set up a standard hydrogen electrode and use it to measure the electrode potential for a half-cell. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6]

11589 13 A method of synthesising aspirin is given below using the following steps: 1. Add 7.5 cm3 (an excess) of ethanoic anhydride to 3.0 g of salicylic acid in a conical flask 2. Add eight drops of concentrated phosphoric acid 3. Heat, with stirring, for 20 minutes in a water bath 4. Add 3 cm3 of deionised water to the flask 5. Add 30 cm3 of deionised water and cool to room temperature, allowing the aspirin to crystallise 6. Filter the crystals by Buchner filtration; continue to suck air through the Buchner funnel for five minutes after completion of the filtration (a) (i) Suggest two reasons why ethanoic anhydride is used in this reaction in preference to ethanoic acid. [2] (ii) Write the equation for the reaction in step 1. [2] 11589 [Turn over (iii) Why is concentrated phosphoric acid added? [1] (iv) Suggest why water is added in step 4. [1] (v) Explain why air is sucked through the apparatus for five minutes. [1] 11589 (vi) Describe, giving full experimental detail, the TLC method which can be used to determine whether the reaction is complete after step 3. The solvent is ethyl ethanoate. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] (b) Calculate the percentage yield if 2.3 g of aspirin is obtained (answer to one decimal place). [3] 11589 [Turn over (c) Salicylic acid is a bifunctional molecule with a carboxylic acid group and a hydroxyl group attached to the benzene ring. The hydroxyl group displays acidic behaviour. (i) Suggest why the hydroxyl group attached to a benzene ring is more acidic than the hydroxyl group in aliphatic alcohols. [2] (ii) Write an equation for the reaction of salicylic acid with excess aqueous sodium hydroxide. [2] (iii) State why it is preferable to use the sodium salt of aspirin. [1] (d) Bromine will give an electrophilic substitution reaction with salicylic acid as shown below: OH COOH OH COOH Br +  Br2  → +  HBr Salicylic acid will react with bromine without a catalyst being present. This differs from benzene, which requires a metal halide catalyst. Name a catalyst which is used in the bromination of benzene. [1]

11589 14 Mesalazine, an anti-inflammatory drug which is used to treat bowel disease, can be synthesised from 2-hydroxybenzoic acid using the flow scheme below. OH C HO O NO2 OH C HO O NH2 OH C HO O NH+ 3Cl− OH C HO O Step 2 Step 1 2-hydroxybenzoic acid mesalazine (a) (i) State the reagents that could be used for Step 1 and Step 2. Step 1: Step 2: [2] (ii) Mesalazine can be converted into azo dyes through reaction with naphth-1-ol or resorcinol: OH naphth-1-ol OH HO resorcinol Draw the structure of the ion mesalazine must be converted into before the azo dye can be formed. [2] 11589 [Turn over (iii) Draw the structure of the azo dye produced by the reaction with resorcinol. [2] (iv) Explain why azo dyes are coloured and suggest why the azo dyes produced by resorcinol and naphth-1-ol have slightly different colours. [4] (b) 2-hydroxybenzoic acid can be converted into an ester by reacting with an equimolar amount of ethane-1,2-diol. Write an equation for this reaction. [2] (c) Polyethylene terephthalate can be produced from ethane-1,2-diol. (i) State a use for polyethylene terephthalate. [1] (ii) Explain why polyethylene terephthalate is biodegradable. [1]

11589 15 An ester, with the molecular formula C7H14O2, produced three signals when analysed by proton nmr. The data is provided in the table below: signal a b c chemical shift 4.1 1.2 1.1 integration ratio 2 3 9 splitting pattern quartet triplet singlet (a) (i) Explain why solvents which contain hydrogen atoms should not be used in nmr spectroscopy. Suggest a suitable solvent which could be used. [2] (ii) Give the name and formula of the molecule used in nmr spectroscopy as a standard. [2] (iii) State two reasons why the molecule identified in part (ii) is used. [2] 11589 [Turn over (b) (i) Explain which alkyl group in the ester produces signals a and b making reference to the spin-spin splitting pattern and the integration ratios. [3] (ii) Draw the alkyl group that would give rise to signal c. [1] (c) Draw the possible structure of the ester based upon the nmr data given. [2]

11589 16 The bromate(V) ion, BrO− 3, is an oxidising agent produced by the reaction of bromine with a hot concentrated solution of sodium hydroxide. (a) (i) Write the ionic equation for the reaction of bromine with sodium hydroxide. [2] (ii) State the colour change observed for the above reaction. [1] (b) Acidified bromate(V) ions will oxidise iodide ions to iodine. (i) Write a half-equation for the reduction of bromate(V) ions to bromide. [1] (ii) Write a half-equation for the oxidation of iodide ions to iodine. [1] (iii) Write the overall equation for this reaction. [1] 11589 [Turn over (c) The iodine produced can then be reduced by thiosulfate ions. Titrations of the liberated iodine with sodium thiosulfate solution can be used to determine the concentration of bromate(V) ions. A 20.0 cm3 solution containing acidified bromate(V) ions was added to a solution containing excess iodide ions and the resulting mixture made up to 1.0 dm3. A 25.0 cm3 aliquot was titrated against 0.10 M sodium thiosulfate, adding starch indicator just before the end point. The titre was found to be 23.8 cm3. (i) Explain why it is necessary to add the starch indicator just before the end point. [1] (ii) Calculate, to two significant figures, the concentration of the original bromate(V) solution. [4]

11589 17 Aspartame is used as a sweetener in many food products. It is a methyl ester of the dipeptide produced in the condensation reaction between aspartic acid and phenylalanine. O C N H C O CH CH2 OCH3 CH CH2 C O HO H2N Aspartame (a) Use the structure of aspartame to suggest structures for aspartic acid and phenylalanine. aspartic acid phenylalanine [2] 11589 [Turn over (b) Another amino acid derivative that is used as a food additive is monosodium glutamate which can be synthesised from glutamic acid. O O NH2 HO ONa monosodium glutamate (i) Circle on the structure above any chiral centre present in monosodium glutamate. [1] (ii) Draw the structure of the zwitterion formed by glutamic acid. [1] (iii) Write an equation for the reaction of glutamic acid with sodium carbonate to form monosodium glutamate. [2]

11589 18 Cisplatin was first described by Peyrone in 1845 and was approved for use in the treatment of testicular and ovarian cancers in the USA in 1978. Pt Cl H3N cisplatin NH3 Cl (a) Explain why cisplatin is effective in acting as an anticancer drug. [1] (b) Cisplatin has a number of undesired side-effects which are believed to be caused by the drug activating before it reaches the targeted tumour. Attempts to reduce these side-effects have included modifying the structure to give derivatives such as carboplatin. Pt O O carboplatin H3N H3N O O Give the molecular formula of carboplatin. [1] 11589 (c) Another method of developing more targetable platinum-based anticancer drugs has been through the development of photoactivable drugs which are activated through photoreduction by light. Early examples of these were diiodo complexes. Pt I H3N B I H3N Pt I H3N A I OH OH H3N (i) Explain, using oxidation states, why converting A into B is regarded as a reduction. [2] (ii) Describe the change in both shape and co-ordination number in converting A into B. [4] THIS IS THE END OF THE QUESTION PAPER 237486 Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Chemistry Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations. gce A/AS examinations chemistry (advanced) 227 89 139 57 256 101 223 87 226 88 140 58 141 59 144 60 147 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 99 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 1 1 * 58–71 Lanthanum series † 90–103 Actinium series a = relative atomic mass (approx.) x = atomic symbol b = atomic number THE PERIODIC TABLE OF ELEMENTS Group a b x 0 VII VI V IV III II I * † One mole of any gas at 20 °C and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3. Planck Constant = 6.63 × 10–34 J s Gas Constant = 8.31 J mol–1 K–1 Avogadro Constant = 6.02 × 1023 mol–1

11177 6 Which of the following is a conjugate acid-base pair for the reaction? NH3  +  H2O  ?  NH4 +  +  OH− conjugate acid conjugate base A NH3 H2O B NH3 NH4 + C H2O NH4 + D H2O OH− 7 Which titration has no suitable indicator? A 0.1 mol dm−3 HCl with 0.1 mol dm−3 NH3 B 0.1 mol dm−3 HCl with 0.1 mol dm−3 NaOH C 0.1 mol dm−3 CH3COOH with 0.1 mol dm−3 NH3 D 0.1 mol dm−3 CH3COOH with 0.1 mol dm−3 NaOH 8 Which reaction can not be used to prepare carboxylic acids? A Hydrolysis of nitriles B Hydrolysis of acyl chlorides C Oxidation of aldehydes D Oxidation of ketones

11177 [Turn over 9 Which reaction has an increase in entropy? A N2(g)  +  3H2(g)  "  2NH3(g) B 4NH3(g)  +  5O2(g)  "  4NO(g)  +  6H2O(g) C 2NO(g)  +  O2(g)  "  2NO2(g) D 4NO2(g)  +  O2(g)  +  2H2O(g)  "  4HNO3(l) 10 Propanone reacts with iodine as follows: CH3COCH3(aq)  +  l2(aq)  "  CH3COCH2l(aq)  +  HI(aq) Which statement is correct? A The brown colour fades B The pH increases C The purple colour fades D This is not a redox reaction 11177 Section B Answer all six questions in this section 11 Barium chloride is formed from its elements as follows: Ba(s)  +  Cl2(g)  "  BaCl2(s)  -855 kJ mol-1 The following enthalpy changes can be used to calculate the lattice enthalpy of barium chloride: I Ba(s)  "  Ba(g) +175 kJ mol−1 II Ba(g)  "  Ba2+(g)  +  2e− +1500 kJ mol−1 III Cl2(g)  "  2Cl(g) +242 kJ mol−1 IV Cl(g)  +  e−  "  Cl−(g) −364 kJ mol−1 (a) What name is given to each of the enthalpy changes I–IV? I II III IV [4] (b) Explain what is meant by the term lattice enthalpy. [2] 11177 [Turn over (c) Calculate, to four significant figures, the lattice enthalpy of barium chloride. [2] (d) What name is given to the cycle used to calculate lattice enthalpy? [1] (e) Given Ba2+(g)  "  Ba2+(aq) −1309 kJ mol−1 Cl-(g)  "  Cl-(aq) −378 kJ mol−1 calculate, to an appropriate number of significant figures, the enthalpy of solution of barium chloride and use it to explain why barium chloride is soluble in water. [3]

11177 12 Malic acid is found in some apples, giving them a sour taste. COOH CHOH CH2 COOH malic acid (a) (i) Draw the structure of malic acid showing all the bonds present. [1] (ii) Suggest the IUPAC name for malic acid. [2] 11177 [Turn over (b) (i) Show the organic products for the reaction of malic acid with an excess of each of the following: PCI5, LiAlH4 and CH3CHOHCH3. COOH CHOH CH2 COOH PCl5 LiAlH4 (CH3)2CHOH [4] (ii) Name the organic product formed from the reaction with LiAlH4. [1] (c) Malic acid melts at 130 °C and has a solubility of 0.558 kg dm−3 at 20 °C. (i) Explain why malic acid has a relatively high melting point. [2] (ii) Calculate, to three significant figures, the molarity of a saturated solution of malic acid at 20 °C. [2] 11177 (d) Malic acid is produced industrially by the double hydration of maleic anhydride. Although malic acid contains an asymmetric centre, the product of this reaction is not optically active. COOH CHOH CH2 COOH O C CH O CH C O +  2H2O maleic anhydride (i) Explain what is meant by the term optically active. [2] (ii) On the above diagram circle the asymmetric centre on the malic acid. [1] (iii) What name is given to this type of optically inactive product? [1] (iv) Explain why the product in this reaction is not optically active. [1] BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) 11177 [Turn over

11177 13 Ethyl ethanoate is hydrolysed in alkaline conditions as follows: CH3COOC2H5  +  OH−  "  CH3COO−  +  C2H5OH (a) Explain, giving experimental details, how you would follow the rate of this reaction with respect to hydroxide ions using pH and how you would use your results to find the order of the reaction with respect to hydroxide ions. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] (b) The following results were obtained for the reaction. [CH3COOC2H5] /mol dm−3 [OH−] /mol dm−3 initial rate of the reaction /mol dm−3 s−1 0.152 0.038 1.13 × 10−2 0.038 0.076 5.65 × 10−3 0.019 0.152 5.65 × 10−3 11177 [Turn over (i) Deduce the rate equation for the reaction. [2] (ii) Calculate, to three significant figures, the value of the rate constant and state its units. [2] (iii) State and explain the effect of increasing the temperature on the value of the rate constant. [2] (c) Ethanoic acid reacts with butan-1-ol to form the ester butyl ethanoate as follows: CH3COOH(l)  +  C4H9OH(l) ?  CH3COOC4H9(l)  +  H2O(l)  −39.8 kJ mol−1 (i) What mass of butan-1-ol is required to produce 58 g of butyl ethanoate when reacted with 45 g of ethanoic acid in 50 cm3 of water? Give your answer to two significant figures. (Kc = 3.0 at 20 °C; the density of water is 1 g cm−3) [4] 11177 (ii) Suggest and explain the effect of increasing the temperature to 40 °C on the position of the equilibrium. [2] (iii) Explain why the equilibrium constant has no units. [1] (d) The ester tallow is an animal fat which is formed from two molecules of stearic acid, CH3(CH2)16COOH, and one molecule of oleic acid, CH3(CH2)7CHCH(CH2)7COOH. (i) Tallow exists as two isomers. Draw the structure of one isomer of tallow. [2] 11177 [Turn over (ii) Tallow can undergo transesterification. Explain what is meant by the term transesterification. [2] (iii) State two uses of transesterification reactions. [2]

11177 14 The buttery flavour of butterscotch is due to the presence of diacetyl, CH3COCOCH3. (a) Suggest the IUPAC name for diacetyl. [1] (b) Diacetyl can be made from the corresponding alcohol. (i) Write an equation for the reaction, using [O] to represent the oxidising agent. [2] (ii) State the reagent and the condition required for this reaction. [2] 11177 [Turn over (iii) Diacetyl is a liquid at room temperature with a melting point of −3 °C and a boiling point of 88 °C. The diacetyl obtained in this reaction contains water. Explain how you would use fractional distillation to purify the diacetyl. Describe how you would dry the diacetyl. State how you would use infrared spectroscopy to confirm the diacetyl is pure. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] 11177 (c) Diacetyl may react with one or two molecules of 2,4-dinitrophenylhydrazine. (i) Write the equation for the reaction of diacetyl with one molecule of 2,4-dinitrophenylhydrazine. [2] (ii) Describe the appearance of the product. [1] (iii) Explain why the melting point of the product formed with one molecule of 2,4-dinitrophenylhydrazine would differ from that formed from the reaction with two molecules of 2,4-dinitrophenylhydrazine. [2] BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) 11177 [Turn over

11177 15 Phenylethanone, C6H5COCH3, used in making resins and pharmaceuticals can be made by reacting benzene with ethanoyl chloride. (a) The reaction is described as electrophilic substitution. (i) Explain what is meant by the term electrophile. [2] (ii) Explain why the reaction is described as a substitution. [1] (b) (i) Write the equation for the formation of ethanoyl chloride from ethanoic acid. [1] (ii) Why is this reaction carried out under anhydrous conditions? [1] 11177 [Turn over (c) (i) Write an equation for the formation of the electrophile when benzene reacts with ethanoyl chloride using a catalyst. [1] (ii) Draw the mechanism for the catalysed reaction using curly arrows. [4]

11177 16 Ammonium perchlorate, NH4ClO4, is used in solid rocket fuels. It can be formed by reacting ammonia with the strong acid perchloric acid as follows: NH3  +  HClO4  "  NH4ClO4 (a) (i) What is the oxidation number of chlorine in ammonium perchlorate? [1] (ii) Explain whether a solution of ammonium perchlorate is acidic, alkaline or neutral. [2] (b) Ammonium perchlorate decomposes, when heated, to produce a mixture of hydrogen chloride, nitrogen, oxygen and water. (i) Write the equation for the thermal decomposition of ammonium perchlorate. [2] (ii) Calculate, to two significant figures, the volume of gas produced by the complete decomposition of 11.75 g of ammonium perchlorate at 250 °C and one atmosphere pressure. (1 mole of a gas occupies 42 dm3 at 250 °C and one atmosphere pressure) [3] 11177 [Turn over (c) Ammonia solution can be used to make buffers by adding ammonium chloride. (i) Explain what is meant by the term buffer solution. [2] (ii) Explain, including equations, how a mixture of ammonia and ammonium chloride solutions acts as a buffer. [4] 11177 (d) Ammonia is produced by the Haber process as follows: N2(g)  +  3H2(g)  ?  2NH3(g) The table below gives the ∆fH and S values for the reactants and products. ∆fH /kJ mol−1 S /J mol−1 K−1 N2 0 192 H2 0 131 NH3 −46.2 193 (i) Calculate, to three significant figures, ∆S for the reaction. [1] (ii) Calculate, to three significant figures, ∆G for the reaction at 298 K. [2] (iii) At what temperature does the reaction become feasible? Give your answer to three significant figures. [2] (iv) State one factor which may prevent the reaction from occurring at the temperature calculated in part (iii). [1] THIS IS THE END OF THE QUESTION PAPER 11177 BLANK PAGE DO NOT WRITE ON THIS PAGE 11177 11177 BLANK PAGE DO NOT WRITE ON THIS PAGE 230406 Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE © CCEA 2017 SYMBOLS OF SELECTED IONS SOLUBILITY IN COLD WATER OF COMMON SALTS, HYDROXIDES AND OXIDES Negative ions Soluble All sodium, potassium and ammonium salts All nitrates Most chlorides, bromides and iodides EXCEPT silver and lead chlorides, bromides and iodides Most sulfates EXCEPT lead and barium sulfates Calcium sulfate is slightly soluble Insoluble Most carbonates EXCEPT sodium, potassium and ammonium carbonates Most hydroxides EXCEPT sodium, potassium and ammonium hydroxides Most oxides EXCEPT sodium, potassium and calcium oxides which react with water Name Symbol Ammonium Chromium(III) Cr3+ Copper(II) Cu2+ Iron(II) Fe2+ Iron(III) Fe3+ Lead(II) Pb2+ Silver Ag+ Zinc Zn2+ Name Symbol Butanoate C3H7COO- Carbonate Dichromate Ethanoate CH3COO- Hydrogencarbonate Hydroxide OH– Methanoate HCOO– Nitrate NO Propanoate C2H5COO– Sulfate Sulfi te New Specifi cation Positive ions © CCEA 2017 For fi rst teaching from September 2017 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Science: Chemistry, Science: Double Award or Science: Single Award Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gcse examinations chemistry 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number THE PERIODIC TABLE OF ELEMENTS Group a bx * † 1 1 1 2 3 4 5 6 7 0 285 112 Copernicium (approx)

11282 12 Ammonium dichromate is used in the “volcano” experiment. When heated, it decomposes to produce a vast amount of green chromium oxide and gases which push out the green “ash” to form a pile of “lava”. (NH4)2Cr2O7 → Cr2O3 + N2 + 4H2O The water forms steam because of the heat of the reaction. (a) Write the equation for the reaction, with state symbols, for the reactants and products. [1] (b) Ammonium dichromate is very soluble in water. At room temperature 10.0 g of ammonium dichromate dissolve in 25.0 cm3 of water. The orange solution can be tested for the presence of ammonium ions. (i) Calculate the solubility of the ammonium dichromate in g dm−3 to 3 significant figures. [1] (ii) Calculate the solubility of the ammonium dichromate in mol dm−3 to 3 significant figures. [1] (iii) Explain how you would show that the orange solution contains ammonium ions. [3] 11282 [Turn over (c) The nitrogen given off in the reaction consists of two isotopes, nitrogen-14 and nitrogen-15. The percentage abundance of nitrogen-14 is 99.632%. (i) Explain what is meant by the term isotopes. [2] (ii) Calculate the percentage abundance of nitrogen-15 given off. [1] (iii) Calculate the relative atomic mass of nitrogen to three decimal places. [2] (iv) Explain why there is a difference between the calculated relative atomic mass and the one provided in the data sheet. [1] . 11282 (d) The dichromate ion is a very strong oxidising agent. The half-equation which shows its oxidising ability is: Cr2O7 2− + 14H+ + 6e− → 2Cr3+ + 7H2O (i) Use this equation to explain, in terms of oxidation numbers, why the dichromate ion is an oxidising agent. [2] (ii) Use this equation to explain, in terms of electrons, why the dichromate ion is an oxidising agent. [1] (e) Dichromates react with chlorides in the presence of concentrated sulfuric acid to produce chromyl chloride, CrO2Cl2, which is a deep red liquid with a boiling point of 117 °C. Using this information, explain whether chromyl chloride is ionic or covalent. [2] 11282 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

11282 13 (a) There are several types of structure which apply to chemical formulae. The species present may be atoms, molecules or ions. In each of the following examples describe which type of structure it is and which type of species is present. sodium chloride diamond bromine In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] (b) The different types of structure have different physical properties. State four physical properties that depend upon structure. [3] 11282 [Turn over (c) The structure of sodium is shown below. + + + + + + + + + (i) Attach words to the labels shown. [2] (ii) Use this diagram to explain whether magnesium has a greater or lower conductivity than sodium. [2] (iii) Explain, using a labelled diagram, how you could compare the electrical conductivities of sodium and magnesium in the laboratory. [3]

11282 14 Ethene is a gas at room temperature and has a boiling point of −104 °C at atmospheric pressure. It has a relative molecular mass of 28 which is approximately the same as the average relative molecular mass of air. It is a planar molecule which has the following structure: H        H C C H        H (a) The ethene molecule contains single bonds and a double bond which are formed from s- and p-orbitals. (i) Draw the shape of an s-orbital. [1] (ii) Draw the shape of a p-orbital. [1] (iii) Explain what is meant by the term orbital. [2] 11282 [Turn over (b) Ethene is a non-polar molecule. There are two reasons why ethene can be considered to be non-polar. One is based on electronegativity and the other is based on shape. (i) What is meant by the term electronegativity? [2] (ii) Explain why ethene is considered non-polar based on electronegativity. [1] (iii) Explain why ethene is considered non-polar based on shape. [1] (c) Ethene contains a double bond. Other molecules can contain triple bonds. (i) Draw the structure of the hydrocarbon ethyne which contains two carbon atoms and a triple bond. [1] (ii) Name an element which contains a triple bond. [1] 11282 (d) When ethene burns, carbon dioxide and water are produced. Describe how you would carry out a test for carbon dioxide and the result expected for a positive test. [2] (e) Gases can be collected by two different methods A or B depending on their relative molecular masses compared to air. gas lighter than air gas heavier than air A B (i) Explain which method could be used to collect methane, CH4. [1] (ii) Explain which method could be used to collect chlorine. [1] 11282 (f) The boiling point of methane is −161 °C. Explain why the boiling point of methane is lower than that of ethene. [2] THIS IS THE END OF THE QUESTION PAPER Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 230321 DO NOT WRITE ON THIS PAGE For Examiner’s use only Question Number Marks Section A 1–10 Section B 11 12 13 14 Total Marks Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

11382 12 Calcium is present in teeth in the form of calcium phosphate. This salt does not react with water although the element calcium does react forming a gas. (a) Write the formula of calcium phosphate. [1] (b) (i) Write an equation for the reaction of calcium with water. [2] (ii) Explain why, using the same mass of strontium in place of calcium, the volume of gas produced when strontium reacts with water is less under the same conditions. [1] (iii) Suggest another difference that would be observed in the reaction with water when strontium is used in place of calcium. Explain your answer. [2] (c) The Group II metal oxides can be formed from the metal hydroxides. (i) How would you convert calcium hydroxide to calcium oxide? [1] (ii) State and explain the trend in thermal stability of the Group II hydroxides as the Group is descended. [3] 11382 [Turn over (d) What chemical property of magnesium oxide makes it suitable for indigestion remedies? [1] (e) Magnesium sulfate is an important compound in horticulture. Industrially, the sulfates of magnesium and calcium are produced by reacting dolomite rock with excess sulfuric acid. MgCO3.CaCO3  +  2H2SO4  →  MgSO4  +  CaSO4  +  2H2O  +  2CO2 (i) Other than a temperature change, suggest two observations during this reaction. [2] (ii) Compare the solubility of magnesium sulfate with calcium sulfate in water. [1] (iii) The solubility of magnesium sulfate at two temperatures is given in the table below. In a batch process, a saturated solution of magnesium sulfate at 70 °C contained 100 tonnes of water. Use the table to calculate the mass of solid magnesium sulfate obtained when this solution is cooled to 20 °C. temperature / °C solubility / g per 100 g of water 20 35.1 70 59.2 [2] 11382 (f) 2.50 g of hydrated magnesium sulfate crystals (MgSO4.xH2O) were heated to constant mass. The anhydrous solid has a mass of 1.22 g. Calculate the value of x and hence deduce the formula for the hydrated salt. [3] 11382 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

11382 13 Propene is an important building block for a large number of chemicals. At low temperatures, propene will react with chlorine in an electrophilic addition reaction. (a) (i) Explain the term electrophile. [2] (ii) Draw a flow scheme to show the mechanism for the reaction between propene and chlorine using curly arrows. [4] (b) At 500 °C in the presence of ultraviolet light, propene will react with chlorine in a similar way to the reaction of propane with chlorine radicals. The product formed is allyl chloride (CH2=CHCH2Cl). Outline the mechanism of the reaction between propene and chlorine giving equations for the initiation, propagation and termination steps. Initiation equation Propagation equations Termination equation [4] 11382 [Turn over (c) (i) Two reactions of allyl chloride are shown. Fill in the structures of Compounds A, B and C. More of compound B is formed than compound C. H H C=C H CH2Cl Compound A Compound C H2/Ni Reaction 1 Reaction 2 HCl Compound B + [3] (ii) Explain why compounds B and C are not formed in equal amounts. [2] (iii) Compound B reacts slowly in humid conditions to form compound D which contains the following percentage masses: C, 40.0%; H, 7.0%; O, 53.0%. The relative formula mass of the compound is 90. Deduce the molecular formula of compound D. [3] 11382 (d) Allyl chloride will undergo an hydrolysis reaction with aqueous sodium hydroxide similar to halogenoalkanes. (i) Draw the structural formula of the organic product formed in this reaction. Show all the bonds present. [2] (ii) Name the inorganic product formed during this hydrolysis reaction. [1] (e) Allyl chloride has a structural isomer which exists as geometrical isomers. Draw and label these geometrical isomers. [3] 11382 [Turn over (f) Allyl chloride is highly flammable. When it burns, one of the products formed is a corrosive gas. (i) Define the term molar gas volume. [1] (ii) 1.50 g of this corrosive gas occupies a volume of 0.986 dm3 at 293 K and 1 atmosphere pressure. Use this information to calculate the relative molecular mass of the gas and suggest its identity. [3]

11382 14 Two million tonnes of ethanol are produced each year by the direct hydration of ethene using a phosphoric acid catalyst at 300 °C and 6000 kPa. C2H4(g)  +  H2O(g)  ?  C2H5OH(g)  −45 kJ mol−1 (a) (i) Describe how a catalyst increases the rate of a reaction. [2] (ii) State and explain the general conditions of temperature and pressure required to give a high yield of ethanol. Explain how a compromise between equilibrium yield and the reaction rate may influence the conditions of temperature and pressure used. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 11382 (b) Ethanol is a liquid at room temperature. It is increasingly used as a fuel. (i) Give the equation, including state symbols, for the standard molar enthalpy of formation of ethanol. [2] (ii) Suggest why this standard enthalpy change cannot be measured directly. [1] (iii) Using the enthalpy changes below, calculate the enthalpy change of formation of gaseous ethanol. C2H4(g) + H2O(g) → C2H5OH(g) −45.0 kJ mol−1 2C(s) + 2H2(g) → C2H4(g) +52.3 kJ mol−1 H2(g) + 1 2O2(g) → H2O(g) −242.0 kJ mol−1 [3] (c) (i) Give the equation for the standard enthalpy of combustion of ethanol. [2] (ii) Using bond enthalpies explain why enthalpy changes of combustion are negative. [2] Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 233793 DO NOT WRITE ON THIS PAGE For Examiner’s use only Question Number Marks Section A 1–10 Section B 11 12 13 14 Total Marks THIS IS THE END OF THE QUESTION PAPER Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

page 02 SECTION 1 — 30 marks Attempt ALL questions 1. Which of the following is not a form of electromagnetic radiation? A Beta B Gamma C Infrared D Ultraviolet 2. The diagram represents the periodic table. The shaded area is the A s-block B p-block C d-block D f-block.

page 03 3. A representation of a d-orbital is shown. x y z The maximum number of electrons that can occupy this orbital is A 2 B 4 C 8 D 10. 4. For the reaction BF3 + F− ↓ BF4 − the three-dimensional arrangement of the bonds around the B atom changes from A trigonal pyramidal to square planar B trigonal pyramidal to tetrahedral C trigonal planar to square planar D trigonal planar to tetrahedral. [Turn over

page 04 5. Which of the following correctly shows the arrangement of the 3d electrons in the Ni2+ ion in [Ni(H2O)6]2+? D C B Energy Energy Energy Energy A

page 05 6. Manganese has an oxidation number of +5 in A MnO4 - B MnO4 2- C MnO4 3- D MnO2 7. When sulfur dioxide and oxygen react the following equilibrium is established. 2SO2(g) + O2(g) Ý 2SO3(g) ∆H = -197 kJ mol-1 Which line in the table is correct if the temperature of the equilibrium mixture is increased? Equilibrium constant, K Concentration of SO3 as temperature increases A decreases decreases B decreases increases C increases decreases D increases increases 8. H2CO3(aq) + CN-(aq) Ý HCN(aq) + HCO3 -(aq) Which line in the table correctly describes H2CO3(aq) and HCN(aq) in the above reaction? H2CO3(aq) HCN(aq) A base conjugate base B base conjugate acid C acid conjugate base D acid conjugate acid [Turn over

page 06 9. What is the concentration of hydroxide ions, in mol l-1, in a solution with a pH of 8·5? A 8·5 × 10-6 B 3·2 × 10-6 C 8·5 × 10-9 D 3·2 × 10-9 10. Butanoic acid is a weak acid which dissociates as shown. C3H7COOH(aq) + H2O(ℓ) Ý C3H7COO-(aq) + H3O+(aq) The equilibrium position can be shifted to the right by the addition of A a catalyst B sulfuric acid C sodium hydroxide D sodium butanoate. 11. Which of the following salts forms an alkaline solution in water? A Sodium sulfate B Lithium chloride C Ammonium nitrate D Potassium propanoate 12. Which of the following combinations would produce a buffer solution? A Sodium chloride and ammonia B Ammonium chloride and ammonia C Sodium chloride and sodium hydroxide D Ammonium chloride and sodium hydroxide

page 07 13. For which of the following reactions would the value of ∆G° - ∆H° be closest to zero? A CaCO3(s) ↓ CaO(s) + CO2(g) B C(s) + H2O(g) ↓ CO(g) + H2(g) C Zn(s) + 2H+(aq) ↓ Zn2+(aq) + H2(g) D Cu2+(aq) + Mg(s) ↓ Mg2+(aq) + Cu(s) 14. The following reaction is first order with respect to P and second order with respect to Q. P + Q ↓ R + S Which of the following statements is not correct? A The reaction is third order overall. B The reaction occurs by a simple one step mechanism. C The rate of the reaction decreases as the reaction proceeds. D The rate of the reaction will double if the initial concentration of P is doubled. 15. H C C H C C H H H H Which of the following types of hybridisation occur in the above compound? A sp3 only B sp3 and sp C sp3 and sp2 D sp3, sp2 and sp [Turn over

page 08 16. Benzofuran is an important starting material in the manufacture of some medicines. O benzofuran The gram formula mass of benzofuran is A 124 g B 120 g C 118 g D 114 g. 17. The diagram represents one enantiomer of an optically active compound where W, X, Y and Z are four different groups. C W X Z Y Which of the following represents the other enantiomer of this compound? C W Z X Y C W Z X Y C W Y X Z C W X Y Z A B C D

page 09 18. The most appropriate reactants for the synthesis of CH3CH2CH2CH2O- Na+ are A sodium and butan-1-ol B sodium and butanoic acid C sodium hydroxide and butan-1-ol D sodium hydroxide and butanoic acid. 19. H C C OH H H O H C C N H H The above reaction is an example of A hydration B oxidation C hydrolysis D hydrogenation. 20. 18 g of an oxide of copper contains 16 g of copper. The empirical formula of this oxide is A Cu4O B Cu2O C CuO2 D CuO4. [Turn over

page 10 21. A simplified mass spectrum of an organic compound is shown below. 15 59 74 m/z Intensity Which of the following compounds could not have produced this spectrum? A CH3OCOCH3 B CH3CH2COOH C CH3CH2CH2CH2NH2 D CH3CH(OH)CH2CH3 22. OCH3 OH CH2CH = CH2 eugenol The infrared spectrum of eugenol would not be predicted to have an absorption in the wavenumber range A 3100 - 3000 cm-1 B 2962 - 2853 cm-1 C 1730 - 1717 cm-1 D 1150 - 1070 cm-1.

page 11 23. Salbutamol is used to treat asthma. It behaves like the body’s natural active compound by triggering a response in the muscles of the airways. Salbutamol is A an agonist B an antagonist C an inhibitor D a receptor. 24. 200 cm3 of water is added to 50 cm3 of 2 mol l-1 sodium hydroxide solution. The concentration of the diluted sodium hydroxide solution in mol l-1, is A 0·5 B 0·4 C 0·2 D 0·1. 25. For solvent extraction from an aqueous solution, the solvent used should be immiscible with water and relatively unreactive. Which of the following would be the most suitable solvent? A CH3CH2CH2CH2CHO B CH3CH2OCH2CH2CH3 C CH3CH2CH2CH2COOH D CH3CH(OH)CH2CH2CH3 26. Which of the following is not a step in a recrystallisation technique? A Allow the filtrate to cool slowly. B Filter the hot solution to remove insoluble impurities. C Dissolve the crystals in a minimum of hot solvent. D Test the filtrate to ensure no more precipitate forms. [Turn over

page 12 27. The melting point of an impure substance was determined to be 111 °C – 114 °C. After purification, the melting point should be A higher and over a wider range B higher and over a narrower range C lower and over a wider range D lower and over a narrower range. 28. During the technique of heating to constant mass, the purpose of the desiccator is to A prevent reaction with oxygen in the air B remove water from the compound C prevent reabsorption of water D prevent decomposition. 29. Using thin-layer chromatography, the components of a sample can be identified by Rf values. Which of the following affects the Rf value for an individual component? A The distance moved by the solvent. B The concentration of the sample. C The length of TLC plate. D The solvent used.

page 13 30. Which of the following diagrams shows the apparatus correctly set up for heating under reflux? water in A water out water in C water out heating mantle heating mantle heating mantle heating mantle water in D water out water in B water out [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET] page 14 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 15 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 16 [BLANK PAGE] DO NOT WRITE ON THIS PAGE AH FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2018 You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Total marks — 100 SECTION 1 — 30 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on page 02. SECTION 2 — 70 marks Attempt ALL questions. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/77/01 MONDAY, 21 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer Grid and Section 2 page 02 SECTION 1 — 30 marks The questions for Section 1 are contained in the question paper X713/77/02. Read these and record your answers on the answer grid on page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 A B C D 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SECTION 1 — Answer Grid [Turn over page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 05 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 70 marks Attempt ALL questions 1. Roman pottery contains traces of metals. (a) The metals present in Roman pottery can be identified using atomic emission spectroscopy. Analysis of a sample from a Roman pot produced a series of spectral lines. The data in the table shows the results for three of the spectral lines produced. Metal Wavelength of spectral line (nm) Relative intensity aluminium 620 651 589 485 titanium 498 375 (i) Name the metal that produces the orange-yellow spectral line at 589 nm. (ii) A fourth line observed in the spectrum obtained from the Roman pot sample was caused by a transition with an energy value of 282 kJ mol-1. Calculate the wavelength, in nm, of this spectral line. (iii) The Roman pot sample was found to have a titanium content of 435 mg kg-1. A different pot sample produced a spectral line at 498 nm with a relative intensity of 75. Calculate the titanium content, in mg kg-1, for this sample. 1 2 1 [Turn over page 06 MARKS DO NOT WRITE IN THIS MARGIN 1. (continued) (b) The Romans may have inadvertently made aluminium metal while producing pottery. Aluminium has the following electronic configuration. 1s2 2s2 2p6 3s2 3p1 (i) This electronic configuration is consistent with the aufbau principle. State the aufbau principle. (ii) For the 3p electron in aluminium, complete the table to show one possible set of values for the four quantum numbers. Quantum number n l m s Value 1 1 page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. Apple jam contains malic acid. HO C C CH2 CH OH O O OH malic acid (a) Malic acid dissociates in two stages. The equation for the first stage dissociation of malic acid is HOOCCH2CH(OH)COOH(aq) + H2O(ℓ) Ý HOOCCH2CH(OH)COO−(aq) + H3O+(aq) (i) Write an expression for the first stage dissociation constant, Ka, for malic acid. (ii) Complete the equation to show the second stage dissociation of malic acid. HOOCCH2CH(OH)COO−(aq) + H2O(ℓ) Ý 1 1 [Turn over page 08 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (b) While making apple jam, the jam will only thicken if the pH is between 2·7 and 3·3. (i) The pH of the apple jam is determined by the first stage dissociation of malic acid (Ka = 3·2 × 10-4). The concentration of malic acid in the jam is 0·0051 mol l-1. Show by calculation that the jam will thicken at this concentration of malic acid. 3 page 09 MARKS DO NOT WRITE IN THIS MARGIN 2. (b) (continued) (ii) Pectin is a natural polymer found in apples which helps jam to thicken. Part of the structure of pectin is shown. O O CO2H HO OH O O OH HO O O HO CO2CH3 CO2CH3 OH O Pectin binds to itself to help the jam thicken. Suggest how the hydroxyl groups allow pectin molecules to bind. 1 [Turn over page 10 MARKS DO NOT WRITE IN THIS MARGIN 3. Sodium carbonate can exist as different hydrated salts with the general formula Na2CO3.nH2O. To determine n in the general formula, a 250 cm3 solution containing 8·10 g of hydrated sodium carbonate was prepared. 25·0 cm3 samples of this solution were titrated with 0·358 mol l-1 hydrochloric acid. Na2CO3(aq) + 2HCl(aq) ↓ 2NaCl(aq) + H2O(ℓ) + CO2(g) The following results were obtained. Titre Volume of HCl added (cm3) 1 20·2 2 19·5 3 19·4 (a) Describe the procedure for the accurate preparation of the 250 cm3 solution from the weighed sample of hydrated sodium carbonate. 2 page 11 MARKS DO NOT WRITE IN THIS MARGIN 3. (continued) (b) (i) Calculate the number of moles of sodium carbonate in the 250 cm3 solution. (ii) Calculate the value of n in the formula Na2CO3.nH2O 2 2 [Turn over page 12 MARKS DO NOT WRITE IN THIS MARGIN 3. (continued) (c) Titration is a very useful analytical technique for volumetric analysis. Using your knowledge of chemistry, discuss factors which should be considered when selecting appropriate chemicals for a titration. 3 page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. But-2-yne and but-1-yne can undergo addition reactions with hydrogen using a palladium-based catalyst. H3C C C CH3 CH2CH3 H C C but-1-yne but-2-yne (a) State how transition metals can act as catalysts. (b) In the reaction of but-2-yne with hydrogen, cis-but-2-ene is formed. Draw the skeletal structure of cis-but-2-ene. (c) In the reaction of but-1-yne with hydrogen, but-1-ene is formed. Explain why but-1-ene has no geometric isomers. 1 1 1 [Turn over page 14 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (d) The equation for the hydrogenation of but-2-yne is shown. C4H6(ℓ) + H2(g) ↓ C4H8(g) Substance Standard free energy of formation, ∆G°f (kJ mol-1) Standard enthalpy of formation, ∆H°f (kJ mol-1) C4H6(ℓ) 185 119 H2(g) 0 0 C4H8(g) 65·9 -6·99 (i) For the hydrogenation of but-2-yne, use the data in the table to calculate: (A) the standard enthalpy change, ∆H°, in kJ mol-1; (B) the standard entropy change, ∆S°. 1 3 page 15 MARKS DO NOT WRITE IN THIS MARGIN 4. (d) (continued) (ii) Calculate the temperature, in K, below which this reaction is feasible. 2 [Turn over page 16 MARKS DO NOT WRITE IN THIS MARGIN 5. Some dyes contain molecules that are coloured. The structures of two different dye molecules are shown below. S S N N + S N + N S blue-green purple (a) State the structural feature present that is responsible for the colour of these dye molecules. (b) Explain fully how colour arises in these dye molecules. 1 2 page 17 MARKS DO NOT WRITE IN THIS MARGIN 5. (continued) (c) A third dye molecule has the following structure. N + N S S Explain fully why this dye molecule will absorb a shorter wavelength of light than the other two dye molecules. 2 [Turn over page 18 MARKS DO NOT WRITE IN THIS MARGIN 6. Ligands can be used in medicine and in quantitative analysis. (a) Explain how ligands bond to metal ions to form complexes. (b) DMPS is a ligand that can be used to treat mercury poisoning. DMPS SH SH S HO O O (i) Write the molecular formula for DMPS. 1 1 page 19 MARKS DO NOT WRITE IN THIS MARGIN 6. (b) (continued) (ii) A possible structure for the mercury-DMPS complex is S Hg S S S S OH S HO O O O O (A) State the term used to classify the DMPS ligand in this complex. (B) State the co-ordination number of mercury in this complex. 1 1 [Turn over page 20 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (c) Nisil is an alloy of nickel and silicon. The mass of nickel in the Nisil alloy can be determined by quantitative analysis using a procedure in which the ligand dimethylglyoxime forms a solid complex with nickel ions. This complex is collected, dried and weighed. C C N Ni N N C C N CH3 CH3 H3C H3C O O H O O H nickel-dimethylglyoxime complex GFM 288·7 g (i) Name the type of quantitative analysis being carried out. (ii) It was found that 1∙02 g of Nisil alloy formed 4∙82 g of the complex. Calculate the percentage by mass of nickel in the alloy. 1 2 page 21 [Turn over for next question DO NOT WRITE ON THIS PAGE page 22 MARKS DO NOT WRITE IN THIS MARGIN 7. Adrenaline is a natural hormone produced in the body. HO HO N OH H adrenaline (a) Adrenaline can be artificially synthesised in the process shown below. HO X HO N OH H N O H O HO HO Cl O Cl Cl + O Cl O H HO HO N + CH3NH2 HO HO HO HO HO HO Step 1 Step 2 Step 3 page 23 MARKS DO NOT WRITE IN THIS MARGIN 7. (a) (continued) (i) Suggest the type of chemical reaction taking place in step 1. (ii) The aromatic product formed in step 2 contains an amine functional group. State the type of amine formed. (iii) Name reagent X used in step 3. (iv) Identify the step(s) in which the product has a carbon chiral centre. 1 1 1 1 [Turn over page 24 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (b) Adrenaline is used as a treatment for severe allergic reactions. A typical dose contains 0·3 cm3 of 500 ppm adrenaline solution. Calculate the mass of adrenaline, in mg, delivered in one dose. (c) Adrenaline can be extracted from the leaves of the agnimantha plant. The adrenaline extracted can be identified using thin layer chromatography, TLC. Complete and label the diagram to show how the TLC should be set up to compare the extracted adrenaline with a sample of pure adrenaline. (An additional diagram, if required, can be found on page 36). solvent TLC plate chromatography tank 1 1 page 25 [Turn over for next question DO NOT WRITE ON THIS PAGE page 26 MARKS DO NOT WRITE IN THIS MARGIN 8. Ethanol biofuel can be made from corn starch. The flow diagram shows the steps involved in the production of ethanol biofuel. pure ethanol biofuel 96% ethanol solution 13% ethanol solution Step 3 Pass through a molecular sieve Step 2 Distillation Step 1 Hydrolysis and fermentation corn starch in water (a) Step 1 produces a solution with a concentration of 13% ethanol by volume. This can be checked by measuring the density of the solution and comparing it to a calculated value. The density of the solution can be calculated using the following expression. 1 2 100 m m d + = d = density of solution, in g cm-3 m1 = mass of ethanol, in g, in 100 cm3 of solution m2 = mass of water, in g, in 100 cm3 of solution Mass of 1 cm3 of ethanol = 0·79 g Mass of 1 cm3 of water = 1·00 g Calculate the density of the ethanol solution, in g cm-3, formed in step 1. 2 page 27 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (b) In step 2, 96% ethanol solution is produced by distillation. Suggest why pure ethanol biofuel cannot be obtained from an ethanol/water mixture by distillation alone. (c) Step 3 uses a molecular sieve to remove water from the 96% ethanol solution. Part of the structure of a molecular sieve is shown. 0·3 nm Suggest how this molecular sieve could remove the water. 1 1 [Turn over page 28 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (d) Ethanol can also be prepared by a nucleophilic substitution reaction. Using your knowledge of chemistry, discuss the role of nucleophilic substitution reactions in the preparation of other chemicals. 3 page 29 [Turn over for next question DO NOT WRITE ON THIS PAGE page 30 MARKS DO NOT WRITE IN THIS MARGIN 9. A mixture of butan-1-ol and butan-2-ol can be synthesised from 1-bromobutane in a two-stage process. H C H H C H H C H H C Br H H H H H C H H C H H C C H H ethanolic KOH stage 1 H C H H C H H C C H H H2O/H+ stage 2 H C H H C H H C H H C OH H H H C H H C H H C OH H C H H H + (a) Name the type of chemical reaction taking place in stage 1. (b) Using structural formulae and curly arrow notation, outline a possible mechanism for the production of butan-2-ol in stage 2. 1 3 page 31 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (c) The high-resolution proton NMR spectrum for butan-2-ol is shown. 0 1 2 3 5 4 ppm Circle the hydrogen atom(s) on the structure below responsible for the multiplet at 3∙7 ppm. (An additional structure, if required, can be found on page 36). H C H H C H H C H OH C H H H 1 [Turn over page 32 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (d) Butan-1-ol can also be synthesised from 1-bromobutane by a different type of chemical reaction. An experiment was carried out to determine the kinetics for the reaction. Under certain conditions, the following results were obtained. [C4H9Br] (mol l-1) [OH-] (mol l-1) Initial rate (mol l-1 s-1) 0∙25 0∙10 3∙3 × 10-6 0∙50 0∙10 6∙6 × 10-6 (i) The reaction is first order with respect to both reactants. Write the overall rate equation for the reaction. (ii) Calculate the value for the rate constant, k, including the appropriate units. 1 2 page 33 MARKS DO NOT WRITE IN THIS MARGIN 10. Decamethylcobaltocene is a powerful reducing agent. H3C H3C CH3 CH3 CH3 CH3 CH3 CH3 H3C Co2+ H3C decamethylcobaltocene (a) The ligand in decamethylcobaltocene has an aromatic ring. State the feature that provides stability to aromatic rings. (b) Write the electronic configuration, in terms of s, p and d orbitals, for Co2+ in this complex ion. 1 1 [Turn over page 34 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (c) Decamethylcobaltocene can be dissolved in petroleum ether to produce a coloured solution. The concentration of this solution can be determined using colorimetry. (i) (A) The first stage is to prepare a calibration graph. Describe fully the procedure required to obtain results that would allow a calibration graph to be drawn. (B) The second stage is to determine the concentration of a sample of the decamethylcobaltocene solution. Describe how this would be carried out. (ii) Name the compound produced when decamethylcobaltocene solution reduces propanal. 2 1 1 page 35 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (d) Decamethylcobaltocene oxidises easily creating impurities in the sample. The purity of decamethylcobaltocene can be checked using low-resolution 1H NMR. H3C H3C CH3 CH3 CH3 CH3 CH3 CH3 H3C Co2+ H3C decamethylcobaltocene Predict the number of peaks that would be observed in a low-resolution 1H NMR spectrum of a pure sample of decamethylcobaltocene. [END OF QUESTION PAPER] 1 page 36 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL DIAGRAM FOR USE IN QUESTION 7 (c) solvent TLC plate chromatography tank ADDITIONAL STRUCTURE FOR USE IN QUESTION 9 (c) H C H H C H H C H OH C H H H page 37 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 38 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 39 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 40 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

page 02 SECTION 1 — 20 marks Attempt ALL questions 1. The potential energy diagram below refers to the reversible reaction involving reactants R and products P. P R 90 80 70 60 50 40 30 20 10 0 Potential energy (kJ mol−1) Reaction pathway What is the enthalpy change, in kJ mol−1, for the reverse reaction? A −40 B −10 C +10 D +30 2. The relative rate of a reaction which reached completion in 1 minute 40 seconds is A 0·010 s−1 B 0·714 s−1 C 0·010 min−1 D 0·714 min−1. page 03 3. T1 Kinetic energy of molecules T2 Number of molecules EA Which of the following is the correct interpretation of the above energy distribution diagram for a reaction as the temperature decreases from T2 to T1? Activation energy (EA) Number of successful collisions A remains the same increases B decreases decreases C decreases increases D remains the same decreases 4. The table shows the first three ionisation energies of aluminium. Ionisation energy (kJ mol−1) First Second Third 578 1817 2745 Using this information, what is the enthalpy change, in kJ mol−1, for the following reaction? Al+(g) ↓ Al3+(g) + 2e− A 1817 B 2395 C 4562 D 5140 [Turn over

page 04 5. An element contains covalent bonding and London dispersion forces. The element could be A boron B neon C sodium D sulfur. 6. Erythrose is a chemical that is known to kill cancer cells. HO C C C C H H OH H OH H O H erythrose The two functional groups present in erythrose are A carboxyl and ester B carbonyl and ester C carbonyl and hydroxyl D carboxyl and hydroxyl. 7. CH3 CH3 OH O C C H H3C H3C C The name of the above compound is A 2,2,3-trimethylbutanoic acid B 2,3,3-trimethylbutanoic acid C 1,1,2,2-tetramethylpropanoic acid D 2,2,3,3-tetramethylpropanoic acid.

page 05 8. Which of the following is an isomer of pentan-3-ol? A CH3CH2CH(OH)CH2CH3 B CH3CHCHCH2CH2OH C CH3CHCHCH(OH)CH3 D CH3CH(CH3)CH2CH2OH 9. Oxidation of 4-methylpentan-2-ol to the corresponding ketone results in the alcohol A losing 2 g per mole B gaining 2 g per mole C losing 16 g per mole D gaining 16 g per mole. 10. Essential amino acids are defined as the amino acids which A are necessary for building proteins B humans must acquire through their diet C plants cannot synthesise for themselves D are produced when any protein is hydrolysed. 11. A mixture of carbon monoxide and hydrogen can be converted into water and a mixture of hydrocarbons. n CO  +  (2n + 1) H2  ↓  n H2O  +  hydrocarbons What is the general formula for the hydrocarbons produced? A CnH2n−2 B CnH2n C CnH2n+1 D CnH2n+2 12. A mixture of sodium chloride and sodium sulfate is known to contain 0∙6 mol of chloride ions and 0∙2 mol of sulfate ions. How many moles of sodium ions are present? A 0∙4 B 0∙5 C 0∙8 D 1∙0 [Turn over

page 06 13. Under the same conditions of temperature and pressure, which of the following gases would occupy the largest volume? A 0·20 g of hydrogen B 0·44 g of carbon dioxide C 0·60 g of neon D 0·80 g of argon 14. 3CuO  +  2NH3  ↓  3Cu  +  N2  +  3H2O What volume of gas, in cm3, would be obtained by reaction between 100 cm3 of ammonia gas and excess copper(II) oxide? All volumes are measured at atmospheric pressure and 20 °C. A 50 B 100 C 200 D 400 15. Cl2(g)  +  H2O(ℓ)  Ý  Cl−(aq)  +  ClO−(aq)  +  2H+(aq ) The addition of which of the following substances would move the above equilibrium to the right? A Hydrogen B Hydrogen chloride C Sodium chloride D Sodium hydroxide 16. When 3·6 g of butanal (mass of one mole = 72 g) was burned, 124 kJ of energy was released. What is the enthalpy of combustion of butanal, in kJ mol−1? A −6·2 B +6·2 C −2480 D +2480

page 07 17. Consider the reaction pathways shown below. CO(g) + ½O2(g) X CO2(g) −283 kJ mol−1 −394 kJ mol−1 C(s) + O2(g) According to Hess’s Law, the enthalpy change, in kJ mol−1, for reaction X is A +111 B −111 C −677 D +677. 18. SO3 2−(aq) + H2O(ℓ) ↓ SO4 2−(aq) + 2H+(aq) + 2e− Which of the following ions could be used to oxidise sulfite ions to sulfate ions? A Cr3+(aq) B Al3+(aq) C Fe3+(aq) D Sn4+(aq) 19. During a redox reaction nitrate ions, NO3 −, are converted to nitrogen monoxide, NO. NO3 − ↓ NO Which line in the table correctly completes the ion-electron equation? Reactants Products A 6H+ + 5e− 3H2O B 4H+ + 3e− 2H2O C 6H+ 3H2O + 5e− D 4H+ 2H2O + 3e− [Turn over page 08 20. ICl(ℓ)  +  Cl2(g)    Ý    ICl3(s)    ΔH  =  −106kJ mol−1 Which line in the table identifies correctly the changes that will cause the greatest increase in the proportion of solid in the above equilibrium mixture? Temperature Pressure A decrease decrease B decrease increase C increase decrease D increase increase [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] H FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2018 Total marks — 100 SECTION 1 — 20 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on page 02. SECTION 2 — 80 marks Attempt ALL questions. You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/76/01 MONDAY, 21 MAY 9:00 AM – 11:30 AM B/HTP Chemistry Section 1 — Answer Grid and Section 2 page 02 SECTION 1 — 20 marks The questions for Section 1 are contained in the question paper X713/76/02. Read these and record your answers on the answer grid on page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 SECTION 1 — Answer Grid [Turn over page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 05 [Turn over for next question DO NOT WRITE ON THIS PAGE page 06 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 80 marks Attempt ALL questions 1. The elements of group 7 in the periodic table are known as the halogens. (a) Going down group 7 the electronegativity of the halogens decreases. (i) State what is meant by the term electronegativity. (ii) Explain why electronegativity values decrease going down group 7. (b) Explain fully why the boiling points of the halogens increase going down group 7. In your answer you should name the intermolecular forces involved. 1 1 3 page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. The elements sodium to argon form the third period of the periodic table. (a) Explain the decrease in atom size going across the third period from sodium to argon. (b) Elements in the third period of the periodic table form chlorides. The structures of three of these chlorides are shown. Cl Si Cl Cl Cl P Cl S Cl Cl Cl Cl (i) Circle the structure of the molecule above that contains bonds with the lowest polarity. (An additional diagram, if required, can be found on page 37). (ii) Explain fully why, of these three chlorides, silicon tetrachloride is the most soluble in hexane. [Turn over 1 1 2 page 08 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (c) Silicon tetrachloride can be used to make silicon nitride (Si3N4), a compound found in many cutting tools. (i) Silicon nitride has a melting point of 1900 °C and does not conduct electricity when molten. Explain fully, in terms of structure and bonding, why silicon nitride has a high melting point. (ii) An equation for the formation of silicon nitride is shown. 3SiCl4    +    16NH3    ↓    Si3N4    +    12NH4Cl mass of mass of mass of mass of one mole one mole one mole one mole = 170·1 g = 17·0 g = 140·3 g = 53·5 g Calculate the atom economy for the formation of silicon nitride. 2 2 page 09 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (d) Aluminium, another element in the third period, also forms a chloride. Aluminium chloride is prepared by reacting aluminium metal and chlorine gas. Chlorine gas is produced by the reaction between hydrochloric acid and sodium hypochlorite. The chlorine is then passed over heated aluminium foil, forming aluminium chloride as a hot gas. The hot aluminium chloride gas and unreacted chlorine gas are passed into a flask where the aluminium chloride cools to a fine white powder. For safety it is important that any unreacted chlorine gas can escape from the flask. (i) Complete a labelled diagram to show an apparatus suitable for carrying out this preparation. (An additional diagram, if required, can be found on page 37). hydrochloric acid sodium hypochlorite solution (ii) Explain why the aluminium foil needs to be heated at the start of the preparation, despite the reaction being highly exothermic. [Turn over 2 1 page 10 MARKS DO NOT WRITE IN THIS MARGIN 3. Methyl benzoate is commonly added to perfumes as it has a pleasant smell. A student carries out a reaction to produce methyl benzoate using the following apparatus. wooden clip supporting small test tube methanol, benzoic acid and catalyst small test tube containing cold water (a) The reaction mixture needs to be heated. Describe a safe method of heating a flammable mixture. (b) Suggest a reason why there is a small test tube filled with cold water in the neck of the tube containing the reaction mixture. 1 1 page 11 MARKS DO NOT WRITE IN THIS MARGIN 3. (continued) (c) The chemical reaction involved in the experiment is shown. C6H5COOH(s) + CH3OH(ℓ) ↓ C6H5COOCH3(ℓ) + X benzoic acid methyl benzoate mass of one mass of one mass of one mole = 122 g mole = 32 g mole = 136 g (i) Name product X. (ii) In a laboratory experiment, a student used 5·0 g of benzoic acid and 2·5 g of methanol to produce methyl benzoate. Explain why benzoic acid is the limiting reactant. You must include calculations in your answer. (iii) The student produced 3·1 g of methyl benzoate from 5·0 g of benzoic acid. Benzoic acid costs £39·80 for 500 g. Calculate the cost, in £, of the benzoic acid needed to make 100 g of methyl benzoate using the student’s method. 1 2 2 [Turn over page 12 MARKS DO NOT WRITE IN THIS MARGIN 4. 3-Methylbutanal is a compound that is found in low concentrations in many types of food. The structure of 3-methylbutanal is shown. H C H H C H C H H C O H C H H H (a) Draw a structural formula for a ketone that is an isomer of 3-methylbutanal. (b) Name a reagent which could be used to distinguish between 3-methylbutanal and a ketone. (c) Name the strongest intermolecular force that occurs between 3-methylbutanal molecules. 1 1 1 page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (d) 3-Methylbutanal is found in olive oil. Explain fully what can happen to 3-methylbutanal that will cause the olive oil to develop an unpleasant taste. (e) 3-Methylbutanal can be used as a reactant in the production of other compounds. One reaction scheme involving 3-methylbutanal is shown. H C H H C H C H H C O H C H H H H3C C O CH3 H C H H C H C H H C H2O C H H H H C C H O C H H H + H C H H C H C H H C C H H H H C C H O C H H H H H + Step 1 product A propanone 3-methylbutanal Step 2 (i) Explain why step 1 is described as a condensation reaction. (ii) Give the systematic name for product A. 2 1 1 [Turn over page 14 MARKS DO NOT WRITE IN THIS MARGIN 5. Many chemical compounds are related to each other by their structural features, the way they are made and how they are used. Using your knowledge of chemistry, describe the relationships between fats, oils, detergents, soaps and emulsifiers. 3 page 15 [Turn over for next question DO NOT WRITE ON THIS PAGE page 16 MARKS DO NOT WRITE IN THIS MARGIN 6. Skin creams contain many different chemicals. (a) Retinol (vitamin A) promotes cell regeneration. One method of supplying retinol to the skin is by using a skin cream containing the compound retinyl palmitate. C15H31 C O O C20H29 retinyl palmitate Retinyl palmitate is absorbed into the skin and then broken down to form retinol. (i) Name the type of reaction that occurs when retinyl palmitate is broken down to form retinol. (ii) Write a molecular formula for retinol. (b) Skin creams often contain vitamin E to prevent damage to the skin caused by free radicals. (i) Describe how free radicals are formed. 1 1 1 page 17 MARKS DO NOT WRITE IN THIS MARGIN 6. (b) (continued) (ii) Hydroxyl free radicals (•OH) can attack fatty acids present in cell membranes. One step in the chain reaction is shown below. C18H31O2    +    •OH    ↓    C18H30O2•    +    H2O State the name given to this step in the chain reaction. (iii) The antioxidant vitamin E is a free radical scavenger. State how free radical scavengers prevent further chain reactions. [Turn over 1 1 page 18 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (c) Palmitoyl pentapeptide-4 is also used in skin creams. CH3(CH2)14 C N C C N C C N C C N C C N O H (CH2)4 NH2 H O H CHOH O H CHOH O H (CH2)4 O H H H CH3 CH3 NH2 H C CH2 OH H C OH O (i) Circle a peptide link in the above structure. (An additional diagram, if required, can be found on page 37). (ii) Palmitoyl pentapeptide-4 is formed from palmitic acid and three different amino acids. Molecule Number of molecules used to form one molecule of palmitoyl pentapeptide-4 palmitic acid 1 threonine 2 serine 1 lysine 2 Draw a structural formula for the amino acid serine. 1 1 page 19 MARKS DO NOT WRITE IN THIS MARGIN 7. Terpenes consist of joined isoprene units (2-methylbuta-1,3-diene). They are classified by the number of isoprene units in the molecule. Class of terpene Number of isoprene units hemiterpene 1 monoterpene 2 sesquiterpene 3 diterpene 4 triterpene 6 (a) Myrcene and humulene are terpenes present in hops which give beer its characteristic flavour and aroma. (i) Circle an isoprene unit on the myrcene structure below. CH2 C H2C CH H2C CH2 CH C H3C CH3 (An additional diagram, if required, can be found on page 38). (ii) Humulene has the molecular formula C15H24. Name the class of terpene to which humulene belongs. [Turn over 1 1 page 20 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (b) (i) Squalene, a triterpene, is included in some flu vaccines to enhance the body’s immune response. A single dose of flu vaccine contains 10∙69 mg of squalene. Calculate the mass of squalene required to produce a batch of 500 000 doses of flu vaccine. Your answer must be given in kg. (ii) Squalane is a fully saturated hydrocarbon used in skin moisturising cream. Squalane can be made by the reaction of squalene with hydrogen. H C 3 C CH3 CH CH2 CH2 CH2 C CH CH3 C CH3 CH2 CH2 CH2 CH CH 2 CH2 CH2 CH C CH3 CH C CH3 CH2 CH C CH3 CH3 squalene State the number of moles of hydrogen needed to fully saturate one mole of squalene to produce one mole of squalane. 2 1 page 21 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (c) The monoterpene limonene, found in lemon oil, can be converted into the alcohol, terpineol. HC CH2 CH3 CH3 H2C H3C CH2 CH3 C H3C C C C CH HC CH2 H2C CH2 CH OH CH2 limonene terpineol (i) Name the type of reaction taking place. (ii) When terpineol is heated with copper(II) oxide, no reaction takes place. Explain why no reaction takes place. [Turn over 1 1 page 22 MARKS DO NOT WRITE IN THIS MARGIN 8. The alkynes are a homologous family of hydrocarbons. (a) The simplest member of the family is ethyne, C2H2, used in welding torches. H C C H Ethyne can be produced from ethane. H H H H H C C H H C H H C H H H + Using bond enthalpies and mean bond enthalpies from the data book, calculate the enthalpy change, in kJ mol−1, for this reaction. (b) Hess’s Law can be used to calculate the enthalpy change for reactions that do not normally take place, such as the formation of propyne from its elements. 3C(s)    +    2H2(g)    ↓    C3H4(g) Calculate the enthalpy change, in kJ mol−1, for this reaction using the following information. C(s)  +  O2(g) ↓ CO2(g) ΔH = −394 kJ mol−1 H2(g)  +  ½O2(g) ↓ H2O(ℓ) ΔH = −286 kJ mol−1 C3H4(g)  +  4O2(g) ↓ 3CO2(g)  +  2H2O(ℓ) ΔH = −1939 kJ mol−1 2 2 page 23 MARKS DO NOT WRITE IN THIS MARGIN 8. (continued) (c) Propyne, C3H4 (1 mole = 40 g), has been suggested as a possible rocket fuel. (i) The enthalpy of combustion of propyne is −1939 kJ mol−1. Calculate the energy released, in kJ, when 1 kg of propyne is burned completely. (ii) The mass of air required to burn 1 g of fuel can be calculated using the relationship shown. Mass of air, in g  =  4·3 × mass of oxygen, in g, for complete combustion of 1 g of fuel Calculate the mass of air, in g, required to burn 1 g of propyne. C3H4(g)    +    4O2(g)    ↓    3CO2(g)    +    2H2O(ℓ) 1 2 [Turn over page 24 MARKS DO NOT WRITE IN THIS MARGIN 8. (c) (continued) (iii) The table shows the mass of air required to burn 1 g of different fuels. Fuel Mass of 1 mole (g) Mass of air required to burn 1 g ethane 30 16·1 propane 44 15·6 methanol 32 6·5 ethanol 46 9·0 Suggest why methanol and ethanol, compared to the other fuels, require less air to burn 1 g. 1 page 25 [Turn over for next question DO NOT WRITE ON THIS PAGE page 26 MARKS DO NOT WRITE IN THIS MARGIN 9. Ethane-1,2-diol can be made from ethene. (a) The flow chart of an industrial process to produce ethane-1,2-diol is shown. recycling gases liquid by-products oxygen Reactor 2 50–70 °C catalyst Separator 2 Separator 1 Reactor 1 200–300 °C catalyst water oxirane liquid ethane-1,2-diol ethene (i) Industrial processes are designed to maximise profit. Using the flowchart, suggest two ways to maximise profit in this industrial process. 2 page 27 MARKS DO NOT WRITE IN THIS MARGIN 9. (a) (continued) (ii) Name the process used in Separator 2 to separate ethane-1,2-diol from the larger liquid by-products. (b) Explain fully why ethane-1,2-diol is more viscous than propan-1-ol. (c) Draw a structural formula for a diol that contains three carbon atoms. [Turn over 1 2 1 page 28 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (d) Ethane-1,2-diol has been found to be harmful to animals. Treatment for affected animals involves using a 20% ethanol solution. (i) The 20% ethanol solution is prepared by accurately measuring 20 cm3 of ethanol and then making up to exactly 100 cm3 with water. Describe the procedure which should be used to prepare 100 cm3 of the 20% ethanol solution. (ii) An affected animal must be treated with 9 doses of 20% ethanol solution. Each dose contains 5 cm3 of the ethanol solution for every kilogram body mass of the animal. Calculate the total volume, in cm3, of the 20% ethanol solution needed to treat a 3·5 kg animal. 2 1 page 29 MARKS DO NOT WRITE IN THIS MARGIN 9. (d) (continued) (iii) Ethane-1,2-diol is harmful because it is oxidised in the body to form glycolic acid. C H H C O OH HO glycolic acid (A) Draw a structural formula for another possible product of oxidation of ethane-1,2-diol. (B) Glycolic acid can be neutralised by sodium hydroxide to form sodium glycolate. Give a formula for sodium glycolate. [Turn over 1 1 page 30 MARKS DO NOT WRITE IN THIS MARGIN 10. The molar volume (in units of litres per mole) is the same for all gases at the same temperature and pressure. Using your knowledge of chemistry, suggest how the molar volume of gases could be measured and compared. Any suitable chemicals and apparatus can be used. Some suggested chemicals and apparatus are given below. Chemicals Apparatus hydrochloric acid gas syringe zinc measuring cylinder magnesium delivery tube calcium stoppers water 500 cm3 flask sodium carbonate vacuum pump calcium carbonate balance cylinder of nitrogen cork ring cylinder of hydrogen burette cylinder of carbon dioxide filter funnel 3 page 31 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) [Turn over page 32 MARKS DO NOT WRITE IN THIS MARGIN 11. Iodine is required for a healthy diet. Food grown in certain parts of the world is low in iodine. To prevent iodine deficiency in people’s diets, table salt can be ‘iodised’ by the addition of very small quantities of potassium iodide, KI. The number of moles of iodide in a sample of salt can be determined by the following procedure. Step 1 Prepare a standard salt solution by dissolving an accurately weighed sample of iodised salt (50·0 g) in water to give a final volume of 250 cm3. Step 2 Transfer 50 cm3 of salt solution to a conical flask and add excess bromine solution to convert the iodide ions to iodine. Step 3 Titrate the iodine (I2) released with sodium thiosulfate solution (Na2S2O3). (a) Describe a procedure to accurately weigh out a 50·0 g sample of iodised table salt. (b) The overall equation for the reaction of bromine solution with iodide ions is shown. 2I−(aq)  +  Br2(aq)    ↓    I2(aq)  +  2Br−(aq) Write the ion-electron equation for the oxidation reaction. 1 1 page 33 MARKS DO NOT WRITE IN THIS MARGIN 11. (continued) (c) Three samples were prepared as described in step 2. Each sample was titrated with 0∙0010 mol l−1 sodium thiosulfate solution. The results are shown below. Sample Volume of sodium thiosulfate (cm3) 1 10∙0 2 9∙4 3 9∙6 (i) Calculate the average volume, in cm3, of sodium thiosulfate solution that should be used to determine the number of moles of iodine released. (ii) Calculate the number of moles of iodine released from 50 cm3 of the standard salt solution. I2(aq)  +  2Na2S2O3(aq)    ↓    2NaI(aq)  +  Na2S4O6(aq) [Turn over 1 2 page 34 DO NOT WRITE IN THIS MARGIN 12. Many modern antiseptics are based on phenol. The table shows the germ-killing power of some phenol compounds. (a) Compound Structure Germ-killing power (relative to phenol) phenol OH 1·0 4-methylphenol OH CH3 2·5 2-chlorophenol OH Cl 3·6 4-ethylphenol OH C2H5 7·5 2,4-dichlorophenol OH Cl Cl 13·0 4-propylphenol OH C3H7 20·0 2,4,6-trichlorophenol OH Cl Cl Cl 23·0 page 35 MARKS DO NOT WRITE IN THIS MARGIN 12. (a) (continued) (i) Suggest two ways in which structural features increase germ-killing power of phenol compounds. (ii) The names of the phenol compounds in the table are derived from their structures using the following rules. Phenol is used as the parent name for the compound. 1. The –OH functional group is assigned as being on carbon 1 of the ring. 2. The ring can be numbered clockwise or anticlockwise to assign numbers to the other atoms or groups. The numbers should be assigned so that the lowest possible numbers are used. 3. If two or more identical atoms or groups are present, use one of the prefixes di, tri or tetra. 4. The names of the atoms or groups attached to the ring are listed alphabetically (ignoring the prefixes for alphabetical purposes). Using these rules, name this molecule. OH Cl CH3 CH3 [Turn over 2 1 page 36 MARKS DO NOT WRITE IN THIS MARGIN 12. (continued) (b) There are different methods of producing phenol. (i) In the early 1900s, phenol was produced by the following reaction. C6H6  +  H2SO4  +  2NaOH  ↓  C6H5OH  +  Na2SO3  +  2H2O benzene phenol mass of mass of one mole one mole = 78·0 g = 94·0 g Calculate the mass of phenol, in kg, produced from 117 kg of benzene if the percentage yield is 90%. (ii) Phenol is now usually produced by the Cumene Process. C O X O H H+ + CH3 CH3 OH phenol cumene hydroperoxide Name the other product, X, formed in the Cumene Process. [END OF QUESTION PAPER] 2 1 page 37 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK ADDITIONAL DIAGRAM FOR USE IN QUESTION 2 (b) Cl Si Cl Cl Cl P Cl S Cl Cl Cl Cl ADDITIONAL DIAGRAM FOR USE IN QUESTION 2 (d) (i) hydrochloric acid sodium hypochlorite solution ADDITIONAL DIAGRAM FOR USE IN QUESTION 6 (c) (i) CH3(CH2)14 C N C C N C C N C C N C C N O H (CH2)4 NH2 H O H CHOH O H CHOH O H (CH2)4 O H H H CH3 CH3 NH2 H C CH2 OH H C OH O page 38 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK ADDITIONAL DIAGRAM FOR USE IN QUESTION 7 (a) (i) CH2 C H2C CH H2C CH2 CH C H3C CH3 page 39 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 40 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK

10 (2410U20-1) 10 © WJEC CBAC Ltd. 10. (a) Halogenoalkanes can be hydrolysed using water in a similar way to using aqueous sodium hydroxide. A student carried out an experiment to investigate the rate of reaction for the hydrolysis of halogenoalkanes using water. The student used aqueous ethanol to dissolve the halogenoalkane and then added a few drops of aqueous silver nitrate. He timed how long it took to produce a precipitate. He obtained the results shown in the table. Halogenoalkane Time / s 1-chloropropane, C3H7Cl 300 1-bromopropane, C3H7Br 90 1-iodopropane, C3H7I 15 Bond Bond enthalpy / kJ mol–1 C—H 413 C—C 348 C—F 485 C—Cl 328 C—Br 276 C—I 240 Element Electronegativity chlorine 3.16 bromine 2.96 iodine 2.66 carbon 2.55 The student tried to explain these results and he looked on the internet to find the following data. 11 (2410U20-1) 11 Examiner only (i) Use both sets of data to explain the student’s results. Include an equation to show the hydrolysis reaction between a halogenoalkane and aqueous sodium hydroxide and name this type of reaction mechanism. [6 QER] (ii) Write an ionic equation, including state symbols, for a reaction that produces a silver halide precipitate. [1] (iii) Suggest a practical method by which the student could have obtained these results. [2] (iv) Suggest the difference that the student would have observed in his experiments if he had not added ethanol to the water before adding the halogenoalkane. [1] © WJEC CBAC Ltd. Turn over. 2410 U201 11 (2410U20-1) 12 12 Examiner only © WJEC CBAC Ltd. 16 (b) Chlorofluorocarbons, CFCs, were historically used for a variety of commercial and domestic purposes but nowadays their use is very restricted. (i) Outline the adverse environmental effects of the use of CFCs. You do not need to include any equations for the reactions involved. [4] (ii) Use relevant data in part (a) to explain why hydrofluorocarbons, HFCs, have replaced CFCs in many of their uses. [2] 13 (2410U20-1) 13 © WJEC CBAC Ltd. Turn over. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

(2410U20-1) 14 14 © WJEC CBAC Ltd. 11. Compound X contains only carbon, hydrogen and oxygen. On analysis it was found to contain 53.3 % carbon and 11.1 % hydrogen by mass. A simplified form of the mass spectrum and the infrared absorption spectrum for X are shown. The low resolution 1H NMR spectrum of X has three peaks. When X is warmed with excess acidified potassium dichromate(VI) there is a colour change. The organic product of this reaction does not react with aqueous sodium carbonate. 0 10 20 30 40 50 60 70 80 90 Intensity m/z 2000 1000 3000 0.0 0.8 1.0 0.6 0.4 0.2 Transmittance Wavenumber (cm–1) (2410U20-1) 15 Turn over. 15 © WJEC CBAC Ltd. Examiner only (a) Use all the data given to find the structure of compound X. Explain what information can be found from each piece of data. [10] Structure of X Examiner only 16 (2410U20-1) 16 © WJEC CBAC Ltd. (b) (i) State the type of reaction that occurs when X is warmed with acidified potassium dichromate(VI). [1] ....................................................................................................................... (ii) Draw the structure of the organic product formed when X reacts with acidified potassium dichromate(VI). [1] 12 (2410U20-1) Turn over. 17 17 © WJEC CBAC Ltd. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE 18 (2410U20-1) 18 © WJEC CBAC Ltd. Examiner only 12. (a) Iodide ions can be oxidised to iodine by reaction with acidified hydrogen peroxide. H2O2 I2 2I– + 2H2O + 2H+ + The rate of reaction can be followed in a clock reaction by the appearance of a blue-black colour. An experiment was carried out to determine the effect on the rate of reaction of varying the concentration of iodide ions. All other volumes and concentrations were kept constant. The results are shown in the table. Concentration I– / mol dm–3 Time for appearance of blue-black colour / s Rate / s–1 × 1000 0.1 56 18 0.2 20 .................................. 0.3 18 .................................. 0.4 12 .................................. 0.5 10 .................................. (i) Use rate = 1000 time to calculate the rate for each experiment and complete the table. [1] (2410U20-1) 19 19 © WJEC CBAC Ltd. Turn over. Examiner only (ii) On the axes below, plot the concentration of I– against rate and draw a suitable line. [3] (iii) From the graph deduce the relationship between concentration of I– and rate of reaction. [1] (iv) Use the graph to calculate the time the reaction would take to turn blue-black using a 0.15 mol dm–3 solution of I–. Show clearly how you obtained your answer. [2] Time = ....................................................... s (2410U20-1) 20 20 © WJEC CBAC Ltd. Examiner only (v) For each experiment the rate was calculated using the time taken to produce excess iodine. Explain why this is only an approximation for the rate as the reaction proceeds. [2] (b) (i) Draw a Boltzmann energy distribution curve. Label the axes. [2] (ii) Use this energy distribution curve to explain how catalysts affect the rate of a reaction. [2] 13 Turn over. (2410U20-1) 21 © WJEC CBAC Ltd. Examiner only 13. (a) Explain what is meant by a carbon-neutral fuel. [3] (b) Ethane and an unknown alkane were burned in oxygen. It follows from the equation below that one volume of ethane produced two volumes of carbon dioxide and three volumes of water vapour. C2H6(g) + 7 2 O2(g) 2CO2(g) + 3H2O(g) 10 cm3 of the unknown alkane CxHy burned according to the following equation. CxHy(g) + (x + y 4 )O2(g) xCO2(g) + y 2  H2O(g) The total volume of carbon dioxide and water vapour produced was 20 cm3 more than the original volume of CxHy and oxygen. All volumes were measured at the same temperature and pressure. (i) State the volumes of carbon dioxide and water vapour produced on burning 10 cm3 of the unknown alkane in terms of x and y. [1] Volume carbon dioxide = ....................................................... cm3 Volume water vapour = ....................................................... cm3 (ii) Calculate the value of y. [2] y = .......................................... END OF PAPER 6 21 (2410U20-1) 22 © WJEC CBAC Ltd. 22 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (2410U20-1) 23 © WJEC CBAC Ltd. 23 Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. (2410U20-1) 24 © WJEC CBAC Ltd. 24 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

12 (1410U30-1) 12 © WJEC CBAC Ltd. 11. Hydrogen peroxide, H2O2, decomposes slowly at 300 K to form water and oxygen gas. 2H2O2(l) 2H2O(l) + O2(g) The reaction profile for this reaction is shown below. Energy / kJ mol–1 Reaction path 0 20 40 60 80 100 120 140 160 180 200 220 240 75 kJ mol–1 98 kJ mol–1 (1410U30-1) Turn over. 13 13 © WJEC CBAC Ltd. Examiner only (a) The rate of decomposition of hydrogen peroxide can be influenced by a range of catalysts. The activation energy when using MnO2 as a catalyst is 58 kJ mol–1. Draw the reaction profile for the catalysed reaction on the grid opposite. [1] (b) Another catalyst was used and this gave a value for the rate constant, k, of 1.68 mol–1 dm3 s–1 and the frequency factor, A, of 1.41 × 104 mol–1 dm3 s–1 at a temperature of 300 K. (i) State the Arrhenius equation. [1] (ii) Calculate the activation energy using this catalyst and hence state whether it is a more effective catalyst than MnO2. [3] Activation energy = .................................................... kJ mol–1 (c) The standard enthalpy change of formation, ΔfHθ, of water is –286 kJ mol–1. Use this information and the graph to calculate the standard enthalpy change of formation of hydrogen peroxide. [2] ΔfHθ(H2O2) = ..................................................... kJ mol–1 (d) State whether you would expect the entropy change for the decomposition of hydrogen peroxide to be positive or negative. Give a reason for your answer. [1] V 14 (1410U30-1) 14 © WJEC CBAC Ltd. Examiner only (e) One way of assessing whether a reaction is feasible is to use standard electrode potentials. Standard electrode potential / V H2O2 + 2H+ + 2e– a 2H2O +1.77 Cr2O7 2– + 14H+ + 6e– a 2Cr3+ + 7H2O +1.33 (i) The apparatus below can be used to measure the standard electrode potential for the Cr2O7 2–/Cr3+ half-cell. B C A hydrogen, 1 atm an acidified mixture of 1 mol dm–3 Cr3+(aq) and 1 mol dm–3 Cr2O7 2– (aq) I. State what is represented by A and B on the diagram. [1] A ..................................................................................... B ..................................................................................... II. On the diagram show the direction of flow of electrons in the external circuit. [1] (1410U30-1) Turn over. 15 15 © WJEC CBAC Ltd. Examiner only III. State what is represented by C on the diagram and state its function. [1] IV. The concentrations of both Cr2O7 2– and Cr3+ ions are 1 mol dm–3. State and explain how the value shown on the high resistance voltmeter would change if the concentration of the Cr3+ ions were increased whilst the concentration of the Cr2O7 2– was left unchanged. [2] (ii) It is suggested that hydrogen peroxide could be used to oxidise Cr3+ ions in acidic solution to form dichromate ions. I. Write an equation for this proposed reaction. [1] II. Use the standard electrode potential values given to predict whether this reaction is feasible. [2] III. Another method of finding whether a reaction is feasible is to use the Gibbs free energy calculated from standard enthalpy of formation and standard entropy values. State, giving a reason, whether Gibbs free energies or electrochemical methods are more appropriate for finding whether this reaction is feasible. [2] 18

16 (1410U30-1) 16 © WJEC CBAC Ltd. 12. A student was provided with five ionic solids containing familiar cations and anions. Each solid contains a different cation. The solids were labelled A, B, C, D and E. The student attempted to dissolve all five solids in water. She then attempted to dissolve those that did not dissolve in water in a stoichiometric amount of acid. The results are given below. Solid Addition of water Addition of dilute sulfuric acid to solid Addition of dilute nitric acid to solid A dissolves giving colourless solution 1 B dissolves giving colourless solution 2 C does not dissolve pale blue solution 3 forms upon warming with the acid D does not dissolve effervescence and solution 4 forms E does not dissolve some effervescence but the solid does not dissolve effervescence and solution 5 forms Pairs of the solutions formed were mixed and the observations recorded. Solution 5 Solution 4 Solution 3 Solution 2 Solution 1 (formed by dissolving solid A) no visible change white precipitate white precipitate bright yellow precipitate Solution 2 (formed by dissolving solid B) no visible change no visible change brown solution with a white solid Solution 3 (formed by reacting solid C with acid) thick white precipitate no visible change Solution 4 (formed by reacting solid D with acid) thick white precipitate Flame tests Flame tests carried out on solutions 1, 2, 3, 4 and 5 gave no colour with one solution, an apple- green flame with another and a lilac flame with a third. The student noted unfamiliar flame test colours for the other two solutions. (1410U30-1) Turn over. 17 17 © WJEC CBAC Ltd. Examiner only (a) Suggest which anion is present in substances D and E. Give a reason for your answer. [2] (b) Use all the information provided to suggest identities for compounds A-E. Explain clearly how you identified compounds A and C. [6 QER] A ......................................................................................................... B ......................................................................................................... C ......................................................................................................... D ......................................................................................................... E ......................................................................................................... Explanation END OF PAPER 8 18 (1410U30-1) 18 © WJEC CBAC Ltd. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (1410U30-1) Turn over. 19 19 © WJEC CBAC Ltd. Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (1410U30-1) 20 20 © WJEC CBAC Ltd. Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only

14 (B410U10-1) Examiner only 13. Compound X contains only carbon, hydrogen and oxygen. 6.57 g of X was burned in excess oxygen to form carbon dioxide and water. 12.57 g of carbon dioxide and 7.74 g of water were collected. (a) Suggest how the mass of carbon dioxide and the mass of water could be measured in this experiment. [2] (b) Find the percentage by mass of each element in X. [3] Percentage carbon = ..................................... % Percentage hydrogen = ..................................... % Percentage oxygen = ..................................... % (c) Calculate the empirical formula of X. [2] Empirical formula .......................................................... © WJEC CBAC Ltd. (B410U10-1) Turn over. 15 Examiner only (d) 9.20 g of X, measured at a pressure of 103 kPa and a temperature of 100 °C, had a volume of 6.02 × 103 cm3. Calculate the relative molecular mass, Mr , of X. [4] Relative molecular mass = ....................................................... (e) Use your answers to parts (c) and (d) to deduce the molecular formula of X. [1] Molecular formula .................................................................. END OF PAPER © WJEC CBAC Ltd. 12 Examiner only (B410U10-1) 16 © WJEC CBAC Ltd. For continuation only.

18 (B410U20-1) © WJEC CBAC Ltd. 10. Hydrogen peroxide reacts with iodide ions in acid solution to produce iodine. The equation for the reaction is as follows. A student is asked to investigate the effect of changing the concentration of hydrogen peroxide on the rate of reaction by a “clock method”. She is told to carry out the following method. • Measure 10.0 cm3 of sulfuric acid, 10.0 cm3 of sodium thiosulfate, 15.0 cm3 of potassium iodide and 1.0 cm3 of starch solution into a conical flask. • Measure 5.0 cm3 of hydrogen peroxide and 9.0 cm3 of water into a boiling tube. • Add the peroxide solution to the other reagents in the flask and start a stopwatch at the same time. • Record the time taken, to the nearest second, for a blue-black colour to form in the reaction mixture. • Repeat the procedure five times, with each run differing only in the peroxide concentration in the mixture, ensuring that the reaction times are neither too short nor too long. She obtains the following results. H2O2(aq) + 2H+(aq) + 2I–(aq) I2(aq) + 2H2O(l) Experiment Volume H2O2 / cm3 Volume H2O / cm3 Time / s 1 Time / s–1 1 5.0 9.0 28 0.0357 2 6.0 8.0 3 7.0 7.0 17 0.0589 4 4.0 10.0 36 0.0278 5 3.0 11.0 54 0.0185 6 2.0 12.0 102 0.0098 (B410U20-1) 19 © WJEC CBAC Ltd. Examiner only Turn over. (a) The student says that it would be better to make up a single batch containing the acid, thiosulfate, iodide and starch solutions in the correct proportions before starting and use 36.0 cm3 of this in each experiment. Is she correct? Justify your answer. [1] (b) State two changes which could be made in order to improve the results in this experiment. Explain your reason in each case. [4] (c) Give a reason why the peroxide is measured into a boiling tube first and not added directly to the flask from a burette. [1] (d) Suggest a reason why the student did not carry out the procedure using 8.0 cm3 of hydrogen peroxide and 6.0 cm3 of water. [1] 20 (B410U20-1) © WJEC CBAC Ltd. (e) She plotted a graph of rate against concentration of peroxide. This is shown below. [ H2O2 ] / mol dm–3 1 Time / s–1 0 0.008 0.012 0.016 0.020 0.024 0.028 0.032 0.036 0.040 0.044 0.048 0.052 0.056 0 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016 0.060 (B410U20-1) Turn over. 21 Examiner only © WJEC CBAC Ltd. (i) State how the rate depends on the concentration of peroxide. [1] (ii) Use the graph to find the time taken for the colour change to occur when she used 6.0 cm3 of hydrogen peroxide and 8.0 cm3 of water. [2] Time = ..................................................... s (f) Suggest another method, not using sodium thiosulfate, by which the rate of this oxidation reaction could be measured. [2] (g) Explain, using simple collision theory, why the rate of this reaction changes as the concentration of hydrogen peroxide changes. [2] END OF PAPER 14 22 (B410U20-1) Examiner only © WJEC CBAC Ltd. For continuation only. BLANK PAGE (B410U20-1) 23 © WJEC CBAC Ltd.

8 (A410U10-1) Examiner only 10. Industrial processes are designed to give the maximum yield of the pure product in the shortest time at the lowest possible cost. The choice of temperature, pressure and catalyst are all key factors of designing an industrial process. (a) (i) The Wacker process is used to produce ethanal from ethene. It is a reaction catalysed by a mixed catalyst containing chlorides of copper and palladium. The reaction may be carried out in the gas phase according to the equation below. C2H4(g) + 1 2 O2(g) [ CH3CHO(g) ΔHθ = –218 kJ mol−1 Outline the factors that would need to be considered when selecting conditions for this process, applying these to suggest appropriate conditions. You should include a full explanation of why catalysts are very important for exothermic equilibria such as this. [6 QER] © WJEC CBAC Ltd. (A410U10-1) Turn over. A 410 U101 0 9 9 Examiner only (ii) This industrial process has a yield of 95.0 %. Calculate the mass of ethanal, in kg, that would be produced from 2.00 tonnes of ethene. [3] Mass of ethanal = ........................................................ kg (b) This process uses a catalyst mixture that contains CuCl2. When copper(II) compounds are dissolved in water they appear pale blue, whilst copper(I) compounds are not coloured. (i) Give the formula of the complex ion present in dilute aqueous solutions of copper(II) compounds. [1] (ii) Explain why copper(I) compounds are not coloured. [2] (iii) State the colour change that occurs when concentrated ammonia solution is added to copper(II) compounds in aqueous solution, drawing the structure of the copper- containing ion present. Explain why the addition of ammonia solution causes the colour to change. [4] © WJEC CBAC Ltd. 16

10 (A410U10-1) Examiner only 11. A student is provided with a set of unknown ionic solids. She is told that the compounds could be any four of the following. lead(II) carbonate lead(II) iodide lead(II) nitrate sodium carbonate sodium iodide potassium carbonate calcium nitrate magnesium hydroxide magnesium sulfate (a) All of the samples provided were white. State which one of the compounds from the list above could not be amongst the samples. Give a reason for your answer. [1] (b) She planned to test each of the samples by following the steps below. © WJEC CBAC Ltd. add a small amount of solid to distilled water and shake hydroxide or oxide ions are present in the original sample; a solution of metal chloride is formed test samples of the solution separately with each of the following solutions • silver nitrate • barium chloride • a small amount of dilute sodium hydroxide • an excess of dilute sodium hydroxide • bromine water carbonate ions are present in the original sample; a solution of metal chloride is formed add a small amount of solid to hydrochloric acid solid does not dissolve effervescence no effervescence solid dissolves (i) Explain why the method as written would not conclusively identify all the unknown samples that contain carbonate ions. [1] (A410U10-1) Turn over. A 410 U101 11 11 Examiner only (ii) Her teacher says that hydrochloric acid is not the correct reagent to use in this method. Give two reasons why hydrochloric acid is not appropriate and suggest an alternative reagent that would avoid these problems. [3] (iii) Another student starts her method with a flame test. State which s-block cations she could identify by this method, giving the colours expected for each. [2] (iv) As time was short the teacher suggested the following simplified method. • Look at the colour of the sample • Carry out a flame test to identify s-block cations • Try to dissolve the sample in water • Add acid to the samples and look for effervescence This method allowed seven of the nine compounds to be identified. lead(II) carbonate lead(II) iodide lead(II) nitrate sodium carbonate sodium iodide potassium carbonate calcium nitrate magnesium hydroxide magnesium sulfate Name the two compounds that could not be distinguished and suggest a test that would tell them apart. Give reagent(s) and observations for both compounds. [4] © WJEC CBAC Ltd. 11

12 (A410U10-1) Examiner only 12. Radioisotopes of elements are often used in the study of biological molecules. One such radioisotope is fluorine-18. (a) Give the numbers of protons and neutrons in the nucleus of a fluorine-18 atom. [1] Protons ……………....................………………… Neutrons ……………....................………………… (b) This radioisotope decays to form oxygen-18 only. Identify the type of radiation that must be emitted for this change to occur and identify any other type(s) of radiation that may also be emitted at the same time. [2] (c) A sample of fluorine gas contains four 18F atoms for every 19F atom. This was used to produce difluoromethanol, CHF2OH. A mass spectrum was taken as soon as the difluoromethanol had been synthesised. Part of the mass spectrum is shown below. © WJEC CBAC Ltd. 66 67 68 Abundance m/z (i) Identify the species that gives rise to the peak at m/z 66. [1] (A410U10-1) Turn over. 13 Examiner only © WJEC CBAC Ltd. (ii) The half-life of the fluorine-18 isotope is 110 minutes, and the original fluorine sample contained four fluorine-18 atoms for every fluorine-19 atom. Find the time taken to synthesise the difluoromethanol. [4] Time taken = …………..................…………………… minutes (d) The electronic structure of the oxygen atoms produced in this decay process may be studied by measuring successive ionisation energies. (i) Sketch a diagram showing the successive ionisation energies for oxygen. Show all eight ionisation energies. [2] 1 2 3 4 5 6 7 8 Number of electrons removed log (Ionisation energy) (ii) Explain how this diagram gives information regarding the position of the element in the Periodic Table. [2] 12 A 410 U101 13 14 (A410U10-1) Examiner only © WJEC CBAC Ltd. 13. Brass is an alloy of copper and zinc only. The copper content of the alloy can be found by volumetric or gravimetric analysis. The brass is dissolved by adding highly acidic mixtures to the alloy which forms Cu2+(aq) and amphoteric Zn2+(aq). (a) Redox titration is one method to find the mass of copper in a known mass of alloy. A 2.877 g sample of alloy is dissolved in concentrated nitric acid. The mixture is neutralised and then made up to a volume of 250.0 cm3. Samples of the solution with a volume of 25.00 cm3 are removed and excess potassium iodide solution added, before titration with 0.105 mol dm–3 sodium thiosulfate solution. The mean volume of sodium thiosulfate needed to completely reduce the iodine in solution is 26.75 cm3. Calculate the percentage by mass of copper in this alloy. You must show your working. [4] Percentage copper = ........................................................ % (A410U10-1) Turn over. 15 © WJEC CBAC Ltd. Examiner only (b) An alternative method is gravimetric analysis. Another sample of alloy is dissolved in concentrated nitric acid. The solution is neutralised and aqueous sodium hydroxide is added until all the copper(II) and zinc(II) ions form metal hydroxide precipitates. This sample is then filtered, dried and weighed (weighing 1). The solid sample is then treated with excess aqueous sodium hydroxide and the remaining solid is removed by filtration, dried and weighed (weighing 2). The results are given below. Mass of empty vessel = 23.34 g Mass of vessel and precipitate (weighing 1) = 25.12 g Mass of vessel and precipitate (weighing 2) = 24.45 g Calculate the percentage by mass of copper in this alloy. You must show your working. [4] Percentage copper = ........................................................ % (c) A student suggests that the alloys in parts (a) and (b) are the same. State and explain whether the evidence supports this statement and suggest what further evidence should be collected to confirm your conclusion. [2] 16 (A410U10-1) Examiner only © WJEC CBAC Ltd. (d) (i) Concentrated nitric acid is used to dissolve the alloy in the experiments above. The pH of this strong acid is typically –1.2. Calculate the concentration of this nitric acid. [2] Concentration = …………...................……………………….. mol dm–3 (ii) The acidic solution is neutralised using aqueous sodium hydroxide of concentration 2.00 mol dm–3. Calculate the pH of this sodium hydroxide solution. [2] [ionic product of water, Kw = 1.00 × 10–14 mol2 dm–6] pH = …………...................……………………….. 14 (A410U10-1) Turn over. 17 © WJEC CBAC Ltd. BLANK PAGE

18 (A410U10-1) Examiner only 14. Materials are often classified according to their physical properties and chemists use their knowledge of their structures to explain these properties. (a) One way to classify materials is according to their physical state. The halogens chlorine, bromine and iodine have different physical states at room temperature. Give the physical state for each of these halogens and explain why they have different physical states. [3] © WJEC CBAC Ltd. Substance Solubility in water at 20 °C / g dm–3 CaCl2 (anhydrous) 745 CaCl2.4H2O (hydrated) 908 butan-1-ol (CH3CH2CH2CH2OH) 73 octan-1-ol (CH3CH2CH2CH2CH2CH2CH2CH2OH) 0.46 (A410U10-1) Turn over. 19 Examiner only (i) A student says that this shows that the concentration of calcium ions in a saturated solution of calcium chloride is the same for solutions formed by dissolving anhydrous and hydrated forms of CaCl2. Is he correct? Give a reason for your answer. [2] (ii) Explain why the alcohols butan-1-ol and octan-1-ol can dissolve in water, giving a reason why the solubility of octan-1-ol is lower than that of butan-1-ol. [3] © WJEC CBAC Ltd. (b) Another way to classify materials is according to their solubility in water. The solubilities of four compounds were found in an online database. 20 (A410U10-1) Examiner only (c) The physical properties of materials can be modified by using additives. AIBN is an additive used to modify the properties of rubber. AIBN decomposes in solution in the solvent dioxane, shown as (sol) below, under standard conditions. NC—C(CH3)2—N=N—C(CH3)2—CN (sol) 2NC—C(CH3)2• (sol) + N2(g) AIBN (i) Give the temperature and pressure used as standard conditions. [1] (ii) The reaction can be followed by measuring the absorbance of the reactant in the solution at a wavelength of light of 350 nm. The dioxane solvent also absorbs a certain amount of light of this wavelength. The graph below shows the results of this experiment undertaken by two students, Anna and Megan. © WJEC CBAC Ltd. 0 10 20 30 40 50 60 70 80 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 Time / s Absorbance / % (A410U10-1) Turn over. 21 Examiner only I. State the percentage absorbance due to the solvent. Explain how you reached your conclusion. [2] II. Describe and explain fully the shape of the graph. Use the graph to prove that the reaction is first order with respect to AIBN. [6 QER] © WJEC CBAC Ltd. 22 (A410U10-1) Examiner only (iii) Upon heating, AIBN decomposes extremely rapidly. The rate equation for this process is as follows. rate = k[AIBN] The value of the rate constant k, can be found using the Arrhenius equation. Anna incorrectly writes the Arrhenius equation as I. State the correct Arrhenius equation. [2] II. Anna uses the correct temperature, frequency factor and activation energy in her incorrect Arrhenius equation. The values of two of these are given below. frequency factor, A = 6.92 × 109 s–1 temperature = 600 K Anna calculates that the rate constant is 4.89 × 1082 s–1. Megan says the true value should be much smaller. Find the value of the activation energy then use the correct Arrhenius equation to find the true value of the rate constant. State whether Megan is correct. [4] Ea = ........................................................ kJ mol–1 k = ........................................................ s–1 © WJEC CBAC Ltd. 23 k = A e Ea T (A410U10-1) Turn over. © WJEC CBAC Ltd. 23 Examiner only 15. Ethyne, H—C C—H, is commonly known as acetylene and is burned as a fuel in oxy-acetylene welding torches. It is stored in cylinders where the gas is dissolved in propanone and this is adsorbed onto an inert substance and kept under pressure. (a) Propanone is used to dissolve the ethyne as this gas is only slightly soluble in water. State why the solubility of ethyne in water is low. [1] (b) (i) When used in an oxy-acetylene torch the ethyne is released at a pressure of 135 kPa at 20 °C. Find the number of moles of ethyne in 1 cm3 and hence calculate the density of ethyne gas, in g cm–3, at this pressure at 20 °C. [4] density = mass ÷ volume Density = ........................................................ g cm–3 (ii) The density of dry air at 0 °C and 135 kPa is 1.27 × 10–3 g cm–3. A student says that this shows that a vessel of negligible mass filled with ethyne will float in air. Calculate the density of dry air at 20 °C and 135 kPa and show whether the student is correct. [2] Density = ........................................................ g cm–3 — — — 24 (A410U10-1) Examiner only © WJEC CBAC Ltd. (c) A student wrote the equation below for the standard enthalpy of combustion (ΔcHθ) of ethyne. 2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(g) (i) Identify two errors that the student has made. [2] (A410U10-1) Turn over. 25 Examiner only (ii) The student found the following data in a reference source. He wanted to calculate the most accurate value for the enthalpy change for his reaction. © WJEC CBAC Ltd. Standard enthalpy values / kJ mol–1 ΔfHθ [C2H2(g)] 227 ΔfHθ [CO2(g)] –394 ΔfHθ [H2O(l)] –242 ΔvaporisationHθ [H2O(l)] 41 Bond Bond energy / kJ mol–1 C—H 412 C C 837 C O 743 O—H 463 O O 496 — — — Select appropriate data to calculate the most accurate value you can for the enthalpy change for the reaction below. Explain your choice of method. [4] 2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(g) Enthalpy change of reaction = ........................................................ kJ mol–1 — — — — 26 (A410U10-1) (iii) The student decided to compare his value with one obtained experimentally. He used the apparatus and method given below. © WJEC CBAC Ltd. thermometer conical flask appropriate volume of water gas burner containing ethyne Method Measure an appropriate volume of water into the conical flask. Measure the mass of the gas burner containing the ethyne on a 3 decimal place balance. Select a thermometer that has 0.2 °C as its smallest division and place this in the conical flask. Record the temperature of the water and then immediately light the gas burner. Heat the water for 2 minutes. Extinguish the gas burner and record the temperature of the water and the mass of the gas burner. (A410U10-1) 27 Examiner only I. The difference between the initial and final temperature readings is 37.4 °C. Calculate the percentage error in this value. [1] Percentage error = ........................................................ % II. An appropriate volume of water was selected for the experiment. Explain why a volume which was much smaller or much greater than this would give results which were of a lower accuracy. [2] Much smaller volume of water ........................................................................................................................... Much greater volume of water ........................................................................................................................... III. Suggest two improvements to the method and explain how these would lead to improved results. [2] END OF PAPER © WJEC CBAC Ltd. 18 (A410U10-1) 28 Examiner only © WJEC CBAC Ltd. For continuation only.

12201 12 In 1931 Moelwyn-Hughes and Hinshelwood monitored the decarboxylation of the strong acid A: O2N CO2H NO2 NO2 O2N NO2 NO2 A (aq)  +  CO2(g) (aq) Heat (a) (i) Suggest an IUPAC name for the organic product. [1] (ii) Moelwyn-Hughes and Hinshelwood followed the kinetics of the reaction by titration. Explain how they could have determined the rate of reaction. Include in your answer the names of an alkali and an indicator which could be used. Indicate what steps and graphs would be needed to determine the order of reaction with respect to A. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. 12201 [Turn over [6] (b) Moelwyn-Hughes and Hinshelwood obtained the following data from their experiments. experiment [A] × 10−4/ mol dm−3 initial rate × 10−6/ mol dm−3min−1 1 2.50 2.40 2 1.67 1.64 3 1.04 1.02 (i) State the order of the reaction. [1] (ii) Using the results from experiment 1 calculate the rate constant, stating its units. [2] (iii) Explain why the rate constant would increase if the experiment was repeated at a higher temperature. [1]

12201 13 Thalidomide was first marketed in 1957 as a sedative to reduce morning sickness during pregnancy. It contains a chiral centre and exists as two optical isomers. O O O N NH O thalidomide (a) Circle the chiral centre in the structure above. [1] (b) Define the term optical isomers. [1] (c) The original use of thalidomide led to babies being born with deformed limbs. It was found that one optical isomer of thalidomide caused these birth defects. Suggest how the drug action may be determined by the stereochemistry of the drug. [1] (d) Thalidomide, in the sedative, was used as a racemic mixture. Define the term racemic mixture and explain why a racemic mixture would be optically inactive. [2]

12201 [Turn over 14 The titration curve for a strong acid with a strong alkali can be determined by measuring pH using specialised pH paper or a pH meter. (a) Suggest an advantage and a disadvantage of using the pH meter compared to pH paper. [2] (b) Explain, using your knowledge of titration curves, why both methyl orange and phenolphthalein are suitable indicators for this titration. [1] (c) Explain whether the salt solution formed from the reaction between sulfuric acid and sodium hydroxide is neutral or not. [1]

12201 15 The ester tripalmitin can be used to make biodiesel using transesterification. Tripalmitin is formed when glycerol reacts with palmitic acid. CH2OCOC15H31 CHOCOC15H31 CH2OCOC15H31 tripalmitin (a) Write an equation for the formation of tripalmitin from glycerol and palmitic acid. [2] (b) Use the structure of tripalmitin to explain whether tripalmitin is a saturated or unsaturated fat. [2] (c) Explain the term transesterification. [2] 12201 [Turn over (d) Write the equation for the reaction between tripalmitin and methanol forming molecules, some of which are used in biodiesel. [1] (e) From the equation written in (d), write the formula of the product that could be used as biodiesel. [1]

12201 16 Benzene is used to synthesise the analgesic, ibuprofen. This occurs using a multi-step reaction involving both Friedel–Crafts acylation and alkylation. COOH ibuprofen (a) The first step in this reaction is the acylation of benzene with 2-methylpropanoyl chloride. The structure of 2-methylpropanoyl chloride is shown below. H O H3C— C— C— CI CH3 2-methylpropanoyl chloride Show the mechanism for the catalysed reaction between 2-methylpropanoyl chloride and benzene, using aluminium chloride as a catalyst. [5] 12201 [Turn over (b) Draw a dot and cross diagram for the aluminium-containing intermediate species formed by the catalyst during this reaction. [1] (c) A later step in the synthesis is shown below. HO Suggest the structure of the organic reagent used for the step shown. [1] (d) The acylation and alkylation reactions of benzene are substitution reactions. Explain why benzene undergoes substitution reactions rather than addition reactions. [1]

12201 17 The dissociation of water is an endothermic process. At 60 °C the ionic product of water, Kw, has a value of 9.3 × 10−14 mol2 dm−6. 2H2O(l)   ⇌    H3O+(aq)    +    OH−(aq) (a) (i) Write the expression for Kw. [1] (ii) Explain why the expression for Kw does not include the concentration of water. [1] (b) (i) Calculate the pH of water at 60 °C. Give your answer to two decimal places. [2] (ii) Explain whether water at 60 °C is neutral, acidic or alkaline. [2] 12201 [Turn over (iii) Calculate the pH of a solution containing 256.5 g of barium hydroxide dissolved in 500 cm3 of water at 60 °C. Give your answer to two decimal places. [4] (c) (i) An acidic buffer is formed when 10.0 cm3 of 0.12 mol dm−3 aqueous sodium hydroxide is added to 25.0 cm3 of 0.18 mol dm−3 ethanoic acid. Calculate the pH of this buffer. The pKa of ethanoic acid is 4.76. Give your answer to two decimal places. [4] (ii) Explain, using an equation, the effect of adding small amounts of acid to the buffer. [2]

12201 18 Sulfur dioxide is reacted with oxygen to form sulfur trioxide in the manufacture of sulfuric acid in the Contact Process. 2SO2(g)    +    O2(g)   ⇌    2SO3(g)    −197 kJ (a) State the pressure and catalyst used in this reaction. [2] (b) Explain why the temperature chosen for this reaction, 450 °C, can be described as a compromise temperature. [2] (c) Write an expression for Kc for the above reaction. [1] 12201 [Turn over (d) Sulfur dioxide, oxygen and sulfur trioxide were mixed and allowed to reach equilibrium in a 20 dm3 container. At equilibrium, 8.0 moles of sulfur dioxide and 10.0 moles of sulfur trioxide were present. Calculate the number of moles of oxygen present if the numerical value of Kc is 27.9 mol−1 dm3. [4]

12201 19 The lattice enthalpy of magnesium chloride is 2493 kJ mol−1 and that of calcium chloride is 2237 kJ mol−1. (a) (i) Write an equation, including state symbols, for the lattice enthalpy of calcium chloride. [2] (ii) Explain why the lattice enthalpy of magnesium chloride is greater than that of calcium chloride. [1] (b) (i) The enthalpy of solution of magnesium chloride is −155 kJ mol−1. Complete the following enthalpy diagram for dissolving magnesium chloride. MgCI2(s) [2] 12201 [Turn over (ii) Calculate the enthalpy of hydration of magnesium ions. The enthalpy of hydration of chloride ions is −364 kJ mol−1. [2]

12201 20 Cinnamaldehyde is a pale yellow liquid that can be obtained from the bark of cinnamon trees. cinnamaldehyde C C H H CHO H5C6 (a) (i) Cinnamaldehyde is a geometric isomer. State and explain which geometric isomer cinnamaldehyde is. [2] (ii) Explain how a pale yellow oil suspected as being cinnamaldehyde, could be identified using 2,4-dinitrophenylhydrazine. Include in your answer experimental details of the preparation of cinnamaldehyde-2,4- dinitrophenylhydrazone. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. 12201 [Turn over [6] (b) Write an equation for the reduction of cinnamaldehyde with lithal using [H] to represent the reducing agent. [1] (c) Oxidation of cinnamaldehyde produces cinnamic acid which is a solid at room temperature with a melting point of 132–133 °C. Explain why cinnamic acid has a higher melting point than cinnamaldehyde. [3]

12201 21 Ethanoyl chloride can be used in the preparation of esters. It reacts readily with moisture in the air. (a) Write an equation for the reaction of ethanoyl chloride with water. [1] (b) Describe a chemical test for the inorganic product of the reaction, indicating a positive result for this test. [2] (c) (i) Write an equation for the reaction of excess ethanoyl chloride with ethane-1,2-diol to produce an ester. [2] (ii) Calculate the percentage yield if 31 g of ethane-1,2-diol produces 49 g of the ester. [3] 12201 (d) State three advantages of using ethanoyl chloride instead of ethanoic acid in esterification reactions. [3] (e) Give the formula and the IUPAC name of a reagent that could convert ethanoic acid into ethanoyl chloride. [2] THIS IS THE END OF THE QUESTION PAPER 12201 BLANK PAGE DO NOT WRITE ON THIS PAGE 12201 BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 245088 DO NOT WRITE ON THIS PAGE Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

12188 12 The reaction between iron(III) and iodide ions may be studied in a cell as shown below. voltmeter – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – - – – – – – – – – – – – – – – – – – – – – – – – – V salt bridge solution of potassium iodide solution of iron(III) chloride Pt Pt A solution of iron(III) chloride is placed in one beaker and a solution of potassium iodide in the other beaker. A salt bridge connects the beakers. (a) The salt bridge can be made using a glass tube or paper. (i) Name a chemical which is usually used to make a salt bridge. [1] (ii) Describe how you would make a salt bridge from paper in the laboratory. [1] (iii) State two reasons for using a salt bridge in an electrochemical cell. [2] 12188 [Turn over (b) The electrode potentials for the two half-cells taking place in the reaction are: Fe3+(aq)  +  e ⇌ Fe2+(aq) +0.77 V I2(aq)  +  2e ⇌ 2I−(aq) +0.54 V (i) Calculate the emf of the cell. [2] (ii) Write a conventional representation for the cell. [2] (iii) Write the equation for the reaction taking place. [1] (iv) Explain which way electrons will flow in the cell. [2] 12188 (c) Before the cell operates Fe3+ ions and I− ions are present. After the cell operates Fe2+ ions are present together with I2 molecules. State how you would test for each of these species and the results expected for positive tests. (i) Fe3+ [2] (ii) Fe2+ [2] (iii) I− [2] (iv) I2 [2] 12188 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

12188 13 Petroselinic acid is a long chain fatty acid which is found in coriander seeds. CH3(CH2)10CH CH(CH2)4COOH petroselinic acid It is of interest because ozonolysis gives auric acid and adipic acid, used in the manufacture of nylon. CH3(CH2)10CH CH(CH2)4COOH →  CH3(CH2)10COOH  +  HOOC(CH2)4COOH petroselinic acid                      auric acid                adipic acid (a) Petroselinic acid is a positional isomer of oleic acid. It has the double bond in position 6; in oleic acid it is in position 9. (i) Suggest the meaning of the term positional isomer. [2] (ii) Draw the structures of the two fatty acids which are produced when oleic acid is ozonolysed. [2] O3 12188 [Turn over (b) The amount of petroselinic acid in coriander seeds can be determined by GLC. Petroselinic acid, which is a white solid, is first converted into its methyl ester which is a liquid. (i) Suggest why petroselinic acid is a solid and methyl petroselinate is a liquid. [2] (ii) Suggest why petroselinic acid is converted into the methyl ester for GLC analysis. [1] (iii) Explain how the percentage of petroselinic acid in a sample can be determined from a GLC chromatography trace. [2] 12188 (c) Nylon is made from the reaction of adipic acid with 1,6-diaminohexane. It is a condensation polymer. (i) Draw one repeating unit of the nylon polymer formed when adipic acid reacts with 1,6-diaminohexane. [2] (ii) Explain what is meant by the term condensation polymer. [1] (iii) Explain why nylon contains an amide bond and not a peptide link despite the fact that both bonds have the same structure. [1] (iv) Kevlar is a polymer formed by the reaction of 1,4-diaminobenzene with terephthaloyl dichloride. Write the equation for the reaction of one molecule of 1,4-diaminobenzene with one molecule of terephthaloyl dichloride. [3] 12188 [Turn over (v) Explain why both nylon and kevlar are biodegradable. [2] (d) Enzymes are also condensation polymers. Explain the primary, secondary and tertiary structures of enzymes. Include in your answer an explanation of the effect of pH and temperature on enzyme activity. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6]

12188 14 Pentane-2,4-dione (acetylacetone) is an unusual compound. It exists as a mixture of isomers. O C C H CH3 C O H3C keto form                            enol form O C C O H3C CH2 CH3 H (a) The nmr spectrum of pentane-2,4-dione at room temperature shows that it is a mixture of isomers. (i) On the following nmr axes draw the expected nmr spectrum, including an integration curve, of pentane-2,4-dione as the keto form. Use the data leaflet for your answer. 5 4 3 2 1 0 chemical shift / ppm [2] 12188 [Turn over (ii) The following is the nmr spectrum of pentane-2,4-dione as an enol at room temperature. Using the data in the data leaflet, label the peaks in the spectrum with the appropriate hydrogen atoms from the enol form. 6 5 4 3 2 1 0 chemical shift / ppm [2] (b) The infrared spectrum of pentane-2,4-dione is shown below. Explain how it suggests that pentane-2,4-dione is a mixture of isomers. 3000 2000 1000 wavenumber / cm−1 1 0.8 0.6 0.4 0.2 [2] 12188 (c) It is possible to titrate the enol isomer of pentane-2,4-dione using bromine because the C C bond reacts faster in an addition reaction than in any possible substitution reaction with bromine. (i) How would you slow down the substitution reaction before the titration was carried out? [1] (ii) How would you know that the end point had been reached? [1] (iii) In a titration, 25.0 cm3 of a 0.008 M solution of pentane-2,4-dione was reacted with a 0.002 M solution of bromine. The titration value was 4.6 cm3 of bromine solution. Use these values to calculate the percentage of pentane-2,4-dione which exists in the enol form. [4] 12188 [Turn over (d) Pentane-2,4-dione is a ligand represented by the symbol acac. It combines with many transition metal ions to form complexes. (i) How many coordinate bonds can pentane-2,4-dione form? [1] (ii) It reacts with copper(II) ions to form [Cu(acac)3]2+ which has an octahedral structure. Draw a 3D structure of this octahedral complex using dotted lines and wedges. [2] (iii) Explain why [Cu(acac)3]2+ reacts with edta. [2] (e) Pentane-2,4-dione does not form a hydrazone with phenylhydrazine. Instead, it forms a substituted pyrazole which has a melting point of 107–108 °C. Explain how this reaction can be used to identify pentane-2,4-dione. [1]

12188 15 Methyl red is a dye and can be used as an indicator. It is synthesised by the reaction of dimethylaniline with the diazonium salt of anthranilic acid. O NH2 HO O N N + HO O N HO N N N methyl red (a) Name the reagents used to produce the diazonium ion and the condition under which they are used. [2] (b) (i) Explain why methyl red is a coloured compound. [4] 12188 [Turn over (ii) Methyl red is red in its acidic form and yellow in its basic form. N H3C CH3 N N COO− H H3C CH3 COO− N N N + +H+ −H+ ⇌ basic form acidic form Suggest why the two forms have different colours. [2] (c) Methyl red is insoluble in water. It forms a sodium salt which has a solubility of 800 mg in 1 cm3 of water. Explain why methyl red is insoluble in water but the sodium salt is soluble in water. [2] 12188 (d) The synthesis of anthranilic acid may be carried out as follows. CH3 CH3 NO2 COOH NO2 COOH NH2 (i) Name the reagents used to carry out the nitration of methylbenzene. [2] (ii) The reagent used to oxidise the 2-methylnitrobenzene is acidified potassium manganate(VII). State the colour change observed. [2] 12188 (e) The reduction of the nitrobenzoic acid is carried out using tin and concentrated hydrochloric acid. (i) Write the equation for the reaction of tin with hydrochloric acid. [2] (ii) The anthranilic acid is obtained as the phenylammonium salt. Draw the structure of the salt and explain why the addition of sodium hydroxide solution liberates the amino group but does not produce anthranilic acid. [3] THIS IS THE END OF THE QUESTION PAPER 12188 BLANK PAGE DO NOT WRITE ON THIS PAGE 12188 BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 243678 DO NOT WRITE ON THIS PAGE Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

12289.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Friday 3 May 2019. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before Friday 3 May 2019. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while he/she is on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

12289.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger him/herself or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification need be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 12289.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Chemistry Practical Booklet A [ACH31] Thursday 9 May 2019 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

11852 [Turn over 10 Which species is the most powerful oxidising agent? A Bromide B Bromine C Chloride D Chlorine 11852 Section B Answer all six questions in the spaces provided. 11 Water can act as an acid or as a base. It can either lose or gain hydrogen ions. (a) State and explain the shape of a water molecule. [3] (b) Water can react with hydrogen ions forming hydroxonium ions, H3O+. (i) Draw a dot and cross diagram to show the bonding in a hydroxonium ion, showing all the outer shell electrons. [2] 11852 [Turn over (ii) Suggest why the bond angle in the hydroxonium ion is greater than the bond angle in water. [2] (iii) Suggest why the hydroxonium ion does not react with a hydrogen ion to form H4O2+. [1]

11852 12 Four new elements have recently been added to the Periodic Table. The four elements are given below, along with their atomic numbers and the mass numbers of their most common isotope. element atomic number mass number nihonium 113 286 moscovium 115 289 tennessine 117 294 oganesson 118 294 (a) What is the meaning of the following terms? (i) Atomic number [1] (ii) Mass number [1] (iii) Isotopes [1] (b) State and explain which element has the most neutrons. [2] 11852 [Turn over (c) Suggest why tennessine is placed in Group VII of the Periodic Table. [1] (d) Erbium is a soft, silvery solid that tarnishes slowly in air. It is used in fibre optic cables. There are six known isotopes of erbium and its relative atomic mass is 167.26. (i) Define the term relative isotopic mass. [2] (ii) The table below gives the percentage abundances of six isotopes in the mass spectrum of erbium. relative isotopic mass 161.93 163.93 165.93 167.93 169.94 % abundance 0.14 1.60 33.50 22.87 26.98 14.91 Calculate the missing relative isotopic mass. [3]

11852 13 Chloroauric acid, HAuCl4, is an orange solid that is used widely in gold refining. During World War II, the Hungarian chemist George de Hevesy dissolved two gold Nobel Prize medals in a mixture of concentrated nitric and hydrochloric acids to prevent the Germans from confiscating them. Later the medals were reconstructed from the dissolved chloroauric acid and returned. (a) The reaction between gold, concentrated hydrochloric acid and concentrated nitric acid produces chloroauric acid, nitrogen(IV) oxide and water. Write the equation for this reaction. [2] (b) Gold is extracted from recycled electronic materials by reaction with chlorine and hydrochloric acid, forming chloroauric acid. Elemental gold is recovered by electrolysis of chloroauric acid. 2Au  +  3Cl2  +  2HCl  →  2HAuCl4 (i) Deduce the oxidation state of gold in chloroauric acid. [1] (ii) With reference to oxidation numbers, explain why this is a redox reaction. [3] 11852 [Turn over (c) When heated, chloroauric acid forms gold(III) chloride and hydrogen chloride gas. The bonding in gold(III) chloride is considered to be covalent. (i) Suggest, in terms of electronegativity, why the bonding in gold(III) chloride is covalent. [1] (ii) Describe the chemical test for hydrogen chloride gas. [2]

11852 14 The recommended daily allowance for salt, sodium chloride, is 6.0 g. Eating too much salt can lead to high blood pressure, potentially causing heart disease and strokes. (a) State the electronic configuration of a sodium atom and use it to explain why sodium is regarded as an s-block element. [2] (b) (i) Define the term Avogadro’s constant. [1] (ii) Calculate the number of sodium ions in the recommended daily allowance of sodium chloride. [2] (c) A solid sample of salt was analysed to confirm the identity of the ions present. A flame test was first conducted on the sample using nichrome wire and concentrated hydrochloric acid to identify sodium ions. The presence of chloride ions was subsequently confirmed. (i) State two reasons why nichrome wire was used. [2] 11852 [Turn over (ii) State two reasons why concentrated hydrochloric acid was used. [2] (iii) State the colour observed in the flame test. [1] (d) Describe how the presence of chloride ions could be confirmed in the solid salt. [4] (e) A second salt sample was thought to be contaminated with sodium carbonate. Describe a chemical test to confirm the presence of carbonate ions. [3] 11852 (f) The salt sample, of mass 6.0 g, contaminated with sodium carbonate was dissolved in water. A solution of magnesium chloride was added, forming a precipitate of magnesium carbonate. The precipitate was filtered off and dried to give 1.4 g of magnesium carbonate. (i) Draw a dot and cross diagram to show the bonding in magnesium chloride showing all the outer electrons. [2] (ii) Write the equation for the reaction between sodium carbonate and magnesium chloride. [2] 11852 [Turn over (iii) Use the following headings to calculate the percentage of sodium carbonate in the salt sample. Relative formula mass of magnesium carbonate Number of moles of magnesium carbonate Number of moles of sodium carbonate Relative formula mass of sodium carbonate Mass of sodium carbonate in the sample Percentage of sodium carbonate in the sample [6]

11852 15 The third Period in the Periodic Table from sodium to argon displays a number of periodic trends. (a) State and explain the general trend in first ionisation energy across Period three. [3] (b) (i) Write an equation, including state symbols, for the first ionisation energy of phosphorus. [2] (ii) Explain why the first ionisation energy of phosphorus is higher than that of sulfur. [2] 11852 [Turn over (c) The graph below shows the melting points of the elements in the third Period. Na Mg Al Si P S Cl Ar 1800 1600 1400 1200 1000 800 600 400 200 0 melting point/K With reference to the structure and bonding of the elements, explain the change in melting point from silicon to argon. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6]

11852 16 Lead(II) iodide is yellow and was once used as a pigment in paint until concerns over its toxicity led to its use being discontinued. It has a low solubility in water. (a) Lead(II) iodide can be prepared by reaction between solutions of potassium iodide and lead(II) nitrate. Write the equation for this reaction. [2] (b) 75.6 mg of lead(II) iodide dissolve in 100 cm3 of water at 20°C. Calculate the molarity of iodide ions in a saturated solution of lead(II) iodide at 20°C. [4] (c) Chlorine water was added to potassium iodide solution in a test tube. (i) State the colour observed. [1] (ii) A solution of starch was then added to the test tube. State the colour observed. [1] 11852 (d) (i) State three observations made when concentrated sulfuric acid is added to solid potassium iodide. [3] (ii) Explain why concentrated phosphoric acid does not give iodine when added to solid potassium iodide. [1] THIS IS THE END OF THE QUESTION PAPER Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 241678 DO NOT WRITE ON THIS PAGE Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

12183.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Monday 29 April 2019. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before 29 April 2019. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while he/she is on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

12183.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger him/herself or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification need be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 12183.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Subsidiary Chemistry Practical Booklet A [SCH31] Wednesday 1 May 2019 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number

page 02 SECTION 1 — 30 marks Attempt ALL questions 1. In an emission spectrum of mercury, the line at 310 nm is due to A energy from the ultraviolet region of the electromagnetic spectrum being absorbed B energy from the ultraviolet region of the electromagnetic spectrum being released C energy from the visible region of the electromagnetic spectrum being absorbed D energy from the visible region of the electromagnetic spectrum being released. 2. In which of the following changes would heating to constant mass allow the mass of water produced to be determined? A CH3CH2OH(ℓ)  ↓  C2H4(g)  +  H2O(ℓ) B CH4(g)  +  2O2(g)  ↓  CO2(g)  +  2H2O(ℓ) C KOH(aq)  +  HCl(aq)  ↓  KCl(aq)  +  H2O(ℓ) D Na2CO3.10H2O(s)  ↓  Na2CO3(s)  +  10H2O(ℓ) 3. Which of the following reagents would be most suitable for the gravimetric determination of magnesium ions in water? A Sodium nitrate B Silver(I) nitrate C Sodium carbonate D Silver(I) carbonate 4. Hund’s rule states that A electrons occupy degenerate orbitals singly with parallel spins before pairing B no two electrons in an atom can have the same set of four quantum numbers C electrons occupy orbitals in order of increasing energy D the energy of an electron in an atom is quantised.

page 03 5. Which of the following molecules contains the smallest bond angle? A BeCl2 B BCl3 C CCl4 D PCl5 6. Iron forms both Fe2+ and Fe3+ ions. Which of the following statements is correct? A Fe2+ ions have more occupied energy levels than Fe3+ ions B Fe2+ ions have more unpaired electrons than Fe3+ ions C Fe3+ ions are a better reducing agent than Fe2+ ions D Fe3+ ions are more stable than Fe2+ ions 7. Which metal in the following ions has the highest oxidation state? A Cr2O7 2− B MnO4 − C VO2+ D Sn4+ [Turn over

page 04 8. The copper complex shown can be used as a green food colouring. Cu O O O ONa ONa ONa N N N N Which line in the table is correct for this complex? Co-ordination number of copper Classification of ligand A 2 monodentate B 2 tetradentate C 4 monodentate D 4 tetradentate 9. 2X(g)  ∏  Y(g)      ∆H = −220 kJ mol−1 Which of the following changes will cause the equilibrium constant to increase? A Decrease in temperature B Increase in temperature C Decrease in pressure D Increase in pressure

page 05 10. The following graph shows the variation in ∆G with temperature (T ) for a reaction. ∆G (kJ mol−1) + 0 200 400 − T (K) Which of the following statements is true? A The reaction is never feasible B The reaction is always feasible C The reaction is feasible above 300 K D The reaction is feasible below 300 K 11. Iron(III) oxide can be reduced to iron using hydrogen. Fe2O3(s)  +  3H2(g)  ↓  2Fe(s)  +  3H2O(g) Substance ∆Hf° (kJ mol−1) Fe2O3(s) −822 H2(g) 0 Fe(s) 0 H2O(g) −242 The enthalpy change, ∆H °, in kJ mol−1, for the reduction of iron(III) oxide using hydrogen is A −580 B −96 C +96 D +580. [Turn over

page 06 12. Which line in the table is correct for water condensing? ∆H ∆S A positive negative B negative negative C positive positive D negative positive 13. The results in the table were obtained for the reaction X  +  2Y  ↓  Z Experiment [X] (mol l−1) [Y] (mol l−1) Initial rate (mol l−1 s−1) 1 0·030 0·030 0·0064 2 0·060 0·030 0·0128 3 0·030 0·015 0·0064 From these results, the rate equation is A rate = k[X] B rate = k[Y] C rate = k[X][Y] D rate = k[X][Y]2. 14. The rate of a chemical reaction is second order overall. The units for the rate constant, k, are A mol l−1 s−1 B l mol−1 s−1 C l2 mol−2 s−1 D l−2 mol2 s−1.

page 07 15. The structure of 2-furonitrile is shown. C O C N C H C H C H The number of pi bonds in 2-furonitrile is A 2 B 3 C 4 D 7. 16. The structure of one form of vitamin B3 is shown. OH N O The molecular formula of this structure is A C6H5O2N B C6H6O2N C C7H5O2N D C7H6O2N. 17. Which of the following compounds exhibits geometric isomerism? CH3 CH3 CH3CH2CH2CH CH2 CH3CH CCH3 CH3CH2CH CH3CH2C CH2 CHCH3 A B C D [Turn over page 08 18. The systematic name of the molecule shown above is A cis-2,3-diethylbut-2-ene B trans-2,3-diethylbut-2-ene C cis-3,4-dimethylhex-3-ene D trans-3,4-dimethylhex-3-ene. 19. The structures shown below are isomeric amines. N H3C CH3 CH3 N H3C C2H5 H ethylmethylamine trimethylamine Which line in the table is correct for trimethylamine when compared to ethylmethylamine? Boiling point Solubility in water A higher higher B higher lower C lower higher D lower lower

page 09 20. The reaction of butanone with lithium aluminium hydride produces A butanoic acid B butan-2-ol C butan-1-ol D butanal. 21. NO2 NH2 NHCOCH3 step 1 step 2 step 3 benzene nitrobenzene phenylamine N-phenylethanamide Which line in the table is correct for the types of reaction taking place at steps 1, 2 and 3? Step 1 Step 2 Step 3 A addition reduction condensation B electrophilic substitution nucleophilic substitution neutralisation C electrophilic substitution reduction condensation D addition nucleophilic substitution neutralisation 22. Carboxylic acids can be prepared in different ways. Which of the following is a suitable method for preparing a carboxylic acid in one reaction? A Addition to an alkene B Hydrolysis of a nitrile C Reduction of an aldehyde D Substitution of a haloalkane [Turn over

page 10 23. A student attempted to predict the mass spectrum of propanone. The predicted spectrum is shown below. intensity m/z 5 10 15 A B C D 20 25 30 35 40 45 50 55 60 The actual mass spectrum of propanone contains only three main peaks. Which of the above peaks would not appear in the actual mass spectrum? 24. Analysis of a compound shows the following percentage composition by mass. C = 80·0%    H = 9·3%    O = 10·7% The empirical formula for this compound is A C10H14O B C14H10O C C14H20O D C20H14O. 25. H O C H H H C H H Which of the following splitting patterns would be observed for the circled atom in the high resolution 1H NMR spectrum of ethanol? A Doublet B Triplet C Quartet D Quintet

page 11 26. Pramipexole is a drug used to treat the symptoms of Parkinson’s disease. Pramipexole acts like a natural compound in the body, dopamine, to stimulate nerve cells. Buprenorphine is a drug used to treat heroin addiction. Buprenorphine stimulates receptors in the body but produces less of a response compared to heroin. Which line in the table best describes pramipexole and buprenorphine? Pramipexole Buprenorphine A agonist agonist B agonist antagonist C antagonist agonist D antagonist antagonist 27. The human nose can generally detect the toxic gas hydrogen sulfide at levels of 0·03 ppm. If a person inhales 6 litres of air per minute, containing 0·03 ppm of hydrogen sulphide, what mass of hydrogen sulfide is inhaled in 10 minutes? A 2 g B 1·8 g C 200 mg D 1·8 mg 28. Which of the following techniques could be used to purify an impure sample of solid caffeine? A Thin layer chromatography B Heating under reflux C Recrystallisation D Distillation [Turn over

page 12 29. When substance X is distributed between equal volumes of two immiscible solvents, water and dichloromethane, an equilibrium will be established. X(H2O)  ∏  X(CH2Cl2)      K = 4 In the diagrams below, the number of dots represents the relative distribution of X in the two solvents. Water is less dense than dichloromethane. Which of the following shows the correct distribution of X between the two solvents at equilibrium? H2O H2O CH2Cl2 CH2Cl2 H2O H2O CH2Cl2 CH2Cl2 A B C D 30. A complexometric titration can be used to determine the concentration of A calcium ions in milk B chloride ions in sea water C ethanoic acid in vinegar D ethanol in wine. [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] AH FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2019 You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Total marks — 100 SECTION 1 — 30 marks Attempt ALL questions. Instructions for the completion of Section 1 are given on page 02. SECTION 2 — 70 marks Attempt ALL questions. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. You should score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X713/77/01 FRIDAY, 10 MAY 9:00 AM – 11:30 AM A/PB Chemistry Section 1 — Answer grid and Section 2 page 02 SECTION 1 — 30 marks The questions for Section 1 are contained in the question paper X713/77/02. Read these and record your answers on the answer grid on page 03 opposite. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the additional space for answers and rough work at the end of this booklet. Sample question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D page 03 A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 A B C D 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SECTION 1 — Answer grid [Turn over page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 05 MARKS DO NOT WRITE IN THIS MARGIN SECTION 2 — 70 marks Attempt ALL questions 1. Chlorine forms many compounds with other elements. (a) The electronic configuration for a chlorine atom in its ground state is shown. 2p 1s 2s 3s 3p Circle one electron in the above diagram that can be described by the following set of quantum numbers. n = 2, l = 1, m = −1, s = + (An additional diagram, if required, can be found on page 28.) (b) A compound of chlorine, boron trichloride, reacts with hydrogen to produce boron. BCl3(g)  + H2(g)  ↓  B(s)  +  3HCl(g)      ∆H ° = 127 kJ mol−1 The standard entropy change, ∆S °, is 79·4 J K−1 mol−1. Calculate ∆G °, in kJ mol−1, for this reaction at 298 K. 1 2 [Turn over page 06 MARKS DO NOT WRITE IN THIS MARGIN 1. (continued) (c) Another compound of chlorine, silver(I) chloride, forms an equilibrium mixture with excess chloride ions. AgCl(s)  +  Cl−(aq)  ∏  AgCl2 −(aq)      ∆G° = 25·6 kJ mol−1 at 298 K ∆G° and the equilibrium constant, K, are related as shown. ∆G ° = −2·30 RT log10 K R = 8·31 × 10−3 kJ K−1 mol−1 T = Temperature in Kelvin Use this information to calculate the equilibrium constant, K, for this reaction. 2 page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. Reaction kinetics can be used to determine the order and mechanism of chemical reactions. A proposed mechanism for the reaction between hydrogen peroxide, H2O2(aq), and iodide ions, I−(aq), is shown below. Step 1 H2O2(aq) + I−(aq) ↓IO−(aq) + H2O(ℓ) slow Step 2 IO−(aq) + H3O+(aq) ↓HIO(aq) + H2O(ℓ) fast Step 3 HIO(aq) + H3O+(aq) + I−(aq) ↓ I2(aq) + 2H2O(ℓ) fast (a) State what is meant by the order of a reaction. (b) (i) Determine the overall order of reaction for the mechanism above. (ii) Write the rate equation for this reaction. (c) Write a balanced equation for the overall reaction. 1 1 1 1 [Turn over page 08 MARKS DO NOT WRITE IN THIS MARGIN 3. Brass is a useful alloy of copper and zinc. To determine the percentage of copper in a brass screw, a student dissolved the screw in 20 cm3 of concentrated nitric acid and made the resulting solution up to 250 cm3 in a volumetric flask. Five standard solutions were prepared by diluting a 0·10 mol l−1 stock solution of copper(II) nitrate with deionised water. (a) One of the standard solutions had a concentration of 0·010 mol l−1. Describe fully how this 0·010 mol l−1 solution should be prepared in a 50 cm3 volumetric flask from the 0·10 mol l−1 stock solution. (b) The colorimeter was fitted with a suitable filter and set to zero using a reference sample. The absorbance of the five standard solutions was determined and a calibration graph was drawn. 0∙30 0∙00 0∙40 0∙10 0∙50 0∙20 0∙60 0∙70 0∙80 absorbance 0∙000 0∙010 0∙020 0∙030 0∙040 0∙050 0∙060 0∙070 0∙080 concentration of Cu2+ (mol l−1) (i) Name the substance that should be used to set the colorimeter to zero. 2 1 page 09 MARKS DO NOT WRITE IN THIS MARGIN 3. (b) (continued) (ii) The absorbance of the sample solution was 0·71. The sample solution was then diluted to decrease the concentration by half. The absorbance of this diluted solution was then measured. Explain why the sample solution was diluted. (iii) The mass of the screw was 1·43 g. The absorbance of the diluted solution was 0·34. Calculate the percentage by mass of copper in the screw. 1 3 [Turn over page 10 MARKS DO NOT WRITE IN THIS MARGIN 4. There are different definitions for acids and bases. (a) One definition for acids and bases was proposed by Johannes Brønsted and Thomas Lowry. (i) State the Brønsted-Lowry definition for a base. (ii) A solution of hydrogen peroxide consists of two acid-conjugate base pairs. H2O2(aq)  +  H2O(ℓ)  ∏  H3O+(aq)  +  HO2 −(aq) Complete the table to identify one of the acid-conjugate base pairs. Acid Conjugate base (b) Another definition for acids and bases was proposed by Gilbert Lewis. A Lewis acid is a substance that can accept a pair of non-bonding electrons. A Lewis base is a substance that can donate a pair of non‑bonding electrons. An example of a Lewis acid-base reaction is shown. B(OH)3(aq)  +  2H2O(ℓ)  ∏  [B(OH)4]−(aq)  +  H3O+(aq) Explain why this is a Lewis acid-base reaction. 1 1 1 page 11 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (c) Acids can be classified as strong or weak. The table contains information about four acids. Name of acid Formula Ka at 298 K ethanoic CH3COOH 1·7 × 10−5 chloroethanoic CH2ClCOOH 1·6 × 10−3 dichloroethanoic CHCl2COOH 5·0 × 10−2 trichloroethanoic CCl3COOH 2·3 × 10−1 (i) Describe the relationship between the number of chlorine atoms in an acid molecule and the strength of the acid. (ii) 1·89 g of chloroethanoic acid was dissolved in deionised water and the solution was made up to 250 cm3 in a volumetric flask. (A) Calculate the concentration, in mol l−1, of the chloroethanoic acid solution. (B) Using your answer to (A) calculate the pH of the chloroethanoic acid solution. 1 1 2 [Turn over page 12 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (d) The action of pH indicators and buffer solutions involves the chemistry of acids and bases. Using your knowledge of chemistry, discuss the role of acids and bases in pH indicators and buffer solutions. 3 page 13 MARKS DO NOT WRITE IN THIS MARGIN 5. Electron transitions are responsible for some of the properties of metals such as sodium, zinc and strontium, and their compounds. (a) The orange-yellow colour emitted by some fireworks is due to electron transitions in sodium. The colour is produced when excited electrons return to their ground state. State what caused the electrons to become excited. (b) A solution containing the complex ion [Zn(H2O)6]2+ is colourless. (i) State the name of this complex ion. (ii) Electron transitions involving the d-subshell can give rise to colour in transition metal complexes. Explain fully why a solution of the complex ion [Zn(H2O)6]2+ is colourless. 1 1 2 [Turn over page 14 MARKS DO NOT WRITE IN THIS MARGIN 5. (continued) (c) Photoelectron spectroscopy is a technique that provides information on electrons and energy levels in atoms. It uses electromagnetic radiation to eject electrons from an atom and measures the kinetic energy of these emitted electrons. (i) A sample of strontium was exposed to electromagnetic radiation with a frequency of 3·08 × 1017 s−1. Calculate the energy, in J, of this electromagnetic radiation. (ii) Binding energy, Eb, is the energy required to eject an electron from an atom. Binding energy is calculated in electron volts, eV, using the relationship Eb = E − Ek Eb = binding energy E = energy of electromagnetic radiation Ek = kinetic energy of electron emitted 1 Joule = 6·24 × 1018 eV An electron was emitted with a kinetic energy, Ek, of 1254 eV. Using your answer to part (i), calculate the binding energy, in eV, for this electron. 1 2 page 15 [Turn over for next question DO NOT WRITE ON THIS PAGE page 16 MARKS DO NOT WRITE IN THIS MARGIN 6. The concentration of ethanol in vodka can be determined by reacting the ethanol with excess acidified potassium dichromate solution. 20·0 cm3 of vodka was transferred to a 1 litre volumetric flask and made up to the mark with deionised water. 1·0 cm3 of the diluted vodka was pipetted into a conical flask. 25·0 cm3 of 0·010 mol l−1 acidified potassium dichromate was added to the conical flask. The conical flask was then stoppered and warmed until the reaction was complete. 3C2H5OH(aq) + 2Cr2O7 2−(aq) + 16H+(aq)  ↓  3CH3COOH(aq) + 4Cr3+(aq) + 11H2O(ℓ) It was found that 1·65 × 10−4 moles of dichromate ions were left unreacted. (a) Calculate the concentration of ethanol, in mol l−1, in the undiluted vodka. (b) Explain why the acidified potassium dichromate was added in excess. 3 1 page 17 MARKS DO NOT WRITE IN THIS MARGIN 6. (continued) (c) The experimentally determined value was higher than the actual concentration of ethanol in the vodka. Other than apparatus uncertainties and transfer errors, suggest a reason why the experimentally determined concentration of ethanol was higher. (d) Describe a suitable control experiment that could be used to validate this technique. 1 1 [Turn over page 18 MARKS DO NOT WRITE IN THIS MARGIN 7. Carmine is a red pigment formed in a precipitation reaction. O OH OH O O O O OH AI O O OH OH −O H2O O O OH OH OH OH HO O OH OH OH HO OH −O Ca2+ carmine (a) Carmine can be removed from the reaction mixture by filtration. Suggest how the filtration could be carried out to ensure fast separation. (b) The structure shown above contains both pi and sigma bonds. (i) Explain how a sigma bond is formed. (ii) A pi bond is formed as a result of sp2 hybridisation. Explain what is meant by sp2 hybridisation. 1 1 1 page 19 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (c) Carmine contains a conjugated system. Explain fully how this conjugated system gives rise to the red colour of carmine. (d) The use of carmine as a dye was largely abandoned in the nineteenth century. One of the pigments used to replace carmine is alizarin. Alizarin can be extracted from the root of a plant using methanol. OH OH O O alizarin (i) Explain why methanol is a suitable solvent for this extraction. 2 1 [Turn over page 20 MARKS DO NOT WRITE IN THIS MARGIN 7. (d) (continued) (ii) The infrared spectrum of alizarin is shown below. 0 50 100 4000 3000 2000 1500 1000 500 wavenumber (cm−1) transmittance (%) (A) Explain the effect infrared radiation has on the bonds within molecules and how this allows different functional groups to be identified. (B) Circle a functional group in the structure below that is responsible for the peak at 3395 cm−1. (An additional diagram, if required, can be found on page 28.) OH OH O O 2 1 page 21 MARKS DO NOT WRITE IN THIS MARGIN 7. (d) (ii) continued (C) For the peak at 3395 cm−1 calculate (I) the wavelength, in metres (II) the energy, in kJ mol−1, associated with this wavelength. 1 2 [Turn over page 22 MARKS DO NOT WRITE IN THIS MARGIN 8. Benzene, cyclohexene and cyclohexane are cyclic hydrocarbons with six carbon atoms. Each hydrocarbon takes part in a wide variety of chemical reactions. Using your knowledge of chemistry, discuss the reactions of these hydrocarbons. 3 page 23 MARKS DO NOT WRITE IN THIS MARGIN 9. Ephedrine can be used to prevent low blood pressure. N OH H ephedrine (a) Ephedrine can exist as different optical isomers due to the presence of chiral centres. (i) Circle a chiral centre in the structure of ephedrine shown above. (An additional diagram, if required, can be found on page 28.) (ii) State what is meant by the term optical isomers. 1 1 [Turn over page 24 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (b) The psychoactive substance cathinone has a similar structure to ephedrine and can be synthesised under certain conditions in two steps as shown. O O Br O O NH Br 2 Step 1 Step 2 1-phenylpropanone, GFM = 134 g cathinone, GFM = 149 g Br2 NH3 (i) Suggest the type of chemical reaction taking place in Step 2 of the synthesis. (ii) Calculate the mass of cathinone produced from 9∙50 g of 1-phenylpropanone, assuming a percentage yield of 71∙8%. 1 3 page 25 MARKS DO NOT WRITE IN THIS MARGIN 10. Compound X can be added to petrol to make it burn more smoothly. H3C C CH3 CH3 CH3 O compound X (a) Compound X belongs to a class of organic compounds. Name this class of organic compounds. (b) (i) Draw a skeletal structural formula for compound X. (ii) Write the systematic name for compound X. 1 1 1 [Turn over page 26 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (c) Compound X can be produced by reacting 2-chloromethylpropane with methoxide ions. C H3C CH3 Cl CH3 H3C O− H3C C CH3 CH3 O CH3 + compound X 2-chloromethylpropane methoxide ion (i) Methoxide ions can be produced by reacting sodium with a reagent. Name the reagent. (ii) The reaction between 2-chloromethylpropane and methoxide ions proceeds by an SN1 mechanism involving a carbocation intermediate. Using structural formulae and curly arrow notation, outline the mechanism for this reaction. (iii) Suggest why this reaction is more likely to proceed by an SN1 mechanism rather than an SN2 mechanism. 1 2 1 page 27 MARKS DO NOT WRITE IN THIS MARGIN 10. (continued) (d) Compound X is not optically active. Draw an isomer of compound X that is optically active. (e) The low resolution 1H NMR spectrum for compound X shown below is incomplete. Complete the spectrum by drawing one line to show the correct chemical shift and relative intensity for the other hydrogen environment. (An additional diagram, if required, can be found on page 29.) 10 9 8 7 6 5 4 3 2 1 0 TMS relative intensity chemical shift (ppm) 11 [END OF QUESTION PAPER] 1 2 page 28 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL DIAGRAM FOR USE IN QUESTION 1 (a) 2p 1s 2s 3s 3p ADDITIONAL DIAGRAM FOR USE IN QUESTION 7 (d) (ii) B OH OH O O ADDITIONAL DIAGRAM FOR USE IN QUESTION 9 (a) (i) N OH H ephedrine page 29 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL DIAGRAM FOR USE IN QUESTION 10 (e) 10 9 8 7 6 5 4 3 2 1 0 TMS relative intensity chemical shift (ppm) 11 page 30 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 31 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 32 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

page 02 Total marks — 25 Attempt ALL questions 1. Hydrogen will form a non-polar covalent bond with an element that has an electronegativity value of A 0·9 B 1·5 C 2·2 D 2·5. 2. Which of the following is a polar molecule? A CCl4 B NH3 C CO2 D CH4 3. Which of the following is most likely to act as a reducing agent? A CO B MnO4 - C H2O2 D Cr2O7 2- 4. The following reactions take place when nitric acid is added to zinc. NO3 - (aq) + 4H+(aq) + 3e- ↓ NO(g) + 2H2O(ℓ) Zn(s) ↓ Zn2+ (aq) + 2e- How many moles of Zn(s) are oxidised by one mole of NO3 - (aq)? A 0·67 B 1·0 C 1·5 D 2·0

page 03 5. Which of the following compounds is a tertiary alcohol? A 2,2-dimethylpropan-1-ol B 2-methylbutan-2-ol C pentan-3-ol D 3-methylbutan-2-ol 6. Molecule X has the structure CH2 C CH COOH H2N CH CH3 O N H N H C O CH(CH3)2 Which of the following could be produced by partial hydrolysis of X? CH COOH H2N CH2 CH(CH3)2 CH COOH H2N CH2 CH3 CH COOH H2N CH CH3 CH(CH3)2 CH2 COOH H2N CH CH CH(CH3)2 C O N H C O N H C O N H C O N H A B C D 7. A compound with molecular formula C6H12O2 could be A pentyl ethanoate B hexan-2-one C 3-methylpentan-2-ol D hexanoic acid. [Turn over

page 04 8. Compound X reacted with hot copper(II) oxide and the resulting product did not give a colour change when heated with Fehling’s solution. Compound X could be A pentan-1-ol B pentan-2-ol C pentan-3-one D pentanoic acid. 9. The structure of pivalic acid is shown. CH3 O C C OH H3C H3C Which of the following is the correct systematic name of pivalic acid? A pentanoic acid B 2,2,2-trimethylethanoic acid C 2-ethylpropanoic acid D 2,2-dimethylpropanoic acid

page 05 10. The table shows four compounds that contribute to the aroma of spices. Which compound is not derived from a terpene? Structural formula Molecular formula A CH C CH C C H2C H2C H2C H3C CH3 O C10H14O B C HC C CH CH H HC HC H3C H3C C O C10H12O C C C CH2 CH2 H2C H3C CH3 HC CH OH CH3 C10H18O D C CH CH HC HC O HC CH HC C H C9H8O 11. Which reaction can be classified as reduction? A methanol ↓ methanoic acid B propanal ↓ propanoic acid C butan-2-one ↓ butan-2-ol D propan-2-ol ↓ propanone [Turn over

page 06 12. A secondary amine has two carbon atoms directly bonded to the nitrogen atom. Which of the following is a secondary amine? C H N H C H H H H H H H H H H C C H C H N H H H C N C H C H H H H H H H H H C N C C C H H H H H H H H H H H C A B C D 13. The number of moles of ions in 1 mol of copper(II) phosphate is A 1 B 2 C 3 D 5.

page 07 14. Which of the following gas samples has the same volume as 4·0 g of methane, CH4? (All volumes are measured at the same temperature and pressure.) A 1·0 g of helium B 1·0 g of hydrogen C 3·5 g of nitrogen D 35·5 g of chlorine 15. Magnesium carbonate reacts with nitric acid. MgCO3(s) + 2HNO3(aq) ↓ Mg(NO3)2(aq) + H2O(ℓ) + CO2(g) 0·05 mol of magnesium carbonate was added to a solution containing 0·06 mol of nitric acid. Which of the following statements is true? A 0·05 mol of carbon dioxide is produced B 0·06 mol of magnesium nitrate is produced C Magnesium carbonate is in excess by 0·02 mol D Nitric acid is in excess by 0·01 mol [Turn over

page 08 16. In which of the following diagrams does the dotted line represent a permanent dipole-permanent dipole interaction between propanone molecules? C H C H C H O H C H C H C H O H H H H H C H C H C H O H H H C H C H C H O H H H C H C H C H H C H C H C H O H O H H H H C H C H C H H C H C H C H O H O H H H H A B C D

page 09 17. Iron can be produced from iron(III) oxide. 2Fe2O3(s) + 3C(s) ↓ 4Fe(s) + 3CO2(g) GFM = 159∙6 g GFM = 12·0 g GFM = 55∙8 g GFM = 44·0 g The atom economy for the production of iron is A 69∙9% B 62∙8% C 58∙2% D 32∙5%. 18. 100 cm3 of propane is mixed with 600 cm3 of oxygen and the mixture is ignited. C3H8(g) + 5O2(g) ↓ 3CO2(g) + 4H2O(ℓ) At the end of the reaction, the total volume of gas would be A 300 cm3 B 400 cm3 C 700 cm3 D 800 cm3. 19. A two-step reaction is shown below. C B step 2 step 1 A The first step gave a yield of 60% and the second step a yield of 90%. The overall yield would be A 30% B 54% C 67% D 150%. [Turn over

page 10 20. The volume of hydrogen gas given off against time when an excess of zinc lumps is added to 100 cm3 of 1 mol l-1 hydrochloric acid is shown. time (seconds) volume of hydrogen (litres) Which of the following graphs would show the volume of hydrogen gas given off when an excess of zinc powder was added to 50 cm3 of 1 mol l-1 hydrochloric acid? time (seconds) time (seconds) time (seconds) time (seconds) volume of hydrogen (litres) volume of hydrogen (litres) volume of hydrogen (litres) volume of hydrogen (litres) A B C D

page 11 21. Consider the reaction pathway shown below. ΔH = b ΔH = c ΔH = d ΔH = a Y Z W X According to Hess’s Law A b = a - c - d B b = a + c + d C b = d - c + a D b = d + c - a. 22. Which of the following is not a factor that affects the rate of a reaction? A Activation energy B Kinetic energies of reactant molecules C Concentration of reactants D Enthalpy change of reaction 23. In which of the following reactions would the yield of product be increased by lowering the pressure? A H2(g) + I2(g) ∏ 2HI(g) B N2(g) + 3H2(g) ∏ 2NH3(g) C N2O4(g) ∏ 2NO2(g) D CO(g) + 2H2(g) ∏ CH3OH(g) [Turn over

page 12 24. The graph shows the distribution of kinetic energies for a reaction involving two gases. Ea kinetic energy number of molecules Which graph would show the effect of increasing temperature? Ea Ea Ea Ea kinetic energy kinetic energy kinetic energy kinetic energy number of molecules number of molecules number of molecules number of molecules A B C D

page 13 25. Alkenes react with ozone, O3, to form ozonides which can be decomposed to give carbonyl compounds. C C H C2H5 O3 H H C O C O + H C2H5 H H decomposition an ozonide Which of the following alkenes would produce a mixture of ethanal and propanone? CH3CH=CHCH2CH3 CH3CH=CHCH3 CH3C=CH2 CH3 CH3CH=CCH3 CH3 A C D B [END OF QUESTION PAPER] page 14 SPACE FOR ROUGH WORK page 15 SPACE FOR ROUGH WORK page 16 [BLANK PAGE] DO NOT WRITE ON THIS PAGE H FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2019 Instructions for the completion of Paper 1 are given on page 02. Record your answers on the answer grid on page 03. Use blue or black ink. Before leaving the examination room you must give your answer booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X813/76/02 Chemistry Paper 1 — Multiple choice Answer booklet FRIDAY, 10 MAY 9:00 AM – 9:40 AM A/PB page 02 Paper 1 — 25 marks The questions for Paper 1 are contained in the question paper X813/76/12. Read these and record your answers on the answer grid on page 03. Use blue or black ink. Do NOT use gel pens or pencil. 1. The answer to each question is either A, B, C or D. Decide what your answer is, then fill in the appropriate bubble (see sample question below). 2. There is only one correct answer to each question. 3. Any rough working should be done on the space for rough work at the end of the question paper X813/76/12. Sample question To show that the ink in a ball-pen consists of a mixture of dyes, the method of separation would be: A fractional distillation B chromatography C fractional crystallisation D filtration. The correct answer is B — chromatography. The answer B bubble has been clearly filled in (see below). A B C D Changing an answer If you decide to change your answer, cancel your first answer by putting a cross through it (see below) and fill in the answer you want. The answer below has been changed to D. A B C D If you then decide to change back to an answer you have already scored out, put a tick (3) to the right of the answer you want, as shown below: A B C D or A B C D page 03 Paper 1 — Answer grid A B C D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Chemistry page 04 [BLANK PAGE] DO NOT WRITE ON THIS PAGE H FOR OFFICIAL USE Fill in these boxes and read what is printed below. Number of seat Town © Mark Full name of centre Forename(s) Surname Scottish candidate number Date of birth Year Day Month National Qualications 2019 Total marks — 95 Attempt ALL questions. You may use a calculator. You may refer to the Chemistry Data Booklet for Higher and Advanced Higher. Write your answers clearly in the spaces provided in this booklet. Additional space for answers and rough work is provided at the end of this booklet. If you use this space you must clearly identify the question number you are attempting. Any rough work must be written in this booklet. Score through your rough work when you have written your final copy. Use blue or black ink. Before leaving the examination room you must give this booklet to the Invigilator; if you do not, you may lose all the marks for this paper. X813/76/01 FRIDAY, 10 MAY 10:10 AM – 12:30 PM A/PB Chemistry Paper 2 page 02 MARKS DO NOT WRITE IN THIS MARGIN Total marks — 95 Attempt ALL questions 1. Sodium thiosulfate, Na2S2O3, can be used to investigate the effect of reaction conditions on the rate of reaction. (a) Sodium thiosulfate solution reacts with hydrochloric acid to form a precipitate of solid sulfur. By placing the reaction mixture in a conical flask over a cross and recording the time taken for the cross to disappear, the effect of changing the reaction conditions can be investigated. sodium thiosulfate and water a cross drawn on paper stop timing when the cross disappears add 5∙0 cm3 hydrochloric acid and start timing (i) The equation for the reaction is Na2S2O3(aq) + HCl(aq) ↓ S(s) + SO2(g) + NaCl(aq) + H2O(ℓ) Balance the equation. 1 page 03 MARKS DO NOT WRITE IN THIS MARGIN 1. (a) (continued) (ii) In one set of experiments, the effect of varying the concentration of sodium thiosulfate was investigated. Experiment Volume of 0·15 mol l-1 Na2S2O3 (cm3) Volume of water (cm3) Rate (s-1) A 50 0 0·0454 B 40 0·0370 C 30 0·0285 D 20 0·0169 E 10 40 0·0063 (A) Complete the table to show the volumes of water that would have been used to vary the concentration of sodium thiosulfate. (B) Calculate the time, in seconds, for the cross to disappear in experiment C. [Turn over 1 1 page 04 MARKS DO NOT WRITE IN THIS MARGIN 1. (a) (continued) (iii) The reaction can also be used to investigate the effect of changing temperature on the rate of reaction. The results from an investigation are shown in the graph below. 80 40 0 0∙08 0∙14 0∙06 0∙12 0∙04 0∙10 0∙02 0∙00 temperature (°C) relative rate (s-1) 70 30 60 20 50 10 Use the graph to determine the temperature rise, in °C, required to double the rate of the reaction. (b) Collision theory states that for particles to react they must first collide with each other. State two conditions necessary for the collisions to result in the formation of products. 1 2 page 05 MARKS DO NOT WRITE IN THIS MARGIN 1. (continued) (c) Sodium thiosulfate also reacts with iron(III) nitrate. The potential energy diagram below shows the change in potential energy during the reaction carried out without a catalyst. potential energy (kJ mol-1) reaction pathway (i) Draw an X on the potential energy diagram above to show where the activated complex is formed. (An additional diagram, if required, can be found on page 41). (ii) Cu2+ ions catalyse the reaction. Add a dotted line to the diagram to show the change in potential energy with the catalyst. (An additional diagram, if required, can be found on page 41). [Turn over 1 1 page 06 MARKS DO NOT WRITE IN THIS MARGIN 2. 2019 is the 150th anniversary of the periodic table’s creation by Dmitri Mendeleev. The patterns identified by Mendeleev form the basis of the modern periodic table. The major periodic trends include ionisation energy and covalent radius. (a) The first ionisation energies of elements with atomic number 1 to 20 are shown in the graph. K Ar Ne He Na Li H atomic number ionisation energy (kJ mol-1) 20 15 10 5 0 2500 2000 1500 1000 500 0 (i) Explain why the first ionisation energy shows an increase going from lithium to neon. (ii) Explain why the first ionisation energy of potassium is less than the first ionisation energy of lithium. 1 1 page 07 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (b) A graph showing the ionisation energies for nitrogen is shown. 7 6 5 4 3 2 1 0 70000 60000 50000 40000 30000 20000 10000 0 ionisation energy (kJ mol-1) ionisation energy number (i) Write the equation for the second ionisation energy of nitrogen. (ii) Explain fully the increase between the 5th and 6th ionisation energies of nitrogen. [Turn over 1 2 page 08 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (c) Ionic radius is a measure of the size of an ion. Explain fully why the ionic radius of phosphorus is greater than the ionic radius of aluminium. 2 page 09 MARKS DO NOT WRITE IN THIS MARGIN 2. (continued) (d) The structure of an ionic compound consists of a giant lattice of oppositely charged ions. The arrangement of ions is determined by the ‘radius ratio’ of the ions involved. radius of positive ion radius ratio radius of negative ion = Na+ ion Cl- ion radius ratio = 0·52 Key sodium chloride Cs+ ion Cl- ion radius ratio = 0·96 Key caesium chloride By using the table of ionic radii on page 17 of the data booklet, predict whether the structure of barium oxide, BaO, is similar to caesium chloride or sodium chloride. Your answer must include a calculated radius ratio. 1 [Turn over page 10 MARKS DO NOT WRITE IN THIS MARGIN 3. The melting point of non-metal elements depends on structure and bonding. Using your knowledge of chemistry, comment on this statement. 3 page 11 MARKS DO NOT WRITE IN THIS MARGIN 4. Cider is made from apples in a process that involves crushing and pressing the apples, converting the sugars into alcohol, maturing and bottling. (a) Brewers add yeast, which contains a mixture of enzymes to convert the sugars in the apples into alcohol and carbon dioxide. (i) State what is meant by the term enzyme. (ii) The % mass of alcohol in the cider can be calculated using the formula mass of alcohol % mass of alcohol 100 mass of cider = × A 50·0 cm3 sample of cider was found to contain 3·05 g of alcohol. 1·0 cm3 of the cider weighed 1·36 g. Calculate the % mass of alcohol in the cider. (b) During the maturing process malic acid is converted to lactic acid and another product. lactic acid malic acid H C 3 HO OH CH2 C CH C CH C OH O O O OH OH X + (i) Name compound X. 1 1 1 [Turn over page 12 DO NOT WRITE IN THIS MARGIN 4. (b) (continued) (ii) The maturing process in cider samples can be monitored using thin layer chromatography. Samples of lactic acid, malic acid and ciders A, B, C, and D are spotted on a silica plate and the solvent allowed to travel up the plate. The chromatogram obtained is shown below. 6 5 4 3 2 1 sample applied solvent direction of movement of solvent distance moved by solvent = 16·4 cm Number Sample applied Distance moved by spot(s) (cm) 1 lactic acid 8·2 2 malic acid 4·1 3 cider A 4·1, 8·2 4 cider B 8·2 5 cider C 4·1 6 cider D 4·1, 8·2 page 13 MARKS DO NOT WRITE IN THIS MARGIN 4. (b) (ii) (continued) The retention factor, Rf, for a substance can be a useful method of identifying the substance. f distance moved by the substance R distance moved by the solvent = (A) Calculate the Rf value of malic acid. (B) The maturing process is complete when all of the malic acid has been converted to lactic acid. The cider is now ready to be bottled. Use the chromatogram to determine which cider is ready to be bottled. [Turn over 1 1 page 14 MARKS DO NOT WRITE IN THIS MARGIN 4. (continued) (c) Glycerol can be added to cider before bottling to produce a sweeter tasting cider. State the systematic name for glycerol. (d) Cider contains many naturally occurring compounds that affect taste and aroma. (i) Procyanidin B2 provides a bitter taste to cider. procyanidin B2 CH C HO C C C CH CH O CH C OH OH OH C C CH HC OH 2 HC CH CH C HO C C C C CH O CH C OH OH OH C C CH HC OH HC CH Explain fully why procyanidin B2 is water soluble. 1 2 page 15 MARKS DO NOT WRITE IN THIS MARGIN 4. (d) (continued) (ii) Cider smells of apples because it contains ethyl 2-methylbutanoate. C H H H C H C H CH3 H O C C H O H H H C H ethyl 2-methylbutanoate Name the carboxylic acid used to make ethyl 2-methylbutanoate. (iii) Farnesene is a terpene responsible for the ripe apple aroma of cider. H C 3 C 2 2 CH CH CH 3 CH 3 CH 3 CH CH 2 C CH 2 CH CH CH C farnesene Name the molecule on which terpenes are based. (e) Ethanol in cider can be oxidised to ethanal, spoiling the aroma. ethanal H3C H C O (i) Name the functional group circled in the ethanal molecule. (ii) Further oxidation of ethanal can produce another product that spoils the flavour of cider. Name this product. 1 1 1 1 [Turn over page 16 MARKS DO NOT WRITE IN THIS MARGIN 5. The combustion reactions of methane and heptane can be studied in different ways. (a) The combustion of methane produces carbon dioxide and water vapour when carried out at temperatures above 100 °C. CH4(g) + 2O2(g) ↓ CO2(g) + 2H2O(g) (i) Using bond enthalpies and mean bond enthalpies from the data booklet, calculate the enthalpy change, in kJ mol-1, for this reaction. (ii) Explain the difference between bond enthalpy and mean bond enthalpy. 2 1 page 17 MARKS DO NOT WRITE IN THIS MARGIN 5. (a) (continued) (iii) Calculate the mass, in g, of carbon dioxide produced by combustion of 200 cm3 methane in excess oxygen. Take the volume of 1 mole of methane gas to be 24 litres. CH4(g) + 2O2(g) ↓ CO2(g) + 2H2O(g) GFM = 44·0 g [Turn over 2 page 18 MARKS DO NOT WRITE IN THIS MARGIN 5. (continued) (b) The enthalpy of combustion of heptane, C7H16, can be determined using a calorimeter. thermometer draught shield container water heptane burner The following results were obtained. Mass of heptane burned (g) 1·1 Mass of 1 mole of heptane (g) 100·0 Volume of water used (cm3) 400 Initial temperature of water (°C) 26 Final temperature of water (°C) 49 (i) State the measurements required to calculate the mass of heptane burned in this experiment. 1 page 19 MARKS DO NOT WRITE IN THIS MARGIN 5. (b) (continued) (ii) Calculate the enthalpy of combustion, in kJ mol-1, for heptane from the experimental results given. (iii) The theoretical value for the enthalpy of combustion of heptane is significantly higher than the experimental value. Suggest why the experimental value is different to the theoretical value. [Turn over 3 1 page 20 MARKS DO NOT WRITE IN THIS MARGIN 6. Thiols are compounds that contain an –SH functional group. They often have very strong, unpleasant odours. (a) Ethanethiol is used to add a smell to gaseous fuels in order to give warnings of gas leaks. H C H H C H H S H ethanethiol (i) A student used the boiling points of ethanethiol and propan-1-ol to compare the strength of intermolecular forces. H C H H C H H S H H C H H C H H C O H H H propan-1-ol boiling point = 97 °C ethanethiol boiling point = 35 °C (A) State the reason why propan-1-ol was a suitable alcohol to compare with ethanethiol. (B) Explain why propan-1-ol has a higher boiling point than ethanethiol. Your answer should include the names of the intermolecular forces broken when each liquid boils. 1 2 page 21 MARKS DO NOT WRITE IN THIS MARGIN 6. (a) (continued) (ii) Name the thiol that contains only one carbon atom. (iii) The minimum concentration of ethanethiol in air that can be detected by humans is 2·7 × 10-7 mg per cm3 of air. Calculate the minimum mass of ethanethiol that needs to be present in a room containing 43 900 litres of air in order for it to be detected. (b) 2-methyl-2-propanethiol is also used to add a smell to gaseous fuels. H C H H C SH CH3 C H H H 2-methyl-2-propanethiol (i) Suggest why 2-methyl-2-propanethiol is classified as a tertiary thiol. [Turn over 1 2 1 page 22 MARKS DO NOT WRITE IN THIS MARGIN 6. (b) (continued) (ii) Thiols can be made by the addition of hydrogen sulfide to alkenes. 2-methyl-2-propanethiol can be made by the addition reaction shown. H C H H C CH3 CH3 C H H S H H H C H H C SH C H H H + 2-methyl-2-propanethiol GFM = 90·1 g 2-methylpropene GFM = 56·0 g (A) Draw the structure for the other isomer formed in this addition reaction. (B) A chemist obtained an 84% yield of 2-methyl-2-propanethiol after starting with 30·5 g of 2-methylpropene. Calculate the mass, in g, of 2-methyl-2-propanethiol made by the chemist. 1 2 page 23 MARKS DO NOT WRITE IN THIS MARGIN 7. Esters can be synthetic or natural. (a) The synthetic polyester PET, poly(ethylene terephthalate), has many ester links. PET can break down by a free radical reaction. One of the steps involved in breaking down PET is shown. C C C C O C C O C C C H H C O O O O• H C C O O H H H H C C C C C C H O H H H C C C + C C C O C C C H C O O O• H C O C O O H H H H C C C C C C H O O H H H H (i) State the name for this step. (ii) Name the component of sunlight that can cause plastics such as PET to break down. (iii) Name the type of substance that can be added to plastics to prevent them breaking down in this way. [Turn over 1 1 1 page 24 MARKS DO NOT WRITE IN THIS MARGIN 7. (continued) (b) (i) Natural cyclic esters called lactones can be formed from hydroxycarboxylic acids. 5-hydroxypentanoic acid is a hydroxycarboxylic acid that when heated, with dilute acid, will form a cyclic ester. HO C OH O CH2 CH2 CH2 CH2 H2C H2C CH2 CH2 C O O Y + Name product Y in this reaction. (ii) Draw the structure for the cyclic compound formed when 4-hydroxypentanoic acid is heated with dilute acid. C OH O OH CH CH2 CH2 H3C 4-hydroxypentanoic acid 1 1 page 25 MARKS DO NOT WRITE IN THIS MARGIN 7. (b) (continued) (iii) Name the hydroxycarboxylic acid shown below. H3C CH CH2 C OH C O OH [Turn over 1 page 26 MARKS DO NOT WRITE IN THIS MARGIN 8. Gelatin is a soluble protein that can be added to different food products. (a) A structure for a section of a protein chain in gelatin is shown. N C C H H N O C H C H H O N H2C CH2 CH2 CH C N O H CH CH2 C O N H C H H C O N H C H CH2 C O CH2 C O OH CH2 CH2 NH C NH2 NH CH3 (i) State the number of amino acids that joined together to form the section of the protein chain shown. (ii) Name the weakest van der Waals’ force between water and gelatin molecules. (b) A student was investigating the viscosity of different concentrations of gelatin solution. (i) The student was asked to prepare a 2% gelatin solution, which is a solution that contains 2 g of gelatin per 100 cm3 of solution. The student prepared this solution by adding 100 cm3 of distilled water into a volumetric flask, then adding 2 g of gelatin. Describe how the student should have made up the solution. 1 1 3 page 27 MARKS DO NOT WRITE IN THIS MARGIN 8. (b) (continued) (ii) The results obtained from the student’s viscosity experiment are shown. Concentration of gelatin solution (%) Viscosity (units) 2·0 1·0 4·0 2·0 6·0 4·0 8·0 7·0 10·0 Predict the student’s result for the viscosity, in units, of a 10·0% gelatin solution. (c) Bromelain is a mixture of enzymes found in pineapple that aid digestion. (i) Adding raw pineapple to gelatin results in the gelatin molecules being hydrolysed. The rate of hydrolysis is reduced if the pineapple is cooked. Explain why the rate of hydrolysis is reduced. (ii) Bromelain can be purchased as tablets that contain 500 mg of bromelain. The flesh from a pineapple contains 13·2 mg of bromelain per gram. Calculate the mass, in g, of this pineapple that would be needed to provide 500 mg of bromelain. [Turn over 1 1 1 page 28 MARKS DO NOT WRITE IN THIS MARGIN 9. Chlorine is used in the production of many other chemicals. (a) Chlorine can be produced by the reaction of hydrogen chloride with air using the Deacon process. 4HCl(g) + O2(g) Ý 2Cl2(g) + 2H2O(g) 250 150 50 -50 reaction pathway -100 -150 potential energy (kJ mol-1) 0 100 200 (i) Using the potential energy diagram, determine the activation energy, in kJ mol-1, for the forward reaction. (ii) Explain why increasing the temperature in the Deacon process results in less chlorine being produced. 1 1 page 29 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (b) One laboratory method for the preparation of chlorine gas involves adding concentrated hydrochloric acid to potassium permanganate. The chlorine gas produced also contains small amounts of hydrogen chloride gas. To remove the hydrogen chloride gas the gases are bubbled through water. Finally, insoluble chlorine gas is collected. potassium permanganate concentrated hydrochloric acid Complete a labelled diagram to show an apparatus suitable for carrying out this preparation. (An additional diagram, if required, can be found on page 41) [Turn over 2 page 30 MARKS DO NOT WRITE IN THIS MARGIN 9. (continued) (c) Carbon tetrachloride, CCl4, is prepared by the reaction of chlorine gas, Cl2, with methane, CH4. CH4(g) + 4Cl2(g) ↓ CCl4(g) + 4HCl(g) Calculate the enthalpy change, in kJ mol−1, for this reaction using the following information. C(s) + 2H2(g) ↓ CH4(g) ΔH = -75 kJ mol-1 C(s) + 2Cl2(g) ↓ CCl4(g) ΔH = -98 kJ mol-1 1 2H2(g) + 1 2Cl2(g) ↓ HCl(g) ΔH = -92 kJ mol-1 2 page 31 [Turn over for next question DO NOT WRITE ON THIS PAGE page 32 MARKS DO NOT WRITE IN THIS MARGIN 10. A student investigated the purity of a sample of magnesium chloride, MgCl2. The sample was dissolved in water and then an excess of silver nitrate, AgNO3, was added to produce a precipitate of silver chloride, AgCl. The precipitate was collected, dried and weighed. MgCl2(aq) + 2AgNO3(aq) ↓ 2AgCl(s) + Mg(NO3)2(aq) (a) The student prepared the magnesium chloride solution by dissolving 2·503 g of impure magnesium chloride in water. Explain why the student should use distilled or deionised water, rather than tap water, when preparing the solution. (b) (i) Complete the table to show the most appropriate piece of apparatus that could be used to measure the required volumes. Measurement Apparatus 20·0 cm3 (accurately) 35 cm3 (approximately) (ii) The steps required to collect, dry and weigh the precipitate are listed below. However, the steps are in the wrong order. A. Weigh the precipitate and the filter paper B. Wash the precipitate with water to remove any impurities C. Filter the precipitate D. Dry the precipitate in an oven E. Weigh the filter paper Complete the flow chart below to show the correct order of steps the student should carry out to collect, dry and weigh the precipitate. last step E first step (An additional diagram, if required, can be found on page 41) 1 2 1 page 33 MARKS DO NOT WRITE IN THIS MARGIN 10. (b) (continued) (iii) 1·393 g of silver chloride precipitate was produced from the magnesium chloride solution. MgCl2(aq) + 2AgNO3(aq) ↓ 2AgCl(s) + Mg(NO3)2(aq) GFM = 95·3 g GFM = 143·4 g Calculate the mass of magnesium chloride, in g, present in the magnesium chloride solution. (c) The average mass of magnesium chloride in 2·503 g of the original impure sample was calculated to be 2·403 g. Calculate the % of magnesium chloride present in the original sample. [Turn over 2 1 page 34 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 11. Differences in physical and chemical properties can be used to distinguish one compound from another. The compounds extracted from orange juice include antioxidants, flavour molecules, essential oils, aroma molecules and coloured molecules. Some examples of these are shown below. H2C H2C CH CH2 CH C CH3 C H3C CH2 limonene O H HO C C H CH2OH CH2OH C OH OH H C fructose CH2 O C HC C C C O HO HO OH HO vitamin C C C C C C OH OH H H H H HO O O HO O C citric acid C C H H C H H H H C H H H C H H C C H H C H H H O octanal C C C H2C H2C CH CH CH CH C CH CH3 CH3 C CH CH C 3 CH3 CH3 CH3 CH3 CH3 CH3 CH2 CH CH2 CH2 CH2 CH CH C CH C CH CH CH CH C C H3C beta-carotene C O O C H H H C H H H C H H C C H H H H ethyl butanoate page 35 MARKS DO NOT WRITE IN THIS MARGIN 11. (continued) Using your knowledge of chemistry, comment on how the differences in physical and chemical properties can be used to distinguish between the compounds extracted from orange juice. [Turn over 3 page 36 DO NOT WRITE IN THIS MARGIN 12. The label from a bottle of pine fresh bleach cleaner is shown. PINE FRESH BLEACH CLEANER Formulated to kill germs and remove stains Ingredients: aqua, sodium hypochlorite, sodium hydroxide, less than 5% anionic surfactants, non-ionic surfactants, soap, perfume 6 000129 7103487 > WARNING! Do not use together with other products. May release dangerous gases (chlorine) DANGER Keep out of reach of children CORROSIVE (a) Surfactant molecules are added to bleach cleaner to act as detergents, soaps or emulsifiers. Information on three of the surfactants in the bleach cleaner is shown in the table. Surfactant structure Type of surfactant Head group H C 3 CH CH2 CH2 CH2 2 2 CH2 2 2 2 2 2 CH CH CH O CH 2 CH O CH CH H Compound A non-ionic polar H C 3 H C 3 NH3+Cl– CH2 CH2 CH2 2 2 CH2 2 2 2 2 2 CH CH CH CH CH 2 2 CH CH C CH 3 CH 3 CH CH CH Compound B O–Na+ O C H C 3 CH CH2 CH2 CH2 2 2 CH2 2 2 2 2 2 2 2 CH CH CH CH CH CH 2 2 2 CH CH CH CH CH Compound C ionic negatively charged page 37 MARKS DO NOT WRITE IN THIS MARGIN 12. (a) (continued) (i) Complete the table for compound B. (ii) Compound C is a soap molecule. (A) Soaps can be made from fats and oils. Name the reaction used to make soaps from fats and oils. (B) Soap molecules allow oil to mix with water. O–Na+ O C H C 3 CH CH2 CH2 CH2 2 2 CH2 2 2 2 2 2 2 2 CH CH CH CH CH CH 2 2 2 CH CH CH CH CH Compound C Explain fully the cleaning action of compound C. You may wish to use diagrams to illustrate your answers. [Turn over 1 1 3 page 38 MARKS DO NOT WRITE IN THIS MARGIN 12. (a) (continued) (iii) The structure of an emulsifier molecule is shown below. 2 H C 2 H C 2 O CH HO C O CH2 CH2 2 2 CH2 2 2 2 2 2 2 CH CH CH CH CH CH CH 2 2 2 CH CH CH CH CH CH 3 CH 2 CH OH State how emulsifiers are made from edible oils. (b) Sodium hypochlorite, Na+OCl-, is the main active compound in bleach. PINE FRESH BLEACH CLEANER Formulated to kill germs and remove stains Ingredients: aqua, sodium hypochlorite, sodium hydroxide, less than 5% anionic surfactants, non-ionic surfactants, soap, perfume 6 000129 7103487 > WARNING! Do not use together with other products. May release dangerous gases (chlorine) DANGER Keep out of reach of children CORROSIVE Sodium hypochlorite, Na+OCl-, is produced by reacting chlorine with sodium hydroxide solution. Cl2(g) + 2Na+OH-(aq) ↓ Na+OCl- (aq) + Na+Cl- (aq) + H2O(ℓ) (i) A chlorine molecule has a pure covalent bond. Explain what is meant by a pure covalent bond. 1 1 page 39 MARKS DO NOT WRITE IN THIS MARGIN 12. (b) (continued) (ii) When the chlorine is reacted with sodium hydroxide solution an excess of sodium hydroxide is used. Suggest why an excess of sodium hydroxide is used. (c) In the bleach cleaner an equilibrium exists. 2H+(aq) + OCl-(aq) + Cl- (aq) Ý Cl2(g) + H2O(ℓ) The label warns that the bleach cleaner should not be used with other products as it may release chlorine gas. Explain clearly why mixing the bleach with an acid would shift the equilibrium to the right, resulting in the release of chlorine gas from the bleach cleaner. [Turn over for next question 1 2 page 40 MARKS DO NOT WRITE IN THIS MARGIN 12. (continued) (d) The concentration of hypochlorite, OCl-, in bleach can be determined by a redox reaction that involves two steps. Step 1 An excess of acidified potassium iodide is added to the bleach. This converts the iodide ions into iodine. OCl-(aq) + 2I- (aq) + 2H+(aq) ↓ I2(aq) + Cl- (aq) + H2O(ℓ) Step 2 The iodine produced in step 1 is titrated with sodium thiosulfate, Na2S2O3. I2(aq) + 2Na2S2O3(aq) ↓ 2NaI(aq) + Na2S4O6(aq) (i) Write the ion-electron equation for the reduction reaction taking place in Step 1. (ii) A 25 cm3 sample of a diluted bleach was transferred into a conical flask and excess acidified potassium iodide added. The iodine produced was titrated with 0·098 mol l−1 Na2S2O3, requiring an average volume of 9·0 cm3 to reach the end point. Calculate the concentration, in mol l−1, of sodium hypochlorite in the diluted bleach. [END OF QUESTION PAPER] 1 3 page 41 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK Additional diagram for question 1 (c) potential energy (kJ mol-1) reaction pathway Additional diagram for question 9 (b) potassium permanganate concentrated hydrochloric acid Additional diagram for question 10 (b) (ii) last step E first step page 42 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 43 MARKS DO NOT WRITE IN THIS MARGIN ADDITIONAL SPACE FOR ANSWERS AND ROUGH WORK page 44 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

14 (B410U10-1) Examiner only 12. (a) Several different compounds containing sodium, chlorine and oxygen exist. One of these decomposes on heating as shown in the equation. 2NaClO3(s) 2NaCl(s) + 3O2(g) (i) What is the oxidation state of chlorine in NaClO3? [1] ..................................................................... (ii) Calculate the maximum volume of gas, measured at 600 K and 1 atm pressure, that can be made by heating 88.0 g of NaClO3. Give your answer to an appropriate number of significant figures. [3] Volume = ........................................................ dm3 (b) The active component of bleach is sodium chlorate(I), NaClO. This is prepared by passing chlorine into aqueous sodium hydroxide. 2NaOH(aq) + Cl2(g) NaClO(aq) + NaCl(aq) + H2O(l) Calculate the atom economy of this process when used to prepare sodium chlorate(I). [2] Atom economy = ........................................................ % © WJEC CBAC Ltd. (B410U10-1) Turn over. 15 Examiner only (c) Another compound containing sodium, chlorine and oxygen has the following composition by mass. Na 18.8 % Cl 29.0 % O 52.2 % Calculate its empirical formula. [2] Empirical formula ....................................................... © WJEC CBAC Ltd. 8

16 (B410U10-1) Examiner only 13. A sample of witherite, an ore of barium, contains barium carbonate, BaCO3. A geologist investigated the ore to determine the percentage of barium carbonate present by adding a sample of ore to excess acid and then finding how much acid had been neutralised. He followed these instructions. Stage 1 Add a known mass of ore to about 100 cm3 of 0.500 mol dm–3 hydrochloric acid in a beaker. Stir until no further reaction occurs. The geologist used 19.15 g of ore. Stage 2 Filter and then add more acid to make the total volume of the solution up to exactly 250 cm3. Stage 3 Titrate 25.0 cm3 samples of this solution against 0.100 mol dm–3 sodium hydroxide using a suitable indicator. The geologist used a mean volume of 27.80  cm3 of the sodium hydroxide to neutralise the acid. (a) Explain why the geologist filtered the mixture in Stage 2 of the process. [1] (b) State which piece of apparatus the geologist would use to make exactly 250 cm3 of solution in Stage 2. [1] (c) State why an indicator is used in Stage 3. [1] (d) State how many titrations the geologist should carry out in Stage 3. Give a reason for your choice. [1] © WJEC CBAC Ltd. (B410U10-1) 17 Examiner only (e) Write the equation for the reaction of barium carbonate with hydrochloric acid. [1] (f) Calculate the total number of moles of hydrochloric acid added to the sample of ore. [1] Number of moles added = ........................................................ mol (g) Calculate the number of moles of hydrochloric acid neutralised in each titration and hence the number of moles neutralised by the original sample of ore. [3] Number of moles neutralised by ore = ........................................................ mol QUESTION 13 CONTINUES ON PAGE 18. © WJEC CBAC Ltd. Turn over. 18 (B410U10-1) Examiner only (h) State the number of moles of barium carbonate present in the original sample of ore and hence calculate the percentage by mass of barium in the ore. [3] Percentage barium in the ore = ........................................................ % (i) The true value for the percentage of barium present in the ore is higher than that calculated in part (h). Suggest a possible reason for this. [1] END OF PAPER © WJEC CBAC Ltd. 13 Examiner only (B410U10-1) 19 © WJEC CBAC Ltd. Additional page.

12 (B410U20-1) Examiner only 10. (a) A student is asked to prepare a sample of ethanal by oxidising ethanol. (i) Write an equation for this reaction. [1] Use [O] to represent the oxidising agent and show the structure of the organic product. (ii) Describe, giving brief experimental details, how he can carry out the reaction. [4] (iii) Ethanol can also be oxidised to ethanoic acid. Describe how the student could use a chemical test to confirm that his sample of ethanal did not contain ethanoic acid. [2] (b) State a difference and a similarity between the 13C NMR spectra of ethanal and ethanol. [2] Difference .................................................................................................................................................................................... ................................................................................................................................................................................................................ Similarity ....................................................................................................................................................................................... ................................................................................................................................................................................................................ © WJEC CBAC Ltd. (B410U20-1) Turn over. 13 Examiner only (c) Ethanol is widely used as a biofuel in some countries. (i) The equation for its combustion is given below. C2H5OH + 3O2 2CO2 + 3H2O Use the average bond enthalpy values given in the table below to calculate the enthalpy of combustion for ethanol. [3] © WJEC CBAC Ltd. ΔcH ethanol = ........................................................ kJ mol–1 (ii) Give a disadvantage of biofuels compared with fossil-based fuels. [1] (d) Ethanol and hexan-1-ol are both primary alcohols. Explain why ethanol is soluble in water but hexan-1-ol is not. [2] 15 Bond Average bond enthalpy / kJ mol–1 C—C 348 C—H 412 C—O 360 O—H 463 496 743 — — — — O O C O

14 (B410U20-1) 11. Compound A contains 55.8 % carbon, 7.00 % hydrogen and 37.2 % oxygen by mass. Part of its infrared spectrum is shown below. © WJEC CBAC Ltd. 3000 2000 1500 1000 500 Transmittance Wavenumber / cm–1 • An aqueous solution of compound A has a pH of less than 7. • In an addition reaction, 2.00 g of compound A reacts with 3.71 g of bromine in a 1 : 1 molar ratio. (B410U20-1) Turn over. 15 Examiner only Use all the data given to identify all the possible structures of compound A. Explain what information can be found from each piece of data. [10] © WJEC CBAC Ltd. 10

16 (B410U20-1) 12. A student carried out an experiment to study the reaction between magnesium and hydrochloric acid. Mg(s) + 2HCl(aq) MgCl2(aq) + H2(g) ΔH = –467 kJ mol–1 He used the following apparatus to measure the volume of hydrogen produced over time. © WJEC CBAC Ltd. gas syringe hydrochloric acid magnesium strip The experiment was carried out at a temperature of 25 °C and 1 atm pressure. The amount of acid used was sufficient to react with all the magnesium. These are the results obtained. Time / s Volume of hydrogen / cm3 0 0 10 32 20 50 30 64 40 75 60 88 80 92 100 100 120 100 (B410U20-1) Turn over. 17 Examiner only (a) Plot the results for the experiment and draw a line of best fit. Label it A. [4] © WJEC CBAC Ltd. (b) Use the graph to calculate the rate of reaction at 20 seconds in cm3 s–1. [2] Rate = ........................................................ cm3 s–1 (c) When he repeated the experiment, it took him 8 seconds to replace the bung in the tube and start the stopwatch after adding the magnesium. On the graph, sketch the curve that would be obtained if the results of this experiment were plotted. Label it B. [2] 18 (B410U20-1) Examiner only (d) Calculate the mass of the magnesium strip used in the experiment. [2] Mass = ........................................................ g (e) The rates of some reactions can be determined from the loss of mass over a period of time. However, the student said that he could not use this method as he only had a two decimal place balance. Is he correct? Justify your answer. [2] (f) He repeated the experiment using the same mass of magnesium and the same volume and concentration of acid, in order to collect 100 cm3 of hydrogen, but over a longer period of time. State one method of slowing down the reaction and use collision theory to explain this change of rate. [3] © WJEC CBAC Ltd. (B410U20-1) Turn over. 19 Examiner only © WJEC CBAC Ltd. Energy Extent of reaction 17 END OF PAPER (g) On the axes below, sketch the energy profile for this reaction, labelling the enthalpy change of reaction, ΔrH. [2] (B410U20-1) 20 © WJEC CBAC Ltd. Additional page. Examiner only (B410U20-1) 21 Examiner only © WJEC CBAC Ltd. Additional page. BLANK PAGE (B410U20-1) 22 © WJEC CBAC Ltd. BLANK PAGE (B410U20-1) 23 © WJEC CBAC Ltd.

10 (A410U10-1) Examiner only 10. The green mineral atacamite contains three different ions, Ma(OH)bXc. It is insoluble in water but can form a solution when added to acid. A student planned to analyse a sample of atacamite using the following method. STEP 1: Add 1.00 g of atacamite to 150 cm3 of strong acid of concentration 0.100 mol dm−3, and then make this up to exactly 250 cm3 with more of the same acid. STEP 2: Take exactly 25.0 cm3 of the solution from step 1 and add excess silver nitrate solution. If any precipitate forms, filter it off and dry completely. Record its colour and the mass formed. STEP 3: Take exactly 25.0 cm3 of the solution from step 1 and add excess barium chloride solution. If any precipitate forms, filter it off and dry completely. Record its colour and the mass formed. STEP 4: Take exactly 25.0 cm3 of the solution from step 1 and add excess sodium hydroxide solution. If any precipitate forms, filter it off and dry completely. Record its colour and the mass formed. STEP 5: To find the amount of acid remaining in the solution, use a pH probe to find the precise pH of the solution prepared in step 1. (a) The student had to select an appropriate strong acid from the common laboratory reagents. Suggest an appropriate acid to use. Explain your choice. [2] (b) In step 2 a white precipitate of mass 0.0672 g was produced. State which ion this step identifies and calculate the number of moles of this ion present in the original 250 cm3 of solution. [3] Ion ....................................................... Number of moles = ....................................................... mol © WJEC CBAC Ltd. (A410U10-1) Turn over. A 410 U101 11 11 Examiner only (c) After completing step 2, the student decides that he does not need to carry out step 3. Is he correct? Give a reason for your answer. [2] (d) A pale blue precipitate is formed in step 4. (i) Give the formula of the ion identified from this observation. [1] ....................................................... (ii) When the student heats the precipitate to ensure it is dry, a colour change is seen with some of the solid turning black but most of it remaining blue. He did not record a mass for the sample. Suggest why he would not have been able to use the mass of the solid to calculate the number of moles of the ion in the original compound. [1] © WJEC CBAC Ltd. 12 (A410U10-1) Examiner only (e) In step 5, the pH of a 25.0 cm3 portion of the remaining solution was found to be 1.36. (i) Calculate the number of moles of acid remaining in 25.0 cm3 of the solution. [2] Number of moles = ........................................................ mol (ii) Calculate the number of moles of hydroxide ion present in the original 1.00 g of atacamite. [3] Number of moles = ........................................................ mol (f) Deduce the formula of atacamite. [3] Formula of atacamite ................................................................................... © WJEC CBAC Ltd. 17 BLANK PAGE (A410U10-1) Turn over. 13 A 410 U101 13 © WJEC CBAC Ltd. (A410U10-1) 14 Examiner only 11. (a) Selenium is an element in the p-block of the Periodic Table. What information regarding the electronic structure of the selenium atom can be deduced from this statement? [1] (b) The illustration below gives some information about the elements surrounding selenium in the Periodic Table. © WJEC CBAC Ltd. S Sulfur electronegativity = 2.58 boiling temperature = 445 first ionisation energy = 1000 standard electrode potential for S(+6) → S(+4) = +0.16 V As Arsenic electronegativity = 2.18 boiling temperature = 603 first ionisation energy = 947 Se Selenium electronegativity = ? boiling temperature = 685 first ionisation energy = ? standard electrode potential for Se(+6) → Se(+4) = ? Br Bromine electronegativity = 2.96 boiling temperature = 60 Te Tellurium electronegativity = 2.10 boiling temperature = 990 standard electrode potential for Te(+6) → Te(+4) = +1.18 V All ionisation energies are given in kJ mol−1 and all temperatures in °C 15 (A410U10-1) Examiner only (i) Both sulfur and selenium have molecules containing rings of eight atoms. Explain the difference in their boiling temperatures. [2] (ii) Suggest values for the missing properties of selenium. Use the ideas you have studied to explain the values you have chosen. [6 QER] © WJEC CBAC Ltd. Turn over. A 410 U101 15 (A410U10-1) 16 Examiner only (c) One radioactive isotope of selenium is selenium-75. It can be used as a medical tracer to identify cartilaginous tumours. (i) The half-life of selenium-75 is 120 days. Samples are provided that have eight times higher concentration of selenium-75 atoms than the minimum needed for use as a tracer. Find the maximum time a sample can be stored before the concentration of selenium-75 becomes too low to use. [2] Time = ....................................................... days (ii) Selenium-75 does not emit alpha particles when it decays. Explain why this is important for its use as a medical tracer. [2] (d) Selenium dioxide, SeO2, is a foul smelling solid, with a smell resembling rotting horseradish. It can be used to oxidise alkenes. SeO2 + C3H6 + H2O H2SeO2 + C3H6O In an oxidation experiment, 2.70 g of C3H6 produced a yield of 62 % of C3H6O. Calculate the mass of C3H6O formed. [2] Mass = ....................................................... g © WJEC CBAC Ltd. 15

17 (A410U10-1) Examiner only 12. Chlorine is one of the most widely used elements, and compounds containing chlorine atoms have a huge range of uses in the home and in industry. (a) Give one large scale use of the element chlorine. [1] (b) Chlorine reacts with hot concentrated sodium hydroxide solution to form two chlorine-containing products. Write the equation for this reaction. [1] (c) Chlorine can be used to produce bromine from the bromide ions present in seawater. An excess of chlorine is usually used in this process. In one experiment, a volume of 2.00 dm3 of chlorine gas was bubbled into seawater at 298 K under 1 atm pressure. A mass of 9.4 g of bromine was produced. Calculate the percentage of chlorine that remains unreacted at the end of the experiment, giving your answer to an appropriate number of significant figures. [3] Percentage of chlorine unreacted = ....................................................... % © WJEC CBAC Ltd. Turn over. (A410U10-1) (d) Chlorine-containing compounds can be studied using mass spectrometry. (i) Explain how ions are formed and separated in the mass spectrometer. [2] (ii) The diagram below shows part of the mass spectrum of a chlorine-containing compound. There are no other significant peaks near this group of peaks and adjacent peaks are two atomic mass units apart. © WJEC CBAC Ltd. m/z Abundance 18 Examiner only 19 (A410U10-1) Examiner only I. State how many chlorine atoms are present in these ions, giving a reason for your answer. [2] II. The height of the first peak is 54 and the height of the final peak is 2. Explain the ratio of these peak heights. [2] (e) Chlorine can form many compounds of general formula AB3, for example AlCl3 and ClF3. (i) Draw the shape of the AlCl3 molecule, giving its bond angle(s). [1] (ii) Explain why the molecule AlCl3 often forms dimers. [2] © WJEC CBAC Ltd. Turn over. (A410U10-1) 20 Examiner only (iii) Use the principles of valence shell electron pair repulsion theory to explain why the shape of ClF3 is not the same as that of BF3. You do not need to identify the shape of the ClF3 molecule. [2] © WJEC CBAC Ltd. 16

21 (A410U10-1) Examiner only 13. Ammonia, NH3, and hydrazine, NH2NH2, are both compounds containing only nitrogen and hydrogen. (a) The production of ammonia in the Haber process uses nitrogen and hydrogen gases as starting materials, a pressure of 200 atm and a temperature of 400 °C. The reaction occurring is shown below. N2(g) + 3H2(g) [ 2NH3(g) ΔH = −94 kJ mol−1 (i) Explain fully why a pressure of 200 atm is used for this reaction. [3] (ii) The enthalpy change value given above is not the standard enthalpy change of formation for ammonia. Give one reason why this is not the standard enthalpy change of formation. [1] (iii) Write an expression for the equilibrium constant, Kc, for this reaction. [1] (iv) State the effect (if any) of increasing temperature on the value of Kc. Give a reason for your answer. [2] © WJEC CBAC Ltd. Turn over. (A410U10-1) 22 Examiner only (v) A mixture of nitrogen and hydrogen has an initial concentration of 0.020 mol dm−3 of each gas. The mixture is allowed to come to equilibrium in a fixed volume. In the equilibrium mixture 20 % of the nitrogen gas had been converted into ammonia. Calculate the value of Kc under these conditions. [3] Kc = ....................................................... (b) The standard enthalpy change of formation for ammonia is −46 kJ mol−1 and for hydrazine it is +51 kJ mol−1. (i) State what information these values provide about the stability of these molecules. [1] (ii) One method of producing hydrazine is to oxidise ammonia using an appropriate oxidising agent, such as hydrogen peroxide. 2NH3(g) + H2O2(l) NH2NH2(l) + 2H2O(l) ΔH θ = −241 kJ mol−1 © WJEC CBAC Ltd. Substance Standard enthalpy change of formation, ΔfH θ / kJ mol−1 Standard entropy, S θ / J K−1 mol−1 NH3(g) −46 193 NH2NH2(l) +51 122 H2O2(l) 102 H2O(l) −286 70 I. Calculate the standard enthalpy change of formation of hydrogen peroxide, H2O2. [2] ΔfH θ = ....................................................... kJ mol−1 II. Calculate the temperature at which the value of ∆Gθ is equal to zero. [3] T = ....................................................... K III. A student states that the temperature calculated in part II is the minimum temperature required for the reaction to occur. Is the student correct? Give a reason for your answer. [2] (iii) An alternative route for producing hydrazine starts with the molecule urea, which is produced in biological systems. (NH2)2CO + NaOCl + 2NaOH N2H4 + H2O + NaCl + Na2CO3 Give one disadvantage of this route over the production of hydrazine from ammonia. [1] (A410U10-1) Turn over. 23 Examiner only © WJEC CBAC Ltd. 24 (A410U10-1) Examiner only © WJEC CBAC Ltd. (iv) Hydrazine can undergo both oxidation and reduction reactions. Electrochemical potentials for both processes are included in the table below. Standard electrode potential, E θ / V Co3+(aq) + e– [ Co2+(aq) +1.82 Fe3+(aq) + e– [ Fe2+(aq) +0.77 N2H4(aq) + 4H2O(l) + 2e– [ 2NH4 +(aq) + 4OH–(aq) +0.11 V3+(aq) + e– [ V 2+(aq) –0.26 Cr3+(aq) + e– [ Cr2+(aq) –0.42 N2(g) + 4H2O(l) + 4e– [ N2H4(aq) + 4OH–(aq) –1.15 I. Suggest whether addition of sodium hydroxide to a hydrazine solution will favour its use as a reducing agent. Give a reason for your answer. [2] II. Identify which of these four M3+ ions (if any) can be reduced by hydrazine under standard conditions. Give a reason for your answer. [2] 23 (A410U10-1) 25 © WJEC CBAC Ltd. BLANK PAGE Turn over. Turn over for Q.14

26 (A410U10-1) 14. It is possible to study the concentration dependence of rate by finding how the rate of a reaction changes over time. This is because the concentrations of the reactants change over time. The reaction below occurs in non-aqueous solution in the presence of a small amount of water. C2H5Br + OH– + H2O C2H5OH + Br – + H2O Three students carried out experiments to find how the concentration of each reactant affects the rate. Each one changed the concentration of a different reactant. They used the initial concentrations shown below and an automated sampling device to take measurements every 10 minutes for 6 hours. © WJEC CBAC Ltd. Initial concentration of each reactant / mol dm–3 [C2H5Br] [OH–] [H2O] George’s experiment: Finding the effect of [C2H5Br] on rate 2.00 × 10–3 2.00 2.00 Hannah’s experiment: Finding the effect of [H2O] on rate 2.00 2.00 2.00 × 10–3 Jamal’s experiment: Finding the effect of [OH–] on rate 2.00 2.00 × 10–3 2.00 (a) The results obtained in George’s experiment are shown on the graph below. 0 0.5 1.0 1.5 2.0 2.5 0 5 10 15 20 25 Time / 103 seconds Concentration of C2H5Br / 10−3 mol dm−3 (A410U10-1) Turn over. 27 Examiner only (i) Calculate the initial rate for the reaction, stating its unit. [3] Initial rate = ....................................................... Unit ....................................................... (ii) Use the graph to show that the reaction is first order with respect to C2H5Br. [2] (b) Suggest why this method uses much lower concentrations of the reactants being studied than those of the other reactants involved. [1] © WJEC CBAC Ltd. 28 (A410U10-1) Examiner only (c) Hannah finds that the concentration of water does not change during her experiment. (i) Give a reason why the concentration of water does not change. [1] (ii) The order of the reaction with respect to water is zero. Suggest how Hannah could confirm this. [1] (d) Jamal carried out his experiment at a slightly different temperature from George. He found that the reaction is first order with respect to hydroxide ions. The final rate equation is therefore as follows. rate = k[C2H5Br][OH–] The value of the rate constant is 4.07 × 10–5. (i) Give the unit of the rate constant. [1] ....................................................................................................... (ii) The activation energy for this reaction is 89.5 kJ mol–1 and its frequency factor, A, has a value of 4.30 × 1011. Calculate the temperature used for Jamal’s experiment. You must show your working. [3] Temperature = ....................................................... K END OF PAPER © WJEC CBAC Ltd. 12 (A410U10-1) 29 Examiner only © WJEC CBAC Ltd. Additional page. Turn over. (A410U10-1) 30 Examiner only © WJEC CBAC Ltd. Additional page. BLANK PAGE (A410U10-1) 31 © WJEC CBAC Ltd.

(A410U20-1) 24 © WJEC CBAC Ltd. 12. (a) The boiling temperatures of five isomers of formula C5H12O are shown in the table below. Compound Formula Boiling temperature / °C A 56 B 71 C 102 D 116 E 137 H3C H3C C H3C O CH3 CH2 CH2 CH3 CH2 O CH3 C CH2 OH CH3 CH3 CH3 C CH2 OH H CH3 CH2CH3 C CH2 H H CH2 CH2 CH3 OH Turn over. 25 (A410U20-1) Examiner only © WJEC CBAC Ltd. Discuss the intermolecular bonding present in these compounds and relate this bonding to the differences observed in their boiling temperatures. [6 QER] (A410U20-1) 26 Examiner only © WJEC CBAC Ltd. (b) The equation below shows the reaction of 2-methylbutan-2-ol with sulfuric acid. C C H2SO4 + H2O H H3C CH3 CH3 CH3 C CH3 OH CH2 CH3 (i) State why the sulfuric acid acts as a catalyst in this reaction. [1] (ii) In the first stage of the mechanism of this reaction, 2-methylbutan-2-ol acts as a base. Suggest how it can react as a base. [1] (iii) The main organic product of the reaction is 2-methylbut-2-ene but a small percentage of 2-methylbut-1-ene, CH3CH2 C(CH3) CH2 is also produced. Suggest why this alkene is also a product. [1] — — 27 (A410U20-1) Examiner only © WJEC CBAC Ltd. Turn over. (iv) The mixture at the end of the reaction contains the two alkenes and a small quantity of unreacted 2-methylbutan-2-ol. A student found that 2-methylbutan-2-ol reacts with sodium to give hydrogen as one of the products. CH3 2Na CH2 CH3 2 CH3 C CH3 O– Na+ CH3 C OH CH2 CH3 2 H2 + + A 10.0 g sample of the mixture was reacted with an excess of sodium. This produced 125 cm3 of hydrogen measured at 298 K and 1 atm pressure. Calculate the mass of 2-methylbutan-2-ol in the mixture. [2] Mass = ……….............................................. g (A410U20-1) 28 Examiner only © WJEC CBAC Ltd. C CH2 CH3 O CH3 CH3 C CH2 CH3 CH3 CH3 Suggest how this compound can be formed in the reaction. [1] (v) A sample of the product mixture from this reaction produced the following gas chromatogram. B A C Abundance Retention time I. State, giving a reason, which of these peaks is given by 2-methylbut-2-ene. [1] II. Suggest how you would confirm which one of the remaining two peaks is given by 2-methylbutan-2-ol. [1] (vi) In this reaction the alcohol is added slowly to an excess of sulfuric acid. However, if sulfuric acid is added slowly to the alcohol, then the product below is also formed. Turn over. 29 (A410U20-1) Examiner only © WJEC CBAC Ltd. (c) (i) Many polymers persist in the environment for many years and are causing severe pollution problems. There is an increasing use of materials that lead to fewer environmental problems. Some cardboard drinking cups have an impervious PLA lining. PLA is made from plants and is biodegradable. The formula of the repeating section of PLA is shown below. O C H C O CH3 n Give the structure of the monomer of PLA. [1] (ii) Suggest two desirable properties of PLA if it is to be used for lining the cardboard of a cup used for hot drinks. [2] 1. ………................................................................................................................................................................................. 2. ………................................................................................................................................................................................. 17 (A410U20-1) 30 Examiner only © WJEC CBAC Ltd. 13. (a) Diacetin is an ester of propane-1,2,3-triol that is used by some plants to attract bees. It reacts with aqueous sodium hydroxide to produce propane-1,2,3-triol and sodium ethanoate. 2NaOH 2CH3COONa + + O C H H2C O HC H2C O C O C H H2C O HC H2C CH3 O O C O H H H2C O HC H2C O H O H H2C O HC H2C O O CH3 diacetin 1.58 g of diacetin was heated with 50.0 cm3 of aqueous sodium hydroxide of concentration 0.500 mol dm–3. After complete reaction with the diacetin 7.00 × 10–3 mol of sodium hydroxide remained. Use this information to show that the relative molecular mass of diacetin is 176. [4] 31 (A410U20-1) Examiner only © WJEC CBAC Ltd. C C C C H H H C H C CH3 CH3 H O H H H 2-methylhept-2-en-6-one Turn over. (b) 2-Methylhept-2-en-6-one acts as an alarm pheromone in certain species of ants. (i) State why this compound does not show E-Z isomerism. [1] (ii) Draw the structure of a ketone with the same molecular formula that can exist as E-Z isomers. [1] (iii) 2-Methylhept-2-en-6-one gives a positive triiodomethane test. State the reagent(s) used for this test and the observation. [2] Reagent(s) ………............................................................................................................................................................... Observation ………............................................................................................................................................................ (iv) The reaction of 2-methylhept-2-en-6-one with aqueous sodium tetrahydridoborate(III) results in the formation of a new compound which has forms that rotate the plane of plane polarised light. Give the structure of the compound formed and explain why it has forms that rotate the plane of plane polarised light. [2] (A410U20-1) 32 Examiner only © WJEC CBAC Ltd. (c) (i) A species of sea slug produces an alarm pheromone which is a mixture of three compounds. One of these compounds is Navenone B. H C C H C C C C C C H H O CH3 C H H H H The visible spectrum of this compound shows an absorption maximum at 377 nm. Calculate the energy of this absorption in kJ mol–1. [3] Energy = …..................................................... kJ mol–1 33 (A410U20-1) Examiner only © WJEC CBAC Ltd. Turn over. (ii) Navenone C is a similar compound. HO H C C H C C C C C C H H O CH3 C H H H H This compound reacts with hydrogen bromide and with bromine. I. State what is seen when bromine is added to a solution of Navenone C. [2] II. State the type of reaction mechanism occurring when Navenone C reacts with hydrogen bromide. [1] III. Complete the table below to show the mole ratios of the added reagent and Navenone C. The table is already completed for the reaction with bromine. [1] Reagent added Mole ratio Added reagent : Navenone C hydrogen bromide bromine 6 : 1 17 END OF PAPER (A410U20-1) 34 Examiner only © WJEC CBAC Ltd. Additional page. 35 (A410U20-1) Examiner only © WJEC CBAC Ltd. Additional page.

3 Turn over 2 This question is about ionisation energies. (a) (i) Which equation represents the second ionisation of bromine? (1) A Br(g) + e– → Br–(g) B Br–(g) + e– → Br2–(g) C Br(g) – 2e– → Br2+(g) D Br+(g) – e– → Br2+(g) (ii) Which set of successive ionisation energies is most likely to be associated with the element boron? (1) A    738, 1 451, 7 733, 10 541, 13 629 B    801, 2 427, 3 660, 25 026, 32 828 C 1 086, 2 353, 4 621,   6 223, 37 832 D 1 402, 2 856, 4 578,   7 475,   9 445 4 (b) (i) Complete the graph to show how the first ionisation energies of the Period 3 elements change across the period. Precise figures are not required. (3) First ionisation energies of the Period 3 elements Na 1600 1400 1200 1000 800 600 400 200 0 First ionisation energy / kJ mol–1 Element Mg Al Si P S Cl Ar 5 Turn over (ii) The successive ionisation energies of sodium are shown on the graph. Successive ionisation energies of sodium 0 1 2 3 4 5 6 7 8 9 10 11 5.5 5.0 4.5 4.0 3.5 3.0 2.5 Log ionisation energy Number of electrons removed State what deductions can be made from this graph. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 2 = 7 marks)

6 3 Nitrogen forms several hydrides. In addition to ammonia, NH3 , it forms hydrazine, N2H4 , in which the two nitrogen atoms are covalently bonded together. (a) (i) Explain what is meant by a covalent bond. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Draw a dot‑and‑cross diagram for hydrazine, showing the outer electrons only. Use crosses (×) to represent the electrons from nitrogen and dots ( • ) to represent the electrons from hydrogen. (1) (iii) Estimate the H N H bond angle in hydrazine. (1) Bond angle = .............................................................. 7 Turn over (b) Hydrazine is very soluble in water. Explain, using a labelled diagram and naming the relevant intermolecular interactions, why hydrazine is very soluble in water. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) Hydrazine has been used as a rocket fuel. It is a powerful reducing agent and will react very exothermically with oxidising agents such as hydrogen peroxide. The equation for the reaction of hydrazine with hydrogen peroxide is N2H4(l) + 2H2O2(l) → N2(g) + 4H2O(g) Give two reasons why hydrazine is a good rocket fuel when reacted with hydrogen peroxide. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 9 marks)

8 4 This question is about isotopes. (a) The table shows data for some isotopes of potassium. Isotope Relative isotopic mass Abundance % 39K 38.9637 93.218 40K 39.9340 0.012 41K 40.9618 6.770 (i) State what is meant by the terms ‘relative isotopic mass’ and ‘relative atomic mass’. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) State what is meant by the term ‘isotopes’. Illustrate your answer by referring to the isotopes of potassium. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Use the data in the table to calculate the relative atomic mass of potassium. Give your answer to 4 significant figures. (2) 9 Turn over (b) The relative isotopic abundances of an element can be measured using a mass spectrometer. A simplified and incompletely labelled diagram of a mass spectrometer is shown. X + vaporised sample to vacuum pump detector A B C (i) Name the feature of the mass spectrometer responsible for the behaviour of the ions in the region indicated by the arrow X. (1) .................................................................................................................................................................................................................................................................................... (ii) Explain the three ion pathways, A, B and C, shown in the region indicated by the arrow X. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Give a reason why the mass spectrometer must be operated under vacuum. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 12 marks)

10 5 This question is about the reactions of the halogens and halide ions. (a) (i) When chlorine gas is bubbled through an aqueous solution of potassium iodide, the reaction involves (1) A oxidation only B reduction only C redox D disproportionation (ii) Cyclohexane was added to the resulting solution from (a)(i). The mixture was shaken and then allowed to stand for a few minutes. Two layers were formed. [ Density: aqueous layer solution = 1.10 g cm–3, cyclohexane layer = 0.78 g cm–3] The colour of the lower layer was (1) A pale yellow B purple C red D pale green (b) Concentrated sulfuric acid was added to a small quantity of solid potassium iodide in a test tube. (i) In this exothermic reaction, which of the following mixtures of gases would be produced? (1) A hydrogen iodide and sulfur dioxide only B hydrogen iodide and hydrogen sulfide only C hydrogen iodide, sulfur dioxide and hydrogen sulfide D hydrogen iodide, hydrogen sulfide and iodine 11 Turn over (ii) Hydrogen iodide is a gas which reacts in a similar way to hydrogen chloride. State the observation when the hydrogen iodide gas is passed over the mouth of an open bottle of concentrated ammonia solution. Write an equation, including state symbols, for the reaction. (3) Observation ................................................................................................................................................................................................................................................. Equation (c) Potassium iodate(V) can be prepared by adding solid iodine to a hot aqueous solution of potassium hydroxide. The equation for the reaction is 3I2 + 6KOH → KIO3 + 5KI + 3H2O Potassium iodate(V) can be separated from the other reaction product using their differing solubilities in water. Solubility in water at 25 °C / mol dm–3 KI 8.92 KIO3 0.43 (i) Outline a procedure that you could use to obtain a sample of dry, solid potassium iodate(V) from the reaction mixture. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 12 (ii) Describe how you would show that iodide ions are present in an aqueous solution of potassium iodide. 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(d) Fluorine is an element in Group 7. Group 7 includes the elements chlorine, bromine and iodine. Some information about the melting and boiling temperatures of Group 7 elements is shown in the table. Element Melting temperature / K Boiling temperature / K chlorine 172 238 bromine 266 332 iodine 387 457 Which is the expected boiling temperature of fluorine, in kelvin, K? (1) A 4 B 85 C 575 D 610 (Total for Question 5 = 12 marks) 13 Turn over BLANK PAGE

14 6 Malachite is a green mineral with the formula Cu2CO3(OH)2 . It has a molar mass of 221 g mol–1. (a) What is the percentage by mass of copper in pure malachite? (1) A 40.3% B 51.4% C 57.5% D 67.9% (b) Describe what you would expect to see when an excess of dilute hydrochloric acid is added to a sample of pure solid malachite. 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(c) (i) Describe how you would carry out a flame test on a sample of powdered malachite. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 15 Turn over (ii) When the atoms of some elements are heated, they produce a characteristic flame colour. For example, the copper in malachite gives a blue-green colour. Explain how atoms of different elements can produce different characteristic flame colours when heated. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 16 (d) (i) When malachite is heated to approximately 300 °C, water, carbon dioxide and copper(II) oxide are formed. The equation for this decomposition is Cu2CO3(OH)2 → 2CuO + CO2 + H2O Calculate the maximum volume of carbon dioxide that could be produced when 0.810 g of malachite is thermally decomposed. Assume that the gas is collected at a temperature of 25 °C and 101 kPa pressure. Give your answer to an appropriate number of significant figures and state the units. [The ideal gas equation is pV = nRT. Gas constant (R) = 8.31 J mol–1 K–1] (5) (ii) The gas was collected in a gas syringe with a stated accuracy of ± 0.5 cm3. Calculate the percentage uncertainty in the volume of gas collected. (1) 17 Turn over (iii) Malachite ore is a mixture of malachite and rock. A 0.810 g sample of malachite ore was thermally decomposed, producing 0.571 g of copper(II) oxide. Calculate the percentage purity of this malachite ore sample. Give your answer to an appropriate number of significant figures. (3) (Total for Question 6 = 20 marks)

18 7 (a) Give the meaning of the term ‘periodicity’. Illustrate your answer by referring to the atomic radii of the Period 2 and Period 3 elements. Specific values of atomic radii are not required. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... *(b) The melting temperatures of the Period 2 elements are shown. Symbol of the element Li Be B C(diamond) N O F Ne Melting temperature / K 454 1551 2573 3970 63 55 53 25 Explain the trend in melting temperatures across the elements of Period 2 in terms of their structure and bonding. 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(Total for Question 7 = 9 marks)

20 8 This question is about the thermal stability of Group 1 and Group 2 nitrates and carbonates. (a) Complete the equations for the thermal decomposition of sodium nitrate, NaNO3 , and for the thermal decomposition of calcium nitrate, Ca(NO3)2 . State symbols are not required. (2) NaNO3 → Ca(NO3)2 → (b) The thermal stability of Group 1 nitrates increases down the group. The decomposition temperatures of some Group 1 nitrates are shown. Name Formula Decomposition temperature / K sodium nitrate NaNO3 653 potassium nitrate KNO3 673 caesium nitrate CsNO3 687 Explain why the thermal stability of caesium nitrate is greater than that of sodium nitrate. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 21 (c) Calcium carbonate is thermally decomposed during the manufacture of cement. (i) Write an equation, including state symbols, for the thermal decomposition of calcium carbonate. (1) (ii) Name all the types of bond present in calcium carbonate. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Give a reason, in terms of the bonding, why a high decomposition temperature is required. 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(Total for Question 8 = 8 marks) TOTAL FOR PAPER = 80 MARKS 22 BLANK PAGE 23 BLANK PAGE 24

5 Turn over 2 This question is about alcohols and their reactions. The table gives some of the names and skeletal formulae of isomers having the formula C4H9OH. (a) Complete the table. (2) Name Skeletal formula OH butan‑2‑ol OH 2‑methylpropan‑1‑ol 2‑methylpropan‑2‑ol OH 6 (b) (i) Some alcohols react with concentrated phosphoric acid to form alkenes. What is the type of this reaction? (1) A addition B elimination C oxidation D substitution (ii) When butan‑2‑ol reacts with concentrated phosphoric acid, two stereoisomers are formed. Explain what is meant by the term stereoisomers. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Draw the structures and give the names of the two stereoisomers. (2) Stereoisomer 1 Stereoisomer 2 Name: Name: (iv) Name this type of stereoisomerism. (1) .................................................................................................................................................................................................................................................................................... 7 Turn over (c) 2‑methylpropan‑2‑ol may be formed by the reaction between 2‑bromo‑2‑methylpropane and aqueous potassium hydroxide. What is the role of the hydroxide ions in this reaction? (1) A alkali B catalyst C electrophile D nucleophile (d) (i) CH3CH2CH2CH2OH reacts with the oxidising agent potassium dichromate(VI) in dilute sulfuric acid. Two organic products can be formed, depending on the conditions. Write a balanced equation for the formation of one of these products, giving its name and the condition required to achieve this product in high yield. Use [O] in the equation to represent each oxygen atom from the oxidising agent. (3) Equation Name .................................................................................................................................................................................................................................................................... Condition . ........................................................................................................................................................................................................................................................ (ii) The colour of the solution at the end of the reaction in (d)(i) will be (1) A brown B green C orange D yellow (Total for Question 2 = 13 marks)

8 3 This question is about reaction kinetics. (a) The best way to describe the activation energy of a reaction is (1) A the average energy of the particles when they react B the difference in energy between the reactants and the products C the minimum energy required to make the particles collide D the minimum energy required for a reaction to occur (b) The diagrams show two reaction profiles for the same reversible reaction involving gaseous reactants. Shown on each diagram are the reaction profiles for the pathway without a catalyst and the pathway catalysed by a heterogeneous catalyst. (i) In which diagram does the arrow represent the activation energy for the backward reaction when a catalyst is present? (1) A B 500 400 300 200 100 Enthalpy / kJ mol−1 reactants products Reaction pathway 500 400 300 200 100 Enthalpy / kJ mol−1 reactants products Reaction pathway C D 500 400 300 200 100 Enthalpy / kJ mol−1 reactants products Reaction pathway 500 400 300 200 100 Enthalpy / kJ mol−1 reactants products Reaction pathway 9 Turn over (ii) Estimate, using the diagram, the decrease in the activation energy for the forward reaction when a catalyst is added. (1) 500 400 300 200 100 Enthalpy / kJ mol−1 reactants products Reaction pathway 450 350 250 150 50 A 75 kJ mol−1 B 100 kJ mol−1 C 175 kJ mol−1 D 200 kJ mol−1 (c) State why a solid (heterogeneous) catalyst is suitable for a reaction in the gas phase. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 10 (d) The diagram shows a Maxwell‑Boltzmann distribution of molecular energies for gaseous molecules. Number of molecules with a given energy Ea (catalyst) Ea Z Y Energy, E (i) Which is the area of the graph corresponding to the number of molecules with sufficient energy to react when a catalyst is present? (1) A Y B Y − Z C Y + Z D Z (ii) Which would always result in a decrease in the number of molecules contained within area Y? (1) A decreasing the temperature of the gas B increasing the pressure of the gas C putting the gas in a smaller container D removing a quarter of the catalyst (Total for Question 3 = 6 marks)

11 Turn over 4 Methanol, CH3OH, is a liquid fuel. An experiment was carried out to determine the enthalpy change of combustion of liquid methanol. thermometer beaker methanol spirit burner water The energy obtained from burning 2.08 g of methanol was used to heat 75.0 g of water. The temperature of the water rose from 25.0 °C to 91.0 °C. [Specific heat capacity of water = 4.18 J g−1 °C−1] (a) Use the data to calculate a value for the enthalpy change of combustion of one mole of methanol. Give your answer to an appropriate number of significant figures and include a sign and units. (4) 12 (b) Methanol can be synthesised from methane and steam by a process that occurs in two steps. Step 1 CH4(g) + H2O(g)  3H2(g) + CO(g) ΔH = +206 kJ mol−1 Step 2 CO(g) + 2H2(g)  CH3OH(g) ΔH = −91 kJ mol−1 (i) Explain the effects of increasing the pressure on the yield of the products and on the rate of the reaction in Step 1. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Step 2 is carried out at a compromise temperature of 500 K. Explain why 500 K is considered to be a compromise for Step 2 by considering what would happen at higher and lower temperatures. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 13 Turn over (c) Calculate a value for the standard enthalpy change of combustion of gaseous methanol using the enthalpy change for Step 2 and the standard enthalpy change of combustion of gaseous carbon monoxide and of hydrogen. Substance Standard enthalpy change of combustion / kJ mol−1 CO −283 H2 −286 (3) (Total for Question 4 = 14 marks)

14 5 This question concerns iodine monochloride, ICl, a red‑brown solid which melts at 27 °C to form a red‑brown liquid. Iodine monochloride is used in measuring unsaturation in organic compounds. (a) Iodine monochloride gas can be produced by the reaction between iodine vapour and chlorine gas. The reaction is exothermic. I2(g)  +  Cl2(g)  →  2ICl(g)    ΔrH = −30 kJ mol−1 The table shows bond energy values for the bonds in iodine and chlorine. Calculate the value of the bond energy of the I Cl bond using these data and the equation. Bond Energy / kJ mol−1 I I 151 Cl Cl 243 (2) 15 Turn over (b) Iodine monochloride is a polar molecule which adds rapidly to double bonds in a similar way to hydrogen chloride. This reaction can be used to determine the degree of unsaturation in oils. (i) Add the dipole to a molecule of iodine monochloride. (1) I Cl (ii) Draw the mechanism for the addition of iodine monochloride to propene. You should include all curly arrows and relevant lone pairs and dipoles. (3) 16 (c) (i) To determine the extent of unsaturation of an oil, 0.250 g of the oil was treated with 25.00 cm3 of a 0.100 mol dm−3 ICl solution. Unreacted ICl reacted with excess potassium iodide solution, forming iodine according to the equation: ICl  +  KI  →  I2  +  KCl The amount of iodine produced was measured by reacting the mixture with a solution of sodium thiosulfate, Na2S2O3. The iodine released reacted with 32.65 cm3 of 0.100 mol dm−3 sodium thiosulfate solution in the mole ratio of 1 mol I2 : 2 mol Na2S2O3. Calculate the number of moles of iodine monochloride which reacted with 0.250 g of the oil. (3) 17 Turn over (ii) Unsaturation in oils is measured using a scale called ‘Iodine number’. This is the mass of iodine which will react with 100 g of the oil. Because iodine adds very slowly to double bonds, the reaction of iodine monochloride is used instead. Given that 1 mol of I2 is equivalent to 1 mol of ICl, use your answer in (c)(i) to calculate the mass of iodine that would react with 100 g of oil and hence identify the unsaturated oil from the list of possible oils and their iodine numbers. Oil Iodine number cocoa butter 35–40 coconut oil 7–10 cod liver oil 145–180 palm oil 44–51 peanut oil 84–106 (2) (iii) Give a reason why the reaction of iodine monochloride is significantly faster than the reaction of iodine. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 12 marks) 18 BLANK PAGE

19 Turn over 6 Aqueous hydrogen peroxide decomposes according to the following equation. 2H2O2(aq)  →  2H2O(l)  +  O2(g) The decomposition is catalysed by manganese(IV) oxide. This can be investigated by measuring the volume of oxygen produced at various times as the reaction proceeds. Part of the apparatus used in the experiment is shown. The manganese(IV) oxide is placed in a small glass container, which is then tipped over to start the reaction. A stop clock is started at the same time. (a) Complete the diagram to show how the gas can be collected and its volume measured, labelling the apparatus used. (2) aqueous hydrogen peroxide manganese(IV) oxide 20 (b) An experiment was carried out using 0.25 g of manganese(IV) oxide granules and 50 cm3 of aqueous hydrogen peroxide of concentration 0.16 mol dm−3. The results are shown in the table and plotted on a graph. Time / s 0.0 20.0 30.0 50.0 60.0 80.0 100 120 150 Volume of O2 / cm3 0 51 68 85 88 91 92 92 92 120 100 80 60 40 20 0 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Time / s Volume / cm3 (i) The rate of reaction may be assumed to be approximately constant up to the first volume measurement (20.0 s in this experiment). Use this approximation to calculate the initial rate of this reaction, giving the units with your answer. (1) 21 Turn over (ii) Draw a tangent at 40 s on the graph on Page 20 and use it to calculate the rate of reaction at this time. (2) (iii) The experiment was repeated on a different day when the laboratory was 20 °C warmer. The volume of oxygen was recorded for the same total time of 150 s. Draw the line that you would expect to obtain in this experiment. Assume the pressure in the laboratory is the same. No calculation is required. (2) 120 100 80 60 40 20 0 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Time / s Volume / cm3 22 (iv) Explain, using collision theory, any differences between the line you have drawn and the original line of best fit. 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(c) Catalysts are not used up during a reaction. Manganese(IV) oxide acts as a heterogeneous catalyst. Describe in outline a method to show that the manganese(IV) oxide is not used up in the decomposition of hydrogen peroxide and that it still functions as a catalyst. 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(Total for Question 6 = 13 marks) 23 Turn over BLANK PAGE

24 7 Halogenoalkanes react with water to produce alcohols and halide ions. C4H9X  +  H2O  →  C4H9OH  +  X−  +  H+ (a) Test tube experiments can be carried out to investigate the relative rates of these substitution reactions. The halogenoalkanes 1‑chlorobutane, 1‑bromobutane and 1‑iodobutane can be used. Some of the steps in these experiments are ● each halogenoalkane is added to a different tube containing 1 cm3 of ethanol ● the test tubes are placed in the same beaker of hot water ● aqueous silver nitrate is added to each tube and the tubes are shaken ● a precipitate forms in each tube. (i) State the purpose of adding ethanol to each of the test tubes. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Give one reason why the test tubes were put in the same beaker of hot water. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Give one reason why the test tubes were shaken after the addition of aqueous silver nitrate. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 25 Turn over (b) (i) State how the halogen atom present in each halogenoalkane can be identified using observations from this experiment in (a). 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(ii) Identify further reagents that can be added, including relevant observations, to confirm the identity of the halogen atom present in each halogenoalkane. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 26 *(c) Outline the method for a test tube experiment, which expands on the steps in (a), to investigate how the rate of the substitution reaction depends on whether the halogenoalkane is primary, secondary or tertiary. Your experiment should test a series of isomeric bromoalkanes reacting with water. Your plan should include ● the chemicals you will use ● an outline of how the experiment will be carried out ● the observations or measurements you will make and how you will interpret them. 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(Total for Question 7 = 12 marks) TOTAL FOR PAPER = 80 MARKS 28

4 2 This question is about alkenes. (a) Which of these has the molecular formula C6H10? (1) A B C D (b) What is the systematic name of this alkene? H2C C CH3 CH3 HC CH3 (1) A 2-methylpent-1-ene B 3-methylpent-1-ene C 2,3-dimethylbut-1-ene D 2,3-dimethylbut-3-ene 5 Turn over (c) Two reactions of ethene are shown. H C C OH H H H H C C H H H H Reaction 1 Reaction 2 HBr Product Complete the table. (3) Reaction Reagent and condition Product 1 HBr at room temperature 2 H C C OH H H H H 6 (d) But-1-ene has the structure C C H CH2CH3 H H (i) Draw the structure of the polymer formed when but-1-ene polymerises. Include two repeat units. (1) (ii) Calculate the number of molecules in 70.0 g of but-1-ene. [Avogadro constant = 6.02 × 1023 mol−1] (2) (Total for Question 2 = 8 marks) 7 Turn over BLANK PAGE

8 3 This question is about the compound potassium bromate, KBrO3 . (a) These bromate ions react with bromide ions in acidic solution. BrO3 −(aq) + 5Br−(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(l) (i) Explain, in terms of oxidation numbers, whether or not this is a disproportionation reaction. (2) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... ...................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) What is the overall order of this reaction? (1) A 3 B 6 C 12 D cannot tell from this information 9 Turn over (b) Potassium bromate decomposes on heating. 2KBrO3 → 2KBr + 3O2 Calculate the maximum volume of oxygen, in dm3, measured at room temperature and pressure (r.t.p.), that could be produced from the complete decomposition of 5.20 g of potassium bromate. [Molar volume of gas at r.t.p. = 24.0 dm3 mol−1] (3) (Total for Question 3 = 6 marks)

10 4 This question is about the identification of some organic compounds. (a) The skeletal formulae of four organic compounds are shown. Compound P O OH Compound Q O O Compound R O O Compound S OH (i) Which of these compounds can be hydrolysed to form methanol as one of the products? (1) A Compound P B Compound Q C Compound R D Compound S (ii) Which of these compounds produces carbon dioxide when it reacts with aqueous sodium hydrogencarbonate? (1) A Compound P B Compound Q C Compound R D Compound S 11 Turn over (b) Compound T, C4H10O, is oxidised by acidified potassium dichromate(VI) to form compound U, C4H8O . U gives an orange precipitate with 2,4-dinitrophenylhydrazine (Brady’s reagent) but does not give a red precipitate when heated with Fehling’s solution. T reacts with ethanoyl chloride to form compound V, C6H12O2 . Deduce the structures of compounds T, U and V. Justify your answers. (6) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... . (Total for Question 4 = 8 marks)

12 5 This question is about hydrocarbons. (a) Which of these molecular formulae represents a non-cyclic, saturated hydrocarbon? (1) A C6H6 B C6H10 C C6H12 D C6H14 (b) How many structural isomers are there with the molecular formula C5H12? . (1) A 2 B 3 C 4 D 5 (c) How many σ bonds and π bonds are there in one molecule of cyclohexene? . (1) σ bonds π bonds A 5 2 B 6 1 C 15 2 D 16 1 13 Turn over (d) When hydrocarbons undergo complete combustion, there is a change in the total volume of gases. (i) Ethane burns in excess oxygen. 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) All gas volumes are measured at the same temperature and pressure when water is a gas. What is the increase in the total volume when 100 cm3 of ethane is burned in excess oxygen? (1) A 50 cm3 B 100 cm3 C 200 cm3 D 500 cm3 14 (ii) A combustion experiment was carried out using conditions under which water was a liquid. A cyclic hydrocarbon, CxHy , was mixed with excess oxygen and ignited. Under the conditions of the experiment, this hydrocarbon was gaseous and had a volume of 25 cm3. The equation for the complete combustion of CxHy is CxHy(g) + (x + y 4 )O2(g) → xCO2(g) + y 2 H2O(l) The total gas volume decreased by 75 cm3. The remaining gases were shaken with aqueous sodium hydroxide and the total gas volume decreased by a further 125 cm3. All gas volumes were measured at the same temperature and pressure. Suggest the identity of the cyclic hydrocarbon by calculating the molecular formula of CxHy . Include the skeletal formula of the cyclic hydrocarbon. (3) 15 Turn over (e) Propene reacts with iodine monochloride, ICl, by an electrophilic addition mechanism. Draw the mechanism for the reaction between propene and iodine monochloride to form the major product. Include the dipole on the ICl molecule, curly arrows and any relevant lone pairs of electrons. (4) 16 (f) Limonene is obtained from the oil in lemon peel and it is the only alkene present. 0.500 g of the oil reacted with exactly 30.6 cm3 of a solution of bromine dissolved in cyclohexane with a concentration of 0.200 mol dm−3. Calculate the percentage by mass of limonene in the oil. Give your answer to an appropriate number of significant figures. Assume that there is nothing else in the oil that reacts with bromine. (4) (Total for Question 5 = 15 marks) 17 Turn over BLANK PAGE

18 6 A bromoalkane, RBr, reacts with aqueous hydroxide ions in a nucleophilic substitution reaction. RBr + OH− → R OH + Br− This reaction is first order with respect to the bromoalkane and the rate equation is rate = k[RBr]1[OH−]x where x is the order of the reaction with respect to hydroxide ions. In an experiment, a sample of the bromoalkane was added to a large excess of aqueous sodium hydroxide and the concentration of the bromoalkane was determined at regular time intervals. Results Time / s [RBr] / mol dm–3 0 0.100 30 0.065 60 0.042 90 0.028 120 0.019 150 0.014 (a) This experiment is carried out using the bromoalkane dissolved in ethanol and the hydroxide ions dissolved in water. Give a reason why a solution of hydroxide ions dissolved in pure ethanol should not be used. (1) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 19 Turn over (b) Plot a graph of [RBr] against time. (3) (c) Explain how the graph shows that the reaction is first order with respect to RBr. Include the values of two consecutive half-lives. You must show your working for the half-lives on the graph. (2) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 20 (d) The experiment was repeated using equal concentrations of RBr and varying the concentration of hydroxide ions. A graph was plotted of the results. Rate / mol dm−3 s−1 [OH−] / mol dm−3 (i) Deduce the value of x in the rate equation. rate = k[RBr]1[OH−]x (1) ..................................................................................................................................................................................................................................................................................... (ii) Give the mechanism for the reaction that is consistent with the orders of reaction with respect to R Br and hydroxide ions. Include curly arrows and relevant lone pairs. (3) 21 Turn over (e) 2-bromobutane can react with aqueous hydroxide ions by an SN1 mechanism. Explain why the butan-2-ol produced from a single optical isomer of 2-bromobutane, using this mechanism, is not optically active. (3) ................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 13 marks)

22 7 This question is about the synthesis of organic compounds. (a) A student suggested the following plan for the synthesis of pentanoic acid from but-2-en-1-ol. OH OH CN OH O Step 1 LiAlH4 in dry ether Step 3 heat under reflux with NaOH(aq) but-2-en-1-ol pentanoic acid butan-1-ol Step 2 KCN in aqueous ethanol (i) LiAlH4 is a source of hydride ions, H−. Give a possible reason why LiAlH4 cannot be used to reduce alkenes. (1) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Give a suitable reagent and condition for Step 1. (2) .................................................................................................................................................................................................................................................................................... (iii) Step 2 is incorrect because alcohols can only be converted to nitriles via an intermediate compound. Identify a suitable intermediate compound by name or formula. (1) .................................................................................................................................................................................................................................................................................... (iv) Step 3 involves the hydrolysis of a nitrile. Give the additional reagent that should be added after heating under reflux with aqueous sodium hydroxide, to produce pentanoic acid. (1) .................................................................................................................................................................................................................................................................................... 23 Turn over (b) Devise a four-step synthesis, involving the use of a Grignard reagent, to convert benzene into benzoyl chloride. O Cl C Include the reagents and conditions for each step in the synthesis and the structures of the intermediates. (7) (Total for Question 7 = 12 marks) 24 BLANK PAGE

25 Turn over 8 This question is about the analysis of organic compounds. (a) X is an organic compound. (i) The accurate relative atomic masses, Ar , of the four elements that could make up X are shown in the table. Element Ar hydrogen, H 1.0078 carbon, C 12.0000 nitrogen, N 14.0031 oxygen, O 15.9949 X gives a molecular ion peak at m / z = 100.0522 on its mass spectrum. Which is the molecular formula of X? (1) A C7H16 B C6H12O C C6H14N D C5H8O2 (ii) The infrared spectrum of X contains major absorption wavenumber ranges at 3300–2500 cm−1, 1725–1700 cm−1 and 1669–1645 cm−1. Identify the two functional groups in X. (2) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) X has an unbranched carbon chain and does not exhibit geometric isomerism. Draw the skeletal formula of X. (1) 26 *(b) There are similarities and differences in the 13C NMR spectra and the high resolution 1H NMR spectra of isomeric organic compounds. Compare the NMR spectra of propan-1-ol with those of propan-2-ol. Include the number of peaks, relative peak areas and splitting patterns, where appropriate. Chemical shift values are not required. (6) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 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(Total for Question 8 = 10 marks)

28 9 This question is about the effect of temperature on the rate of decomposition of nitrogen(V) oxide. 2N2O5(g) → 2N2O4(g) + O2(g) (a) The diagram shows the Maxwell-Boltzmann distribution of molecular energies for nitrogen(V) oxide at a temperature T1 . Ea is the activation energy of this reaction. Energy, E Ea T1 (i) Give the label for the vertical axis. (1) .................................................................................................................................................................................................................................................................................... (ii) Draw a second curve on the same set of axes for the same gas at a lower temperature, T2. (2) (iii) Explain, in terms of collisions and energy, why lowering the temperature decreases the rate of reaction. (2) ..................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .............................................................................................................................................................................................................................................................................. ....... (iv) A catalyst is added to the gas. Label the diagram above with the symbol Ecat to show a possible activation energy for the reaction in the presence of a catalyst. (1) 29 (b) The rate constant for the decomposition of nitrogen(V) oxide was determined at two temperatures. Temperature / K Rate constant / s−1 328 1.50 × 10−3 338 4.87 × 10−3 Calculate the activation energy for this reaction. Include units and give your answer to an appropriate number of significant figures. You should not attempt to use any graphical method to answer this question. The Arrhenius equation relating two rate constants, k1 and k2 , at two different temperatures, T1 and T2 , can be expressed as ln k k E R T T 2 1 2 1 1 1    = − −     a (5) (Total for Question 9 = 11 marks) TOTAL FOR PAPER = 90 MARKS 30 BLANK PAGE 31 BLANK PAGE 32

10 (B410U10-1) Examiner only 11. Explain the following statements. (a) Bromine is a liquid at room temperature and iodine is a solid. [3] (b) Graphite conducts electricity but diamond does not. [3] (c) The molecular ion peaks are at m/z 158, 160 and 162 in the mass spectrum of bromine, Br2. The areas of these peaks are in the ratio of 1 : 2 : 1. [3] © WJEC CBAC Ltd. 9 (B410U10-1) Turn over. 11 © WJEC CBAC Ltd. BLANK PAGE

12 (B410U10-1) 12. Barium chloride exists as a hydrated salt, BaCl2.xH2O, where x is the number of molecules of water of crystallisation. To determine the value of x, the hydrated salt is heated to remove the water of crystallisation. The following method was carried out. • Weigh an empty crucible with its lid. • Place about 2.00 g of hydrated barium chloride in the crucible and re-weigh, with its lid. • Place the lid on the crucible and heat gently at first, then remove the lid and heat strongly for about 2 minutes. © WJEC CBAC Ltd. lid heat crucible • Place the lid on the crucible and allow it to cool. • Weigh the cooled crucible with its lid and residue. The following results were recorded. Mass of crucible + lid = 10.24 g Mass of crucible + lid + hydrated barium chloride = 12.25 g Mass of crucible + lid + residue after heating = 11.97 g (B410U10-1) Turn over. 13 Examiner only (a) Calculate the mass of hydrated barium chloride and the mass of residue. Hence determine the value of x. [5] x = ........................................................ (b) (i) Suggest why the crucible was heated initially with the lid in place. [1] (ii) Suggest why the lid was placed on the crucible when it was left to cool. [1] © WJEC CBAC Ltd. 14 (B410U10-1) Examiner only (c) (i) When this experiment is carried out the value of x obtained is often less than the theoretical value. Suggest a reason for this, assuming that the compound contains no impurities. [1] (ii) State an improvement that could be made to the practical procedure to overcome the problem you have identified in (c)(i). [1] (d) If the error in each balance reading is ± 0.05 g, calculate the percentage error in the mass of hydrated barium chloride used in the experiment. [1] Percentage error = ........................................................ % (e) Apart from the improvement you identified in (c)(ii), suggest another change that could be made to improve the accuracy of the experiment. [1] © WJEC CBAC Ltd. 11 (B410U10-1) Turn over. 15 © WJEC CBAC Ltd. BLANK PAGE TURN OVER FOR QUESTION 13

16 (B410U10-1) Examiner only 13. (a) A compound of carbon, hydrogen and oxygen contains 40.0 % carbon and 6.7 % hydrogen by mass. 1.52 g of the gaseous compound has a volume of 1.76 dm3 at a temperature of 150 °C and a pressure of 1 atm. Use the data to determine the empirical formula and the molecular formula of this compound. You must show clearly how you carried out your calculations. [5] Empirical formula ........................................................ Molecular formula ........................................................ (b) (i) State what is meant by an acid. [1] (ii) Describe how ammonia, NH3, is able to act as a base. [2] (iii) Calculate the pH of 0.43 mol dm–3 hydrochloric acid. [2] pH = ........................................................ © WJEC CBAC Ltd. (B410U10-1) 17 Examiner only (c) In the table below name the type of structure and bonding present in magnesium oxide, MgO, and chlorine dioxide, ClO2. [2] © WJEC CBAC Ltd. Compound Structure Bonding MgO ............................................................. ............................................................. ClO2 ............................................................. ............................................................. 12 Turn over. END OF PAPER 18 (B410U10-1) © WJEC CBAC Ltd. Examiner only For continuation only. (B410U10-1) 19 © WJEC CBAC Ltd. BLANK PAGE

(A410U10-1) 18 Examiner only 10. Copper and cobalt are both considered to be transition elements whilst zinc is not. (a) Give a reason why zinc is not considered to be a transition element. [1] (b) Transition elements are able to form complex ions and these ions are usually coloured. Give the colour of the [Co(H2O)6]2+ ion. [1] ……………...................................................................................…………….. © WJEC CBAC Ltd. 19 (A410U10-1) Examiner only (c) When an aqueous solution containing Cu2+ ions is treated with a concentrated aqueous solution of ammonia a pale blue precipitate forms. This dissolves when more ammonia is added to form a royal blue solution, labelled A in the scheme below. (i) Identify the pale blue precipitate. [1] ........................................................................................................................ (ii) Some of the colour changes observed when other solutions are added to solution A are given in the following scheme. © WJEC CBAC Ltd. Turn over. royal blue solution, A pale blue solution, B green solution, C add dilute hydrochloric acid add concentrated ammonia solution add water add concentrated hydrochloric acid Identify the species causing these colours and use Le Chatelier’s principle to explain the changes that occur. Your answer should include appropriate equations. [6 QER] (A410U10-1) (d) Give another typical property of transition elements and use it to show that copper is a typical transition element but zinc is not. [2] © WJEC CBAC Ltd. 20 Examiner only 11 BLANK PAGE (A410U10-1) Turn over. 21 © WJEC CBAC Ltd.

22 (A410U10-1) Examiner only 11. Fuel cells are an electrochemical method of obtaining energy from fuels. (a) Give one advantage and one disadvantage of the use of fuel cells. [2] Advantage ..................................................................................................................................................................................... Disadvantage .............................................................................................................................................................................. (b) Hydrogen gas is a common fuel used in fuel cells. Hydrogen can be produced in the electrolysis of sodium chloride solution. The reaction occurring is shown below. © WJEC CBAC Ltd. 2NaCI(aq) H2(g) CI2(g) 2H2O(l) 2NaOH(aq) + + + (i) Electrolysis was undertaken on 250 cm3 of a solution of sodium chloride of concentration 5.00 mol dm–3 until 2856 cm3 of hydrogen gas was produced at a temperature of 320 K and a pressure of 1.14 × 105 Pa. Calculate the concentration of the sodium hydroxide present at the end of the process. [4] Concentration = ………............................………………… mol dm–3 23 (A410U10-1) Examiner only © WJEC CBAC Ltd. Turn over. (ii) The chlorine gas produced in the reaction was stored under a pressure of 5.05 × 105 Pa at a temperature of 283 K. Calculate the volume of the chlorine gas under these conditions. [2] Volume = ………............................………………… cm3 (iii) At the end of the electrolysis process the solution contained a base and a salt. A student suggests that this could therefore be used as a buffer. Is the student correct? Explain your answer. [3] (A410U10-1) 24 (c) When an electrical discharge is passed through hydrogen gas, the atoms emit light and other frequencies of electromagnetic radiation. These form the emission spectrum shown below. © WJEC CBAC Ltd. 91 nm 122 nm 365 nm 650 nm 820 nm 1875 nm 1282 nm 1094 nm 102 nm ultraviolet infrared Wavelength visible region (A410U10-1) Turn over. 25 Examiner only Explain why this pattern of sharp lines forms and how it can be used to find the ionisation energy of hydrogen. You should also calculate the ionisation energy of hydrogen in kJ mol–1. [6 QER] Ionisation energy = ………............................………………… kJ mol–1 © WJEC CBAC Ltd. 26 (A410U10-1) Examiner only © WJEC CBAC Ltd. (d) Another fuel that can be used in fuel cells is methanol. The equation for the combustion of gaseous methanol at a temperature of 120°C is given below. 2CH3OH(g) 4H2O(g) ∆H = –1286 kJ mol –1 3O2(g) 2CO2(g) + + (i) Calculate the bond energy of the C―O bond in methanol. [3] Bond energy = ………............................………………… kJ mol–1 Bond Bond energy / kJ mol–1 414 498 464 803 C H O O O H C O (A410U10-1) © WJEC CBAC Ltd. Turn over. (ii) Give a reason why the value calculated in part (i) may not precisely match the actual energy of this C―O bond. [1] (iii) The standard enthalpy change of combustion of methanol has a value of –715 kJ mol–1. Give reasons why this value is very different from the value associated with the equation. [3] 24 27 Examiner only

(A410U10-1) 28 Examiner only 12. The oxidation of carbon monoxide to carbon dioxide in the presence of suitable catalysts is an important method of removing this toxic gas from gas mixtures produced during incomplete combustion. © WJEC CBAC Ltd. 2CO O2 2CO2 + Some catalysts for this reaction are produced by soaking aluminium oxide pellets in a solution of a transition metal chloride followed by drying. Two suitable transition metal chlorides are palladium chloride and ruthenium chloride. (a) These catalysts are examples of heterogeneous catalysts. (i) State what is meant by heterogeneous in this context. [1] (ii) Give another example of a heterogeneous catalyst, clearly identifying the reaction that it catalyses. [1] (b) Some information regarding these catalysed reactions is given below. (A410U10-1) Turn over. 29 Examiner only © WJEC CBAC Ltd. Activation energy / kJ mol–1 Frequency factor, A / mol dm–3 s–1 palladium catalyst 61.7 6.1 × 109 ruthenium catalyst 79.4 14.1 × 109 (i) At a temperature of 600 K, the value of the rate constant for the reaction catalysed by palladium is 2.58 × 104. I. Give the unit for this rate constant. [1] ............................................................................................................... II. Find the value of the rate constant for the ruthenium catalyst under the same conditions and hence identify which of these two catalysts is the more effective. [4] (ii) Under certain conditions the oxidation of carbon monoxide can occur without a catalyst. The rate equation for this process is rate = k[CO][O2] Suggest a two-step mechanism for the uncatalysed oxidation of carbon monoxide. Label the rate determining step clearly. [3] 30 (A410U10-1) Examiner only (c) Carbon monoxide is classed as a reducing agent. (i) State what is meant by a reducing agent. [1] (ii) Explain why carbon monoxide is a reducing agent whilst the corresponding oxide of lead, PbO, is not. [2] © WJEC CBAC Ltd. 13 BLANK PAGE TURN OVER TO PAGE 32 FOR QUESTION 13 (A410U10-1) Turn over. 31 © WJEC CBAC Ltd.

32 (A410U10-1) © WJEC CBAC Ltd. 13. A student is given several magnesium compounds containing common anions and designs the scheme below to identify the anion present in each compound. no no no no no no no yes yes yes A C B D E F G yes yes yes yes does it dissolve in water? barium chloride solution is added to a sample of the solution does it give a white precipitate? silver nitrate solution is added to a sample of the solution does it give a precipitate? concentrated ammonia solution is added to the precipitate does the precipitate dissolve completely? does it dissolve in hydrochloric acid? does it fizz as it dissolves? nitrate anions present is the precipitate white? (A410U10-1) © WJEC CBAC Ltd. Turn over. (a) The student labels seven possible results as A-G. He is able to suggest likely identities for anions that would give six of these results, and his teacher said that none of the common anions that he had studied would give the seventh result. Suggest possible anions for six of the seven results below. Write ‘UNKNOWN’ for the result that would not correspond to a common anion. [4] A …………………………...................................................................………………………… B …………………………...................................................................………………………… C …………………………...................................................................………………………… D …………………………...................................................................………………………… E …………………………...................................................................………………………… F …………………………...................................................................………………………… G …………………………...................................................................………………………… (b) The planned method would not be suitable for identifying all these anions in sodium compounds. Explain why the method would not be suitable and suggest how it could be modified to make it suitable. [3] (c) Concentrated aqueous ammonia solution at 298 K contains 31.0 % ammonia by mass. The density of this solution is 0.900 g cm–3. Calculate the concentration of this solution in mol dm–3. [3] Concentration = ………............................………………… mol dm–3 33 Examiner only (A410U10-1) (d) The student is provided with a solution containing chloride as the only anion. He is told that the solution also contains sodium ions, magnesium ions, or a mixture of both sodium and magnesium ions. He proposes using a flame test to identify the cation(s) present in the mixture. State the observations expected for each possibility and explain whether this method would be appropriate. [3] END OF PAPER © WJEC CBAC Ltd. 34 Examiner only 13 (A410U10-1) Turn over. 35 Examiner only © WJEC CBAC Ltd. Additional page. (A410U10-1) 36 Examiner only © WJEC CBAC Ltd. Additional page.

4 2 This question is about sodium carbonate. (a) Sodium carbonate forms a number of hydrates with the general formula Na2CO3.xH2O. A 250 cm3 standard solution of one of these hydrates contained 10.0 g of the compound. Describe, including the names of any relevant apparatus, how to make this standard solution when provided with 10.0 g of the hydrate in a beaker. (5) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 5 (b) 25.0 cm3 portions of the standard solution described in (a) are titrated with hydrochloric acid solution of concentration 0.300 mol dm–3, using methyl orange as an indicator. The table shows the results for this titration. Titration 1 Titration 2 Titration 3 Final volume / cm3 30.25 29.75 31.25 Initial volume / cm3 0.30 0.90 2.60 Total titre / cm3 29.95 28.85 28.65 (i) What is the colour change at the end-point of the reaction? (1) From To A red orange B red yellow C yellow orange D yellow red (ii) State why the value for the total titre in Titration 1 should not be used to calculate the mean titre. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Calculate the mean titre. (1) 6 (iv) Calculate the relative formula mass, Mr , of the hydrated sodium carbonate, Na2CO3.xH2O. The equation for the reaction in the titration is Na2CO3 + 2HCl → 2NaCl + H2O + CO2 (4) (c) In an experiment, the Mr of a different hydrated sodium carbonate was found to be 286 g mol–1. (i) Calculate the relative formula mass of anhydrous sodium carbonate, Na2CO3 . (1) (ii) Calculate the number of molecules of water of crystallisation, x, for this hydrated sodium carbonate, Na2CO3.xH2O. (1) Turn over 7 (d) Sodium carbonate is manufactured from sodium chloride in a two-stage process. NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl 2NaHCO3 → Na2CO3 + H2O + CO2 Calculate the maximum mass of sodium carbonate, Na2CO3 , which could be obtained from 500 kg of sodium chloride. (3) (Total for Question 2 = 17 marks)

8 3 Ammonia reacts with sodium to form sodium amide, NaNH2 , and hydrogen. (a) (i) Write the equation for this reaction. State symbols are not required. (1) (ii) Draw diagrams showing the 3-dimensional shape of an ammonia molecule and of an amide ion, NH2 –. Include any lone pairs of electrons in each species. (3) ammonia molecule amide ion (iii) What is the H–N–H bond angle in an ammonia molecule? (1) A 104.5° B 107° C 109.5° D 120° Turn over 9 (iv) Explain the difference between the H–N–H bond angle in ammonia and in the amide ion. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Give a possible reason why samples of sodium amide are stored in oil. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 8 marks)

10 4 Sulfur is a bright yellow crystalline solid at room temperature. Sulfur forms rings of 8 sulfur atoms so the formula of the yellow solid is S8. (a) A section of a periodic table showing values of first ionisation energy in kJ mol–1 is shown. N 1400 P 1010 As 950 O 1310 S 1000 Se 940 F 1680 Cl 1250 Br 1140 (i) Which equation represents the first ionisation energy of sulfur? (1) A S(s) → S+(g) + e– B S8(s) → S8 +(g) + e– C S(g) → S+(g) + e– D S8(g) → S8 +(g) + e– (ii) Explain the trend in the values of the first ionisation energies for the group containing sulfur. 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Turn over 11 (iii) Explain why the first ionisation energy of sulfur is lower than that of chlorine. 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(iv) Explain why the first ionisation energy of sulfur is lower than that of phosphorus. 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A gaseous sample of 0.318 g of X occupied a volume of 132 cm3 at a temperature of 420 K and pressure of 105 kPa. The number of moles of a gas and the volume occupied by it can be found using the ideal gas equation pV = nRT Calculate the relative molecular mass of X and hence its molecular formula. You must show all your working. [R = 8.31 J mol–1 K–1] (5) Turn over 13 (c) Sulfur and the other elements in Group 6 form dihydrogen compounds. Compound Atomic number of Group 6 element Melting temperature / K H2O 8 273 H2S 16 To be estimated H2Se 34 207 H2Te 52 224 H2Po 84 238 (i) Plot a graph of atomic number of the Group 6 element on the x-axis against melting temperature of the dihydrogen compound on the y-axis. (2) Melting temperature / K Atomic number 150 200 250 300 (ii) Give an estimate of the melting temperature of H2S. (1) .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 16 marks)

14 5 This question is about crystalline solids. (a) Iodine and diamond are crystalline solids at room temperature. Explain why diamond has a much higher melting temperature than iodine. 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Turn over 15 (b) Graphite is also a crystalline solid at room temperature. Unlike diamond, graphite conducts electricity. Describe the key feature of the bonding of the carbon atoms in graphite that results in it being an electrical conductor. 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(Total for Question 5 = 7 marks)

16 6 This question is about the reactions of the halogens and their salts. (a) The potassium halides react with concentrated sulfuric acid to form hydrogen halides. (i) The equation for this reaction for potassium chloride can be written KCl + H2SO4 → HCl + KHSO4 The hydrogen chloride does not react further. State why this reaction is not a redox reaction. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 17 (ii) On descending Group 7, the hydrogen halides become better reducing agents. Explain how the reactions of potassium chloride, potassium bromide and potassium iodide with concentrated sulfuric acid provide evidence for this statement. No explanation of the trend is required. 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(i) At room temperature the reaction that occurs is Cl2 + NaOH → NaClO + NaCl Explain, with reference to oxidation numbers, why this is a disproportionation reaction. 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(ii) With hot sodium hydroxide solution, a different disproportionation reaction occurs. Sodium chlorate(V) is one of the products. Complete the equation for this reaction. State symbols are not required. (2) ………………….Cl2 + ………………….NaOH → Turn over 19 (c) Chlorine is used as a bleach in the textiles industry. Any excess chlorine can be removed by reduction to chloride ions. The half-equation for the reaction of chlorine is Cl2 + 2e– → 2Cl– In one reaction, 768 cm3 of chlorine gas was reduced. (i) Calculate the number of moles of electrons gained by chlorine molecules during this reaction. [Under these conditions one mole of gas occupies 24 dm3] (2) (ii) The reducing agent was a solution containing thiosulfate ions, S2O3 2–. The chlorine reacted with 40 cm3 of a 0.20 mol dm–3 solution of these ions. Deduce the number of moles of electrons lost by each atom of sulfur in the thiosulfate ion, and hence the final oxidation state of the sulfur in the product. (3) (Total for Question 6 = 13 marks)

20 7 The nitrates of lithium, rubidium and strontium are all white solids. The compounds are held together by ionic bonds. (a) State the meaning of the term ‘ionic bond’. 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(b) What is the percentage by mass of strontium in strontium nitrate? (1) A 38.0 % B 41.4 % C 58.6 % D 74.5 % Turn over 21 (c) These three compounds cannot be identified with certainty from a flame test as the colours seen are similar. Concentrated hydrochloric acid is used in a flame test procedure. (i) Which of the following is a reason for dipping the flame test wire in concentrated hydrochloric acid during a flame test procedure? (1) A it dissolves metal ions from the wire B it neutralises hydroxide ions that might colour the flame C it reduces the metal ions to metal atoms D it reacts with the compounds to form volatile chlorides (ii) The flame colour given by these three solids in the flame test are shades of (1) A green B lilac C red D yellow (iii) What is the best explanation for why metal ions produce different flame colours? (1) Different wavelengths of light energy are A required to promote electrons to higher energy levels B released because electrons move from lower to higher energy levels C released due to different gaps between energy levels D required for electron transfer from non-metal ions to metal ions 22 *(d) Devise a procedure to identify the nitrates of lithium, rubidium and strontium using the effect of heat on the three solids and any precipitation reactions of the compounds. Practical details are not required, but you should give the observations expected in each case. 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(Total for Question 7 = 12 marks) TOTAL FOR PAPER = 80 MARKS 24

4 2 Phosphorus(V) chloride, PCl5 , can be thermally decomposed to phosphorus(III) chloride, PCl3 , and chlorine, Cl2 . The equation for this reaction is PCl5(g) → PCl3(g) + Cl2(g) The enthalpy change for this reaction cannot be measured directly. (a) (i) Complete the Hess’s Law cycle to include the enthalpy change of formation of both phosphorus chlorides. Include the labels of the missing enthalpy changes. ΔvH is the enthalpy change for the vaporisation of the substance from the state shown to the gaseous state. (3) PCl5(g) PCl5(s) ΔvH [PCl5(s)] ΔrH ................................... ................................... ΔvH [PCl3(l)] PCl3(g) + Cl2(g) PCl3(l) + Cl2(g) Turn over 5 (ii) Calculate the enthalpy change for the thermal decomposition of PCl5(g) to PCl3(g) and Cl2(g), using the data given in the table. Include a sign and units in your answer. (2) Enthalpy change / kJ mol–1 ΔfH [PCl5(s)] –443.5 ΔfH [PCl3(l)] –319.7 ΔvH [PCl5(s)] +64.9 ΔvH [PCl3(l)] +30.5 (b) Another source gave a different value for the enthalpy change of this reaction. PCl5(g)  PCl3(g) + Cl2(g) ΔrH = +87.9 kJ mol–1 Explain the effect, if any, of increasing the temperature on the position of the equilibrium at constant volume. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 2 = 7 marks)

6 3 The Maxwell‑Boltzmann distribution of molecular energies for the reactant molecules in an uncatalysed reaction is shown. Number of molecules with energy E Kinetic energy E Which of these Maxwell‑Boltzmann distributions would you expect for the same molecules in the presence of a catalyst at the same temperature and pressure? All diagrams are drawn to the same scale. Number of molecules with energy E Kinetic energy E A Number of molecules with energy E Kinetic energy E B Number of molecules with energy E Kinetic energy E C Number of molecules with energy E Kinetic energy E D (Total for Question 3 = 1 mark) Turn over 7 BLANK PAGE

8 4 When solid calcium sulfate dihydrate, CaSO4·2H2O, is heated in a crucible, it forms solid calcium sulfate hemihydrate, CaSO4·½H2O. (a) Write an equation, including state symbols, for this reaction. (1) (b) Which two terms could be used to describe this reaction? (1) Enthalpy change Type of process A endothermic hydration B exothermic hydration C exothermic dehydration D endothermic dehydration (c) When water is added to calcium sulfate hemihydrate, there is a rise in temperature. A student decided to investigate this reaction using the following procedure: Step 1    10 cm3 of distilled water is measured using a measuring cylinder having an uncertainty of ±0.5 cm3, and is placed in an insulated cup with a lid. Step 2    A thermometer with an uncertainty of ±0.5 °C is placed in the water. Step 3    Exactly 10.00 g of calcium sulfate hemihydrate is weighed out using a balance with an uncertainty of ±0.005 g. Step 4    The weighed quantity of calcium sulfate hemihydrate is added to the water in the insulated cup. Step 5    The mixture in the insulated cup is stirred until no further temperature change is observed. Results Temperature of the water before adding the solid = 23.5 °C Maximum temperature of the mixture after adding the solid = 26.3 °C Other data Molar mass of calcium sulfate hemihydrate, CaSO4·½H2O = 145.2 g mol–1 Density of water = 1.00 g cm–3 Turn over 9 (i) Calculate the minimum volume of water needed to convert 10.00 g of CaSO4·½H2O into CaSO4·2H2O. (2) (ii) Calculate the enthalpy change, in kJ mol–1, for this reaction. Include a sign in your answer and give your answer to an appropriate number of significant figures. Assume that the liquid has a mass of 10.00 g and a specific heat capacity of 4.18 J g–1 °C–1. (4) (iii) Deduce which measurement has the greatest uncertainty in this experiment. Justify your answer by calculating the percentage uncertainty of this piece of apparatus. (2) (Total for Question 4 = 10 marks)

10 5 This question concerns the combustion of fossil fuels in power stations. (a) One type of power station uses the combustion of methane gas to generate power. Write an equation for the incomplete combustion of methane gas to form carbon monoxide and water only. State symbols are not required. (2) (b) One of the problems associated with the combustion of some fossil fuels is the production of acidic gases, including the oxides of nitrogen and sulfur. (i) Explain how oxides of sulfur and nitrogen can be formed from the combustion of fossil fuels. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 11 (ii) Some power stations use a process of flue gas desulfurisation (FGD) to remove sulfur oxides from the gaseous combustion products. One such process, known as wet scrubbing, uses a mixture of calcium carbonate and water to react with sulfur dioxide. Two relevant equations are SO2(g) + CaCO3(s) → CaSO3(s) + CO2(g) CaSO3(s) + 2H2O(l) + ½O2(g) → CaSO4·2H2O(s) Explain why this process is an incomplete solution to the problem of burning fossil fuels. Use the equations provided to illustrate your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) Draw a dot‑and‑cross diagram for sulfur dioxide, showing outer electrons only. (1) (Total for Question 5 = 7 marks)

12 6 This question is about halogenoalkanes. 2‑chloro‑2‑methylpropane can be hydrolysed by water. The equation for this reaction is (CH3)3CCl + H2O → (CH3)3COH + H+ + Cl− The graph shows how the concentration of 2‑chloro‑2‑methylpropane changes with time during an investigation of this reaction. 0 [(CH3)3CCl] / mol dm–3 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Time / s 50 100 150 200 (a) Calculate the rate of reaction at 50 s. Show your working on the graph. Include units with your final answer. (3) Rate of reaction at 50 s = .............................................................. (b) What is the classification of the mechanism for the hydrolysis of 2‑chloro‑2‑methylpropane by water? (1) A addition B elimination C free radical substitution D nucleophilic substitution Turn over 13 (c) The letters X, Y and Z refer to three different halogenoalkanes: X 1‑bromobutane Y 2‑bromobutane Z 2‑bromo‑2‑methylpropane 1 cm3 of each of these halogenoalkanes was added to separate test tubes containing 5 cm3 of ethanol and 5 cm3 of aqueous silver nitrate solution in a water bath at 50 °C. (i) State the visible change in the reaction of an ethanol/silver nitrate solution with halogenoalkane X. Include the formula of the compound responsible for this observation. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) The three halogenoalkanes were placed in order of decreasing rate of reaction. Which is the correct sequence? (1) A X, Z, Y B Z, X, Y C Z, Y, X D X, Y, Z 14 (d) Under different conditions, 2‑chloro‑2‑methylpropane can react to produce 2‑methylpropene, (CH3)2C CH2 . (i) State the reagent and conditions needed for this reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Draw the displayed formula for the repeat unit of a polymer that is made by the polymerisation of 2‑methylpropene, (CH3)2C CH2 . (1) (iii) Draw a mechanism for the addition of hydrogen bromide, HBr, to 2‑methylpropene to form 2‑bromo‑2‑methylpropane. Include curly arrows, and any relevant dipoles and lone pairs. (4) (Total for Question 6 = 14 marks)

Turn over 15 7 This question is about the solubility of some alcohols. The table shows the solubility in water of the first six alcohols in a homologous series. Alcohol Solubility / g dm–3 methanol soluble in all proportions ethanol soluble in all proportions propan-1‑ol soluble in all proportions butan-1‑ol 632 pentan-1‑ol 22 hexan-1‑ol 5.9 (a) State what is meant by a homologous series. You may use the alcohols in the table to illustrate your answer. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Explain why methanol and water are ‘soluble in all proportions’. You must include a diagram in your answer. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 7 = 4 marks)

16 8 This question is about some reactions of cyclohexanol. cyclohexene cyclohexanol potassium dichromate(VI) in dilute sulfuric acid B A 50 % concentrated sulfuric acid and potassium bromide (a) Write the skeletal formula of compound A. (1) (b) (i) Give the name and displayed formula of compound B. (2) Turn over 17 (ii) The infrared (IR) spectra of cyclohexanol and compound B are shown. IR Spectrum of cyclohexanol Transmittance / % 100 50 0 4000 Wavenumbers / cm–1 3000 2000 1500 1000 100 IR Spectrum of compound B Transmittance / % 100 50 0 4000 Wavenumbers / cm–1 3000 2000 1500 1000 100 Identify the bonds, using both IR spectra, that help to confirm the reaction of cyclohexanol to produce compound B. Your answer must include the wavenumber ranges of any relevant bonds. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 18 (iii) The mass spectrum of compound B is shown. Relative intensity 100 80 60 40 20 0 10 20 30 40 50 60 70 80 90 100 m/z Deduce the relative molecular mass of compound B using the mass spectrum. Justify your answer. 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(iv) In the mass spectrum of cyclohexanol, there is a peak at m/z = 83. Give the formula of a fragment that could be responsible for this peak. (2) Turn over 19 (c) (i) Cyclohexanol can be converted to cyclohexene. What is the classification for this reaction? (1) A addition B elimination C oxidation D substitution (ii) In an experiment, 10.0 cm3 of cyclohexanol was converted to cyclohexene with a 63.0 % yield. Compound Molar mass / g mol–1 Density / g cm–3 cyclohexanol 100 0.962 cyclohexene 82.0 0.811 Calculate the volume of cyclohexene produced. (4) 20 *(iii) Cyclohexene can be prepared by reacting cyclohexanol with phosphoric(V) acid. The mixture is warmed in a water bath for 15 minutes before distilling off a mixture of cyclohexene and water. Devise a procedure to obtain a pure, dry sample of cyclohexene from the distillate. Include a reason for each step. [ Boiling temperature of cyclohexene = 83 °C Density of cyclohexene = 0.811 g cm–3] (6) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 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22 9 An equation for the formation of ammonia using the Haber process is shown. N2(g) + 3H2(g)  2NH3(g) (a) (i) Calculate the enthalpy change for the forward reaction shown in the equation, selecting from the bond enthalpies in the table. Include a sign in your answer. (3) Bond Mean bond enthalpy / kJ mol–1 N N 158 N N 410 N N 945 N H 391 H H 436 Turn over 23 (ii) A data book gives the standard enthalpy change of formation of ammonia as –46.1 kJ mol–1. Give two reasons for the difference between this value and the value that you calculated in (a)(i). (2) Reason 1 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Reason 2 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) What is the percentage atom economy, by mass, for ammonia in the forward reaction? N2(g) + 3H2(g)  2NH3(g) (1) A 17.6 % B 50.0 % C 82.4 % D 100 % (iv) What is the equilibrium expression for Kc? (1) A Kc = [N ][3H ] [2NH ] 2 2 3 B Kc = [2NH ] [N ][3H ] 3 2 2 C Kc = [NH ] [N ][H ] 3 2 2 2 3 D Kc = [N ][H ] [NH ] 2 2 3 3 2 24 (b) In the chemical industry, many processes involve reversible reactions. The product is often removed before equilibrium is attained. Give three reasons why the product may be removed before its maximum concentration is achieved. 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Turn over 25 (c) Ammonia is stable in air but can be oxidised on the surface of a copper catalyst. An equation for this reaction is 4NH3(g) + 5O2(g) → 6H2O(g) + 4NO(g) ΔrH = –905.2 kJ mol–1 The catalyst is usually warmed to approximately 300 °C to start the reaction, but after a short reaction time the copper catalyst often melts. (i) Give a reason why the catalyst is warmed and a reason why the catalyst may melt. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 26 (ii) Complete the reaction profile for this catalysed oxidation of ammonia, showing the enthalpy change, ΔrH. (2) Reactants Reaction path Enthalpy 27 (iii) Describe the processes that occur on the surface of a heterogeneous catalyst during the oxidation of ammonia in air. 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(Total for Question 9 = 17 marks) TOTAL FOR PAPER = 80 MARKS 28

4 2 Barium ions can be identified by their flame colour. (a) Which of the following should be used for a flame test on barium carbonate? (1) A iron wire and water B iron wire and concentrated hydrochloric acid C nichrome wire and water D nichrome wire and concentrated hydrochloric acid (b) What colour do barium ions give in a flame test? (1) A green B lilac C red D yellow (c) A flame test was carried out on a mixture of barium chloride and magnesium chloride. How does the presence of magnesium ions affect the appearance of the flame colour of barium ions? (1) A the colour is more intense B a bright white colour completely masks the barium colour C there is no change D the barium colour is decreased by the white magnesium flame colour (Total for Question 2 = 3 marks)

Turn over 5 3 This question is about catalytic converters. (a) Catalytic converters contain metals such as platinum. Describe the bonding in platinum. You may include a diagram in your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) A catalytic converter decreases the emissions of gases, such as carbon monoxide and nitrogen monoxide, from an internal combustion engine. Describe the stages in a catalytic converter that result in this decrease. No equations are required. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 5 marks)

6 4 Ionisation energies provide information about the number of electrons and the arrangement of the electrons in an atom of an element. (a) A student’s definition of first ionisation energy is shown. First ionisation energy is the energy released when one mole of gaseous atoms loses one mole of electrons to form one mole of gaseous 1+ ions. There is one incorrect word in the student’s definition. Identify the word, giving the reason why this word is incorrect. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Write an equation for the second ionisation energy of oxygen. Include state symbols. (2) Turn over 7 (c) A sodium atom has 11 protons whereas a potassium atom has 19 protons. Explain why the first ionisation energy of sodium is greater than that of potassium. 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Electron number removed 1 2 3 4 5 6 7 8 9 10 11 12 Ionisation energy / kJ mol–1 738 1451 7733 10 541 13 629 17 995 21 704 25 657 31 644 35 463 169 996 189 371 Log (ionisation energy) 2.87 3.16 3.89 4.02 4.13 4.34 4.41 4.50 4.55 5.23 (i) Complete the table. (1) (ii) Give a reason why the logarithm of the ionisation energy, rather than just the ionisation energy, is used to plot a graph. 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(iii) Give a reason why the successive ionisation energies increase. 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Turn over 9 (iv) Plot the graph of log(ionisation energy) against electron number removed. Join the individual points using straight lines. (3) (v) Identify on the graph, using a circle, the points that represent the removal of the electrons in the outermost energy level of magnesium. (1) 10 (e) Estimate a value for the first ionisation energy of oxygen given the data in the table. (1) Element First ionisation energy / kJ mol–1 carbon 1086 nitrogen 1402 oxygen ................ (Total for Question 4 = 15 marks)

Turn over 11 5 The halogens are elements in Group 7 of the Periodic Table. (a) Chlorine compounds have many uses, including water treatment. (i) Chlorine and phosphorus (P4) can react to form phosphorus(V) chloride. The structure of a molecule of phosphorus is P P P P Some mean bond enthalpy values are shown in the table. Bond Mean bond enthalpy / kJ mol–1 P P +198 Cl Cl +243 P Cl +326 Calculate the enthalpy change for the reaction between chlorine and phosphorus to form phosphorus(V) chloride. 10Cl2 + P4 → 4PCl5 (3) 12 (ii) Give a reason why bond enthalpy values are always positive. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Sodium chlorate(I) is a bleaching agent. (i) Sodium chlorate(I) can be made by the reaction of chlorine with sodium hydroxide. Show, by using oxidation numbers, that this reaction is disproportionation. 2NaOH + Cl2 → NaClO + NaCl + H2O (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) A different bleaching agent can be made by the reaction of chlorine with sodium hydroxide under different conditions. Balance this equation. ............NaOH + ............Cl2 → NaClO3 + ............NaCl + ............H2O (1) (iii) What conditions are required for the reaction in (b)(ii)? (1) A cold and dilute alkali B cold and concentrated alkali C hot alkali D excess chlorine Turn over 13 (c) The halogens can be identified by their colour in an organic solvent such as hexane or cyclohexane. Which sequence of colours is correct for chlorine, bromine and iodine dissolved in an organic solvent? (1) Chlorine Bromine Iodine A orange red‑brown black B pale green orange black C orange red‑brown purple D pale green orange purple (d) Halide ions can be identified by their reaction with silver nitrate. (i) Write the ionic equation for the reaction between aqueous solutions of sodium iodide and silver nitrate. Include state symbols. (2) (ii) A solution containing 0.010 mol of a halide ion was reacted with excess silver nitrate and produced 1.88 g of precipitate. Identify the halide ion. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 13 marks)

14 6 This question is about entropy. (a) Some hydrated barium hydroxide is added to ammonium thiocyanate in a flask which is placed on a few drops of water on a wooden block. After the addition, the contents are stirred and then the flask can be lifted up with the wooden block attached, as shown. hydrated barium hydroxide ammonium thiocyanate table table water wooden block wooden block flask with mixed contents The equation for the reaction is Ba(OH)2.8H2O(s) + 2NH4SCN(s) → Ba(SCN)2(aq) + 2NH3(g) + 10H2O(l) (i) Give two reasons why you would expect ΔS d system to be positive. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why the wooden block is lifted up by the flask. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15 (b) What is the standard molar entropy change, ΔS d system , in J K–1 mol–1, for the reaction shown? 2Mg(s) + O2(g) → 2MgO(s) Substance Standard molar entropy, S d / J K–1 mol–1 Mg(s) 32.7 O2(g) 205.0 MgO(s) 26.9 (1) A +210.8 B –210.8 C +216.6 D –216.6 (Total for Question 6 = 5 marks)

16 7 This question is about acids and buffer solutions. (a) Ethanoic acid, CH3COOH, is a monobasic acid. CH3COOH + H2O  CH3COO– + H3O+ Give a reason why only the proton from the carboxylic acid group, and not from the methyl group, is donated to a water molecule. 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(b) The reaction of ammonia with water can be represented by NH3 + H2O  NH4 + + OH– Which is the acid‑conjugate base pair? (1) Acid Conjugate base A NH3 OH– B NH3 NH4 + C H2O OH– D H2O NH4 + Turn over 17 (c) A commercial nitric acid solution, HNO3(aq), has a concentration of 15.9 mol dm–3. A 15.0 cm3 sample was made up to 100 cm3 by adding deionised water. Calculate the pH of this diluted solution. (2) 18 (d) Propanoic acid is a weak acid. (i) Calculate the pH of a 0.100 mol dm–3 solution of propanoic acid at 298 K. Give your answer to an appropriate number of significant figures. [Ka = 1.35 × 10–5 mol dm–3 at 298 K] (3) (ii) State two assumptions that you made in the calculation in d(i). 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Turn over 19 (e) A buffer solution was made using 20.0 cm3 of a butanoic acid solution, of concentration 0.100 mol dm–3 and 30.0 cm3 of sodium butanoate solution, of concentration 0.305 mol dm–3. [Ka = 1.52 × 10–5 mol dm–3 at 298K] (i) Calculate the pH of this buffer solution at 298 K. (4) (ii) Explain why the pH of the buffer solution hardly changes when a few drops of sodium hydroxide solution are added to it. Include an equation or equations in your answer. Use C3H7COOH as the formula for butanoic acid. 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(Total for Question 7 = 15 marks)

20 8 Transition metals form complex ions. (a) Complex ions have a central metal ion surrounded by ligands. (i) Give a reason why the ammonium ion cannot act as a ligand. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why the complex ions [Co(NH3)6]2+ and [Co(H2O)6]2+ are coloured and have different colours. 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(b) Which of these complexes is used in the treatment of cancer? (1) A OH2 H2O Pt Cl Cl B OH2 Cl Pt Cl OH2 C NH3 Cl Pt Cl NH3 D OH2 H3N Pt Cl Cl Turn over 21 (c) Compare and contrast the complex ions formed by cobalt(III) ions with the ligand ethane‑1,2‑diamine and with the ligand EDTA4–. Ignore any difference in colour. H2N NH2 O –O O– –O O O– O N N O ethane‑1,2‑diamine EDTA4– (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 22 (d) Hydrated chromium(III) chloride, CrCl3.6H2O, dissolves in water to form a number of different complex ions containing both chloride and water ligands. The general formula of these complex ions is [Cr(H2O)x(Cl)y](3–y)+ In an experiment, 0.10 mol of a complex reacted with excess silver nitrate solution to produce 0.20 mol of silver chloride. Chloride ions which are ligands within the complex do not react with silver nitrate. Deduce the formula of this chromium(III) complex ion. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 8 = 12 marks)

Turn over 23 9 This question is about lattice energies. (a) The table shows the theoretical and experimental lattice energy values of two compounds. Compound Theoretical lattice energy / kJ mol–1 Experimental lattice energy / kJ mol–1 magnesium iodide –1944 –2327 barium iodide –1831 –1877 (i) State what can be deduced by the close similarity of the lattice energy values for barium iodide. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why there is a significant difference in the lattice energy values for magnesium iodide. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 24 (b) Data for the Born‑Haber cycle for copper(II) oxide are given in the table. Label Energy change Value / kJ mol–1 A standard enthalpy change of atomisation of copper +338 B standard enthalpy change of atomisation of oxygen +249 C sum of first and second ionisation energies of copper +2704 D first electron affinity of oxygen –141 E second electron affinity of oxygen +798 F standard enthalpy change of formation of copper(II) oxide –157 (i) Complete the diagram of the Born‑Haber cycle for copper(II) oxide. Include labels of enthalpy changes with arrows indicating the direction of change, and the respective species with state symbols. (4) Cu(s) + ½O2(g) F CuO(s) Turn over 25 (ii) Calculate the lattice energy of copper(II) oxide. (1) (c) A different energy cycle can be used to calculate lattice energy. Ca2+(g) + 2Br–(g) CaBr2(s) Ca2+(aq) + 2Br–(aq) Enthalpy change Value / kJ mol–1 enthalpy change of solution of CaBr2 –73 enthalpy change of hydration of Ca2+ –1577 enthalpy change of hydration of Br– –336 Calculate the lattice energy of calcium bromide. (2) (Total for Question 9 = 12 marks) 26 10 * A student wrote: Whether or not a reaction occurs depends only on the thermodynamic feasibility calculated using ∆G = ∆H — T∆Ssystem Discuss this statement. Include reference to:  changes in the values and signs of the terms in the equation for both endothermic and exothermic reactions  circumstances where a reaction that is predicted to be thermodynamically feasible may not occur in practice. 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(Total for Question 10 = 6 marks) TOTAL FOR PAPER = 90 MARKS 28

Turn over 3 4 This question is about alkenes with the molecular formula C5H10 . (a) Draw the skeletal formulae of three branched chain alkenes with the molecular formula C5H10 . (3) 4 (b) Which of these compounds would form pent-2-ene only, when reacted with concentrated phosphoric acid, H3PO4? (1) A CH3CH(OH)CH(CH3)2 B CH2(OH)CH2CH2CH2CH3 C CH3CH2CH2CH(OH)CH3 D CH3CH2CH(OH)CH2CH3 (c) Pent-2-ene reacts with hydrogen bromide, HBr, to form two bromoalkanes. Complete the diagram to show the mechanism for the formation of 2-bromopentane in this reaction. Include curly arrows, and relevant lone pairs and dipoles. (4) H Br Turn over 5 (d) A sample of pent-1-ene, with a mass of 1.33 g, is warmed to 60 °C in a sealed container. The volume of the container is 500 cm3. Calculate the pressure inside the container. Include units and give your answer to an appropriate number of significant figures. [Gas constant (R) = 8.31 J mol−1 K−1] (4) (Total for Question 4 = 12 marks)

6 5 Compound X is a component of synthetic oils used as lubricants, for instance in the gearboxes of ships. O O OH OH compound X (a) Name the three functional groups present in compound X. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) The effectiveness of this synthetic oil is much reduced if it is contaminated with water. Give, in terms of a chemical reaction, a possible reason for this. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 7 (c) An alternative to synthetic oil is known as mineral oil and consists solely of hydrocarbons separated from crude oil. (i) What is the name of the process used to separate different hydrocarbons from crude oil? (1) A cracking B reforming C fractional distillation D heating under reflux (ii) Explain why compound X is likely to have a higher boiling temperature than hydrocarbons of a similar molecular mass and shape. A detailed description of how the intermolecular forces arise is not required. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 6 marks)

8 6 This question is about carbon monoxide, CO, which is a toxic and colourless gas used widely in the chemical industry. (a) Draw a dot-and-cross diagram of a molecule of carbon monoxide. Use dots (•) for the carbon electrons and crosses (×) for the oxygen electrons. (2) (b) Carbon monoxide can be made by the thermal decomposition of sodium ethanedioate. Na2C2O4 → Na2CO3 + CO Calculate the atom economy, by mass, for the production of carbon monoxide in this reaction. (2) Turn over 9 (c) Carbon monoxide can also be made by the thermal decomposition of ethanal, CH3CHO, in the gas phase. CH3CHO(g) → CH4(g) + CO(g) This reaction was carried out at two different temperatures, and all other variables were kept constant. Temperature / K Rate / mol dm−3 s−1 1/Temperature (1/T) / K−1 ln rate 700 0.0108 1.43 × 10−3 850 4.90 1.59 (i) Complete the data in the table. (1) (ii) Calculate the activation energy, Ea , for the reaction without plotting a graph. Include a sign and units in your answer. The Arrhenius equation may be written as In rate = − 1 × a E R T + constant [R = 8.31 J mol−1 K−1] (3) 10 (d) Haemoglobin (Hb) found in red blood cells reacts almost irreversibly with carbon monoxide. Initial rate experiments were carried out to investigate the effect of the concentrations of Hb and CO on the rate of this reaction. Experiment [Hb] / mol dm−3 [CO] / mol dm–3 Rate / mol dm−3 s−1 1 2.09 × 10 –6 1.40 × 10 –6 8.20 × 10–7 2 4.18 × 10 –6 1.40 × 10 –6 1.64 × 10 –6 3 3.26 × 10 –6 2.80 × 10 –6 2.56 × 10 –6 (i) Deduce the order of reaction with respect to haemoglobin. (1) .................................................................................................................................................................................................................................................................................... (ii) Determine the order with respect to carbon monoxide using your answer to (d)(i) and the data in the table. Justify your answer. 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(iii) Write the rate equation for this reaction using your answers to (d)(i) and (d)(ii). (1) Turn over 11 (iv) Calculate the rate constant, k, for the reaction, using the data from Experiment 1 and the rate equation from (d)(iii). Include units in your answer. (3) (Total for Question 6 = 15 marks) 12 *7 This question is about polymers. (a) Compare and contrast how each of these monomers forms a polymer. cyclohexene 4-hydroxycyclohexanecarboxylic acid OH O C HO Include equations, showing the formation of a single repeat unit for each polymer. 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.................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 14 (b) Give three ways in which waste polymers can be utilised to improve their sustainability. 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(Total for Question 7 = 9 marks)

Turn over 15 8 This question is about a dicarboxylic acid Y which is present in some citrus fruits. Y contains only the elements carbon, hydrogen and oxygen. (a) A sample of Y with a mass of 1.98 g was burned completely in excess oxygen. The reaction formed 2.51 g of carbon dioxide, CO2 , and 0.69 g of water, H2O. Use these data to calculate the empirical formula of Y. (4) 16 (b) A solution was prepared using 4.34 g of the dicarboxylic acid Y made up to a volume of 250 cm3 with distilled water. A 25.0 cm3 sample of this solution was then titrated using sodium hydroxide solution, NaOH(aq), of concentration 0.320 mol dm−3. The mean titre of sodium hydroxide solution was 26.10 cm3. Calculate the molar mass of Y using the titration data, and hence deduce its structure. You must show your working. (5) (c) Which of these is used to convert a dicarboxylic acid into a diol? (1) A LiAlH4 and ether B KMnO4 and H2SO4 C Sn and HCl D Na2Cr2O7 and H2SO4 (Total for Question 8 = 10 marks)

Turn over 17 9 The painkiller paracetamol can be synthesised from phenol in three steps. The percentage yield for each step is shown. OH OH NO2 OH NH2 OH NHCOCH3 Step 1 32% Step 3 70% Step 2 85% phenol paracetamol (a) In Step 1 another product also forms. The two products can be distinguished using their 13C NMR spectra. Complete the table to show the number of peaks in each 13C NMR spectrum. (2) Product OH NO2 NO2 OH Number of peaks in the 13C NMR spectrum (b) Calculate the minimum mass of phenol needed to synthesise 1.00 kg of paracetamol. [Mr values: paracetamol = 151.0 phenol = 94.0] (3) 18 (c) When metabolised in the body, paracetamol forms a toxic compound Z. This is then removed in the liver by a reaction with the tripeptide glutathione. OH NHCOCH3 O N O O NH2 HO O N H H N O O OH SH paracetamol compound Z glutathione (i) The conversion of paracetamol to compound Z is (1) A addition B hydrolysis C oxidation D reduction (ii) Draw a circle around each of the chiral carbon atoms in glutathione. (1) O NH2 HO O N H H N O O OH SH Turn over 19 (iii) Glutathione is formed from glycine and two other amino acids. Which two amino acids combine with glycine to form glutathione? (1) NH2 O OH NH2 HS O OH NH2 HO O OH O S O OH NH2 O OH NH2 HO O glycine cysteine aspartic acid methionine glutamic acid A aspartic acid and cysteine B glutamic acid and cysteine C glutamic acid and methionine D aspartic acid and methionine (d) Explain why amino acids such as glycine are crystalline solids at room temperature. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 9 = 10 marks)

20 10 This question is about the amines butylamine, C4H9NH2 , and phenylamine, C6H5NH2 . The reaction scheme shows some reactions of butylamine, a primary amine. CH3CH2CONHC4H9 C4H9NH2 CH3CH2Br CuSO4(aq) [Cu(C4H9NH2)4]2+ solution of pH > 7 H2O Reaction 1 Reaction 2 Reaction 4 Reaction 3 C4H9NH(CH2 CH3) (a) (i) Write the equation for Reaction 1 to show why the pH of the solution is greater than 7. State symbols are not required. (1) (ii) Explain why phenylamine is a weaker base than butylamine. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Give the name and structural formula of the compound needed to react with butylamine in Reaction 2. (2) Name ................................................................................................................................................................................................................................................................... Structural formula ................................................................................................................................................................................................................................. Turn over 21 (c) What is seen when excess butylamine is used in Reaction 3? (1) A blue solution B blue precipitate C yellow solution D yellow precipitate (d) (i) What is the type and mechanism of the reaction in Reaction 4? (1) A electrophilic addition B electrophilic substitution C nucleophilic addition D nucleophilic substitution (ii) Complete the diagram to show the mechanism for Reaction 4. Include curly arrows, and relevant lone pairs and dipoles. (4) H3C H H C H CH3 Br C H2 C H2 C H2 H N (Total for Question 10 = 12 marks)

22 11 A series of experiments was carried out to determine the kinetics of the reaction between a chloroalkane, RCl, and potassium hydroxide in aqueous solution. A large excess of the chloroalkane was used. The data obtained are shown. [OH−] / mol dm−3 Time / s 0.00100 39 0.00200 31 0.00300 23 0.00400 16 0.00500 8 (a) Plot a graph of the concentration of the hydroxide ions against time. (2) Turn over 23 (b) State the order with respect to hydroxide ions. Justify your answer by reference to your graph in (a). (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) Deduce the type of mechanism occurring. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (d) Give the classification of the chloroalkane in this reaction. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 11 = 7 marks)

24 12 The alcohol 2,2-dimethylbutan-1-ol has the structure H3C C H2 C H2 C OH CH3 CH3 Devise a reaction scheme for a synthesis of this alcohol starting from 2-bromo-2-methylbutane. Include in your answer all reagents and conditions and the structures of any intermediate compounds. (6) (Total for Question 12 = 6 marks) TOTAL FOR PAPER = 90 MARKS 25 BLANK PAGE 26 BLANK PAGE 27 BLANK PAGE 28

2 Answer ALL the questions. Write your answers in the spaces provided. 1 This question is about chlorine. (a) Chlorine has two isotopes with mass numbers 35 and 37. (i) Complete the table to show the numbers of subatomic particles in a 35Cl atom and a 37Cl− ion. (2) Particle Protons Neutrons Electrons 35Cl atom 37Cl− ion (ii) A sample of chlorine contained 75 % of 35Cl and 25 % of 37Cl. Complete the mass spectrum to show the peaks you would expect for the molecular ion Cl2 + from this sample of chlorine gas. (2) 100 90 80 70 60 50 40 30 20 10 0 69 70 71 72 73 74 75 Relative abundance m / z Turn over 3 (b) Write the formula of potassium chlorate(V). (1) .................................................................................................................................................................................................................................................................................... (c) Write the equation for the first electron affinity of chlorine. Include state symbols. (2) (d) The standard electrode potential for the chlorine / chloride ion half-cell is ½Cl2(aq) + e− ⇌ Cl−(aq)  E O cell = +1.36 V (i) Identify an oxidising agent from the Data Booklet that will convert chloride ions into chlorine under standard conditions. (1) .................................................................................................................................................................................................................................................................................... (ii) Calculate the value of E O cell for the reaction in (d)(i). (1) (Total for Question 1 = 9 marks)

4 2 Analysis shows that a compound has the molecular formula C4H8O2. A student suggests that the compound could be either A or B. CH3CH2CH2COOH or HOCH2CH=CHCH2OH A B (a) Deduce a chemical test which would give a positive result for A but not for B. Include the reagent and observation. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Deduce a chemical test which would give a positive result for B but not for A. Include the reagent and observation. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 5 (c) Another student suggests that the compound could contain an aldehyde and an alcohol functional group, with structure C. HOCH2CH2CH2CHO C Complete the table to show how the infrared spectra of A, B and C would be expected to differ in the wavenumber range 1800-1600 cm−1. Use information from the Data Booklet. (3) Absorbance Wavenumber range / cm−1 Absorbance expected in infrared spectrum of A but not in B or C Absorbance expected in infrared spectrum of B but not in A or C Absorbance expected in infrared spectrum of C but not in A or B (Total for Question 2 = 7 marks)

6 3 This question is about aluminium chloride. (a) Complete the electronic configuration of an aluminium atom. (1) 1s2 ………………………………………………………………………………………………………………………… (b) At high temperatures, aluminium chloride exists as AlCl3 molecules. (i) Draw a dot-and-cross diagram of an aluminium chloride molecule, AlCl3. Show the outer shell electrons only. (1) (ii) Predict the shape of an AlCl3 molecule and the Cl−Al−Cl bond angle. (2) Shape of AlCl3 Cl−Al−Cl bond angle Turn over 7 (iii) Aluminium chloride is used as a catalyst in the alkylation of benzene. Draw the mechanism for the reaction between benzene and chloromethane using aluminium chloride as the catalyst. Include an equation for the formation of the electrophile, and any relevant curly arrows. (4) (c) Aluminium chloride exists as a dimer, Al2Cl6 , just above its boiling temperature. (i) Draw a diagram to show how two AlCl3 molecules are joined together in the dimer. (1) (ii) State the type of bond that joins the two AlCl3 molecules together. (1) .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 10 marks)

8 4 A series of experiments was carried out to investigate the factors which affect the rate of reaction between calcium carbonate and dilute hydrochloric acid. CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g) • 50.0 cm3 of hydrochloric acid was added to 10 g of calcium carbonate (an excess) in a conical flask placed on an electronic balance. • The loss in mass of the flask and its contents was recorded every 30 seconds for 10 minutes. • The experiment was repeated using different sized pieces of calcium carbonate, a different concentration of hydrochloric acid or a different temperature. Experiment Size of calcium carbonate Concentration of hydrochloric acid / mol dm−3 Temperature /°C 1 small pieces 0.50 20 2 small pieces 0.50 60 3 one large piece 0.50 20 4 small pieces 1.00 20 The results of Experiment 1 are shown on the graph. 1.0 0.8 0.6 0.4 0.2 0 0 120 240 360 480 600 Loss in mass /g Time /s Experiment 1 (a) Draw curves on the graph to show the results you would expect for Experiments 2, 3 and 4. Label the curves 2, 3 and 4. (3) Turn over 9 (b) Determine the initial rate of reaction for Experiment 1. You must show your working on the graph. Include units in your answer. (3) 1.0 0.8 0.6 0.4 0.2 0 0 120 240 360 480 600 Loss in mass /g Time /s Experiment 1 Initial rate of reaction …………………………………………………………………………………………… 10 (c) A student was required to devise an alternative method of carrying out this experiment that involved collecting the gas produced. Outline the procedure that the student could use, including a diagram and the measurements needed. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 10 marks) Turn over 11 BLANK PAGE

12 5 Tests are carried out on aqueous solutions of two salts, X and Y. (a) X contains one cation and one anion. The observations for each test are recorded in the table. (i) Complete the table by writing the names or formulae of the species. (2) Test Observation Inference Test 1 Add aqueous sodium hydroxide to an aqueous solution of X A green precipitate forms The precipitate turns brown on the top after a few minutes The cation in X is ..................................................................................................... Test 2 To an aqueous solution of X, add dilute hydrochloric acid followed by aqueous barium chloride A white precipitate forms The anion in X is ..................................................................................................... (ii) Write the ionic equation for the reaction between the cation in X and aqueous sodium hydroxide in Test 1. Include state symbols. (2) (iii) Give a reason why the green precipitate turns brown on the top after a few minutes. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iv) Give a reason why dilute hydrochloric acid is needed in Test 2. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 13 (b) Y contains one cation and one anion. The observations for each test are recorded in the table. (i) Complete the table by writing the names or formulae of the species. (2) Test Observation Inference Test 3 Add dilute aqueous ammonia to an aqueous solution of Y until it is present in excess A pale blue precipitate forms The precipitate dissolves in excess ammonia to form a deep blue solution The cation in Y is .......................................................................... Test 4 To an aqueous solution of Y, add dilute nitric acid followed by aqueous silver nitrate A white precipitate forms The anion in Y is .......................................................................... (ii) Give the formula of the complex ion present in the deep blue solution at the end of Test 3. (1) .................................................................................................................................................................................................................................................................................... (iii) Give a reagent that could be added to the mixture at the end of Test 4 to confirm the identity of the anion in Y. Include the observation when this reagent is added. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 11 marks)

14 6 This question is about the preparation and analysis of paracetamol. HO N C CH3 H O paracetamol Paracetamol may be prepared from phenol in three stages. HO HO HO Stage 1 Stage 2 Stage 3 NO2 NO2 HO HO NO2 NH2 HO N C CH3 H O 4-nitrophenol 4-aminophenol HO NH2 paracetamol 2-nitrophenol (a) In Stage 1, phenol is nitrated using dilute nitric acid. The nitration of benzene requires concentrated nitric acid at 55°C with a catalyst of concentrated sulfuric acid. Both these reactions are electrophilic substitution. (i) Explain why phenol can be nitrated using milder conditions than benzene. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15 (ii) A mixture of 2-nitrophenol and 4-nitrophenol is produced in Stage 1. They are separated by steam distillation. The boiling temperature of 2-nitrophenol is 215°C and that of 4-nitrophenol is 279°C. Explain, in terms of intermolecular forces, why 4-nitrophenol has a higher boiling temperature than 2-nitrophenol. You may include a diagram in your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 16 (b) State the type of reagent needed to convert 4-nitrophenol into 4-aminophenol in Stage 2. (1) .................................................................................................................................................................................................................................................................................... (c) The outline procedure for Stage 3 is: • place 1.0 g of 4-aminophenol in a conical flask. Add 9 cm3 of distilled water and stir the mixture • add 1 cm3 of ethanoic anhydride to the flask and shake the mixture until a precipitate of impure paracetamol forms • remove the paracetamol by filtration under reduced pressure • recrystallise the paracetamol using water as the solvent • determine the melting temperature of the pure, dry paracetamol. (i) Draw a labelled diagram of the apparatus used for filtration under reduced pressure. (3) Turn over 17 (ii) Describe the recrystallisation process to obtain a pure, dry sample of paracetamol. (5) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) The melting temperature of pure paracetamol is 170°C. Describe what happens to the melting temperature if the paracetamol is not pure. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 18 (d) The percentage by mass of paracetamol in three brands of paracetamol tablets are shown in the table. Brand of tablet Percentage by mass of paracetamol P 92.1 Q 93.6 R 99.7 The amount of paracetamol in a tablet can be determined using a titration with cerium(IV) ions. The tablets are crushed and then hydrolysed in acid to form 4-aminophenol. HO N C CH3  +  H2O HO NH2  +  CH3COOH H O 4-aminophenol is oxidised by cerium(IV) ions. HO NH2  +  2Ce4+ O NH   +  2Ce3+  +  2H+ A tablet from one of the three brands of paracetamol was analysed following the outline procedure. • one of the tablets was crushed and 0.500 g of the powder was added to dilute sulfuric acid • the mixture was heated under reflux until the hydrolysis was complete • the solution was made up to 100.0 cm3 in a volumetric flask • 25.0 cm3 portions of the solution were titrated against 0.100 mol dm−3 Ce4+ using ferroin as indicator Result The mean titre was 16.50 cm3. Turn over 19 (i) Give the molecular formula of paracetamol. (1) .................................................................................................................................................................................................................................................................................... (ii) Determine, by calculation, which brand of tablet was analysed. (5) (Total for Question 6 = 21 marks)

20 7 The enthalpy change for the decomposition of sodium hydrogencarbonate can be determined indirectly using Hess’s Law. 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g) A student carried out two experiments. (a) Experiment 1 involved the reaction between sodium hydrogencarbonate and hydrochloric acid. The student used the following procedure: • use a measuring cylinder to measure 50 cm3 of 2.00 mol dm−3 hydrochloric acid and pour it into a polystyrene cup • measure the initial temperature of the acid • weigh the test tube containing sodium hydrogencarbonate • tip the sodium hydrogencarbonate into the hydrochloric acid in the polystyrene cup, stir the mixture and record the lowest temperature reached • weigh the empty test tube. Results Measurement Value Mass of test tube + NaHCO3 / g 21.23 Mass of empty test tube / g 15.61 Mass of NaHCO3 used / g Initial temperature / °C 21.0 Final temperature / °C 14.4 Temperature fall / °C (i) Complete the table. (1) (ii) Show, by calculation, that the hydrochloric acid is in excess. You must show your working. NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g) (2) ∆rH Turn over 21 (iii) Calculate the enthalpy change for the reaction between sodium hydrogencarbonate and hydrochloric acid, using the results of the experiment. Include a sign and units in your answer. f p Assume: mass of reaction mixture = 50.0 g specific heat capacity of the reaction mixture = 4.18 J g−1 °C−1 (3) 22 (b) Experiment 2 involved the reaction between sodium carbonate and hydrochloric acid. The student repeated the procedure for Experiment 1 but used sodium carbonate instead of sodium hydrogencarbonate and measured the maximum temperature rise. Na2CO3(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g) The student calculated the enthalpy change for this reaction as −29.4 kJ mol−1. (i) Complete the Hess cycle with appropriate formulae and labelled arrows. (2) 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g) (ii) Calculate the enthalpy change for the decomposition of sodium hydrogencarbonate. Include a sign and units in your answer. 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g) (3) ∆rH ∆rH Turn over 23 (c) Another student carried out the same two experiments and obtained a value for the enthalpy change of decomposition of sodium hydrogencarbonate of +74 kJ mol−1. The data book value for this enthalpy change is +90 kJ mol−1. (i) Calculate the percentage error in this student’s value. (1) (ii) Calculate the percentage uncertainties in measuring 50 cm3 of hydrochloric acid using a burette and using a measuring cylinder. (1) Apparatus Uncertainty Percentage uncertainty Measuring cylinder ±0.5 cm3 for each volume measured Burette ±0.05 cm3 for each reading (iii) Give a reason why using a burette rather than a measuring cylinder will not improve the accuracy of the experiment. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 24 (iv) Describe changes to the method and how the data is used that would improve the accuracy of the determination of the temperature change in Experiment 2. Your description should involve the use of a clock and plotting a graph. 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(Total for Question 7 = 19 marks) Turn over 25 BLANK PAGE

26 8 This question is about some carbonyl compounds with the molecular formula C5H10O. (a) Describe a chemical test, and its result, to distinguish between pentan-2-one, CH3CH2CH2COCH3, and pentan-3-one, CH3CH2COCH2CH3. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Pentan-2-one reacts with hydrogen cyanide in the presence of cyanide ions to form 2-hydroxy-2-methylpentanenitrile. H    H    H  OH      H H    H    H  CN      H H     C    C     C    C    C     H 2-hydroxy-2-methylpentanenitrile (i) Draw the mechanism for the reaction between pentan-2-one and hydrogen cyanide in the presence of cyanide ions. Include curly arrows and any relevant lone pairs. (4) Turn over 27 (ii) The product of this reaction, 2-hydroxy-2-methylpentanenitrile, has a chiral centre. Explain why a racemic mixture of 2-hydroxy-2-methylpentanenitrile is formed in this reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) An aldehyde with molecular formula C5H10O has a 13C NMR spectrum with three peaks. The high resolution 1H NMR spectrum of this aldehyde has two peaks and neither of them is split. Deduce the displayed formula of this aldehyde. Justify your answer by referring to both NMR spectra. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 28 *(d) Describe the oxidation and reduction reactions of pentanal and pentan-3-one. Include the reagents and the structures of the organic products formed in any reactions that take place. 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(Total for Question 8 = 18 marks)

30 9 Ammonia is manufactured by the Haber Process. N2(g) + 3H2(g) ⇌ 2NH3(g) Kp = p p p ( ) ( ) ( ) NH N H 3 2 2 2 3 (a) The pressure used in the Haber Process is 200 atm. Explain the effect, if any, of increasing the pressure on the equilibrium yield of ammonia. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) The equilibrium constants for Kp and Kc are related by the equation Kp = K RT c n ( )∆ where ∆n is the number of moles of reactants minus the number of moles of products. Calculate the value of Kc at 500 K when the value of Kp = 3.55 × 10−2 atm−2. Include the units for Kc . [Use the value of R = 0.0821 dm3 atm K−1 mol−1] (4) Turn over 31 (c) A mixture of 1.0 mol of nitrogen and 3.0 mol of hydrogen is left to reach equilibrium at 700 K. Calculate the total pressure, in atmospheres, needed to produce a yield of 0.30 mol of ammonia at 700 K. Give your answer to an appropriate number of significant figures. You must show your working. [Kp = 7.76 × 10−5 atm−2 at 700 K] (5) 32 (d) The value of the equilibrium constant, Kp , varies with temperature. The equation relating the values of the equilibrium constant at two temperatures is In K K 2 1 H R 1 1 T T 1 2 The equilibrium constant, K1 , for the formation of ammonia is 6.76 × 105 atm−2 when the temperature T1 = 298 K. The enthalpy change ∆H = −92 400 J mol−1. Calculate the value of the equilibrium constant for this reaction at 310 K. [Use the value of R = 8.31 J mol−1 K−1] (4) (Total for Question 9 = 15 marks) TOTAL FOR PAPER = 120 MARKS 33 BLANK PAGE 34 BLANK PAGE 35 BLANK PAGE 36

4   2 This question is about the elements in Group 2 of the Periodic Table. (a) Magnesium powder is added to a beaker of water containing a few drops of Universal Indicator. The apparatus is set up as shown and allowed to stand for a few days. test tube filled with water water and Universal Indicator filter funnel magnesium powder State two changes that will be seen after a few days. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Explain how the trend in the reactivity of the Group 2 elements is determined by their electronic configurations. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 5   (c) Calcium reacts with chlorine. Ca(s) + Cl2(g) → CaCl2(s) Explain, in terms of electrons, why this is a redox reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (d) An experiment was carried out to determine the molar volume of hydrogen at room temperature. 0.035 g of magnesium was added to excess hydrochloric acid and 32 cm3 of hydrogen was produced. Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) Calculate the molar volume of hydrogen from the results of this experiment. Include units in your answer. (2) (Total for Question 2 = 9 marks)

6   3 This question is about the elements in Group 7 of the Periodic Table and some of their compounds. (a) What is the colour of iodine in the solid and gas states? (1) Colour of iodine solid Colour of iodine gas A purple brown B purple purple C grey/black brown D grey/black purple (b) Which of these reactions occurs? (1) A Br2(aq) + 2NaCl(aq) → 2NaBr(aq) + Cl2(aq) B Br2(aq) + 2NaF(aq)  → 2NaBr(aq) + F2(aq) C Cl2(aq) + 2NaBr(aq) → 2NaCl(aq) + Br2(aq) D Cl2(aq) + 2NaF(aq)   → 2NaCl(aq) + F2(aq) (c) The halogens can form halide ions during reactions. Complete the electronic configuration of the chloride ion. (1) 1s2 ....................................................................................................................................... Turn over 7   (d) The standard electrode potentials for two half‑equations involving bromine are given. Br2(aq) + 2e–  2Br–(aq) E d = +1.09 V 2HOBr(aq) + 2H+(aq) + 2e–  Br2(aq) + 2H2O(l) E d = +1.57 V (i) Explain why the disproportionation of bromine in water is not thermodynamically feasible under standard conditions. Include the overall equation for the disproportionation and its E d cell value. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Bromine disproportionates in water to a small extent at 298 K. Give a possible reason why this reaction occurs. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 8   (e) The hydrogen halides have the general formula HX, where X represents the symbol of the halogen. (i) Which diagram shows the trend in the boiling temperatures of the hydrogen halides? (1) 300 250 200 150 Boiling temperature / K HF HCl HBr HI A 300 250 200 150 Boiling temperature / K HF HCl HBr HI B Hydrogen halide Hydrogen halide Hydrogen halide Hydrogen halide 300 250 200 150 Boiling temperature / K HF HCl HBr HI C 300 250 200 150 Boiling temperature / K HF HCl HBr HI D (ii) What type of reaction occurs when ammonia gas reacts with hydrogen chloride gas? (1) A acid‑base B displacement C redox D substitution (Total for Question 3 = 9 marks) Turn over 9   4 This question is about structure and bonding. (a) Ionic bonding is the strong electrostatic attraction between (1) A anions and cations B atoms and delocalised electrons C cations and delocalised electrons D two nuclei and a shared pair of electrons (b) An aqueous solution of copper(II) chromate(VI) was electrolysed using the apparatus shown in the diagram. 6 V DC F – + copper(II) chromate(VI) solution E Deduce the colours of the solutions in regions E and F after the electrolysis has occurred. (2) Colour in region E ...................................................................... Colour in region F ...................................................................... 10   (c) Some ionic radii are given in the table. Ion Ionic radius / nm Na+ 0.102 Mg2+ 0.072 Cl– 0.180 Br– 0.195 Deduce the formula of the compound, formed from the ions in the table, that has the strongest ionic bonding. (1) .................................................................................................................................................................................................................................................................................... (d) The names of four substances are given. Substance Name P copper Q iodine R silicon(IV) oxide S sodium chloride (i) Which of these substances exists at room temperature as a giant lattice of oppositely charged ions? (1) A Substance P B Substance Q C Substance R D Substance S Turn over 11   (ii) Which of these substances has a high melting temperature, and conducts electricity when solid and when molten? (1) A Substance P B Substance Q C Substance R D Substance S 12   *(e) Water has two significant anomalous properties: • it has a higher melting temperature than hydrogen sulfide, H2S, even though it has fewer electrons in its molecules • the density of ice at 0 °C is less than that of water at 0 °C. Explain these properties. You should include a labelled diagram to show the intermolecular forces between two molecules of water. (6) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 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(Total for Question 4 = 12 marks)

14   5 This question is about enthalpy changes and energy changes. (a) Magnesium carbonate reacts with dilute hydrochloric acid at room temperature. MgCO3(s) + 2HCl(aq) → MgCl2(aq) + CO2(g) + H2O(l) When the reaction is carried out in a sealed container with a constant volume, the heat energy change is not the same as the enthalpy change for this reaction. Give a reason why this is so. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) State what is meant by the standard enthalpy change of formation of aluminium oxide, Al2O3(s). Include standard conditions. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15   (c) Use the data in the table to answer the questions. Enthalpy change Value / kJ mol–1 Enthalpy change of hydration of K+ –322 Enthalpy change of hydration of Ca2+ –1650 Enthalpy change of solution of KCl +17.2 Lattice energy of KCl –711 (i) Name the two properties of ions that affect the value of their enthalpy change of hydration. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Calculate the enthalpy change of hydration for chloride ions by completing the energy cycle, including labels, and using the data in the table. (3) KCl(s) + aq K+(aq) + Cl–(aq) ΔsolnH enthalpy change of hydration for Cl– ions .............................................................. kJ mol–1 (Total for Question 5 = 9 marks)

16   6 This question is about acids and bases. (a) State what is meant by a Brønsted‑Lowry base. (1) .................................................................................................................................................................................................................................................................................... (b) Write the ionic equation for the reaction between magnesium oxide and an acid. State symbols are required. (2) (c) Calculate the concentration of hydrogen ions, in mol dm –3, in a solution with a pH of 9.43 (1) (d) The pH of two salt solutions, J and K, are solution J pH = 5 solution K pH = 9 The solutions are equimolar. Which acids and bases could form the salts in solutions J and K? (1) A B C D Acid and base forming the salt in solution J Acid and base forming the salt in solution K HCl(aq) and NH3(aq) CH3COOH(aq) and NaOH(aq) HCl(aq) and NaOH(aq) CH3COOH(aq) and NH3(aq) CH3COOH(aq) and NaOH(aq) HCl(aq) and NaOH(aq) CH3COOH(aq) and NH3(aq) HCl(aq) and NH3(aq) Turn over 17   (e) The ionic product of water, Kw , varies with temperature as shown. Temperature /  °C Kw / mol2 dm–6 0 0.11 × 10–14 10 0.29 × 10–14 20 0.68 × 10–14 30 1.47 × 10–14 40 2.92 × 10–14 50 5.48 × 10–14 (i) Determine the value of Kw at 45 °C by plotting a suitable graph. You must show your working on the graph. (3) Kw at 45 °C = .............................................................. 18   (ii) The ionic product of water at 30 °C is 1.47 × 10–14 mol2 dm–6. Calculate the pH of water at this temperature. (3) (f) Hydrochloric acid, with a concentration of 0.100 mol dm–3, is added to 25.0 cm3 of 0.100 mol dm–3 aqueous sodium carbonate and the pH is measured. The titration curve is shown. 14 12 10 8 6 4 2 0 pH 0 Volume HCl(aq) / cm3 10 20 30 40 50 second equivalence point X first equivalence point The reaction takes place in two steps. The equation for the reaction taking place in the first step is Na2CO3(aq) + HCl(aq) → NaHCO3(aq) + NaCl(aq) Turn over 19   (i) Deduce a suitable indicator to identify the first equivalence point. Justify your answer using values from the Data Booklet. 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(ii) Write the equation for the reaction taking place at the second equivalence point. State symbols are not required. (1) (iii) Explain how the solution at point X on the graph can act as a buffer solution. 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(Total for Question 6 = 17 marks) 20   BLANK PAGE Turn over 21   7 This question is about chromium and some of its compounds. (a) The common oxidation numbers of chromium are +2, +3 and +6. Give a reason, in terms of ionisation energies, why chromium can show variable oxidation numbers. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) The bonding in chromate(VI) ions, CrO4 2–, is similar to that in sulfate(VI) ions, SO4 2–. Draw a possible dot‑and‑cross diagram for a chromate(VI) ion. (2) 22   (c) A student added some pieces of zinc to an acidified solution of potassium dichromate(VI). Some standard electrode potentials are given in the table. Right‑hand electrode system E d / V Zn 2+(aq) + 2e–  Zn(s) –0.76 Cr 3+(aq) + e–  Cr 2+(aq) –0.41 Cr2O7 2–(aq) + 14H +(aq) + 6e–  2Cr 3+(aq) + 7H2O(l) +1.33 (i) Write the overall equation for the reduction of dichromate(VI) ions to chromium(III) ions by zinc in acid conditions. State symbols are not required. (2) (ii) Calculate E d cell for the reaction in (c)(i). (1) (iii) Predict whether or not a further reduction of chromium(III) ions to chromium(II) ions will occur. Justify your answer. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 23   (iv) Aqueous solutions containing chromium(III) ions and chromium(II) ions have different colours. Explain why these solutions differ in colour. An explanation of the origin of the colours is not required. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 24   (d) An iron nail was analysed using the following outline procedure. • An iron nail was placed in a beaker and excess dilute sulfuric acid was added. • After all the iron had reacted to form iron(II) ions, the solution was made up to 1.00 dm 3 in a volumetric flask. • 25.0 cm3 portions of the solution were acidified and titrated with potassium dichromate(VI) solution of concentration 0.0167 mol dm –3. Results mass of iron nail = 3.54 g mean titre = 15.50 cm3 The table shows the percentage by mass of iron in four different brands of nail. Brand of nail Percentage by mass of iron A 92 B 94 C 96 D 98 Potassium dichromate(VI) in acid solution oxidises iron(II) ions as shown in the equation Cr2O7 2– + 14H + + 6Fe 2+ → 2Cr 3+ + 6Fe 3+ + 7H2O Determine, using the experimental data, the brand of nail that was analysed. (5) Turn over 25   (Total for Question 7 = 14 marks)

26   8 This question is about electrode potentials, cells and equilibrium constants. (a) Chlorine gas can be prepared by the oxidation of chloride ions with manganate(VII) ions in acid solution. MnO4 –(aq) + 5Cl –(aq) + 8H +(aq)  Mn 2+(aq) + 2½Cl2(g) + 4H2O(l) E d cell = +0.15 V During this reaction, each manganate(VII) ion accepts five electrons. Calculate the equilibrium constant, K, for this reaction at 298 K using the expression lnK =  n F RT E d cell where n is the number of electrons transferred in the overall equation, F is the Faraday constant (96 500 C mol –1) and R is the gas constant (8.31 J mol –1 K –1). Units of K are not required. (2) Turn over 27   (b) A fuel cell produces a voltage from the reaction between a fuel and oxygen. The reaction occurring at one electrode in a methanol fuel cell is CH3OH(g) + H2O(l) → HCOOH(aq) + 4H +(aq) + 4e– Which reaction occurs at the other electrode? (1) A 4H +(aq) + O2(g) + 4e– → 2H2O(l) B 2H2(g) + 2O2(g) + 4e– → 4OH –(aq) C 4OH –(aq) → 2H2(g) + 2O2(g) + 4e– D 2H2O(l) → 4H +(aq) + O2(g) + 4e– (c) Lead‑acid batteries are used as storage cells in some cars. The electrolyte is sulfuric acid, one electrode is lead and the other is lead(IV) oxide, PbO2. As the cell discharges, the lead and the lead(IV) oxide are both converted to solid lead(II) sulfate, PbSO4 , and the concentration of the sulfuric acid decreases. Deduce, using the information given, the two half‑equations occurring in the lead‑acid battery. State symbols are required. (3) 28   (d) When solid lead(II) sulfate is added to aqueous sodium iodide, an equilibrium is established. PbSO4(s) + 2I –(aq)  PbI2(s) + SO4 2–(aq) The expression for the equilibrium constant, Kc , for this reaction is Kc =  [SO (aq)] [ (aq)]2 4 2− −I In an experiment, Kc may be determined by adding excess lead(II) sulfate to 25.0 cm3 of 0.100 mol dm –3 sodium iodide. The volume remains constant at 25.0 cm3. The mixture is left to reach equilibrium at room temperature. Ice‑cold water is added to freeze the position of equilibrium and the mixture is then titrated with standard silver nitrate solution. The whole mixture requires 12.20 cm3 of 0.0500 mol dm –3 silver nitrate solution to react with the aqueous iodide ions at equilibrium. Ag +(aq) + I –(aq) → AgI(s) Calculate the equilibrium concentrations of the sulfate ions and the iodide ions, and hence the value of Kc at room temperature. Give your answer to an appropriate number of significant figures and include units for Kc , if any. (7) 29   (Total for Question 8 = 13 marks) TOTAL FOR PAPER = 90 MARKS 30   BLANK PAGE 31   BLANK PAGE 32  

4   2 This is a question about hydrocarbons. (a) State what is meant by the term hydrocarbon. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Explain why 2,2‑dimethylpropane has a much lower boiling temperature than its isomer pentane. Detailed descriptions of the forces involved are not required. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) The heterolytic bond fission of a sigma (σ) bond in an alkane would produce (1) A only carbocations B only free radicals C free radicals and ions D ions (Total for Question 2 = 4 marks) Turn over 5   3 This is a question about dihalogenoalkanes. (a) Dihalogenoalkanes are formed when alkenes react with halogens. (i) Complete the mechanism for the production of a dihalogenoalkane from 2‑methylbut‑1‑ene and chlorine. Include curly arrows and any relevant lone pairs. (3) Cl Cl (ii) Give the name of the dihalogenoalkane produced. (1) .................................................................................................................................................................................................................................................................................... (b) What is the classification of the dihalogenoalkane shown? Cl Cl (1) A primary B secondary C tertiary D primary and secondary (Total for Question 3 = 5 marks)

6   4 This question is about nitrogen and some nitrogen compounds. (a) A study of one brand of crisps found that each packet contained 0.420 g of nitrogen gas at a pressure of 120 kPa and a temperature of 20 °C. (i) Calculate the volume of nitrogen gas, in cm3, in one packet of crisps. [R = 8.31 J mol–1 K–1] (4) (ii) Give a possible reason why nitrogen gas and not air is used in packets of crisps. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Draw dot‑and‑cross diagrams for a molecule of nitrogen gas and for the nitride ion, N3–, in sodium nitride, Na3N. Use dots () for nitrogen electrons and crosses (X) for electrons from sodium. (2) Nitrogen molecule Nitride ion Turn over 7   (c) Ammonia accepts a proton to form an ammonium ion. NH3 + H+ → NH4 + Explain why the ammonia molecule and the ammonium ion have different shapes and different bond angles. 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(d) Butylamine, C4H9NH2 , reacts with ethanoyl chloride. 2C4H9NH2 + CH3COCl → C4H9NHCOCH3 + C4H9NH3 +Cl– Explain how this equation illustrates that butylamine acts as a nucleophile and as a base. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 15 marks)

8   5 Ice has a density of 0.92 g cm–3 and water has a density of 1.00 g cm–3. (a) About 200 cm3 of water and 200 cm3 of cooking oil were placed in a large beaker and two layers formed. The cooking oil formed the upper layer. An ice cube made from water with a water‑soluble blue food dye was added. Initially the ice cube floated on top of the cooking oil but on melting the blue‑coloured water sank into the bottom layer of water. Give a possible value for the density of the cooking oil. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Calculate how many more molecules there are in 5.00 cm3 of water compared to 5.00 cm3 of ice. (3) (Total for Question 5 = 5 marks) Turn over 9   6 Aldehydes and ketones are carbonyl compounds. (a) Which of these compounds does not contain a ketone functional group? (1) A B HO O O OH O O C D OH O O OH O O (b) Which of these compounds has both an aldehyde functional group and a ketone functional group? (1) A B O O O O C D O O O O 10   (c) Propanal can be produced from the oxidation of propan‑1‑ol. (i) A student assembled the apparatus shown for this oxidation. pear-shaped flask Liebig condenser anti-bumping granules water out water in reaction mixture heat Explain why the use of this apparatus would give a very low yield of propanal. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) The oxidising agent is acidified Na2Cr2O7 . State the oxidation number of chromium in Na2Cr2O7 . (1) .................................................................................................................................................................................................................................................................................... (iii) Complete the ionic half‑equation for the oxidation of propan‑1‑ol. (1) CH3CH2CH2OH → CH3CH2CHO + ...............H+ + ...............e– Turn over 11   (iv) State how the use of anti‑bumping granules gives smoother boiling. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (v) Another student used the correct apparatus for this oxidation. 1.50 g of propan‑1‑ol produced 0.609 g of propanal. Calculate the percentage yield of propanal by mass. (3) 12   (d) The table contains data on propanone and ethanoic acid. Substance Molar mass / g mol–1 Boiling temperature / °C Solubility in water Propanone 58 56 completely miscible Ethanoic acid 60 118 completely miscible (i) Explain, by reference to the data and any intermolecular forces involved, the difference in the boiling temperatures. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 13   (ii) Explain, with the aid of a diagram, why propanone is completely miscible with water. 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(Total for Question 6 = 16 marks)

14   7 Organic compounds containing nitrogen include amides, amines, amino acids and nitriles. (a) Propylamine, CH3CH2CH2NH2 , may be formed from either a nitrile or a halogenoalkane. (i) Give the reagent and essential condition for the formation of propylamine from a nitrile. Include an equation for the reaction. (2) .................................................................................................................................................................................................................................................................................... (ii) Give the reagent and essential conditions for the formation of propylamine from a halogenoalkane. Include an equation for the reaction. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) A compound produced a peak due to an N–H stretching vibration in its infrared spectrum with a wavenumber of 3220 cm–1. This compound could be (1) A an amide B an amine C either an amide or an amine D neither an amide nor an amine Turn over 15   *(c) Alanine and glycine are amino acids. Amino acid Structure alanine H N C C CH3 H O O H H glycine H N C C H H O O H H Compare and contrast the structures, optical activity and reactions with acids and bases of alanine and glycine. Include diagrams, structures and equations to illustrate your answer. 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Turn over 17   (d) Lysine and serine are two more amino acids. Amino acid Structure of amino acid lysine H N C C (CH2)4 H O O H H NH2 serine H N C C CH2 H O O H H OH Explain the difference in the volumes of 0.010 mol dm–3 hydrochloric acid required to completely react with separate 10.0 cm3 samples of aqueous lysine and of aqueous serine, both of concentration 0.010 mol dm–3. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 7 = 14 marks)

18   8 Esters have many uses due to their characteristic aromas and often have common names. For example, isoamyl acetate is referred to as banana oil and amyl acetate has a scent similar to apples. O O O O isoamyl acetate amyl acetate (a) What is the number of peaks in a 13C NMR spectrum of isoamyl acetate and of amyl acetate? (1) isoamyl acetate amyl acetate A 5 6 B 6 6 C 6 7 D 7 7 (b) State the molecular formula of amyl acetate. (1) .................................................................................................................................................................................................................................................................................... (c) Deduce the structural formula of the carboxylic acid that could be used to form both isoamyl acetate and amyl acetate. (1) (d) Deduce the name of the alcohol that forms isoamyl acetate. (1) .................................................................................................................................................................................................................................................................................... (e) Give the systematic name for amyl acetate. (1) .................................................................................................................................................................................................................................................................................... Turn over 19   (f) The carboxylic acid used to make isoamyl acetate and amyl acetate can also be used to make six further ester isomers. The structures of two of these esters, A and B, are shown. (i) Complete the skeletal formulae of three of the remaining esters. Names are not required. (3) O O isoamyl acetate O O amyl acetate O O O O ester A O O O O ester B O O (ii) Write an equation to show the formation of ester A from an acyl chloride and an alcohol. (2) 20   (g) Esters can be hydrolysed by heating under reflux with aqueous acid or alkali. Compare and contrast these two methods of hydrolysis for amyl acetate. 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(Total for Question 8 = 14 marks) Turn over 21   9 At high temperatures, ethanal decomposes to form methane and carbon monoxide. The reaction is second order with respect to ethanal and second order overall. CH3CHO → CH4 + CO (a) Write the rate equation for this reaction. (1) (b) Deduce the units of the rate constant given that the units of rate are mol dm–3 s–1. (1) (c) The table shows the concentration of ethanal in a sample at different times. Time / s Concentration of ethanal / mol dm–3 0 0.72 420 0.36 1260 0.18 Calculate average values for the rate of reaction between 0 and 420 seconds and between 420 and 1260 seconds. Give your answers to an appropriate number of significant figures. (2) 0 s – 420 s ..................................................................................................... 420 s – 1260 s ..................................................................................................... 22   (d) Explain why the data given and your answers in (c) show that the reaction is neither zero order nor first order. 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(e) The rate constant for the reaction was determined at five temperatures. The results are given in the table. Temperature (T) / K 1/ Temperature (1/T) / K–1 Rate constant (k) / units in (b) ln k 700 1.43 × 10–3 0.011 –4.51 730 1.37 × 10–3 0.035 –3.35 760 1.32 × 10–3 0.105 –2.25 790 0.343 810 1.23 × 10–3 0.787 –0.24 Determine the activation energy, Ea , in kJ mol–1, by completing the data in the table and plotting a graph of ln k against 1/T. You should include the value of the gradient of the line and its units. The Arrhenius equation can be expressed as  ln k = – E R a  ×  1 T + constant (7) 23   Total for Question 9 = 13 marks) TOTAL FOR PAPER = 90 MARKS 24  

4   2 Ammonium cobalt(II) sulfate is made by mixing aqueous solutions of ammonium sulfate and excess cobalt(II) sulfate. (a) Dry crystals of ammonium cobalt(II) sulfate, (NH4)2SO4·CoSO4·6H2O, are obtained by the procedure shown. Step 1    The reaction mixture is transferred to an evaporating basin, heated gently and then left to crystallise. Step 2    The crystals are separated by gravity filtration. Step 3    The crystals are then rinsed with a small amount of ice‑cold water. Step 4    The rinsed crystals are placed in a warm oven for 30 minutes. (i) The colour of the cobalt(II) sulfate solution used is pink due to the complex cobalt(II) ion, [Co(H2O)6]2+. Explain why the solution is coloured. 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(ii) Explain the shape of the cobalt(II) ion, [Co(H2O)6]2+ , using electron‑pair repulsion theory. 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Turn over 5   (iii) Give the reasons for carrying out Steps 3 and 4 of the procedure, referring particularly to the words in bold. 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(b) The percentage yield of this reaction is 70.0 %. Give two possible reasons, other than an incomplete reaction, why the yield is less than 100 %. 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(Total for Question 2 = 12 marks)

6   3 A group of students design and carry out experiments to deduce the formulae of two salts, X and Y. X contains one cation and one anion. Y contains water of crystallisation. (a) (i) A flame test is carried out on X. Describe how to carry out a flame test. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) The colour of the flame is yellow. Give the formula of the metal ion present in salt X. (1) .................................................................................................................................................................................................................................................................................... (b) A sample of X is placed in a test tube and dissolved in deionised water. The solution is acidified with hydrochloric acid and barium chloride solution is added. A white precipitate forms. (i) Give the formula of the anion present in X. (1) .................................................................................................................................................................................................................................................................................... (ii) Deduce the formula of X, using your answers to (a)(ii) and (b)(i). (1) .................................................................................................................................................................................................................................................................................... Turn over 7   (c) Y is identified as hydrated potassium carbonate, K2CO3·nH2O. Two of the students were asked to determine the number of moles of water of crystallisation, n, in Y using the procedure shown: • weigh a sample of hydrated Y into a pre‑weighed crucible • place a lid loosely on the crucible and heat it for five minutes to remove the water of crystallisation • allow the crucible and lid to cool, remove the lid and then reweigh the crucible with its contents. lid crucible heat hydrated Y pipeclay triangle (i) The first student carried out the experiment but forgot to use the lid. Explain how this mistake would affect the calculated value of n. 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(ii) The second student carried out the experiment but heated the apparatus for only one minute. Explain how this mistake would affect the calculated value of n. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 8   (iii) In an accurate experiment, Y is found to consist of 71.9 % K2CO3 by mass. Calculate the value of n. (3) (Total for Question 3 = 13 marks) Turn over 9   BLANK PAGE

10   4 This question is about the white solid barium carbonate. (a) Barium carbonate decomposes under suitable conditions to form barium oxide and carbon dioxide. BaCO3(s) → BaO(s) + CO2(g) ΔrH d = +169.3 kJ mol–1 Standard molar entropy data related to this reaction are shown. Substance Standard molar entropy, S d / J K–1 mol–1 BaCO3(s) 112.1 BaO(s) 70.4 CO2(g) 213.6 (i) Show that barium carbonate is thermally stable at 298 K, using the data in the equation and in the table. (5) Turn over 11   (ii) Calculate the lowest temperature, in °C, at which it is thermodynamically feasible for barium carbonate to decompose. Give your answer to three significant figures. (3) (b) Explain whether magnesium carbonate is more or less thermally stable than barium carbonate. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) A white solid was thought to be barium carbonate. A student suggested that the presence of the carbonate ion could be tested for by adding a small amount of sulfuric acid. Explain whether or not this suggestion is valid. 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(Total for Question 4 = 13 marks) 12   5 * Explain the difference in the reactivity of bromine with benzene and with phenol. Include the type of reaction, the products that form, and any conditions required. Mechanisms for the reactions are not required. 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(Total for Question 5 = 6 marks)

14   6 An ester Q has the molecular formula C8H16O2 . (a) When burned in excess oxygen, 1.879 g of Q formed 4.594 g of carbon dioxide and 1.879 g of water. Show that the empirical formula of Q is C4H8O. (4) (b) Data from the high resolution 1H (proton) NMR spectrum of the ester Q are shown in the table. Chemical shift (δ) / ppm Splitting pattern of peak Relative peak area 2.50 singlet 3 1.56 quartet 4 1.43 singlet 3 0.92 triplet 6 Turn over 15   Part of the structure of Q is shown. Complete the structure of Q. Justify your answer by linking the proton environments in your structure to the relative peak areas and the splitting pattern of the peaks. (7) O O H3C C .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 11 marks)

16   7 This question is about some reactions of carbonyl compounds. (a) Methyl methacrylate is the monomer used to make the polymer perspex. It can be synthesised from propanone using the reaction scheme shown. propanone O CN O O methyl methacrylate Dehydration Compound A Compound B Reaction type 4 Reagent 2 Reagent 4 + conc. H2SO4 Step 2 Step 4 Step 3 HCl(aq) OH Reaction type 3 HCN / KCN Step 1 (i) Draw the mechanism for the reaction in Step 1. Include curly arrows and any relevant lone pairs and dipoles. (4) Turn over 17   (ii) Complete the table to show the information missing from the reaction scheme. (6) Reagent 2 Structure of compound A Reaction type 3 Structure of compound B Reagent 4 Reaction type 4 (iii) Complete the equation for the formation of the polymer from methyl methacrylate. (2) ............... O O 18   (b) Propanone can be formed from the fermentation of polysaccharides such as starch. The propanone can be separated from the fermentation mixture by distillation. Draw the apparatus used in the laboratory for distillation of propanone from the reaction mixture. (3) Turn over 19   (c) Carbonyl compounds, such as propanone, react with 2,4‑dinitrophenylhydrazine in solution (Brady’s reagent) to form a precipitate which can be used to identify the compound. The precipitate can be purified by recrystallisation. Details of the recrystallisation process are shown. Step 1 Dissolve the precipitate in the minimum volume of hot ethanol. Step 2 Warm a filter paper and funnel in an oven for use in Step 3. Step 3 Filter the solution whilst still warm to remove any undissolved solids, using gravity filtration. Step 4 Allow the filtrate to cool and recrystallise. Step 5 Filter the crystals under reduced pressure. Step 6 Rinse the crystals with a small amount of ice‑cold ethanol. Step 7 Dry the crystals between filter papers and leave in a desiccator. (i) Explain why the filter paper and funnel are warmed in an oven before Step 3. 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(ii) Explain how Steps 4 and 5 remove impurities from the crystalline product. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 20   (iii) State how the purified crystals can be used to identify the carbonyl compound that reacts with 2,4‑dinitrophenylhydrazine. Detailed descriptions of practical procedures are not required. 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(Total for Question 7 = 21 marks) Turn over 21   8 This question is about acids and bases. (a) Devise an experiment to determine the acid dissociation constant, Ka , for a solution of ethanoic acid, CH3COOH, of unknown concentration. Assume you have access to a pH meter and a solution of sodium hydroxide of similar concentration to the acid. Include how to determine Ka from your results. 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.................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 22   (b) 500 cm3 of a buffer solution of pH = 4.70 is required. Calculate the volume of 0.800 mol dm–3 sodium ethanoate solution and of 0.800 mol dm–3 ethanoic acid needed to make this buffer. [Ka for ethanoic acid = 1.74 × 10–5 mol dm–3] (3). (3) Turn over 23   (c) Calculate the pH of the solution formed when 51.2 cm3 of 0.927 mol dm–3 NaOH(aq) is mixed with 40.4 cm3 of 0.370 mol dm–3 H2SO4(aq). [Ionic product of water Kw = 1.00 × 10–14 mol2 dm–6] (6) (Total for Question 8 = 14 marks)

24   9 Pineapple juice contains the weak acids citric acid (C6H8O7) and ascorbic acid (C6H8O6). The amount of each compound in a sample of 150 cm3 of pineapple juice can be determined by titration. (a) Experiment 1 is designed to determine the total amount of acid. 10.0 cm3 samples of pineapple juice are transferred to separate conical flasks and titrated with a solution of sodium hydroxide of known concentration. The total amount of acid in the 150 cm3 sample of pineapple juice is 8.00 × 10–3 mol. (i) Give a reason why methyl orange would not be a suitable indicator to use in this titration. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) A student did not notice an air bubble in the tip of the burette before carrying out one of their accurate titrations. During this titration, the air bubble escaped. Explain the effect this mistake would have on the value of this titre. 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Turn over 25   (b) Experiment 2 is carried out to determine the amount of ascorbic acid (C6H8O6) in the pineapple juice. An outline procedure for this experiment is given. Step 1 5.00 cm3 of the pineapple juice is added to a conical flask. Step 2 Deionised water, a small amount of HCl(aq), a few crystals of potassium iodide, KI, and 3 drops of starch solution are also added to the flask. Step 3 The contents of the flask are swirled to ensure the KI dissolves fully. Step 4 The resultant mixture is titrated with a solution of potassium iodate(V), KIO3(aq), of concentration 0.00100 mol dm–3. The reactions that take place are IO3 –(aq) + 5I–(aq) + 6H+(aq) → 3I2(aq) + 3H2O(l) C6H8O6(aq) + I2(aq) → C6H6O6(aq) + 2H+(aq) + 2I–(aq) Only the ascorbic acid reacts with the iodine. (i) The end-point of the titration is when the starch changes colour. Explain how this occurs, including the colour change. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 26   (ii) The total amount of acid in the 150 cm3 sample is 8.00 × 10–3 mol. The mean titre in Experiment 2 using 5.00 cm3 of pineapple juice is 9.50 cm3. Calculate the mass of citric acid in the 150 cm3 sample. (5) Turn over 27   (c) While doing background research for the experiment, a student found that three other compounds, D, E and F, are often present in pineapple juice. Compound F Compound D CH3 H3C HO O O Compound E O OH HO O OH CH3 CH3 CH3 CH3 CH3 CH3 H3C CH3 H3C H3C Predict which one of these compounds is most likely to affect the result of Experiment 1 and hence predict the effect on the mass of citric acid calculated in (b)(ii). Justify your answer. 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(Total for Question 9 = 14 marks)

28   10 The progress of the reaction between iodine and propanone with an acid catalyst can be followed in an experiment using a titrimetric method. Procedure Step 1 Mix 25 cm3 of 1 mol dm–3 aqueous propanone with 25 cm3 of 1 mol dm–3 sulfuric acid in a beaker. Both these reactants are in excess. Step 2 Start the stop clock as 50 cm3 of 0.02 mol dm–3 iodine solution is added to the beaker. Mix the reactants thoroughly. Step 3 Withdraw a 10.0 cm3 sample of the reaction mixture, using a pipette, and transfer it to a conical flask. Step 4 Add a spatula measure of sodium hydrogencarbonate, noting the exact time. Step 5 Titrate the iodine present in the 10.0 cm3 sample with 0.01 mol dm–3 sodium thiosulfate solution, using starch indicator. Step 6 Continue to withdraw 10.0 cm3 samples about every two minutes, repeating Steps 4 and 5 with each sample. (a) (i) Explain why sodium hydrogencarbonate is added in Step 4. 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(ii) Write the ionic equation for the reaction that takes place during Step 4. State symbols are not required. (1) Turn over 29   (b) Some data from the experiment are shown. Time sodium hydrogencarbonate is added / min 2.0 5.0 6.5 8.0 10.5 12.0 Volume of sodium thiosulfate / cm3 19.2 15.5 14.0 12.1 9.5 7.2 (i) Plot a graph of the volume of sodium thiosulfate against the time the sodium hydrogencarbonate is added. (2) 30   (ii) Explain how the graph of volume of thiosulfate against time confirms the reaction is zero order with respect to iodine, I2. 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Turn over 31   (c) The overall rate equation for the reaction is rate = k[H+(aq)][CH3COCH3(aq)]. A student researching the mechanism for the reaction found this example. Step 1 Step 2 O CH3 H3C C Step 3 OH CH3 H2C C OH CH3 H2C C O + CH3 H2 H I C C O + CH3 H2 H I C C + H+ + I– + H+ + H+ O CH3 H2 I C C + I2 O CH3 H3C C O CH3 IH2C C acidic conditions Overall reaction + H+ + I– + I2 (i) Predict which of the three steps is the rate‑determining step. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 32   (ii) The student stated that ‘The hydrogen ions cannot be acting as a catalyst. One hydrogen ion is a reactant in Step 1 but two hydrogen ions are formed as products in Steps 1 and 3.’ Explain whether or not this statement is valid. 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(Total for Question 10 = 12 marks) TOTAL FOR PAPER = 120 MARKS 33   BLANK PAGE 34   BLANK PAGE 35   BLANK PAGE 36  

13028 [Turn over 12 The halogens are Group VII in the Periodic Table. (a) Compare the colour and relative solubility of iodine in water and hexane. [3] (b) The boiling points of the hydrogen halides are shown in the table below. Hydrogen halide HF HCl HBr HI Boiling point /°C 20 −85 −67 −35 Explain the change in boiling points of the hydrogen halides. [4] 13028 (c) Bromine is an important reagent in producing chemicals such as NaBrO and NaBrO3. (i) Give the systematic names of NaBrO and NaBrO3. NaBrO NaBrO3 [2] (ii) NaBrO and NaBrO3 can be prepared by the reaction of bromine with sodium hydroxide solution. State the conditions and write the equations for the formation of NaBrO and NaBrO3. NaBrO Conditions: Equation: NaBrO3 Conditions: Equation: [6] (iii) Describe the test to show the presence of bromide ions in solution. [2] 13028 [Turn over (d) Both chlorine and ozone can be used in the treatment of drinking water. (i) Give one advantage and one disadvantage of chlorine and ozone in treating drinking water. chlorine Advantage: Disadvantage: ozone Advantage: Disadvantage: [4] (ii) Describe the test to identify chlorine gas. [2]

13028 13 The table below shows the first ionisation energies and the electronegativity values of the elements in the second period. Element Li Be B C N O F Ne First ionisation energy /kJ mol-1 520 900 800 1090 1400 1310 1680 2086 Electronegativity 1.0 1.5 2.0 2.5 3.0 3.5 4.0 (a) (i) Write an equation which represents the first ionisation energy of lithium. [2] (ii) State and explain the general trend in the first ionisation energy across the second period. Identify and explain any exceptions to this general trend. In this question you will be assessed on using your written communication skills including the use of specialist terms. [6] 13028 [Turn over (b) (i) State what is meant by electronegativity. [2] (ii) Explain the change in electronegativity across the second period. [2] 13028 (c) Fluorine forms an ionic compound with lithium, lithium fluoride (LiF), and a covalent compound with oxygen, oxygen difluoride (OF2). (i) Using electronegativity, explain why lithium fluoride is ionic. [1] (ii) Draw a dot and cross diagram for a molecule of oxygen difluoride using outer electrons only. [2] (iii) Show the polarity of an oxygen–fluorine bond, using partial charges. O—F [1] (iv) State the shape of the oxygen difluoride molecule. [1] 13028 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13028 14 Saline solution contains 0.90 g sodium chloride in 100 cm3 of solution. (a) The relative formula mass of sodium chloride is 58.5. (i) State what is meant by relative formula mass. [2] (ii) Calculate the molarity of saline solution. Give your answer to 2 significant figures. [2] (b) Draw a dot and cross diagram, using outer electrons only, to show the formation of sodium chloride from a sodium atom and a chlorine atom. [2] 13028 [Turn over (c) Concentrated sulfuric acid reacts with sodium chloride to form hydrogen chloride. (i) Write the equation for the reaction of concentrated sulfuric acid with sodium chloride. [2] (ii) Describe the chemical test for hydrogen chloride. [2]

13028 15 (a) Thallium is a metallic element that exhibits typical metallic properties. It has a relatively high melting point and is a good electrical conductor. (i) Explain why thallium has a relatively high melting point. [2] (ii) Explain why thallium conducts electricity. [2] (b) The electron configuration of thallium can be represented as [Xe] 4f14 5d10 6s2 6p1 . (i) Explain why thallium is described as a p-block element. [1] (ii) State the period and group of the Periodic Table in which thallium is found. period: group: [2] (iii) Thallium forms the ions Tl+ and Tl3+. Using the representation above, write the electron configuration of these ions. Tl+:    [Xe] Tl3+: [Xe]                             [2] 13028 [Turn over (c) Thallium(I) sulfate was used in rat poison. It was prepared by the reaction of thallium with sulfuric acid. Write the equation for the reaction of thallium with sulfuric acid. [2] (d) Thallium(III) oxide is a black solid which decomposes into thallium(I) oxide and oxygen at 800 °C according to the equation: Tl2O3(s)  →  Tl2O(s)  +  O2(g) Calculate the loss in mass when 1.72 g of thallium(III) oxide are heated to constant mass. Give your answer to 3 significant figures. [3]

13028 16 Oxalic acid is a weak acid which can form a hydrated salt, (COOH)2.xH2O. (a) Explain what is meant by the term hydrated. [1] (b) Explain what is meant by a weak acid. [1] (c) The value of x in (COOH)2.xH2O may be found by titration with a standard solution of sodium hydroxide. 1.60 g of the hydrated oxalic acid were dissolved in 250 cm3 of distilled water. 25.0 cm3 of the solution were transferred to a conical flask. A suitable indicator was added. 25.4 cm3 of 0.100 mol dm-3 sodium hydroxide solution were needed for neutralisation. The equation for the reaction is: (COOH)2  +  2NaOH  →  (COONa)2  +  2H2O (i) Suggest a suitable indicator and state the colour change at the endpoint. Indicator: From:                             to                               [3] 13028 THIS IS THE END OF THE QUESTION PAPER (ii) Calculate the mass of oxalic acid (COOH)2 in the 250 cm3 of solution. Give your answer to two decimal places. [3] (iii) Calculate the value of x in the formula (COOH)2.xH2O. [3] Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE SCH14/6 260544 For Examiner’s use only Question Number Marks Section A 1–10 Section B 11 12 13 14 15 16 Total Marks Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13147 12 Analysis of an organic compound shows that it contains carbon, hydrogen and oxygen and it has a relative molecular mass of 88. The empirical formula of the compound can be determined using percentage composition by mass. The molecular formula can then be established using the relative molecular mass. (a) Define the term molecular formula. [1] (b) (i) The compound contains 54.5% carbon and 9.1% hydrogen by mass. Determine the empirical formula of the compound. [3] (ii) Determine the molecular formula of the compound. [1] 13147 [Turn over (iii) Using your answer to (b)(ii), suggest a possible structure for the compound which contains only one functional group and another structure which contains two different functional groups. [2]

13147 13 Bromoethane and 2-bromo-2-methylpropane both react with a hot dilute aqueous solution of sodium hydroxide to form the corresponding alcohol. Both mechanisms are classified as nucleophilic substitution but the mechanisms are not identical. Aqueous hydroxide ions behave as nucleophiles and the products are formed via a transition state or an intermediate. (a) Give the IUPAC names of the alcohols formed. [1] (b) (i) Define the term nucleophile. [2] (ii) Show the polarity of the C—Br bond and explain why aqueous hydroxide ions attack bromoethane. C—Br [2] (iii) Draw the structure of the transition state when bromoethane reacts with aqueous sodium hydroxide and suggest why 2-bromo-2-methylpropane does not form a transition state. [2] 13147 [Turn over (c) Draw the mechanism, using curly arrows, for the reaction of 2-bromo-2-methylpropane with aqueous sodium hydroxide. [4]

13147 14 The standard enthalpy of combustion of ethane can be estimated using average bond enthalpies. (a) Define the following terms: (i) standard enthalpy of combustion [2] (ii) average bond enthalpy [2] (b) Suggest why the bond enthalpy value for O O is not an average value. [1] 13147 [Turn over (c) The complete combustion of ethane can be represented by the equation: 2C2H6 + 7O2 → 4CO2 + 6H2O Use the bond enthalpies in the table below to calculate the standard enthalpy of combustion for ethane. Bond Bond enthalpy /kJ mol-1 C H 413 C C 348 O O 497 C O 803 O H 464 [4] (d) Suggest why a mixture of ethane and oxygen is stable at room temperature and does not react to form carbon dioxide and water. [1]

13147 15 At very high temperatures, in a closed system, nitrogen can be oxidised to form nitrogen(II) oxide in a reversible reaction: N2(g) + O2(g) ⇌ 2NO(g)      ∆H = +180 kJ A position of dynamic equilibrium is established and the equilibrium is described as homogeneous. (a) Define the term homogeneous. [1] (b) (i) Deduce an expression and corresponding units for the equilibrium constant, Kc, for this reaction. [2] (ii) What is the significance of a small value of Kc? [1] 13147 [Turn over (c) Explain the effect of increasing the pressure on the equilibrium yield of nitrogen(II) oxide. [2] (d) Explain the effect of increasing the temperature on the equilibrium yield of nitrogen(II) oxide. [3]

13147 16 Strontium and magnesium are both s-block elements. The chemistry of the two elements is very similar but strontium is significantly more reactive. Strontium oxide and magnesium oxide are both basic and will neutralise dilute nitric acid to form nitrates. (a) (i) Deduce the electronic configuration of a strontium atom and a strontium cation: atom cation [2] (ii) Suggest why strontium is more reactive than magnesium. [2] (b) Write an equation for the reaction of strontium with water. [1] (c) Write an equation for the reaction of strontium oxide with dilute nitric acid. [2] 13147 [Turn over (d) It is possible to distinguish between solutions of magnesium nitrate and strontium nitrate by adding a solution which contains hydroxide ions. (i) What would be observed when a few drops of sodium hydroxide solution were added separately to a solution of magnesium nitrate and a solution of strontium nitrate? [2] (ii) Write an ionic equation, with state symbols, for a reaction which occurs in (d)(i). [2] (iii) Suggest an alternative solution which could be used, instead of a solution which contains hydroxide ions, to distinguish between solutions of magnesium nitrate and strontium nitrate. [1]

13147 17 There are five aliphatic structural isomers with molecular formula C5H10. (a) Define the term structural isomers. [1] (b) Two of the aliphatic structural isomers are described as having unbranched structures and three are described as branched. Complete the table below for the five aliphatic structural isomers of C5H10. IUPAC name of isomer Skeletal formula 2-methylbut-1-ene [5] 13147 [Turn over (c) The molecule on the left below does not exist as E–Z isomers whereas the molecule on the right does. Draw the Z isomer of the molecule on the right and explain, in terms of priority, why the structure is classified as the Z isomer. Explain why the molecule on the left does not exist as E–Z isomers whereas the molecule on the right does. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. Z isomer: [6]

13147 18 Propan-2-ol is a secondary alcohol which has a relatively high boiling point. It is soluble in water and can be oxidised to form a ketone. (a) (i) Why does propan-2-ol have a much higher boiling point than a hydrocarbon of similar relative molecular mass? [2] (ii) Draw a diagram to show the strongest type of attraction which forms between a propan-2-ol molecule and a water molecule. Show lone pairs of electrons and partial charges. [2] 13147 (b) (i) Name a reagent which can be used to oxidise propan-2-ol. Give the condition(s) required and the observations which are made. Reagent Condition(s) Observations [4] (ii) Draw the structure of the ketone formed on oxidation of propan-2-ol and give its IUPAC name. [2] (iii) State two differences between the infrared spectrum of propan-2-ol and the ketone formed. [2] THIS IS THE END OF THE QUESTION PAPER 13147 13147 BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE SCH24/7 262167 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13003.02 4 [Turn over Question 2 • solid potassium iodide labelled X (which should be carried over from question 1) • 1 × thermometer (capable of reading between 0 and 50 °C clearly to nearest whole number) • 1 × 50 cm3 measuring cylinder • 1 × polystyrene cup • 1 × spatula • 1 × 250 cm3 beaker • 4 × weighing boats • 1 × wash bottle of deionised water • 1 × marker for labelling weighing boats • access to an electronic balance (accurate to at least 1 decimal place) 13003.03 [Turn over ADVANCED SUBSIDIARY (AS) General Certificate of Education 2022 Chemistry Assessment Unit AS 3 Practical Assessment Practical Booklet A [SCH31] MONDAY 9 MAY, MORNING Confidential Instructions to the Supervisor of the Practical Examination

13003.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Wednesday 4 May 2022. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before 4 May 2022. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while they are on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

13003.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger themselves or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification needs to be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 13003.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Subsidiary Chemistry Practical Booklet A [SCH31] Monday 9 May 2022 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number

page 02 SECTION 1 — 25 marks Attempt ALL questions 1. Which of the following statements about atomic emission spectroscopy is not correct? A Each element has a characteristic spectrum. B Visible light is used to promote electrons to higher energy levels. C The lines arise from electron transitions between one energy level and another. D The quantity of the element can be determined from the intensity of the radiation emitted. 2. How many electrons are there in the highest energy subshell of a Cr+ ion, in its ground state? A 1 B 2 C 4 D 5 3. The formula of an octahedral complex ion containing a metal ion, M2+, and the bidentate ligand, L−, is: A [ML2]− B [ML2]2+ C [ML3]2+ D [ML3]− 4. Which of the following statements about heterogeneous catalysts is not correct? A They are found in the same state as their reactants. B They adsorb reactive molecules onto their active sites. C They provide reaction pathways with lower activation energies. D They have unpaired d electrons that allow activated complexes to form.

page 03 5. A disproportionation reaction is a redox reaction in which an element in a single substance is both oxidised and reduced. In which of the following does a halogen undergo disproportionation? A Cl2  +  2KI  ↓  2KCl  +  I2 B IO3 −  +  5I−  +  6H+  ↓  3I2  +  3H2O C I2  +  6H2O  +  5Cl2  ↓  2HIO3  +  10HCl D Cl2  +  2NaOH  ↓  NaCl  +  NaClO  +  H2O 6. Which of the following is true for a neutral solution at 325 K? A pH = 7.00 B Kw = 1.01 × 10−14 C [H3O+] = [OH−] D [H3O+] = 1.00 × 10−7 7. 2SO2(g)  +  O2(g)  Ý  2SO3(g) ΔH = −196 kJ mol−1 Which line in the table is correct for the concentration of SO3(g) at equilibrium and the equilibrium constant, K, when the pressure of the equilibrium mixture is increased at constant temperature? [SO3(g)] at equilibrium Equilibrium constant, K A increase no change B increase increase C no change increase D no change no change 8. The standard enthalpy of formation of sodium chloride is represented by: A Na+(g)  +  Cl−(g)  ↓  Na+Cl−(g) B Na+(g)  +  Cl−(g)  ↓  Na+Cl−(s) C Na(s)  +  Cl(g)  ↓  Na+Cl−(s) D Na(s)  +  1 2Cl2(g)  ↓  Na+Cl−(s) [Turn over

page 04 9. The rate equation for a reaction is rate = k[A]2[B] Which of the following statements is correct for this reaction? A Doubling the concentration of A will double the reaction rate. B Doubling the concentration of B will double the reaction rate. C Doubling the concentration of B will have no effect on the reaction rate. D Doubling the concentration of A and B will have no effect on the reaction rate. 10. The order of a reaction: A depends on the stoichiometry of the overall reaction B is the sequence of steps in the mechanism C controls the speed of the overall reaction D can only be obtained by experiment.

page 05 11. Which of the following graphs shows the variation in entropy, S , as a substance is heated from below its melting point to above its boiling point? A entropy temperature entropy temperature entropy temperature entropy temperature B C D [Turn over

page 06 12. Which of the following diagrams represents the hybridisation of orbitals in a carbon atom of ethyne? A energy 2s 2p energy 2s 2p energy 2s 2p energy 2s 2p B C D 13. Which of the following molecules contains only sigma bonds? A C2H4 B H2O C O2 D N2

page 07 14. The addition reaction of propene and hydrogen bromide is a two‑step process. Which of the following shows the first step in this mechanism? C C Brδ− :Br− Hδ+ H H H H H3C C C H H3C H H C C Brδ− :Br− Hδ+ H H H H H3C C C H H3C H H C C Brδ− :Br− Hδ+ H H3C C H H H H C H H :Br− C H H C H H H3C C C Brδ− Hδ+ H H3C H H H3C A B C D [Turn over

page 08 15. Which of the following compounds contains a phenyl group? O O N OH O O OH A B C D 16. Consider the following reaction sequence. 2‑chlorobutane CN− X H+/H2O Y Compound Y is likely to be: A 2‑methylpropanoic acid B butanoic acid C 2‑methylbutanoic acid D pentanoic acid. 17. What is the systematic name of the molecule shown below? O A 1‑ethoxy‑2‑methylpropane B 1‑ethoxy‑3‑methylbutane C 2‑ethoxy‑2‑methylpropane D 2‑ethoxy‑3‑methylbutane

page 09 18. When propanone dissolves in water the following equilibrium is established. H3C C O CH3 H3C C OH CH2 propanone (a ketone) propenol (an enol) The ketone and enol are isomers and are called tautomers. Which of the following ketones does not have an enol tautomer? O CH3 (H3C)3C C (H3C)2HC C (H3C)3C C O CH2CH3 O C(CH3)3 (H3C)3 O C(CH3)3 C C A B C D [Turn over

page 10 19. Which of the following compounds has non‑superimposable mirror images? C H C H H C C H H H H OH C H CH3 H C H H C C H H H H OH C CH3 H H H O OH N C C H H H H O OH N C C CH3 H H H A B C D

page 11 20. Compound X underwent elemental microanalysis and was found to contain 0.12 g of carbon and 0.02 g of hydrogen. Compound X could be: C C H H H H C C C C H H H H H H C C C H H C H H H C C H H H C H H C H H H C C H H H H H A B C D 21. The mass spectrum of an organic compound had a molecular ion peak at m/z 74. There were also peaks at 15, 31 and 43. The organic compound that produced this mass spectrum is: A CH3CH2COOH B CH3COOCH3 C CH3COCH2CH3 D CH3CH2CH2CHO [Turn over

page 12 22. The structural formula of malic acid is shown below. OH O O OH HO How many moles of sodium carbonate, Na2CO3, would be required to neutralise 6.7 g of malic acid (GFM = 134 g)? A 0.050 B 0.075 C 0.10 D 0.15 23. A student carried out a gravimetric analysis by heating a 2.52 g sample of hydrated calcium chloride, CaCl2·2H2O, until it reached constant mass. What was the mass of the calcium chloride sample after heating to constant mass? A 1.70 g B 1.90 g C 2.11 g D 2.21 g 24. Which of the following techniques can be used to both purify and identify a compound? A Distillation B Recrystallisation C Solvent extraction D Melting point determination

page 13 25. The progress of a reaction was followed by periodically sampling the reaction mixture and analysing it using thin‑layer chromatography. The chromatogram for the analysis of one sample is shown. R is a spot of pure reactant C is a co‑spot of pure reactant and the reaction mixture sample S is a spot of the reaction mixture sample R C S Which of the following conclusions must be correct for this thin‑layer chromatogram? A The reaction mixture does not contain impurities. B All of the reactant has been used up. C Only the desired product is present. D The reaction is complete. [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] page 14 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 15 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 16 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

page 02 Total marks — 25 Attempt ALL questions 1. An element contains covalent bonding and London dispersion forces. The element could be: A boron B neon C sodium D sulfur. 2. The graph below shows the relative quantities of energy equivalent to successive ionisation energies for an element. 6th 4th 5th 3rd 2nd 1st ionisation ionisation energy (kJ mol−1) The most stable ion formed from an atom of this element has a charge of: A 2+ B 3+ C 2− D 3− 3. HCl has a higher boiling point than H2 because: A the polar covalent bonds in HCl are stronger than the covalent bonds in H2 B the polar covalent bonds in HCl are stronger than the van der Waals’ forces in H2 C the van der Waals’ forces in HCl are stronger than the van der Waals’ forces in H2 D the van der Waals’ forces in HCl are stronger than the covalent bonds in H2.

page 03 4. Which line in the table would best describe elements that act as reducing agents? Gains or loses electrons Electronegativity A gains low B loses low C gains high D loses high 5. The correct redox equation for the reaction of iron(II) ions with acidified dichromate ions is: A Cr2O7 2−(aq)  +  14H+(aq)  +  Fe2+(aq) ↓  2Cr3+(aq)  +  7Η2Ο(ℓ)  +  Fe(s) B Cr2O7 2−(aq)  +  14H+(aq)  +  Fe2+(aq) ↓  2Cr3+(aq)  +  7H2O(ℓ)  +  Fe3+(aq) C Cr2O7 2−(aq)  +  14H+(aq)  +  6Fe2+(aq) ↓  2Cr3+(aq)  +  7H2O(ℓ)  +  6Fe(s) D Cr2O7 2−(aq)  +  14H+(aq)  +  6Fe2+(aq) ↓  2Cr3+(aq)  +  7H2O(ℓ)  +  6Fe3+(aq) 6. A mixture of magnesium bromide and magnesium sulfate is known to contain 3 moles of magnesium ions and 4 moles of bromide ions. How many moles of sulfate ions are present? A 1 B 2 C 3 D 4 7. H C H H H C C H O O C H H H C H C H H H H C H H H C The correct name for this ester is: A butyl propanoate B propyl butanoate C pentyl propanoate D propyl pentanoate. [Turn over

page 04 8. The structural formula for a compound is shown. H C H H H H H C C C C OH C H H H C H H CH3 H Which of the following is not an isomer of this compound? A octan-4-one B 2-ethylhexanal C 2-ethylhexan-1-ol D 5-methylheptan-3-one 9. Gabapentin is a medicine that can be used to treat nerve pain. CH C C C CH C H H H H H H H H C C HO H O H N C H H H H Which line in the table shows the two functional groups present in this compound? A amine carboxyl B amine hydroxyl C hydroxyl carboxyl D hydroxyl carbonyl

page 05 10. Prenol is a compound that occurs naturally in citrus fruits. H3C H3C H2C H C C OH Which line in the table correctly describes the reaction of prenol with bromine solution and with hot copper(II) oxide? Reaction with bromine solution Reaction with hot copper(II) oxide A no reaction no reaction B no reaction brown solid formed C decolourises brown solid formed D decolourises no reaction 11. The iodine number of an oil is the mass of iodine, in grams, that will react with 100 g of oil and is a measure of the degree of saturation. Olive oil has an iodine number of 84 and palm oil has an iodine number of 48. Which of the following statements is correct? A Palm oil is more saturated and has a lower melting point than olive oil. B Palm oil is more saturated and has a higher melting point than olive oil. C Palm oil is less saturated and has a lower melting point than olive oil. D Palm oil is less saturated and has a higher melting point than olive oil. [Turn over

page 06 12. The structure of a soapless detergent molecule is given below. H3C O S O O O CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 tail section head section Which line in the table describes a step in the cleansing action of a soapless detergent? Head section Tail section A The hydrophobic head dissolves in water. The hydrophilic tail dissolves in oil. B The hydrophilic head dissolves in water. The hydrophobic tail dissolves in oil. C The hydrophobic head dissolves in oil. The hydrophilic tail dissolves in water. D The hydrophilic head dissolves in oil. The hydrophobic tail dissolves in water. 13. Which of the following is a secondary alcohol? A 2-methylbutan-1-ol B 2-methylbutan-2-ol C butan-1-ol D butan-2-ol

page 07 14. The compounds below are examples of flavour molecules found in some plants. CH2 OH O C H CH CH2 CH2 CH CH CH CH2 CH3 CH3 H2C H2C H3C CH3 O CH2 C CH2 CH2 CH2 CH2 CH2 CH CH3 OH C C C C C H C C O O CH3 H H H C C CH CH CH2 CH2 OH C H2C C C C C C H H HO cucumber flavour ginger flavour orange flavour vanilla flavour Which line in the table shows the solubilities of these compounds in water and in oil? Water soluble Oil soluble A cucumber and ginger orange and vanilla B cucumber and orange ginger and vanilla C ginger and vanilla cucumber and orange D orange and vanilla cucumber and ginger [Turn over

page 08 15. The structural formula for a compound is shown. H3C CH3 H H CH2 C C CH3 OH The product of oxidation of this compound is: A 2-methylpentan-4-one B 4-methylpentan-2-one C 2-methylpentanal D 4-methylpentanal. 16. Which of the following describes how to fill a burette with acid and take the initial reading in a titration? A Rinse the burette with the acid. Fill to above the scale with acid. Drain some of the acid and read from the top of the meniscus. B Rinse the burette with deionised water. Fill to above the scale with acid. Drain some of the acid and read from the bottom of the meniscus. C Rinse the burette with the acid. Fill to above the scale with acid. Drain some of the acid and read from the bottom of the meniscus. D Rinse the burette with deionised water. Fill to above the scale with acid. Drain some of the acid and read from the top of the meniscus.

page 09 17. Tomato juice contains a mixture of terpenes including lycopene and beta-carotene. Terpenes can be separated using chromatography. C C C H2C H3C H2C CH CH CH CH C CH CH3 CH3 C CH CH C 3 CH3 CH3 CH3 CH3 CH3 CH3 CH2 CH CH2 CH2 CH2 CH CH C CH C CH CH CH CH CH C CH3 CH C CH3 CH CH C CH3 CH CH C CH3 CH C CH3 CH C CH3 CH C CH3 CH2 CH2 CH2 CH2 C CH CH CH CH CH CH CH CH CH CH3 CH3 C C H3C lycopene beta-carotene Which of the following is the most suitable solvent to separate lycopene and beta-carotene? A Ethanol B Pentane C Propanoic acid D Water [Turn over

page 10 18. The graph shows how the rate of a reaction varies with the concentration of a reactant. 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0 0 0.001 0.002 0.003 0.004 0.005 0.006 concentration (mol l−1) rate of reaction (1/t) (s−1) When the concentration of the reactant is 0.06 mol l−1, the reaction time is: A 0.004 s B 0.09 s C 17 s D 250 s. 19. Butene reacts with oxygen as shown. C4H8(g)  +  6O2(g)  ↓  4CO2(g)  +  4H2O(g) 100 cm3 of butene was reacted with excess oxygen. Compared with the total volume of gases before reaction, what would be the total volume of gases after complete reaction? A 100 cm3 more B 100 cm3 less C 300 cm3 more D 300 cm3 less

page 11 20. In aqueous solution ethanoic acid forms an equilibrium mixture with its ions. CH3COOH(aq)  ∏  H+(aq)  +  CH3COO−(aq) Which of the following solutions, when added to the equilibrium mixture, would favour the forward reaction? A NaCl(aq) B HCl(aq) C NaOH(aq) D CH3COONa(aq) [Turn over

page 12 21. Some energy values associated with a chemical reaction are shown in the table. Enthalpy of reactants (kJ mol−1) Activation energy of forward reaction (kJ mol−1) Activation energy of reverse reaction (kJ mol−1) 30 110 70 Which of the following correctly shows the potential energy diagram for the above conditions? 0 0 0 0 20 20 20 20 40 40 40 40 60 60 60 60 80 80 80 80 100 100 100 100 120 120 120 120 140 140 140 140 potential energy (kJ mol−1) potential energy (kJ mol−1) potential energy (kJ mol−1) potential energy (kJ mol−1) reaction pathway reaction pathway reaction pathway reaction pathway reactants reactants reactants reactants products products products products A B C D

page 13 22. Consider the reaction pathway below. W Z Y X ∆H = −210 kJ mol−1 ∆H = −50 kJ mol−1 ∆H = −86 kJ mol−1 According to Hess’ law, the ∆H value, in kJ mol−1, for reaction Z to Y is: A −74 B +74 C −346 D +346 23. 50.0 cm3 of 0.100 mol l−1 ammonia solution was transferred to a 250 cm3 volumetric flask. The flask was made up to the mark with deionised water. The final concentration, in mol l−1, of the ammonia solution is: A 2.0 × 10−2 B 2.5 × 10−2 C 4.0 × 10−2 D 5.0 × 10−2 24. An experiment involves reacting 0.02 moles of silver ions with ions of a group 7 element to form 2.868 g of precipitate. Which of the following is the precipitate? A Silver(I) fluoride B Silver(I) chloride C Silver(I) bromide D Silver(I) iodide [Turn over

page 14 25. A titration experiment was carried out to determine the concentration of vitamin C in orange juice. A sample of the orange juice solution was pipetted into a flask and 10 cm3 water was added to dilute the sample. Starch indicator was added to the flask. The mixture was then titrated in the flask using iodine solution of known concentration. Which line in the table shows the most appropriate apparatus to use when carrying out this procedure? To add water Type of flask A measuring cylinder conical flask B beaker conical flask C measuring cylinder volumetric flask D beaker volumetric flask [END OF QUESTION PAPER] page 15 SPACE FOR ROUGH WORK page 16 SPACE FOR ROUGH WORK

10 (2410U10-1) Examiner only 10. (a) Group 1 and Group 2 metals are in the s-block of the Periodic Table. Using potassium and calcium as examples, discuss the similarities and differences between Group 1 and Group 2 with respect to: • the reaction of the metals with cold water. • the solubility of the carbonates. [6 QER] You should include appropriate chemical equations in your answer. © WJEC CBAC Ltd. 10 (2410U10-1) Turn over. 11 Examiner only (b) The equation for the reaction between potassium carbonate and hydrochloric acid is given below. K2CO3 2KCl 2HCl + H2O + CO2 + A 1.40 g sample of impure potassium carbonate was added to excess dilute hydrochloric acid. The impurity is unreactive and only the potassium carbonate reacts with the acid. The volume of carbon dioxide released was 186 cm3 when measured at 298 K and 1.01 × 105 Pa. Calculate the mass of the impurity. [3] mass of impurity = ........................................................ g (c) A solution is thought to contain potassium chloride. Describe suitable tests that a student could do to confirm this. Include the expected observations. [2] (d) By referring to ionisation energies, explain why stable compounds containing K2+ ions are unlikely to form. [2] © WJEC CBAC Ltd. 11 13 12 (2410U10-1) Examiner only 11. (a) Arsenic oxide, As2O3, is prepared on an industrial scale by roasting arsenic-containing ores such as arsenopyrite, FeAsS, in air. The other products formed are iron(III) oxide and sulfur dioxide. (i) State the oxidation state of arsenic in As2O3. [1] (ii) Give a balanced chemical equation for the industrial production of As2O3 from FeAsS. [2] (b) As2O3 is moderately soluble in water. 100 cm3 of a saturated solution at 25 °C contains 2.06 g. When dissolved in water, the oxide reacts to form arsenous acid. As2O3 2H3AsO3 3H2O + (i) Calculate the concentration of the arsenous acid, in mol dm–3, in the saturated solution. [3] concentration of H3AsO3 = ........................................................ mol dm–3 (ii) A solution of arsenous acid has a pH of 5.11. Calculate the hydrogen ion concentration of this solution. [1] [H+] = ........................................................ mol dm–3 © WJEC CBAC Ltd. 12 (2410U10-1) Turn over. 13 Examiner only (c) The formula for arsenous acid can be written as As(OH)3 since it contains three hydroxyl (OH) groups bonded to arsenic. Suggest the shape around the arsenic atom in As(OH)3. Justify your answer by using VSEPR theory. [3] (d) Phosphorus can form two chlorides, PCl3 and PCl5. 0.181 g of a chloride of phosphorus gave 39 cm3 of vapour at 1 atm pressure when heated to 87 °C. The sample was completely vapourised. Show that the chloride of phosphorus was PCl3. [4] © WJEC CBAC Ltd. 13 14 (2410U10-1) © WJEC CBAC Ltd. 14 Examiner only (e) The molecular ion region of the mass spectrum of PCl3, is shown below. 0 20 40 60 80 100 10 30 50 70 90 60 70 80 90 100 110 120 130 140 Relative abundance Mass / charge ratio (m/z) C D E (i) Identify the species responsible for peak C at m/z 101. [1] (ii) Explain why the height ratio of peaks C:E is 9:1. [2] 17 (2410U10-1) Turn over. 15 © WJEC CBAC Ltd. 15 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE 16 (2410U10-1) © WJEC CBAC Ltd. 16 Examiner only 12. A student was asked to find the identity of a Group 1 metal carbonate by titration. He was told to use the following method. • Weigh a sample of the carbonate in a weighing bottle. • Transfer the carbonate into a beaker and weigh the bottle afterwards. • Add water to the beaker to dissolve the carbonate. • Transfer the solution to a volumetric flask. • Add more water to make the final volume 250.0 cm3 of solution. • Accurately transfer 25.0 cm3 of this solution into a conical flask. • Add 2–3 drops of a suitable indicator to this solution. • Fill a burette with 0.100 mol dm–3 hydrochloric acid solution. • Carry out a rough titration of the carbonate solution with the hydrochloric acid. • Accurately repeat the titration until you get concordant titres and calculate a mean titre. (a) Another student said that there were two errors in making the 250.0 cm3 carbonate solution. Error 1: A small amount of solid remained in the weighing bottle. Error 2: A small amount of solution remained in the beaker. Comment on the suggested errors. If the student is correct suggest how the method could be improved. If the student is incorrect, explain why. [2] Error 1 Error 2 (b) State why he adds an indicator to this solution. [1] (c) Suggest why he was told to carry out a rough titration first. [1] (2410U10-1) Turn over. 17 © WJEC CBAC Ltd. 17 Examiner only (d) State what you understand by the term ‘concordant titres’. [1] (e) Some of the student’s results are shown below: Mass of weighing bottle + carbonate / g 13.73 Mass of weighing bottle / g 12.48 Titration Rough 1 2 3 Final reading / cm3 24.20 23.70 .............................. .............................. Initial reading / cm3 0.00 0.10 .............................. .............................. Titre / cm3 .............................. .............................. .............................. .............................. concentration of hydrochloric acid = 0.100 mol dm–3 The diagrams below show the initial burette reading and the final burette reading for the second and third titrations. 1 0 Titration 2 Initial reading Final reading Titration 3 Initial reading Final reading 1 0 24 23 24 23 Complete the student’s table and calculate the mean titre. [3] mean titre = ........................................................ cm3 Examiner only 18 (2410U10-1) © WJEC CBAC Ltd. 18 (f) The equation for the reaction between the metal carbonate and hydrochloric acid is given below. M represents the symbol of the Group 1 metal. M2CO3 2MCl 2HCl + H2O + CO2 + (i) Calculate the number of moles of M2CO3 in 25.0 cm3 of the solution. [2] number of moles = ........................................................ (ii) Calculate the relative formula mass of the carbonate and hence deduce the Group 1 metal in the carbonate. You must show your working. [4] group 1 metal = ........................................................ END OF PAPER 14 (2410U10-1) Turn over. 19 © WJEC CBAC Ltd. 19 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only 20 (2410U10-1) © WJEC CBAC Ltd. 20 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only BE*(S22-2410U10-1A) © WJEC CBAC Ltd. GCE AS/A LEVEL 2410U10-1A TUESDAY, 17 MAY 2022 – MORNING CHEMISTRY – AS unit 1 Data Booklet Avogadro constant NA = 6.02 × 1023 mol –1 molar gas constant R = 8.31 J mol –1 K –1 molar gas volume at 273 K and 1 atm Vm = 22.4 dm3 mol –1 molar gas volume at 298 K and 1 atm Vm = 24.5 dm3 mol –1 Planck constant h = 6.63 × 10 –34 J s speed of light c = 3.00 × 108 m s –1 density of water d = 1.00 g cm –3 specific heat capacity of water c = 4.18 J g –1 K –1 ionic product of water at 298 K Kw = 1.00 × 10 –14 mol 2 dm – 6 fundamental electronic charge e = 1.60 × 10 –19 C temperature (K) = temperature (°C) + 273 1 dm3 = 1000 cm3 1 m3 = 1000 dm3 1 tonne = 1000 kg 1 atm = 1.01 × 105 Pa Multiple Prefix Symbol 10 –9 nano n 10 –6 micro μ 10 –3 milli m Multiple Prefix Symbol 10 3 kilo k 10 6 mega M 10 9 giga G Z22-2410U10-1A 2 © WJEC CBAC Ltd. (2410U10-1A) 10 to 70 5 to 40 20 to 50 25 to 60 50 to 90 90 to 150 110 to 125 110 to 160 160 to 185 190 to 220 N C R C C C O C C R Cl or Br C O C R C O (carboxylic acid / ester) C R (aldehyde / ketone) O C R N R C 13C NMR chemical shifts relative to TMS = 0 Type of carbon Chemical shift, δ (ppm) Infrared absorption values Bond Wavenumber / cm –1 500 to 600 650 to 800 1000 to 1300 1620 to 1670 1650 to 1750 2100 to 2250 2800 to 3100 2500 to 3200 (very broad) 3200 to 3550 (broad) 3300 to 3500 C Br C Cl C O C C C O C N C H O H (carboxylic acid) O H (alcohol / phenol) N H Turn over. 3 © WJEC CBAC Ltd. (2410U10-1A) *variable figure dependent on concentration and solvent 1H NMR chemical shifts relative to TMS = 0 Type of proton Chemical shift, δ (ppm) 0.9 0.1 to 2.0 3.1 to 4.3 1.3 2.0 2.0 to 3.0 2.0 to 2.5 2.2 to 2.3 R CH3 R CH2 R CH3 C N CH3 C O CH3 CH3 CH2 C O 4.5 * 4.5 to 6.3 6.5 to 7.5 6.5 to 8.0 R OH 3.3 to 4.3 HC Cl or HC Br C CH HC O C CH H 7.0 * OH 9.8 * 11.0 * R C O H R C O OH 5.8 to 6.5 C CH CO 6.94 Li Lithium 3 9.01 Be Beryllium 4 10.8 B Boron 5 12.0 C Carbon 6 14.0 N Nitrogen 7 16.0 O Oxygen 8 19.0 F Fluorine 9 20.2 Ne Neon 10 23.0 Na Sodium 11 24.3 Mg Magnesium 12 27.0 Al Aluminium 13 28.1 Si Silicon 14 31.0 P Phosphorus 15 32.1 S Sulfur 16 35.5 Cl Chlorine 17 40.0 Ar Argon 18 39.1 K Potassium 19 40.1 Ca Calcium 20 45.0 Sc Scandium 21 47.9 Ti Titanium 22 50.9 V Vanadium 23 52.0 Cr Chromium 24 54.9 Mn Manganese 25 55.8 Fe Iron 26 58.9 Co Cobalt 27 58.7 Ni Nickel 28 63.5 Cu Copper 29 65.4 Zn Zinc 30 69.7 Ga Gallium 31 72.6 Ge Germanium 32 74.9 As Arsenic 33 79.0 Se Selenium 34 79.9 Br Bromine 35 83.8 Kr Krypton 36 85.5 Rb Rubidium 37 87.6 Sr Strontium 38 88.9 Y Yttrium 39 91.2 Zr Zirconium 40 92.9 Nb Niobium 41 95.9 Mo Molybdenum 42 98.9 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 112 Cd Cadmium 48 115 In Indium 49 119 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 133 Cs Caesium 55 137 Ba Barium 56 139 La Lanthanum 57 179 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 (210) Po Polonium 84 (210) At Astatine 85 (222) Rn Radon 86 (223) Fr Francium 87 (226) Ra Radium 88 (227) Ac Actinium 89 THE PERIODIC TABLE 1 2 Group 3 4 5 6 7 0 1 2 3 4 5 6 7 1.01 H Hydrogen 1 4.00 He Helium 2 d block s block Period p block 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 (147) Pm Promethium 61 150 Sm Samarium 62 (153) Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 163 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 (231) Pa Protactinium 91 238 U Uranium 92 (237) Np Neptunium 93 (242) Pu Plutonium 94 (243) Am Americium 95 (247) Cm Curium 96 (245) Bk Berkelium 97 (251) Cf Californium 98 (254) Es Einsteinium 99 (253) Fm Fermium 100 (256) Md Mendelevium 101 (254) No Nobelium 102 (257) Lr Lawrencium 103 f block Actinoid elements Ar Symbol Name Z relative atomic mass atomic number Key Lanthanoid elements ▴ ▴▴ ▴ ▴▴ © WJEC CBAC Ltd. (2410U10-1A) 4

12 (2410U20-1) 12 8. Compound A contains only carbon, hydrogen and an unknown halogen. Refluxing compound A in aqueous sodium hydroxide followed by the addition of nitric acid and aqueous silver nitrate produces a white precipitate. Elemental analysis of compound A indicates it contains 39.02% carbon and 3.25% hydrogen by mass. When bromine is added to compound A, 123 g of compound A reacts with 320 g of bromine. The 1H NMR spectrum of compound A consists of only one peak. The 13C NMR spectrum of compound A consists of two peaks. The infrared spectrum and simplified mass spectrum are shown below and overpage. 2000 1000 3000 0.6 0.7 0.8 0.9 1 Infrared spectrum Wavenumber (cm-1) Relative transmittance © WJEC CBAC Ltd. (2410U20-1) Turn over. 13 13 Examiner only 50 40 60 70 80 90 m/z 52 87 122 Relative intensity 100 110 120 130 140 150 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Mass spectrum Use all of the data provided to determine the identity of compound A. Explain your answer using information from all of the data sources provided. [10] © WJEC CBAC Ltd. 2410 U201 13 14 (2410U20-1) 14 Examiner only © WJEC CBAC Ltd. 10 (2410U20-1) Turn over. 15 15 © WJEC CBAC Ltd. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE 16 (2410U20-1) 16 Examiner only 9. Chloe was investigating the effect of using catalysts on the rate of reaction. She added 50 cm3 of 0.1 mol dm–3 iron(III) nitrate solution to 50 cm3 of 0.2 mol dm–3 sodium thiosulfate solution. The reaction forms a deep violet iron(III) complex which is unstable and is gradually reduced to form a light green iron(II) complex. Chloe monitored the rate of reaction by measuring the absorption of light at a wavelength of 500 nm every 10 seconds for two minutes using a data logger. (a) The violet complex appears black at the beginning of the reaction. State the name of the technique used to monitor the rate of reaction by measuring the absorption of light. [1] (b) Chloe repeated the experiment three times adding 1 cm3 of a different catalyst each time at a concentration 0.10 mol dm–3. Below is a graph showing her results: 0 0.2 0.4 0.6 0.1 0.3 0.5 0.7 0 20 40 60 Time / s Absorbance / arbitrary units 80 100 120 10 30 50 70 90 110 Key: No catalyst Co2+ Fe2+ Cu2+ (i) State which catalyst is the most effective. Explain your answer. [2] © WJEC CBAC Ltd. (2410U20-1) Turn over. 17 17 Examiner only (ii) Calculate the initial rate of reaction for the reaction catalysed by the copper(II) ions. [2] rate = ........................................................ s–1 (iii) Each catalysed reaction contained the same number of moles of catalyst at the beginning of the reaction. Calculate the moles of catalyst left at the end of the reaction. [1] moles = ........................................................ mol © WJEC CBAC Ltd. 18 (2410U20-1) 18 Examiner only (c) Increasing temperature and the addition of a catalyst are two ways of increasing the rate of a reaction. Using your knowledge of the Boltzmann distribution and particle theory, explain how the rate of reaction is increased using these two different methods. You may use a diagram(s) to support your answer. [6 QER] © WJEC CBAC Ltd. 12 (2410U20-1) Turn over. 19 19 © WJEC CBAC Ltd. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

20 (2410U20-1) 20 10. The crystallisation of sodium ethanoate from a super-saturated solution is used to release heat in reusable hand warmers. (a) A super-saturated solution of sodium ethanoate was made by dissolving 320 g of hydrated sodium ethanoate (CH3COONa.3H2O) in 60 cm3 of hot water. It was then allowed to cool to room temperature, which was measured as 17 °C. A thermometer was added to the solution, which caused the sodium ethanoate to start crystallising. The temperature of the process was recorded every 30 seconds for 3 minutes. The results are shown below: Time / s Temperature / °C 0 17 30 27 60 35 90 41 120 40 150 39 180 38 © WJEC CBAC Ltd. (2410U20-1) Turn over. 21 21 Examiner only (i) Plot the results on the graph paper below. [2] Temperature / °C Time / s (ii) Use your graph to calculate the maximum temperature change for this crystallisation. [2] maximum temperature change = ........................................................ °C © WJEC CBAC Ltd. 22 (2410U20-1) 22 Examiner only (iii) Use the total mass of the sodium ethanoate solution and the temperature change from the graph to calculate the enthalpy change of crystallisation per mole of sodium ethanoate. Assume the density of water is 1.00 g cm–3 and the specific heat capacity of sodium ethanoate solution is 4.18 J K–1 g–1. Mr(CH3COONa.3H2O) = 136 [4] enthalpy change = ........................................................ kJ mol–1 (iv) Suggest a reason why the experimental enthalpy change is often lower than the theoretical enthalpy change. [1] (b) Sodium ethanoate can be made in a neutralisation reaction. Complete the following equation: [2] CO2 H2O CH3COONa + + + ......................................................................... ......................................................................... (c) The carboxylic acid used to produce sodium ethanoate can be produced using an oxidation reaction. (i) Name the reagents and give the expected observations. [2] © WJEC CBAC Ltd. (2410U20-1) Turn over. 23 23 Examiner only (ii) A student proposed that the apparatus below should be used to perform this oxidation reduction experiment. The teacher said that this would not work and would be unsafe. Draw a labelled diagram of the apparatus that should be used in this experiment. [3] END OF PAPER © WJEC CBAC Ltd. 16 24 (2410U20-1) 24 © WJEC CBAC Ltd. Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (2410U20-1) 25 Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. © WJEC CBAC Ltd. 25 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (2410U20-1) 26 © WJEC CBAC Ltd. 26 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (2410U20-1) 27 © WJEC CBAC Ltd. 27 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (2410U20-1) 28 © WJEC CBAC Ltd. 28 BE*(S22-2410U20-1A) © WJEC CBAC Ltd. GCE AS/A LEVEL 2410U20-1A FRIDAY, 27 MAY 2022 – AFTERNOON CHEMISTRY – AS unit 2 Data Booklet Avogadro constant NA = 6.02 × 1023 mol –1 molar gas constant R = 8.31 J mol –1 K –1 molar gas volume at 273 K and 1 atm Vm = 22.4 dm3 mol –1 molar gas volume at 298 K and 1 atm Vm = 24.5 dm3 mol –1 Planck constant h = 6.63 × 10 –34 J s speed of light c = 3.00 × 108 m s –1 density of water d = 1.00 g cm –3 specific heat capacity of water c = 4.18 J g –1 K –1 ionic product of water at 298 K Kw = 1.00 × 10 –14 mol 2 dm – 6 fundamental electronic charge e = 1.60 × 10 –19 C temperature (K) = temperature (°C) + 273 1 dm3 = 1000 cm3 1 m3 = 1000 dm3 1 tonne = 1000 kg 1 atm = 1.01 × 105 Pa Multiple Prefix Symbol 10 –9 nano n 10 –6 micro μ 10 –3 milli m Multiple Prefix Symbol 10 3 kilo k 10 6 mega M 10 9 giga G Z22-2410U20-1A (2410U20-1A) 2 © WJEC CBAC Ltd. 10 to 70 5 to 40 20 to 50 25 to 60 50 to 90 90 to 150 110 to 125 110 to 160 160 to 185 190 to 220 N C R C C C O C C R Cl or Br C O C R C O (carboxylic acid / ester) C R (aldehyde / ketone) O C R N R C 13C NMR chemical shifts relative to TMS = 0 Type of carbon Chemical shift, δ (ppm) Infrared absorption values Bond Wavenumber / cm –1 500 to 600 650 to 800 1000 to 1300 1620 to 1670 1650 to 1750 2100 to 2250 2800 to 3100 2500 to 3200 (very broad) 3200 to 3550 (broad) 3300 to 3500 C Br C Cl C O C C C O C N C H O H (carboxylic acid) O H (alcohol / phenol) N H Turn over. (2410U20-1A) 3 © WJEC CBAC Ltd. *variable figure dependent on concentration and solvent 1H NMR chemical shifts relative to TMS = 0 Type of proton Chemical shift, δ (ppm) 0.9 0.1 to 2.0 3.1 to 4.3 1.3 2.0 2.0 to 3.0 2.0 to 2.5 2.2 to 2.3 R CH3 R CH2 R CH3 C N CH3 C O CH3 CH3 CH2 C O 4.5 * 4.5 to 6.3 6.5 to 7.5 6.5 to 8.0 R OH 3.3 to 4.3 HC Cl or HC Br C CH HC O C CH H 7.0 * OH 9.8 * 11.0 * R C O H R C O OH 5.8 to 6.5 C CH CO (2410U20-1A) 4 © WJEC CBAC Ltd. 6.94 Li Lithium 3 9.01 Be Beryllium 4 10.8 B Boron 5 12.0 C Carbon 6 14.0 N Nitrogen 7 16.0 O Oxygen 8 19.0 F Fluorine 9 20.2 Ne Neon 10 23.0 Na Sodium 11 24.3 Mg Magnesium 12 27.0 Al Aluminium 13 28.1 Si Silicon 14 31.0 P Phosphorus 15 32.1 S Sulfur 16 35.5 Cl Chlorine 17 40.0 Ar Argon 18 39.1 K Potassium 19 40.1 Ca Calcium 20 45.0 Sc Scandium 21 47.9 Ti Titanium 22 50.9 V Vanadium 23 52.0 Cr Chromium 24 54.9 Mn Manganese 25 55.8 Fe Iron 26 58.9 Co Cobalt 27 58.7 Ni Nickel 28 63.5 Cu Copper 29 65.4 Zn Zinc 30 69.7 Ga Gallium 31 72.6 Ge Germanium 32 74.9 As Arsenic 33 79.0 Se Selenium 34 79.9 Br Bromine 35 83.8 Kr Krypton 36 85.5 Rb Rubidium 37 87.6 Sr Strontium 38 88.9 Y Yttrium 39 91.2 Zr Zirconium 40 92.9 Nb Niobium 41 95.9 Mo Molybdenum 42 98.9 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 112 Cd Cadmium 48 115 In Indium 49 119 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 133 Cs Caesium 55 137 Ba Barium 56 139 La Lanthanum 57 179 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 (210) Po Polonium 84 (210) At Astatine 85 (222) Rn Radon 86 (223) Fr Francium 87 (226) Ra Radium 88 (227) Ac Actinium 89 THE PERIODIC TABLE 1 2 Group 3 4 5 6 7 0 1 2 3 4 5 6 7 1.01 H Hydrogen 1 4.00 He Helium 2 d block s block Period p block 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 (147) Pm Promethium 61 150 Sm Samarium 62 (153) Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 163 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 (231) Pa Protactinium 91 238 U Uranium 92 (237) Np Neptunium 93 (242) Pu Plutonium 94 (243) Am Americium 95 (247) Cm Curium 96 (245) Bk Berkelium 97 (251) Cf Californium 98 (254) Es Einsteinium 99 (253) Fm Fermium 100 (256) Md Mendelevium 101 (254) No Nobelium 102 (257) Lr Lawrencium 103 f block Actinoid elements Ar Symbol Name Z relative atomic mass atomic number Key Lanthanoid elements ▴ ▴▴ ▴ ▴▴

14 (1410U30-1) 10. A student used a solution of weak acid HA in a titration. A 25.0 cm3 sample of the acid was titrated against a sodium hydroxide solution of concentration 0.250 mol dm–3 giving the pH titration curve shown. The initial pH value is missing from the graph. © WJEC CBAC Ltd. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 5 10 15 20 25 30 35 40 45 Volume of sodium hydroxide added / cm3 pH 14 (1410U30-1) Turn over. 15 Examiner only (a) Several indicators are listed in the table. Identify all the indicator(s) which are appropriate for this titration. Give a reason for your choice(s). [2] © WJEC CBAC Ltd. Indicator pH range methyl orange 3.1 - 4.4 bromocresol purple 5.2 - 6.8 bromothymol blue 6.0 - 7.6 naphtholphthalein 7.3 - 8.7 cresolphthalein 8.2 - 10.1 (b) Calculate the concentration of the HA solution. [2] Concentration = ....................................................... mol dm–3 15 16 (1410U30-1) Examiner only (c) Find the pH of the mixture after addition of 10.0 cm3 of sodium hydroxide solution and hence calculate the initial pH of the HA solution. [4] You must show your working. pH after addition of 10.0 cm3 = ....................................................... Initial pH = ....................................................... (d) HA is a weak acid and so it can be used to make a buffer solution. Suggest one important use for buffer solutions. [1] © WJEC CBAC Ltd. 16 (1410U30-1) Turn over. 17 Examiner only (e) Some data regarding the dissociation of another weak acid, HX, at two different temperatures are given in the table. © WJEC CBAC Ltd. HX H+ X– + HX at 298 K HX at temperature T Percentage dissociated 3.9 3.4 ΔG for acid dissociation / kJ mol–1 15.9 16.7 ΔH for acid dissociation / kJ mol–1 –10.0 ΔS for acid dissociation / J K–1 mol–1 –87.0 Find temperature T and hence explain in terms of equilibrium why the percentage dissociation is different at this temperature. [3] T = ....................................................... K 12 17

18 (1410U30-1) Examiner only 11. Chlorine can form a range of oxyanions with chlorine present in oxidation states including +1, +5 and +7. (a) Chlorate(I) ions, ClO–, are commonly present in household bleaches. These ions can oxidise iodide ions to iodine. © WJEC CBAC Ltd. H2O I2 CIO– 2OH– CI– 2I– + + + + Dewi took a 25.0 cm3 sample of a household bleach and diluted it to form 250 cm3 of solution in a standard volumetric flask. Four 25.0 cm3 portions of the diluted solution were measured and placed in separate conical flasks and a spatula of solid potassium iodide was added to each. Each portion was titrated against standard sodium thiosulfate solution from a burette. 1 2 3 4 Volume of Na2S2O3 solution / cm3 6.45 6.40 6.50 6.45 (i) Calculate the mean volume of sodium thiosulfate solution used. [1] Mean volume = ....................................................... cm3 2S2O3 2– I2 + S4O6 2– 2I– + 18 Dewi had access to five concentrations of sodium thiosulfate: 2.00 mol dm–3, 1.00 mol dm–3, 0.500 mol dm–3, 0.200 mol dm–3 and 0.0500 mol dm–3. He selected the 0.500 mol dm–3 solution and his results are shown in the table. (1410U30-1) Turn over. 19 Examiner only (ii) Find the concentration of sodium chlorate(I) in the initial bleach sample. [3] Concentration = ....................................................... mol dm–3 (iii) Bleach concentrations are often quoted on labels as % w/v, that is the mass of sodium chlorate(I) dissolved in 100 cm3 of water. Calculate the % w/v concentration of sodium chlorate(I) in this bleach. [1] Concentration = ....................................................... % w/v (iv) The teacher tells Dewi that he has selected an inappropriate concentration of sodium thiosulfate solution. Suggest which concentration of sodium thiosulfate he should have chosen. Give two reasons for your answer. [2] © WJEC CBAC Ltd. 19 20 (1410U30-1) Examiner only (b) Chlorate(V) anions, ClO3 –, are strong oxidising agents and can oxidise bromide ions in acid solution to form bromine and chloride ions. © WJEC CBAC Ltd. 3H2O CIO3 – CI– 6Br 3Br2 6H+ + + + + – The initial rate of this reaction was measured at a temperature of 298 K using different concentrations of reactants. (i) I. Find the orders of reaction with respect to chlorate(V) and bromide ions. [2] You must show your working. Order with respect to chlorate(V) ions ....................................................... Order with respect to bromide ions ....................................................... Experiment Concentration of ClO3 – / mol dm–3 Concentration of Br– / mol dm–3 pH Initial rate / mol dm–3 s–1 1 0.30 0.20 0 3.06 × 10–7 2 0.60 0.20 0 6.12 × 10–7 3 0.30 0.60 0 9.18 × 10–7 4 0.30 0.60 1 20 (1410U30-1) Turn over. 21 Examiner only II. The student finds that the rate of reaction is proportional to [H+]3. This is described as third order with respect to hydrogen ions. Find the expected initial rate for experiment 4. [2] Initial rate = ................................................................................... mol dm–3 s–1 (ii) Chemists often use an approximate rule that the rate of a reaction doubles when the temperature is increased by 10 °C. Show that this rule is true if this reaction is warmed from 298 K to 308 K. The activation energy for the reaction is 52.8 kJ mol–1. [3] © WJEC CBAC Ltd. 21 22 (1410U30-1) Examiner only (c) The acid formed from chlorate(VII) ions is commonly called perchloric acid, HClO4. It is a very strong acid and is commonly classed as a superacid as it is a stronger acid than sulfuric acid. (i) State how the Ka value of a stronger acid will compare with that of a weaker acid, giving a reason. [1] (ii) The concentration of 25.0 cm3 of an aqueous solution of perchloric acid can be found by adding an excess of calcium carbonate and then measuring the amount of carbon dioxide gas released. This can be done by either: • measuring the volume of the gas released using a gas syringe, or • measuring the mass lost as the carbon dioxide is released by placing the reaction flask on a digital balance. Joe uses the first method to study his sample of perchloric acid and finds that the reaction releases 87 cm3 of carbon dioxide at 30 °C and 1 atm pressure. Heledd uses the second method and finds that the mixture loses a total of 0.1533 g during the reaction. © WJEC CBAC Ltd. 22 (1410U30-1) Turn over. 23 Examiner only © WJEC CBAC Ltd. I. Find the number of moles of carbon dioxide released in each experiment and hence state whether the two solutions provided to Joe and Heledd are of the same concentration. [4] You must show your working and give your answers to appropriate numbers of significant figures. Moles of CO2 using Joe’s method = ....................................................... mol Moles of CO2 using Heledd’s method = ....................................................... mol II. Suggest, from the data provided, which of the two methods will give better results. Give a reason for your suggestion. [1] III. Isha suggests using excess magnesium in place of calcium carbonate for Joe and Heledd’s experiments. This will produce hydrogen gas in place of carbon dioxide. Explain which of the two methods will suffer the greater loss in accuracy. [2] 23 Examiner only 24 (1410U30-1) © WJEC CBAC Ltd. (iii) One common salt of perchloric acid is ammonium perchlorate. Suggest a pH value for a solution of ammonium perchlorate. Give a reason for your answer. [2] END OF PAPER 24 24 (1410U30-1) Turn over. 25 25 © WJEC CBAC Ltd. Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. 26 (1410U30-1) 26 © WJEC CBAC Ltd. Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (1410U30-1) 27 27 © WJEC CBAC Ltd. BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (1410U30-1) 28 28 © WJEC CBAC Ltd.

16 © WJEC CBAC Ltd. (1410U40-1) 16 10. (a) Compound G contains only carbon, hydrogen and oxygen. It has a molar mass of 72 g mol–1 of which 50.0% is carbon. The compound reacts positively with Tollens’ reagent and gives a yellow solid when treated with alkaline iodine solution. It reacts with sodium tetrahydridoborate(III) to give a new compound which has a molar mass of 76 g mol–1. The high resolution 1H NMR spectrum of compound G is shown below. 10 8 6 4 2 0 peak area 1 peak area 3 δ / ppm Turn over. 17 © WJEC CBAC Ltd. (1410U40-1) 17 Use all of this information to deduce a structure for compound G. You should comment on how each piece of data has helped you to deduce the structure. [6 QER] Examiner only 18 Examiner only © WJEC CBAC Ltd. (1410U40-1) 18 (b) The absorption spectrum of compound G shows a maximum absorption at 450 nm. Light energy measured in kJ mol–1 (E) is related to wavelength (λ) by the equation E = constant λ The energy of light of wavelength 656 nm is 183 kJ mol–1. Calculate the energy of the maximum absorption of compound G at 450 nm. [2] Energy = ........................................................ kJ mol–1 Examiner only Turn over. 19 © WJEC CBAC Ltd. (1410U40-1) 19 13 .............. HNO2 + + .............. N2 + .............. H2O NH2 C O H2N (c) The formula of 4-aminobenzamide is (i) When this compound is warmed with excess aqueous sodium hydroxide, only the amide group reacts. I. Give the structure of the organic product. [1] II. State the nature of the attacking reagent and explain why the NH2 group bonded to the benzene ring is not removed. [2] (ii) Both the functional groups in 4-aminobenzamide are attacked by nitric(III) acid at room temperature, giving 4-hydroxybenzoic acid, nitrogen gas and water as the products. Complete the equation for this reaction. [2] NH2 C O H2N 20 Examiner only © WJEC CBAC Ltd. (1410U40-1) 20 11. (a) Tyrosine is one of the amino acids making up casein, the protein in milk. (i) Using a particular solvent tyrosine has an Rf value of 0.67. On the chromatogram below show the spot given by tyrosine. [1] OH O tyrosine NH2 HO 6 5 4 3 2 10 9 8 7 1 cm solvent front start line Turn over. 21 © WJEC CBAC Ltd. (1410U40-1) 21 Examiner only (ii) Write the formula for the zwitterion of tyrosine. [1] (iii) Tyrosine is described as a hydrophobic amino acid, as its solubility in water is very low. Use the formula of tyrosine to give a reason for this low solubility. [1] 22 © WJEC CBAC Ltd. (1410U40-1) 22 Examiner only (iv) Amino acids, such as tyrosine, react with nitric(III) acid to give the corresponding hydroxy acid and nitrogen gas. I. A sample of tyrosine was treated with an excess of nitric(III) acid and produced 147 cm3 of nitrogen, measured at 298 K and 1 atm pressure. Show that this volume of nitrogen will be produced from 1.09 g of tyrosine. [2] II. The experiment was repeated with a sample of tyrosine from a different batch. This time the same starting mass gave 132 cm3 of nitrogen under the same conditions. Suggest one reason for this different result. [1] OH O Mr 181 NH2 HO + HNO2 OH O OH HO + N2 + H2O Turn over. 23 © WJEC CBAC Ltd. (1410U40-1) 23 Examiner only (b) There is increasing interest in the production of important chemicals by biotechnology, rather than from the use of fossil fuels. One of these compounds is butane-1,4-dioic acid, which can be made from glucose. In practice, a constant pH is maintained by the addition of calcium hydroxide. As butane-1,4-dioate ions are produced they react with calcium hydroxide to give insoluble calcium butane-1,4-dioate, which is then filtered from the mixture. (i) Calculate the atom economy for the production of calcium butane-1,4-dioate. [2] Atom economy = ........................................................ % HOOC(CH2)2COOH anaerobic bacteria C6H12O6 other products + butane-1,4-dioic acid Mr 118 glucose Mr 180 (CH2)2(COO)2Ca Ca(OH)2 C6H12O6 other products + + calcium butane-1,4-dioate Mr 74 glucose Mr 180 24 © WJEC CBAC Ltd. (1410U40-1) 24 © WJEC CBAC Ltd. Examiner only (ii) In an experiment, 54.0 g of glucose produced 41.2 g of calcium butane-1,4-dioate. Calculate the minimum volume of sulfuric acid, of concentration 2.5 mol dm–3, necessary to convert all the calcium butane-1,4-dioate into butane-1,4-dioic acid. [2] (CH2)2(COO)2Ca + H2SO4 HOOC(CH2)2COOH + CaSO4 Volume of sulfuric acid = ........................................................ cm3 (1410U40-1) Turn over. 25 © WJEC CBAC Ltd. 25 Examiner only 12 Use the formula to help you to describe the 13C NMR spectrum of this compound. Your answer should include the number of peaks seen and your reasoning. The position and size of the peaks is not required. [2] C C H H3C H C C H CH3 H hexa-2,4-diene (c) Hexa-2,4-diene is one of the important products that can be produced from butane-1,4-dioic acid. 26 (1410U40-1) © WJEC CBAC Ltd. 26 Examiner only 12. (a) People are increasingly concerned about the effect of the Sun’s ultraviolet rays on the skin. A number of compounds have been developed for use as sunscreens. One of these compounds is compound A. (i) The ultraviolet absorption spectrum of compound A is shown below. Ultraviolet radiation is divided into three regions. Region Wavelength / nm UVA 320-400 UVB 290-320 UVC 200-290 Use this information to explain why it may be necessary to use another sunscreen compound, together with compound A, when producing a commercial sunscreen. [1] CH CH2 CH2 CH3O CH O CH CH2 CH2 CH3 CH2 CH3 C O compound A 200 300 400 Absorbance Wavelength / nm (1410U40-1) Turn over. 27 © WJEC CBAC Ltd. 27 Examiner only (ii) Compound A is an ester that is made by reacting together 2-ethylhexanol and the appropriate acid, in the presence of a catalyst. Give the molecular formula of the acid used in this reaction. [1] (iii) Compound A displays both forms of stereoisomerism. I. State how structural isomerism differs from stereoisomerism. [2] II. Indicate the position of a chiral centre on the formula of compound A below. [1] III. When compound A is made by the method described in part (ii) above, an equimolar mixture of both enantiomers is produced. State how a solution of this mixture affects the plane of plane polarised light. [1] IV. Exposure of a mixture of both E- and Z- forms of compound A to UV radiation results in the E- form gradually changing to the Z- form. Using the general formula of compound A as CH CH R R’, draw and label these two forms of compound A. [2] CH CH2 CH2 CH3O CH O CH CH2 CH2 CH3 CH2 CH3 C O 28 (1410U40-1) © WJEC CBAC Ltd. 28 (b) Palm oil contains around 40% of unsaturated oil and 60% of saturated oil. The amount of unsaturation in an oil can be measured indirectly in a reaction with iodine. (i) In the first stage of this method bromine adds across the C C double bonds present. State the type of mechanism occurring when bromine adds across these double bonds. [1] ................................................................................................................ (ii) The overall reaction with iodine can be represented by the following equation. In palm oil, most of the unsaturated oils are present as glyceryl trioleate (Mr 885). This compound contains three C C double bonds per molecule. An 8.41 g sample of palm oil reacted indirectly with 0.0128 mol of iodine (I2). Calculate the percentage of unsaturated oil (as glyceryl trioleate) present in the palm oil. [2] Percentage of unsaturated oil = ........................................................ % CH Br CH CH CH Br I CH CH I Br2 I2 Examiner only (1410U40-1) Turn over. 29 Examiner only © WJEC CBAC Ltd. (iii) Oils such as palm oil can be refined and used to make soaps such as sodium oleate. Complete the equation below, which represents the alkaline hydrolysis of the unsaturated oil. [2] (iv) Fats and oils are esters of carboxylic acids and glycerol. Give the systematic name of glycerol (seen in part (iii) above). [1] END OF PAPER O O O + H2C HC H2C ......... NaOH 3 ............................................ OH HC OH H2C OH H2C + glycerol sodium oleate O C C17H33 O C C17H33 O C C17H33 14 29 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (1410U40-1) 30 © WJEC CBAC Ltd. 30 (1410U40-1) 31 Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. © WJEC CBAC Ltd. Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. 31 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE (1410U40-1) 32 © WJEC CBAC Ltd. 32

26 (A410U10-1) 26 © WJEC CBAC Ltd. 13. The elements of Group 5 react with hydrogen to form compounds of formula XH3. Some information regarding the physical properties of these compounds is shown in the table. Compound Formula Boiling temperature / °C Solubility in water / g dm–3 ammonia NH3 –33 470 phosphane PH3 –83 0.312 arsane AsH3 –63 0.710 stibane SbH3 –17 4.24 (a) Identify and explain the patterns seen in these physical properties. [6 QER] Examiner only (A410U10-1) Turn over. 27 27 Examiner only © WJEC CBAC Ltd. (b) Use VSEPR theory to predict the shape of the PH3 molecule, giving reasons for your answer. [3] 28 (A410U10-1) 28 © WJEC CBAC Ltd. (c) Stibane is a gas that decomposes slowly at a temperature of 350 °C. 2Sb(s) 3H2(g) 2SbH3(g) + The decomposition of stibane was studied in a sealed vessel, with the pressure measured over a period of 100 hours. The results are shown on the graph. 40 000 42 000 44 000 46 000 48 000 50 000 52 000 54 000 56 000 58 000 60 000 0 10 20 30 40 50 60 70 80 90 100 Gas pressure / Pa Time / hours (A410U10-1) Turn over. 29 29 Examiner only © WJEC CBAC Ltd. (i) The initial pressure in the vessel was 42 000 Pa. Calculate the pressure in the vessel when all the stibane had decomposed. [2] Pressure = ...................................................... Pa (ii) Calculate the initial rate of change of pressure in Pa hr –1. [2] Rate of change of pressure = ...................................................... Pa hr –1 (iii) Use the initial pressure and your answer to part (i) to calculate the pressure in the vessel when half the stibane had decomposed. Use this and the graph to show that the reaction is first order with respect to stibane. [4] Pressure when half the stibane had decomposed = ...................................................... Pa 30 (A410U10-1) 30 © WJEC CBAC Ltd. Examiner only (d) Ammonia is produced industrially using the Haber process. 3H2(g) N2(g) + 2NH3(g) The reaction traditionally used iron-based catalysts which reduce the activation energy of the reaction to 101.4 kJ mol–1. Newer catalysts have been developed using ruthenium which reduce the activation energy further to 64.0 kJ mol–1. (i) These are examples of heterogeneous catalysts. State what is meant by a ‘heterogeneous’ catalyst. [1] (ii) State, giving a reason, the effect of changing the catalyst on the position of this equilibrium. [2] (A410U10-1) Turn over. 31 31 © WJEC CBAC Ltd. Examiner only (iii) The Haber process typically uses a temperature of 500 °C. Replacing the iron-based catalyst with a newer ruthenium-based catalyst increases the initial rate of reaction by a factor, f, at this temperature. Use the Arrhenius equation to calculate the value of f. You may assume that the frequency factor in both cases is the same. [3] f = ...................................................... 32 (A410U10-1) 32 © WJEC CBAC Ltd. (e) When water is added to gaseous phosphane no visible reaction occurs. However, studies using isotopes of hydrogen have shown that hydrogen atoms are exchanged between the phosphane and water. The following gas phase equilibrium occurs, where D represents deuterium, a hydrogen isotope with a mass number of 2. H2O(g) PH2D(g) + HDO(g) + PH3(g) A sealed vessel of volume 500 cm3 contained 1.00 × 10–3 mol of PH2D(g). A sample of 4.90 × 10–4 mol of H2O(g) was added and the mixture allowed to reach equilibrium. The mass spectrum of the equilibrium mixture shows that 36% of the phosphorus is present in PH3 and 64% of the phosphorus is present in PH2D. Calculate the value of the equilibrium constant Kc for this reaction. [4] Kc = ...................................................................... END OF PAPER 27 Examiner only (A410U10-1) Turn over. 33 © WJEC CBAC Ltd. 33 Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. 34 (A410U10-1) © WJEC CBAC Ltd. 34 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (A410U10-1) 35 © WJEC CBAC Ltd. 35 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE 36 (A410U10-1) © WJEC CBAC Ltd. 36 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE BE*(S22-A410U10-1A) © WJEC CBAC Ltd. GCE A LEVEL A410U10-1A MONDAY, 13 JUNE 2022 – MORNING CHEMISTRY – A level component 1 Data Booklet Avogadro constant NA = 6.02 × 1023 mol –1 molar gas constant R = 8.31 J mol –1 K –1 molar gas volume at 273 K and 1 atm Vm = 22.4 dm3 mol –1 molar gas volume at 298 K and 1 atm Vm = 24.5 dm3 mol –1 Planck constant h = 6.63 × 10 –34 J s speed of light c = 3.00 × 108 m s –1 density of water d = 1.00 g cm –3 specific heat capacity of water c = 4.18 J g –1 K –1 ionic product of water at 298 K Kw = 1.00 × 10 –14 mol 2 dm – 6 fundamental electronic charge e = 1.60 × 10 –19 C temperature (K) = temperature (°C) + 273 1 dm3 = 1000 cm3 1 m3 = 1000 dm3 1 tonne = 1000 kg 1 atm = 1.01 × 105 Pa Multiple Prefix Symbol 10 –9 nano n 10 –6 micro μ 10 –3 milli m Multiple Prefix Symbol 10 3 kilo k 10 6 mega M 10 9 giga G Z22-A410U10-1A (A410U10-1A) 2 © WJEC CBAC Ltd. 500 to 600 650 to 800 1000 to 1300 1620 to 1670 1650 to 1750 2100 to 2250 2800 to 3100 2500 to 3200 (very broad) 3200 to 3550 (broad) 3300 to 3500 C Br C Cl C O C C C O C N C H O H (carboxylic acid) O H (alcohol / phenol) N H 10 to 70 5 to 40 20 to 50 25 to 60 50 to 90 90 to 150 110 to 125 110 to 160 160 to 185 190 to 220 N C R C C C O C C R Cl or Br C O C R C O (carboxylic acid / ester) C R (aldehyde / ketone) O C R N R C 13C NMR chemical shifts relative to TMS = 0 Type of carbon Chemical shift, δ (ppm) Infrared absorption values Bond Wavenumber / cm –1 Turn over. (A410U10-1A) 3 © WJEC CBAC Ltd. *variable figure dependent on concentration and solvent 1H NMR chemical shifts relative to TMS = 0 Type of proton Chemical shift, δ (ppm) 0.9 0.1 to 2.0 3.1 to 4.3 1.3 2.0 2.0 to 3.0 2.0 to 2.5 2.2 to 2.3 R CH3 R CH2 R CH3 C N CH3 C O CH3 CH3 CH2 C O 4.5 * 4.5 to 6.3 6.5 to 7.5 6.5 to 8.0 R OH 3.3 to 4.3 HC Cl or HC Br C CH HC O C CH H 7.0 * OH 9.8 * 11.0 * R C O H R C O OH 5.8 to 6.5 C CH CO (A410U10-1A) 4 © WJEC CBAC Ltd. 6.94 Li Lithium 3 9.01 Be Beryllium 4 10.8 B Boron 5 12.0 C Carbon 6 14.0 N Nitrogen 7 16.0 O Oxygen 8 19.0 F Fluorine 9 20.2 Ne Neon 10 23.0 Na Sodium 11 24.3 Mg Magnesium 12 27.0 Al Aluminium 13 28.1 Si Silicon 14 31.0 P Phosphorus 15 32.1 S Sulfur 16 35.5 Cl Chlorine 17 40.0 Ar Argon 18 39.1 K Potassium 19 40.1 Ca Calcium 20 45.0 Sc Scandium 21 47.9 Ti Titanium 22 50.9 V Vanadium 23 52.0 Cr Chromium 24 54.9 Mn Manganese 25 55.8 Fe Iron 26 58.9 Co Cobalt 27 58.7 Ni Nickel 28 63.5 Cu Copper 29 65.4 Zn Zinc 30 69.7 Ga Gallium 31 72.6 Ge Germanium 32 74.9 As Arsenic 33 79.0 Se Selenium 34 79.9 Br Bromine 35 83.8 Kr Krypton 36 85.5 Rb Rubidium 37 87.6 Sr Strontium 38 88.9 Y Yttrium 39 91.2 Zr Zirconium 40 92.9 Nb Niobium 41 95.9 Mo Molybdenum 42 98.9 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 112 Cd Cadmium 48 115 In Indium 49 119 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 133 Cs Caesium 55 137 Ba Barium 56 139 La Lanthanum 57 179 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 (210) Po Polonium 84 (210) At Astatine 85 (222) Rn Radon 86 (223) Fr Francium 87 (226) Ra Radium 88 (227) Ac Actinium 89 THE PERIODIC TABLE 1 2 Group 3 4 5 6 7 0 1 2 3 4 5 6 7 1.01 H Hydrogen 1 4.00 He Helium 2 d block s block Period p block 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 (147) Pm Promethium 61 150 Sm Samarium 62 (153) Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 163 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 (231) Pa Protactinium 91 238 U Uranium 92 (237) Np Neptunium 93 (242) Pu Plutonium 94 (243) Am Americium 95 (247) Cm Curium 96 (245) Bk Berkelium 97 (251) Cf Californium 98 (254) Es Einsteinium 99 (253) Fm Fermium 100 (256) Md Mendelevium 101 (254) No Nobelium 102 (257) Lr Lawrencium 103 f block Actinoid elements Ar Symbol Name Z relative atomic mass atomic number Key Lanthanoid elements ▴ ▴▴ ▴ ▴▴

13619.06R [Turn over 10 Calculate the standard enthalpy of formation of propane using the data below. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l) ∆HO —  =  -2220 kJ mol-1 H2(g) + 1 2 O2(g) → H2O(l) ∆HO —  =  -286 kJ mol-1 C(s) + O2(g) → CO2(g) ∆HO —  =  -394 kJ mol-1 A -1540 kJ mol-1 B -106 kJ mol-1 C +106 kJ mol-1 D +1540 kJ mol-1 Answer                         [1] 13619.06R Section B Answer all five questions in the spaces provided. 11 The Solvay process is used to produce sodium carbonate. The process consists of several steps involving the use of ammonia, sodium chloride and calcium carbonate. (a) The overall equation for the formation of sodium carbonate may be written as the reaction between calcium carbonate and sodium chloride. Write the overall equation for this process. [2] (b) The equation for one of the steps in the process is shown below. 2NH4Cl + Ca(OH)2 → CaCl2 + 2NH3 + 2H2O (i) Calculate the percentage atom economy for the formation of ammonia in the above reaction. Give your answer to 1 decimal place. Answer                         % [2] (ii) During this stage of the process, 3.25 tonnes of ammonium chloride are reacted with an excess of calcium hydroxide and 0.92 tonnes of ammonia were obtained. Calculate the percentage yield of ammonia. Give your answer to 1 decimal place. Answer                         % [3]

13619.06R [Turn over 12 The thermal decomposition of potassium hydrogencarbonate establishes a dynamic equilibrium in a closed vessel at 200 °C. The enthalpy change for the decomposition reaction is difficult to determine directly. 2KHCO3(s) ⇌ K2CO3(s) + CO2(g) + H2O(g) (a) (i) The equilibrium is heterogeneous. Define the term heterogeneous. [1] (ii) Suggest why the water is present as a gas in the equilibrium mixture. [1] (b) The enthalpy change for this thermal decomposition reaction can be calculated from the enthalpy changes of neutralisation of both potassium carbonate and potassium hydrogencarbonate. K2CO3 + 2HCI → 2KCI + H2O + CO2 KHCO3 + HCI → KCI + H2O + CO2 Both of these enthalpy changes may be determined using the following procedure:  Using a measuring cylinder, place 25 cm3 of 2.0 mol dm-3 hydrochloric acid into a polystyrene cup.  Measure the temperature of the acid with a thermometer.  Add a known mass of either potassium carbonate or potassium hydrogencarbonate to the acid in the polystyrene cup, stir, and measure the highest or lowest temperature reached. (i) Define the term standard enthalpy of neutralisation. [2] 13619.06R (ii) When the procedure was carried out using 2.5 g of potassium carbonate, a temperature rise of 5.5 °C was recorded. Calculate the enthalpy change for the reaction per mole of potassium carbonate. Give your answer in kJ mol-1 to 1 decimal place. (c = 4.2 J g-1 °C-1, density of solution = 1 g cm-3) Answer                         kJ mol-1 [3] (iii) When the procedure was repeated using potassium hydrogencarbonate, the enthalpy change for the reaction was determined to be +29.1 kJ mol-1 (per mole of potassium hydrogencarbonate). Use this value and the value calculated in (b)(ii) to calculate the enthalpy change for the thermal decomposition of potassium hydrogencarbonate. 2KHCO3(s) ⇌ K2CO3(s) + CO2(g) + H2O(g) Answer                         [2]

13619.06R [Turn over 13 Isooctane (2,2,4-trimethylpentane) is an important component of petrol used in cars. It is a liquid at room temperature. Isooctane is one of eighteen structural isomers of C8H18. (a) (i) Draw the skeletal formula of isooctane. [1] (ii) Define the term structural isomers. [2] (iii) Draw the structural formula and state the IUPAC name of the structural isomer of C8H18 which is the most branched. IUPAC name: [2] 13619.06R (b) (i) Write an equation for the complete combustion of isooctane, C8H18. [2] (ii) Suggest why a sooty flame is observed when a sample of isooctane burns. [1] (iii) When 1.00 g of liquid isooctane reacts completely in excess oxygen, the enthalpy change is -47.9 kJ. Calculate the heat energy released when 5.00 dm3 of liquid isooctane burns completely in oxygen (density of isooctane = 0.692 g cm-3). Give your answer to 3 significant figures. Answer                         kJ [3] (c) The combustion of organic compounds has contributed to the increase in the percentage composition of carbon dioxide in the atmosphere. (i) State the percentage increase in atmospheric carbon dioxide caused by the combustion of organic compounds. [1] (ii) State a consequence of an increase in atmospheric carbon dioxide. [1] 13619.06R [Turn over (d) Pollutants such as carbon monoxide and oxides of nitrogen are also produced when alkane fuels are burned. Catalytic converters are used to reduce the environmental impact of burning alkane fuels. They consist of a thin layer of a metal catalyst on a ceramic honeycomb structure. (i) Suggest why a catalytic converter has a honeycomb structure. [1] (ii) Suggest why a thin layer of the metal catalyst is used in a catalytic converter. [1] (iii) Write an equation for the overall reaction between nitrogen(II) oxide and carbon monoxide in a catalytic converter. [2] (iv) Define the term catalyst. [1] (v) State the name given to the graphical distribution of molecular energies in gaseous reactions. [1] 13619.06R (vi) Explain, with reference to the graphical distribution named in (d)(v), how a catalyst changes the rate of reaction between nitrogen(II) oxide and carbon monoxide. [3]

13619.06R [Turn over 14 The Group II elements are known as the alkaline earth metals and they display trends in their physical and chemical properties. (a) State and explain the trend in atomic radius down Group II. [2] (b) The Group II elements react with oxygen to form the corresponding metal oxides. (i) Write an equation for the reaction of magnesium with oxygen. [1] (ii) The magnesium oxide produced in (b)(i) was added to a flask containing water and phenolphthalein. Suggest and explain, using an ionic equation, why the solution will change colour. [2] 13619.06R (c) Magnesium oxide may also be produced by reacting magnesium with steam. The diagram below shows the apparatus used in the reaction. magnesium HEAT HEAT damp mineral wool boiling tube delivery tube gas gas jar trough beehive shelf water (i) State why the damp mineral wool is heated. [1] (ii) State two observations which would be made in the boiling tube during the reaction. [2] (iii) Write an equation for the reaction which takes place in the boiling tube. [1] (iv) Suggest why the gas produced is collected over water. [1] 13619.06R [Turn over (v) The reaction was carried out using 0.08 g of magnesium. Calculate the volume of gas at 20 °C and 1 atm pressure that should be produced and suggest why this volume of gas was not obtained in the gas jar. Answer                         cm3 [3] (d) Group II oxides can react with dilute acids. Write an equation for the reaction between magnesium oxide and dilute nitric acid. [1]

13619.06R 15 Propene (C3H6) is a raw material obtained from crude oil which can be used to produce many important chemicals. A reaction scheme is shown below. C3H6 C3H8 propene C3H7Br C3H7CI C3H8O C3H6O reaction A reaction D reaction B reaction C (a) State the name of the mechanism for reaction A and reaction B. A B [4] (b) (i) Write an equation for reaction A. [1] (ii) Two isomers of C3H7Br are produced in reaction A. State the IUPAC name of the isomer which is the major product. [1] (iii) Draw a mechanism to show the formation of the major product in reaction A. [3] 13619.06R [Turn over (c) (i) Write the formula of the reagent required in reaction B. [1] (ii) Describe the conditions required for reaction B. [2] (iii) The reagent required in reaction B can also be used, under different conditions, to convert C3H7Br back to C3H6. State the type of reaction which occurs when C3H7Br is converted to C3H6. [1] (d) (i) Draw the structural formulae of the two isomers of C3H6O which are produced in reaction C. [2] (ii) Name the reagent used to carry out reaction C. [1] 13619.06R (e) C3H8 reacts with Cl2 to form C3H7Cl in reaction D. One by-product in this reaction is C6H14. (i) Name the mechanism for this reaction. [1] (ii) Write an equation for the initiation step in this mechanism. [1] (iii) Write equations for the two propagation steps in this mechanism. [2] (iv) Write an equation for a termination step which produces C3H7Cl. [1] (v) Write an equation to show how C6H14 may be produced in this reaction. [1] 13619.06R (f) Pentane, C5H12, is also obtained from crude oil. It has the same relative formula mass as butanal, C4H8O, and a similar relative formula mass to butan-1-ol, C4H9OH. However, the three compounds have very different boiling points. Identify which compound (pentane, butanal or butan-1-ol) has the highest boiling point and which has the lowest boiling point. Explain the variation in boiling points of the three compounds with reference to intermolecular forces. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] THIS IS THE END OF THE QUESTION PAPER 13619.06R BLANK PAGE DO NOT WRITE ON THIS PAGE 13619.06R BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE SCH24/8 276814 Sources Q7.....© Science Ready Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13620.08R 3 [Turn over Practical Examination Question 1 Each candidate must be supplied with: • 1 × watch glass • 1 × piece of nichrome wire • 1 × spatula • 1 × Bunsen burner • 1 × heat proof mat • 2 × 250 cm3 beakers • 1 × glass rod • Several 3 cm3 graduated disposable pipettes • 1 × 250 cm3 volumetric flask • 2 × filter funnel • 1 × 25.0 cm3 pipette of at least class B quality • 1 × safety pipette filler • 1 × white tile • 2 × 250 cm3 conical flasks • 1 × 50.0 cm3 burette of at least class B quality • 1 × wash bottle of deionised water • 1 × retort stand, boss head and clamp/burette holder • 2.5 g of a 50/50 mixture of anhydrous sodium carbonate and sodium hydrogencarbonate in a stoppered container labelled S and moderate hazard (exclamation mark label) • approximately 150 cm3 of dilute hydrochloric acid in a container labelled 0.1 mol dm–3 hydrochloric acid and moderate hazard (exclamation mark label). This solution should be approximately 0.1 mol dm–3 • access to concentrated hydrochloric acid (fume cupboard) for use in a flame test labelled concentrated hydrochloric acid and corrosive and moderate hazard (exclamation mark label) 13620.08R 4 [Turn over • methyl orange indicator labelled methyl orange • phenolphthalein indicator labelled phenolphthalein and flammable and moderate hazard (exclamation mark label) • access to an electronic balance

13620.08R 5 [Turn over Question 2 Each candidate must be supplied with: • approximately 50 cm3 of toluene in a stoppered container labelled A and flammable and moderate hazard (exclamation mark label) • approximately 50 cm3 of ethanol in a stoppered container labelled B and flammable and moderate hazard (exclamation mark label) • approximately 50 cm3 of deionised water in a stoppered container labelled C • 8 × test tubes • 3 × stoppers for test tubes • 2 × test tube racks • 1 × spatula • 1 × piece of universal indicator paper • 2 × 250 cm3 beakers • 1 × stopclock • 1 × 50.0 cm3 burette of at least class B quality (burette from Q1 can be rinsed and reused) • 1 × filter funnel for filling the burette • 1 × plastic rod/plastic 30 cm ruler • 1 × cloth for rubbing plastic rod/plastic ruler • several 3 cm3 graduated disposable pipettes • access to potassium manganate(VII) solution labelled potassium manganate(VII) solution. This solution should be approximately 0.02 mol dm–3. Each candidate will require 10 drops. • access to dilute sulfuric acid. This solution should be approximately 1.0 mol dm–3 and labelled dilute sulfuric acid and moderate hazard (exclamation mark label). Each candidate will require 3 cm3. • access to phosphorus(V) chloride (fume cupboard) labelled phosphorus(V) chloride and corrosive and moderate hazard (exclamation mark label) • access to iodine solution labelled iodine solution. This solution should be approximately 0.01 mol dm–3. Each candidate will require 5 cm3. • access to a kettle of hot water 13620.03 [Turn over ADVANCED SUBSIDIARY (AS) General Certificate of Education 2023 Chemistry Assessment Unit AS 3 Practical Assessment Practical Booklet A [SCH31] TUESDAY 9 MAY, MORNING Confidential Instructions to the Supervisor of the Practical Examination

13620.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Wednesday 3 May 2023. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before 3 May 2023. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while they are on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

13620.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger themselves or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification needs to be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 13620.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Subsidiary Chemistry Practical Booklet A [SCH31] Tuesday 9 May 2023 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number

13616.08RRR 12 Benzaldehyde is an aromatic aldehyde with an almond odour. It can be obtained from natural sources and is widely used in the preparation of dyes, perfumes and flavourings. C O H benzaldehyde (a) Describe how you would practically carry out the reaction of a solution of benzaldehyde with Tollens’ reagent and with acidified potassium dichromate(VI) solution and state all observations which occur. Write an equation for the oxidation of benzaldehyde and half equations for the reduction of each reagent. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] 13616.08RRR [Turn over (b) (i) Benzaldehyde undergoes an addition reaction with hydrogen cyanide to form a hydroxynitrile called mandelonitrile. Outline the mechanism for this reaction. Include an equation for the formation of the nucleophile from hydrogen cyanide. [4] (ii) The addition of cyanide ions to a carbonyl group is carried out at a pH of 4 – 5. Suggest why a very low pH is not used. [1] (iii) Explain why the mandelonitrile formed from the reaction in (b)(i) is optically inactive. [2] 13616.08RRR (c) The hydrolysis of mandelonitrile forms mandelic acid C6H5CH(OH)COOH. This is a weak acid with a Ka value of 3.88 × 10-4 mol dm-3. Excess mandelic acid reacts with sodium hydroxide to form a buffer solution. (i) Write an equation for the reaction of mandelic acid with sodium hydroxide. [1] (ii) Define the term buffer solution. [1] (iii) Calculate the pH of the buffer formed on mixing 35.0 cm3 of 0.125 mol dm-3 mandelic acid with 15.0 cm3 of 0.175 mol dm-3 sodium hydroxide solution. Give your answer to 2 decimal places. Answer                      [4] 13616.08RRR BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13616.08RRR 13 Phenylethanone is used as a fragrance in perfumes and soaps. C O H3C phenylethanone It is prepared by the reaction of benzene with ethanoyl chloride in the presence of an aluminium chloride catalyst. (a) (i) Outline a mechanism for the acylation of benzene to form phenylethanone. The mechanism should include equations to show the formation of the electrophile and the regeneration of the catalyst. [5] (ii) Define the term electrophile. [1] 13616.08RRR [Turn over (b) Phenylethanone can be nitrated to form (3-nitrophenyl)ethanone which is a solid at room temperature. (i) State the reagents required for this nitration. [2] (ii) Write an equation for the nitration of phenylethanone to form (3-nitrophenyl)ethanone. [1] (iii) Describe how the melting point of a solid sample of (3-nitrophenyl)ethanone could be determined. State two effects that the presence of impurities would have on the melting point. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 13616.08RRR (c) Phenylethanone reacts with 2,4-dinitrophenylhydrazine. (i) Write an equation for the reaction of phenylethanone with 2,4-dinitrophenylhydrazine. [2] (ii) Calculate the volume of phenylethanone needed to form 5.00 g of the 2,4-dinitrophenylhydrazone assuming a 90.0% yield. The density of phenylethanone is 1.03 g cm-3. Give your answer to 3 significant figures. Answer                              [4] 13616.08RRR [Turn over (d) Ketones react with hydroxylamine to form an oxime as shown by the general equation below. C O R1 R2 OH H2O NH2OH C N R1 R2 ketone oxime When 0.8764 g of a ketone was treated with excess hydroxylamine it produced 1.103 g of an oxime. Calculate the relative molecular mass of the ketone. Answer                              [2]

13616.08RRR 14 The table shows the names and boiling points of four carboxylic acids with molecular formula C5H10O2. They are structural isomers. Name Boiling point /°C 2,2-dimethylpropanoic acid 164 2-methylbutanoic acid 176 3-methylbutanoic acid 177 pentanoic acid 186 (a) (i) Define the term structural isomers. [1] (ii) Explain the difference in the boiling point of 2,2-dimethylpropanoic acid and pentanoic acid. [2] (b) Pentanoic acid may be formed by the acid catalysed hydrolysis of methyl pentanoate. (i) Write the equation for this reversible reaction. [1] 13616.08RRR [Turn over (ii) A different product is formed if the hydrolysis of methyl pentanoate is carried out using dilute sodium hydroxide solution. Name the different product formed and state an advantage of the base catalysed hydrolysis of an ester rather than acid catalysed hydrolysis. [2] 13616.08RRR (c) 2-methylbutanoic acid can be prepared in a two-step synthesis. Br Step 1 Step 2 OH O OH 1-bromo-2-methylbutane 2-methylbutan-1-ol 2-methylbutanoic acid (i) State the name of the reagent and the reaction conditions required to carry out Step 1 of the synthesis. [2] (ii) State the type of reaction occurring in Step 2. [1] (iii) 2-methylbutanoic acid is reduced using excess lithium tetrahydridoaluminate(III). Write the equation for this reaction. [2] 13616.08RRR [Turn over (d) 2,2-dimethylpropanoic acid reacts with phosphorus(V) chloride to form the acyl chloride, pivaloyl chloride. This acyl chloride is used in the manufacture of insecticides and pesticides. (i) Write the equation for this reaction. [1] (ii) State two observations for the reaction between phosphorus(V) chloride and 2,2-dimethylpropanoic acid. [2]

13616.08RRR 15 Palm oil is used in many food products and cosmetics. (a) The fat molecule below is found in palm oil. The fatty acid in this fat is palmitic acid. (CH2)14CH3 H2C H2C C O HC (CH2)14CH3 C O (CH2)14CH3 C O O O O (i) Write an equation for the complete combustion of one mole of this fat molecule. [2] (ii) Explain whether the fat is saturated or unsaturated based on the structure. [1] (b) The fat undergoes the reaction below with ethanol. The products are labelled A and B. (CH2)14CH3 H2C H2C C O HC (CH2)14CH3 C O (CH2)14CH3 C O O O O H2C H2C OH HC OH OH 3CH3CH2OH 3CH3CH2O (CH2)14CH3 C O A B 13616.08RRR [Turn over (i) State the IUPAC name for product A. [1] (ii) Name the process occurring in this reaction. [1] (iii) State one use for product B. [1] (iv) The IUPAC name for palmitic acid is hexadecanoic acid. State the IUPAC name for product B. [1] (v) Calculate the mass of product B produced when 125 g of the fat reacts with 30.0 g of ethanol. Answer                      g [4] 13616.08RRR (c) A second fat found in palm oil is shown below. This fat may be catalytically hydrogenated. H2C H2C C O HC C O C O O O O (i) Name the catalyst used in catalytic hydrogenation. [1] (ii) Explain why fats such as this are hydrogenated. [1] 13616.08RRR BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13616.08RRR 16 Lithium tetrahydridoaluminate(III) may be prepared by the reaction of lithium hydride with aluminium hydride. (a) Write an equation for this reaction. [1] (b) The incomplete Born–Haber cycle diagram below is for lithium hydride. LiH(s) (i) Complete the diagram. [5] 13616.08RRR (ii) Using the values in the table below, calculate the bond enthalpy of hydrogen. Enthalpy change ∆H O — /kJ mol-1 Enthalpy of formation of lithium hydride −91 Enthalpy of atomisation of lithium +159 First ionisation energy of lithium +520 First electron affinity of hydrogen −72 Lattice enthalpy of lithium hydride +916 Answer                      kJ mol-1 [3] [Turn over 13616.08RRR (c) Lithium hydride reacts vigorously with water producing lithium hydroxide and hydrogen gas. The equation for the reaction is: LiH  +  H2O  →  LiOH  +  H2 The reaction is an acid-base reaction. (i) Write an ionic equation for this reaction. [1] (ii) State and explain the role of water in the reaction in terms of the Brønsted– Lowry theory of acids and bases. [2] THIS IS THE END OF THE QUESTION PAPER 13616.08RRR BLANK PAGE DO NOT WRITE ON THIS PAGE 13616.08RRR BLANK PAGE DO NOT WRITE ON THIS PAGE 13616.08RRR BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE ACH14/10 278229 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13622.06R 10 Which one of the following is the formula of copper(II) arsenate(V)? A CuAsO4 B Cu2AsO4 C Cu(AsO4)2 D Cu3(AsO4)2 Answer               [1] 13622.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over 13622.06R Section B Answer all five questions in the spaces provided. 11 Small molecules which combine to form a polymer are called monomers. (a) The repeating unit of a polymer called nylon-6,6 is shown below. O H N H O N nylon-6,6 (i) State the IUPAC names of two monomers used to form this polymer. [2] (ii) State two different terms which may be used to describe the type of polymer shown. [2] (iii) Explain why the polymer is referred to as nylon-6,6. [1] (iv) A section of nylon-6,6 contains 240 of the repeating unit shown above. Calculate the relative formula mass of this section of polymer. Answer [1] 13622.06R [Turn over (v) Nylon is a biodegradable polymer. Define the term biodegradable and explain why nylon is biodegradable. [2] (vi) Explain why nylon-6,6 melts at a higher temperature than a polymer such as polythene. [2] (b) Hydroxyethanoic acid can form a polymer. (i) Draw the structural formula of the organic molecule formed from the polymerisation of three hydroxyethanoic acid molecules in acidic conditions. [2] (ii) Name the functional group formed when hydroxyethanoic acid undergoes polymerisation. [1]

13622.06R 12 Many inorganic reactions involve the production of a gas or the formation of a precipitate. (a) A series of reactions occurs when a piece of solid barium is added to a solution containing copper(II) sulfate. Bubbles of hydrogen gas are formed in the solution. A white precipitate and a blue precipitate are both produced. (i) Write an equation for barium reacting with water in the solution. [1] (ii) Write ionic equations for the reactions which occur to produce both precipitates. Identify the white precipitate and the blue precipitate. [4] 13622.06R [Turn over (b) The following tests were carried out on solutions labelled A, B and C and the results recorded in the table. Solution Test A B C Add silver nitrate solution white precipitate yellow precipitate no change Add hydrochloric acid no effervescence no effervescence effervescence Add ammonia solution green precipitate which dissolved in excess ammonia solution to form a blue solution blue precipitate which dissolved in excess ammonia solution to form a yellow solution no observable change (i) Write the formulae for the following which are highlighted in bold in the table. White precipitate Gas which causes effervescence Green precipitate Yellow solution [4] (ii) Identify A and B. A B [2] (iii) C cannot be fully identified from the tests carried out. Suggest one possible identity for C and describe another test which could be carried out to identify it more fully. [2]

13622.06R 13 Some standard electrode potentials are given below. Half-equation for standard electrode potential EO — /V V3+(aq) + e- ⇌ V2+(aq) -0.26 SO2 4 -(aq) + 4H+(aq) + 2e- ⇌ SO2(g) + 2H2O(l) +0.17 VO2+(aq) + 2H+(aq) + e- ⇌ V3+(aq) + H2O(l) +0.32 Cu2+(aq) + 2e- ⇌ Cu(s) +0.34 I2(aq) + 2e- ⇌ 2I-(aq) +0.54 VO+ 2(aq) + 2H+ (aq) + e- ⇌ VO2+(aq) + H2O(l) +1.00 Cl2(g) + 2e- ⇌ 2Cl-(aq) +1.36 (a) VO+ 2 in acidic solution can be reduced to VO2+ by iodide ions. (i) Write an ionic equation for the reaction. [2] (ii) Calculate the emf for the reaction in (a)(i). Answer [1] 13622.06R [Turn over (b) A solution containing 131 mg of (VO2)2SO4 is acidified using an excess of sulfuric acid and mixed with a solution containing 441 mg of VSO4. The following reaction occurs. (VO2)2SO4(aq)  +  4H2SO4(aq)  +  4VSO4(aq)  →  3V2(SO4)3(aq)  +  4H2O(l) (i) Complete the table, giving the colour of the vanadium compounds in solution. Vanadium compound Colour (VO2)2SO4(aq) VSO4(aq) V2(SO4)3(aq) [3] (ii) Calculate the mass, in mg, of V2(SO4)3 which will be present in the solution when the reaction is complete. Answer mg [4] (iii) Identify an oxidising agent from the table of standard electrode potentials which would oxidise vanadium from the +2 to the +4 oxidation state but not to the +5 oxidation state. [1] 13622.06R (c) Describe how the standard electrode potential of the Cu2+/Cu half-cell could be measured using a standard hydrogen electrode. State the conditions needed. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 13622.06R [Turn over (d) A hydrogen-oxygen fuel cell may operate in acidic or alkaline conditions. The standard electrode potentials involved in the alkaline hydrogen-oxygen fuel cell are: EO — / V Electrode 1: 2H2O(l)  +  2e-  ⇌  H2(g)  +  2OH-(aq) -0.83 Electrode 2: O2(g)  +  2H2O(l)  +  4e-  ⇌  4OH-(aq) +0.40 (i) State and explain which electrode (1 or 2) would be the negative electrode. [1] (ii) Calculate the emf of the alkaline hydrogen-oxygen fuel cell. Answer [1] (iii) Write an overall equation for the reaction occurring in the cell. [1] (iv) Complete the conventional cell representation of the alkaline hydrogen- oxygen fuel cell. Pt(s)    H2(g)    OH-(aq)    H2O(l)    O2(g)    H2O(l)    OH-(aq)    Pt(s) [2] (v) State one environmental advantage of using a hydrogen-oxygen fuel cell. [1] 13622.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf)

13622.06R [Turn over 14 Aspirin, C9H8O4, may be synthesised in the laboratory using the reaction of salicylic acid with excess ethanoic anhydride. The equation for the reaction is given below. salicylic acid C O OH OH ethanoic anhydride C O C O H3C H3C O aspirin C O O OH ethanoic acid C O CH3 C O HO H3C (a) State the IUPAC name for salicylic acid. [1] (b) State the IUPAC name and draw the structural formula of another compound which will react with salicylic acid to form aspirin. Explain why ethanoic anhydride is used in preference to this compound. [3] (c) Identify the ion which causes the peak at an m/z ratio of 43 in the mass spectrum of ethanoic anhydride. [1] 13622.06R (d) State the approximate chemical shifts, peak integration and any splitting patterns observed in the 1H nmr spectrum of ethanoic acid. chemical shift: peak integration: splitting pattern: [3] (e) Both the - COOH group and the - OH group in salicylic acid can ionise in solution. (i) Write an equation for the ionisation of salicylic acid in which both of these groups are ionised. [1] 13622.06R [Turn over (ii) The synthesis of aspirin may be monitored using iron(III) chloride solution. The iron(III) ion forms a purple complex with the completely ionised salicylic acid. This complex is shown below. O O C O OH2 OH2 OH2 OH2 Fe Write an ionic equation for the formation of the complex from an aqueous solution of iron(III) ions and the ionised salicylic acid. [1] (iii) State the co-ordination number and shape of the complex in (e)(ii). co-ordination number shape [2] 13622.06R (f) Thin-layer chromatography (TLC) may also be used to monitor the progress of the synthesis of aspirin in the laboratory. The solvent used is ethyl ethanoate. The chromatogram is dried thoroughly and developed using an alkaline solution of potassium manganate(VII) which stains the TLC plate purple. After strong heating of the TLC plate, most organic compounds show as a yellow/brown spot due to the presence of a mixture of green manganate(VI) ions, MnO2 4 -, and black manganese(IV) oxide. The Rf values for the reactants and products are shown below. Rf salicylic acid aspirin ethanoic anhydride ethanoic acid 0.315 0.800 0.545 0.380 (i) Write a half-equation for the conversion of manganate(VII) to manganate(VI). [1] (ii) Suggest the type of reaction which organic compounds undergo in the presence of alkaline potassium manganate(VII). [1] 13622.06R [Turn over (iii) Describe, giving experimental details, how TLC can be carried out on a sample of the reaction mixture and the Rf values calculated and used to determine if the reaction is complete. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 13622.06R (g) 4.50 g of a sample of impure solid aspirin were mixed with an excess of sodium hydroxide in solution (40.0 cm3 of 1.25 mol dm-3). The mixture was heated and diluted to 250.0 cm3 using deionised water in a volumetric flask. A 25.0 cm3 sample of the solution was titrated against 0.140 mol dm-3 hydrochloric acid using phenolphthalein indicator. 14.3 cm3 of hydrochloric acid were required. Aspirin reacts with sodium hydroxide according to the equation: C9H8O4  +  2NaOH  →  C7H5O3Na  +  CH3COONa  +  H2O (i) State the colour change observed at the end point of the titration. [1] (ii) Name the two types of reaction occurring when sodium hydroxide reacts with aspirin. [2] (iii) Calculate the mass of aspirin in the sample. Give your answer to 3 significant figures. Answer g [5] 13622.06R [Turn over (iv) The manufacturer’s given value for the percentage of aspirin in the sample was 65%. Calculate the percentage of aspirin in the sample from the titration. Answer % [1] (v) Suggest why the value calculated in (g)(iv) may be different to the manufacturer’s given value. [1] (h) Aspirin is metabolised in the liver to form gentisic acid which is excreted by the kidneys in urine as it is more soluble in water than aspirin. gentisic acid C O HO OH OH (i) Suggest the IUPAC name of gentisic acid. [1] (ii) Explain why gentisic acid is more soluble in water than aspirin. [2]

13622.06R 15 Dopamine is a neurotransmitter in the human body. It is synthesised from the amino acid phenylalanine via another amino acid, tyrosine, and L-DOPA. NH2 O OH OH NH2 O HO phenylalanine tyrosine OH NH2 O L-DOPA NH2 HO HO HO HO dopamine Reaction A Reaction C Reaction B (a) Suggest the IUPAC name for phenylalanine. [2] (b) Draw the structure of a dipeptide formed between phenylalanine and glycine. Circle the peptide group. [3] 13622.06R (c) Phenylalanine reacts with nitrous acid. (i) Name the reagents used to prepare nitrous acid. [1] (ii) Write an equation for the reaction of nitrous acid with phenylalanine. [2] (iii) What is observed during the reaction of nitrous acid with phenylalanine? [1] (d) Reaction C is a decarboxylation reaction. (i) Suggest what is meant by decarboxylation. [1] (ii) Suggest the name of the inorganic product of this reaction. [1] (e) (i) Explain why dopamine is not optically active. [1] [Turn over 13622.06R (ii) Write an equation for the reaction of excess dopamine with sulfuric acid. [2] (f) Dopamine may be synthesised in the laboratory from (3,4-dihydroxyphenyl)ethanoic acid. Step 1 OH OH H2C OH C O OH OH H2C NH2 OH OH H2C H2 C NH2 C O OH OH H2C C N Step 2 Step 3 Complete the table below to give the reagents and type of reaction for Steps 2 and 3. Step Reagent(s) Type of reaction 2 3 [4] 13622.06R BLANK PAGE DO NOT WRITE ON THIS PAGE THIS IS THE END OF THE QUESTION PAPER Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE ACH24/9 278231 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13623.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Friday 5 May 2023. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before Friday 5 May 2023. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while they are on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

13623.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger themselves or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification needs to be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 13623.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Chemistry Practical Booklet A [ACH31] Thursday 11 May 2023 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number

13618.06R 12 Concentrated sulfuric acid reacts with the solids, sodium chloride, sodium bromide and sodium iodide. Concentrated sulfuric acid is a source of sulfate ions. (a) Give the systematic name of the sulfate ion. [1] (b) The reaction between concentrated sulfuric acid and solid sodium chloride is not a redox reaction. One of the products is hydrogen chloride. (i) Write an equation for this reaction. [1] (ii) Describe a test which would indicate the presence of hydrogen chloride. [2] (c) During the reaction between concentrated sulfuric acid and solid sodium bromide, hydrogen bromide is formed and oxidised by the acid. Write an equation for oxidation of hydrogen bromide by concentrated sulfuric acid. [2] (d) Iodide ions are stronger reducing agents than bromide ions. (i) Define reducing agent. [1] (ii) Suggest why iodide ions are stronger reducing agents than bromide ions. [1] 13618.06R [Turn over (e) When concentrated sulfuric acid is added to solid sodium iodide, iodine and three sulfur containing products are formed. (i) Determine the oxidation state of sulfur in each of the following sulfur containing products. SO2 S H2S [2] (ii) What observation would suggest the formation of H2S in this reaction? [1] (iii) What observation would suggest the formation of sulfur in this reaction? [1] (iv) Complete the half-equation for the formation of H2S. SO2 4 -      +      H+      +        →    H2S      +      H2O [2] (v) Write a half-equation for the formation of iodine. [1] (vi) Combine the half-equations in (e)(iv) and (e)(v) to give a balanced redox equation. [1]

13618.06R 13 Elements and compounds show different types of bonding and structure. (a) Describe the bonding and structure of carbon (graphite) and oxygen and explain the difference in the melting points of the two substances. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 13618.06R [Turn over (b) Carbon (graphite) reacts with oxygen and with ozone (O3). Both reactions form carbon dioxide. (i) Write an equation for the reaction of carbon (graphite) with ozone. [1] (ii) Describe a chemical test for carbon dioxide. [1] (iii) Explain why carbon dioxide is non-polar. [2] (c) Carbon dioxide reacts with potassium hydroxide to form potassium carbonate. Potassium carbonate is an ionic compound which melts at 891° C and is very soluble in water. (i) State how you could show experimentally that potassium carbonate is an ionic compound based on its physical properties. [1] (ii) Write an equation for the formation of potassium carbonate from carbon dioxide and potassium hydroxide. [1] 13618.06R (iii) Describe how you would carry out a flame test on a sample of solid potassium carbonate to show the presence of potassium ions. [3] 13618.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13618.06R 14 Ethane (CH3CH3) and methylamine (CH3NH2) have similar relative molecular masses. (a) (i) Draw a dot and cross diagram to show the bonding in a molecule of methylamine. [1] (ii) State the value for the H C H bond angles in a methylamine molecule. [1] (iii) Suggest and explain the shape around the nitrogen atom in a methylamine molecule. [3] 13618.06R [Turn over (b) (i) Define electronegativity. [1] (ii) Show the polarity of the N H bond below, using partial charges. N H [1] (iii) Predict which of the compounds, ethane or methylamine, has the higher boiling point. Explain the difference in boiling points between these two compounds. [3] 13618.06R (c) Methylamine is a weak base and a solution of methylamine reacts with strong acids to form the methylammonium ion (CH3NH3 +). (i) Write an equation for the reaction of methylamine with sulfuric acid to form methylammonium sulfate. [2] (ii) Explain, with reference to the type of bond formed, how a methylamine molecule forms a methylammonium ion. [2] (iii) Draw a diagram to show two hydrogen bonds which can form between one methylamine molecule and two water molecules. Show all lone pairs. [2] 13618.06R BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13618.06R 15 Sodium hydroxide solution is used in precipitation reactions and in titrations. (a) When a sample of 175 cm3 of a 0.100 mol dm-3 solution of sodium hydroxide is added to 125 cm3 of a 0.100 mol dm-3 solution of magnesium chloride, magnesium hydroxide forms as a white precipitate. MgCl2  +  2NaOH  →  Mg(OH)2  +  2NaCl (i) Write an ionic equation, including state symbols, for this reaction. [2] (ii) Calculate the maximum mass of magnesium hydroxide which could form. Give your answer to 3 significant figures. Answer                         [4] 13618.06R (b) In a titration, 25.0 cm3 of sulfuric acid were titrated using 0.18 mol dm-3 sodium hydroxide solution. The table below shows the titration values obtained. The mean titre was calculated to be 21.2 cm3. Rough Accurate 1 Accurate 2 Initial burette reading /cm3 1.5 24.9 Final burette reading /cm3 23.4 44.5 Titre /cm3 21.3 (i) Complete the table. [3] (ii) Calculate the concentration of the sulfuric acid in g dm-3. Give your answer to an appropriate number of significant figures. Answer                         g dm-3 [4] (iii) Name a suitable indicator for this titration and state the colour change observed at the end point. Indicator: Colour change: [2] THIS IS THE END OF THE QUESTION PAPER 13618.06R 13618.06R BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE SCH14/7 276813 Examiner Number For Examiner’s use only Question Number Marks Section A 1–10 Section B 11 12 13 14 15 Total Marks

4   3 This question is about compounds containing elements from Group 7. (a) Which change occurs when concentrated sulfuric acid is added to potassium bromide? (1) A bromide ions oxidise sulfuric acid forming sulfur B bromide ions oxidise sulfuric acid forming sulfur dioxide C bromide ions reduce sulfuric acid forming sulfur D bromide ions reduce sulfuric acid forming sulfur dioxide (b) Chemists can test for the presence of bromide ions in solution by adding a small amount of acidified silver nitrate solution. The solubility of the precipitate in aqueous ammonia is then tested. (i) Which statement is correct for bromide ions? (1) A a white precipitate forms that dissolves in concentrated ammonia only B a white precipitate forms that dissolves in both dilute and concentrated ammonia C a cream precipitate forms that dissolves in concentrated ammonia only D a cream precipitate forms that dissolves in both dilute and concentrated ammonia (ii) Give a reason why the silver nitrate must be acidified. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Explain which acid needs to be used to acidify the silver nitrate solution and why other acids are unsuitable. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 5   (c) Iodine trichloride forms a dimer, I2Cl6 , in the solid state. When molten, it is suggested that it breaks down as shown. I2Cl6  ICl2 + + ICl4 – (i) Draw a labelled diagram of a simple experiment to confirm this dissociation has occurred, stating the positive result. (2) Result ................................................................................................................................................................................................................................................................... (ii) What is the shape of the ICl4 – ion? (1) A octahedral B square planar C tetrahedral D trigonal bipyramidal (iii) The equilibrium position for the dissociation of molten I2Cl6 lies to the left. I2Cl6  ICl2 + + ICl4 – What is the most likely numerical value of Kc for this equilibrium? (1) A 1.0 × 106 B 5.0 × 103 C 1.0 D 5.0 × 10–3 (Total for Question 3 = 9 marks)

6   4 The graph shows the melting temperatures of some elements in Period 3. Na Mg Al Si P 1800 1600 1400 1200 1000 800 600 400 200 0 Melting temperature / K Elements in Period 3 Explain the variations in melting temperature across the period in terms of the structure and bonding in these elements. 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(Total for Question 4 = 6 marks)

8   5 This question is about the decomposition of dinitrogen tetroxide. The reaction eventually reaches equilibrium. N2O4(g)  2NO2(g) colourless brown (a) The table shows values of ΔG at different temperatures for this reaction. Temperature / K ΔG / kJ mol–1 350 –4.0 400 –13 450 –22 500 –31 550 –40 (i) Plot a graph of ΔG against temperature. (2) ΔG / kJ mol–1 Temperature / K Turn over 9   (ii) Calculate the entropy change of the system, ΔSsystem , in J K–1 mol–1, using your straight line from the graph in (a)(i) and the equation shown. ΔG = –TΔSsystem + ΔH (3) (iii) What feature of the graph in (a)(i) gives the enthalpy change of the reaction? (1) A intercept of the x‑axis B (intercept of the x‑axis) × –1 C intercept of the y‑axis D (intercept of the y‑axis) × –1 10   (b) What happens to the position of the equilibrium and the colour of the mixture when the pressure is increased? The volume of the system remains constant. N2O4(g)  2NO2(g) colourless brown (1) A B C D (Total for Question 5 = 7 marks) Position of equilibrium Change in colour moves to the right mixture gets lighter moves to the right mixture gets darker moves to the left mixture gets lighter moves to the left mixture gets darker Turn over 11   6 Benzoic acid is a weak acid found in cranberries. O C OH C6H5COOH – benzoic acid (a) Which of these answers identifies the types of species present when benzoic acid is mixed with nitric acid? [Ka of benzoic acid = 6.3 × 10–5 mol dm–3;          Ka of nitric acid = 40 mol dm–3] (1) C6H5COOH + HNO3  C6H5COOH2 + + NO3 – A B C D (b) The ionic salts sodium benzoate and potassium benzoate are both used as food preservatives. Explain why the melting temperature of sodium benzoate is higher than the melting temperature of potassium benzoate. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... acid base acid base acid base base acid base acid base acid base acid acid base 12   (c) The value of Ka for benzoic acid = 6.28 × 10–5 mol dm–3. (i) Write the expression for the acid dissociation constant, Ka , of benzoic acid. (1) (ii) Calculate the mass of benzoic acid needed to prepare 250 cm3 of a solution with a pH = 3.51 (4) Turn over 13   (d) Weak acids such as benzoic acid can be neutralised by sodium hydroxide solution. C6H5COOH(aq) + NaOH(aq) → C6H5CO2Na(aq) + H2O(l) (i) Which of these could be used to show the end‑point of a titration of benzoic acid with sodium hydroxide solution? (1) A bromothymol blue B litmus C methyl orange D phenolphthalein (ii) Another weak acid found in cranberries is quinic acid, C6H7(OH)4COOH. It is neutralised by sodium hydroxide solution in a similar way to benzoic acid. A 25.0 cm3 sample of 0.500 mol dm–3 quinic acid solution was neutralised under standard conditions in a polystyrene cup using 25.0 cm3 of 0.800 mol dm–3 of sodium hydroxide solution. This resulted in a temperature rise of 2.9 °C. Calculate the standard enthalpy change of neutralisation, ΔneutH d, of quinic acid in kJ mol–1. [Assume the density of both solutions is 1.0 g cm–3. specific heat capacity of solution formed = 4.18 J g–1 °C–1] (3) 14   (iii) The standard enthalpy change of neutralisation of the weak acid HCN by sodium hydroxide is –11.7 kJ mol–1 while that of the strong acid HCl is –57.9 kJ mol–1. Explain the difference between these values. 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(Total for Question 6 = 14 marks) Turn over 15   7 This question is about chromium and chromium compounds. (a) Naturally occurring chromium has four isotopes, 50Cr, 52Cr, 53Cr and 54Cr. State what is meant by the term isotopes. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Both chromium and calcium can form ions with a +2 charge. (i) Complete the electronic configuration of a Cr2+ ion. (1) 1s2 . .............................................................................................................................................................................................................................................. (ii) Explain which of chromium or calcium most easily forms a +2 ion using all of the data in the table. Element Atomic number 1st ionisation energy / kJ mol–1 2nd ionisation energy / kJ mol–1 Metallic radius / nm Chromium 24 653 1592 0.129 Calcium 20 590 1145 0.197 (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 16   (c) Chromium(III) sulfate, Cr2(SO4)3 , dissolves in water to form the complex ion [Cr(H2O)6]3+(aq). (i) State the colour of this complex ion. (1) .................................................................................................................................................................................................................................................................................... (ii) Explain why the aqueous solution of this complex ion has an acidic pH by considering the interaction between the metal ion and the ligands. 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Turn over 17   (d) A student researching the role of dichromate(VI) ions, Cr2O7 2– , as an oxidising agent made the statement shown. ‘Standard electrode potential data shows that it is never feasible for a 1.00 mol dm–3 solution of potassium dichromate(VI) to oxidise the chloride ions in hydrochloric acid.’ Comment on this statement using the data and equilibria shown. Equilibrium 1 Cr2O7 2–(aq) + 14H+(aq) + 6e–  2Cr3+(aq) + 7H2O(l) E d = +1.33 V Equilibrium 2 Cl2(aq) + 2e–  2Cl–(aq) E d = +1.36 V (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 7 = 13 marks) 18   8 * Transition metals and their compounds can act as catalysts in many reactions such as the ones shown: • platinum, Pt, in the catalytic converters of vehicles • manganese(II) ions, Mn2+(aq), in the oxidation of ethanedioate ions, C2O4 2–(aq), by manganate(VII) ions, MnO4 –(aq). Compare and contrast the role of the catalysts in these reactions. 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(Total for Question 8 = 6 marks)

20   9 This question is about silver compounds. (a) The diagram shows a Born–Haber cycle for the formation of silver(I) oxide, Ag2O. All quantities are measured in kJ mol–1. 2Ag+(g) + Ag2O(s) O2–(g) +798 O(g) 2Ag(s) + ½O2(g) ΔatH d(Ag(s)) × 2 +731 × 2 –141.1 –31 +249.2 –2969 (i) Complete the diagram by adding appropriate species and state symbols to the empty boxes. (2) (ii) Explain why the value for the first electron affinity of oxygen is negative and the value for the second electron affinity is positive. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 21   (iii) Calculate a value for the standard enthalpy change of atomisation of silver, ΔatH d, using the Born–Haber cycle. (3) 22   (b) Another silver compound is silver chloride, AgCl. Values for its lattice energy can be found by experiment or by theoretical calculation. Compound Experimental lattice energy / kJ mol–1 Theoretical lattice energy / kJ mol–1 Silver chloride –905 –833 (i) Give two assumptions used in the model to calculate the theoretical lattice energy. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain the difference in the two values for the lattice energy of silver chloride by considering the possible bonding models. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 9 = 13 marks) Turn over 23   10 Manganese compounds can be used to determine the amounts of dissolved molecular oxygen in water samples. (a) Draw the dot‑and‑cross diagram for an oxygen molecule, O2 . Show outer shell electrons only. (1) (b) The solubility of oxygen in water under standard conditions is 1.22 × 10–3 mol dm–3. Comment on this value by considering the type and strength of the intermolecular forces in • pure water • pure oxygen • a mixture of water and oxygen. Detailed descriptions of the forces involved are not required. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 24   (c) The amount of dissolved oxygen in a sample of river water was found using the process outlined. • excess alkaline manganese(II) sulfate, MnSO4 , was added to a 150 cm3 sample of river water • the Mn2+ ions reacted with the dissolved oxygen forming a precipitate of manganese(IV) oxide hydroxide 2Mn2+(aq) + O2(aq) + 4OH–(aq) → 2MnO(OH)2(s) • the precipitate was then dissolved using excess sulfuric acid, forming Mn4+(aq) ions MnO(OH)2(s) + 4H+(aq) → Mn4+(aq) + 3H2O(l) • excess potassium iodide solution was then added, forming iodine Mn4+(aq) + 2I–(aq) → Mn2+(aq) + I2(aq) • the liberated iodine was then titrated with sodium thiosulfate solution, Na2S2O3(aq), of concentration 0.00518 mol dm–3 I2(aq) + 2S2O3 2–(aq) → 2I–(aq) + S4O6 2–(aq) • the mean volume of the titre of Na2S2O3(aq) was 34.20 cm3. (i) Calculate the concentration of dissolved oxygen in the sample of river water, in g dm–3. (5) 25   You may use this space to continue your answer to 10(c)(i). (ii) The concentration of oxygen in water is often expressed in parts per million (ppm), where 1 ppm equals 1 g of solute dissolved in 1 × 106 g of solvent. Calculate the concentration of the oxygen in the sample of river water in ppm. Assume the density of the river water is 1.00 g cm–3. (1) Turn over 26   (d) Some data is shown for electrode systems involving the Mn3+(aq) ion. Half‑cell Electrode system E d / V A MnO2(s) + 4H+(aq) + e–  Mn3+(aq) + 2H2O(l) +0.95 B Mn3+(aq) + e–  Mn2+(aq) +1.51 Explain why Mn3+ ions are unstable in aqueous solution. Include an equation and the type of reaction that occurs. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 10 = 15 marks) TOTAL FOR PAPER = 90 MARKS 27   BLANK PAGE 28  

4   2 This question is about alcohols. (a) Ethanol is a fuel and can be made by either the fermentation of carbohydrates or the hydration of ethene. How is the ethanol formed by the fermentation of carbohydrates classified? (1) A a biofuel and non‑renewable B a biofuel and renewable C a fossil fuel and non‑renewable D a fossil fuel and renewable (b) Write the equation for the complete combustion of methanol. State symbols are not required. (1) (c) Identify, by name or formula, the reagent(s) needed to convert propan‑1‑ol into 1‑iodopropane. (1) .................................................................................................................................................................................................................................................................................... (d) A sample of pure propan‑2‑ol is analysed using infrared and 13C NMR spectroscopy. (i) Which of these sets of wavenumber ranges, in cm–1, will be seen in the infrared spectrum of propan‑2‑ol? (1) A 1485 – 1365, 2962 – 2853 and 3300 – 2500 B 1485 – 1365, 2962 – 2853 and 3750 – 3200 C 1669 – 1645, 2962 – 2853 and 3750 – 3200 D 1740 – 1720, 3300 – 2500 and 3750 – 3200 (ii) State the number of peaks in the 13C NMR spectrum of propan‑2‑ol. (1) .................................................................................................................................................................................................................................................................................... Turn over 5   (e) The equation for the oxidation of ethanol by acidified dichromate(VI) ions is shown. 3CH3CH2OH + 2Cr2O7 2– + 16H+ → 3CH3COOH + 4Cr3+ + 11H2O Deduce the half‑equation for the oxidation of ethanol to ethanoic acid. State symbols are not required. (1) (Total for Question 2 = 6 marks)

6   3 This question is about the molar masses of three organic compounds, X, Y and Z. (a) The accurate relative atomic masses, Ar , of four of the elements that could be present in an organic compound are shown. Element Ar hydrogen, H 1.0078 carbon, C 12.0000 nitrogen, N 14.0031 oxygen, O 15.9949 The mass spectrum of organic compound X gives a molecular ion peak at m/z = 60.0323 What is compound X? (1) A ethanamide, CH3CONH2 B ethanoic acid, CH3COOH C trimethylamine, (CH3)3N D urea, CO(NH2)2 (b) 9.90 g of a gaseous organic compound, Y, occupies a volume of 5.40 dm3 at room temperature and pressure (r.t.p.). Calculate the molar mass of the compound Y. [molar gas volume at r.t.p. = 24.0 dm3 mol–1] (2) Turn over 7   (c) A quantity of a volatile organic liquid, Z, is placed in a 60.0 cm3 flask and heated to 95.0°C. When all the liquid has vaporised, the flask is sealed. Mass of vapour = 0.170 g Pressure = 100.6 kPa Gas constant (R) = 8.31 J mol–1 K–1 Calculate the molar mass of compound Z, giving your answer to an appropriate number of significant figures. Assume there was no air left in the flask once the liquid Z had vaporised. (4) (Total for Question 3 = 7 marks)

8   4 This question is about some hydrocarbons. (a) A 2.50 g sample of a hydrocarbon gave 7.59 g of carbon dioxide on complete oxidation. Calculate the empirical formula of the hydrocarbon. (4) Turn over 9   (b) Benzene and ethene react with bromine under different conditions but both reactions involve an electrophile. (i) An electrophile is a substance that (1) A accepts a pair of electrons B accepts an unpaired electron C donates a pair of electrons D donates an unpaired electron (ii) Explain why benzene is resistant to bromination but ethene reacts readily with bromine at room temperature. 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(Total for Question 4 = 9 marks)

10   5 Nitrogen monoxide reacts with oxygen to form nitrogen dioxide. 2NO(g) + O2(g) → 2NO2(g) The rate is proportional to the concentration of oxygen and to the square of the concentration of nitrogen monoxide. (a) The rate of this reaction can be determined by measuring the change in the total gas pressure. (i) Give a reason why this method can be used in this reaction. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) State two factors, other than initial amounts of reactants, that must be kept constant for this method to work. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 11   (b) The graph shows four lines of a quantity Y plotted against a quantity X. Y X P Q R S (i) Which line shows the relationship between the concentration of nitrogen monoxide (Y) and time (X)? (1) A line P B line Q C line R D line S (ii) Which line shows the relationship between rate (Y) and concentration of oxygen (X)? (1) A line P B line Q C line R D line S (c) The rate of this reaction is z mol dm–3 s–1 under certain conditions. The concentration of nitrogen monoxide is doubled and the concentration of oxygen is halved. All other conditions remain the same. What will be the new rate of reaction in mol dm–3 s–1? (1) A z/2 B z C 2z D 4z 12   (d) Nitrogen monoxide is formed in car engines. It is removed by the catalytic converter in the car exhaust. 2NO(g) + 2CO(g) → 2CO2(g) + N2(g) The reaction is exothermic and the most active catalyst is platinum. (i) Complete the labelled reaction profile for the catalysed reaction. (3) Enthalpy 2NO(g) + 2CO(g) Progress of reaction (ii) Catalysts, such as platinum, are very expensive. Explain an economic benefit of using a catalyst in an industrial process. 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(Total for Question 5 = 10 marks) Turn over 13   6 Iodine reacts with propanone in acidic conditions. I2(aq) + CH3COCH3(aq) CH3COCH2I(aq) + H+(aq) + I–(aq) A student was asked to investigate the kinetics of this reaction. The student predicted that the rate equation for the reaction would be rate = k[I2(aq)][CH3COCH3(aq)][H+(aq)]0 because the balanced equation shows that one molecule of iodine reacts with one molecule of propanone and the acid is a catalyst. (a) The student first determined the order of reaction with respect to iodine by keeping the concentrations of propanone and acid constant. The student used the outline procedure shown. • mix 25 cm3 of aqueous propanone with 25 cm3 of dilute sulfuric acid in a conical flask • add 25 cm3 of aqueous iodine, immediately start a stopwatch and swirl the mixture in the conical flask • use a pipette to remove a 10.0 cm3 sample of the solution and place it in a clean conical flask • add a spatula measure of sodium hydrogencarbonate and note the exact time it is added • take four more 10.0 cm3 samples of the mixture and add sodium hydrogencarbonate to each of them at regular time intervals • titrate the unreacted iodine in the samples with sodium thiosulfate solution using starch indicator. (i) State how the student could ensure that the concentrations of propanone and acid are effectively constant throughout the experiment. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why sodium hydrogencarbonate is added. 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H+(aq) 14   (b) The student obtained these results. Time / min 5 10 15 20 25 Volume of thiosulfate / cm3 15.0 13.8 12.6 11.4 10.2 (i) Give a reason why it is not necessary to calculate the concentration of iodine at each time to work out the order of reaction with respect to iodine. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Plot a graph to show that the order of reaction with respect to iodine is zero. (2) (iii) Give a reason why the graph shows that the order of reaction with respect to iodine is zero. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15   (c) Further experiments showed that the correct overall rate equation is rate = k[CH3COCH3(aq)][H+(aq)][I2(aq)]0 (i) Deduce a possible rate determining step in the mechanism of this reaction. Curly arrows are not required. (2) (ii) Data from two experiments carried out at the same temperature are shown. Experiment [CH3COCH3(aq)] / mol dm–3 [H+(aq)] / mol dm–3 [I2(aq)] / mol dm–3 Rate / mol dm–3 s–1 1 3.0 0.4 0.02 3.36 × 10–5 2 4.0 0.2 0.04 What is the rate, in mol dm–3 s–1, in Experiment 2? (1) A 2.24 × 10–5 B 3.36 × 10–5 C 4.48 × 10–5 D 8.96 × 10–5 (iii) The experiment in (a) is repeated but using aqueous bromine instead of aqueous iodine. All other conditions are kept the same. Explain how you would expect the rate of reaction of bromination of propanone to compare with the rate of iodination of propanone. Assume that the reaction between bromine and propanone in acidic conditions has the same rate equation as that between iodine and propanone in acidic conditions. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 12 marks)

16   7 This question is about carbonyl compounds. (a) Ethanal, CH3CHO, and ethanoic acid, CH3COOH, are both soluble in water but ethanoic acid has a much higher boiling temperature than ethanal. Explain these physical properties of ethanal and ethanoic acid in terms of intermolecular forces. Include a labelled diagram to show why ethanal is soluble in water. 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Turn over 17   (b) Propanal reacts with hydrogen cyanide in the presence of potassium cyanide to form 2‑hydroxybutanenitrile. C2H5 C H OH CN (i) Draw the mechanism for this reaction. Include curly arrows and any relevant lone pairs and dipoles. (4) (ii) Explain whether or not the 2‑hydroxybutanenitrile formed will be a racemic mixture. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 18   (c) Carbonyl compounds can be identified by reacting them with 2,4‑dinitrophenylhydrazine (2,4‑DNPH) to form a solid derivative. These derivatives have characteristic melting temperatures. (i) Identify the steps required to prepare a sample of a pure, dry derivative of a carbonyl compound X. (3) Carbonyl compound X Precipitate in reaction mixture Dry solid derivative Impure solid derivative Purified solid derivative 2,4‑DNPH Step 1 Step 2 Step 3 Step 1 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 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Step 3 .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 19   (ii) The melting temperature ranges of the derivatives of some carbonyl compounds that could be X are shown in the table. Carbonyl compound Melting temperature range of derivative / °C ethanal 165 – 168 propanal 154 – 156 propanone 127 – 129 cyclohexanone 158 – 160 The melting temperature of the derivative of carbonyl compound X is 156–158 °C and X has an absorption at 1717 cm–1 in its infrared spectrum. Deduce the identity of X. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) These carbonyl compounds may also be identified using modern methods such as proton NMR spectroscopy. The structure of the pentan‑3‑one derivative formed with 2,4‑DNPH is shown. O2N N CH2 CH3 H H H H N C CH2 CH3 NO2 Label the different proton environments that would give rise to the peaks in the low resolution proton NMR spectrum. (2) (Total for Question 7 = 18 marks)

20   8 This question is about isomerism in organic compounds. (a) How many structural isomers are there with the formula C5H12? (1) A 2 B 3 C 4 D 5 (b) Propene reacts with bromine to form 1,2‑dibromopropane as the only product. Draw the mechanism for the reaction between propene and bromine. Include curly arrows and any relevant lone pairs and dipoles. (3) Turn over 21   (c) When propene reacts with a mixture of bromine and sodium chloride, it forms 1,2‑dibromopropane, 1‑bromo‑2‑chloropropane and 2‑bromo‑1‑chloropropane but no 1,2‑dichloropropane. (i) Explain, by reference to your mechanism in (b), why no 1,2‑dichloropropane forms. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why far more 1‑bromo‑2‑chloropropane forms than 2‑bromo‑1‑chloropropane. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 22   *(d) Discuss the different types of stereoisomerism that occur in organic compounds. Use only molecules A and B as examples. CHCl C(CH3)Br CH3CH(OH)COOH A B Include in your answer: • how the different types of isomerism arise • the naming of alkenes with the formula A • the properties of isomers with the formula B • diagrams of the different isomers. 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(Total for Question 8 = 14 marks)

24   9 This question is about the analysis of some organic compounds. (a) A compound A (C3H7Cl) reacts with dilute aqueous sodium hydroxide to produce B (C3H8O). B can be oxidised to C (C3H6O), which cannot be oxidised any further. A reacts with magnesium in dry ether to give D (C3H7MgCl). When carbon dioxide is passed through the solution of D, followed by acidification, E (C4H8O2) is formed. Identify the structures of A to E. (5) 25   (b) An organic compound, Q, contains carbon, hydrogen and nitrogen only. When a 1.19 g sample of the compound was heated with sodium hydroxide solution, all of the nitrogen was converted into ammonia. The ammonia was passed into 100.0 cm3 of 0.225 mol dm–3 hydrochloric acid. NH3(g) + HCl(aq) → NH4Cl(aq) 25.0 cm3 portions of the resulting solution containing unreacted hydrochloric acid required a mean titre of 15.5 cm3 of 0.100 mol dm–3 sodium hydroxide for neutralisation. Calculate the percentage of nitrogen in Q. (5) (Total for Question 9 = 10 marks) TOTAL FOR PAPER = 90 MARKS 26   BLANK PAGE 27   BLANK PAGE 28  

8   4 This question is about hydrated magnesium sulfate, MgSO4·7H2O. *(a) Devise an experimental procedure to determine the enthalpy change of solution for hydrated magnesium sulfate. MgSO4·7H2O(s) + aq → MgSO4(aq) Details of the method of calculation are not required. 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.................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 10   (b) The enthalpy changes of solution for anhydrous and hydrated magnesium sulfate were found by experiment to be MgSO4(s) + aq → MgSO4(aq) ΔrH = –63.2 kJ mol–1 MgSO4·7H2O(s) + aq → MgSO4(aq) ΔrH = +15.7 kJ mol–1 Calculate, using Hess’s law, the enthalpy change for the hydration of anhydrous magnesium sulfate. Include a sign and units in your answer. MgSO4(s) + 7H2O(l) → MgSO4·7H2O(s) (2) (c) Explain how the enthalpy change of hydration of magnesium ions in magnesium sulfate is different from the enthalpy change of hydration of calcium ions in calcium sulfate. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 10 marks) Turn over 11   5 This question is about electrochemical cells. (a) A diagram is shown of the apparatus that is used to measure the emf of a cell with a zinc/zinc(II) electrode and an acidified manganese(II)/manganate(VII) electrode system. Complete the labels Y and Z by naming the substances needed. Temperature and concentrations are not required. (3) solution of zinc nitrate (aq) salt bridge voltmeter Y ............................................................................... Z ............................................................................... ............................................................................... ............................................................................... V Zn 12   (b) Excess zinc is added to an acidified solution of sodium dichromate(VI). Some electrode data are given in the table. Electrode system E d / V Cr2+(aq) + 2e–  Cr(s) –0.91 Cr3+(aq) + e–  Cr2+(aq) –0.41 ½Cr2O7 2–(aq) + 7H+(aq) + 3e–  Cr3+(aq) + 3½H2O(l) +1.33 Zn2+(aq) + 2e–  Zn(s) –0.76 Explain, using only the data in the table, the final oxidation state of chromium that is formed when zinc is added to acidified dichromate(VI) ions. Include E d cell values where appropriate. Equations are not required. (5) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 13   (c) A cell diagram is shown. Ni(s) ½ Ni2+(aq) ½½ [NO3 –(aq) + 2H+(aq)], [NO2(g) + H2O(l)] ½ Pt(s) E d cell = +1.06 V Deduce the reduction half‑equation. State symbols are not required. (1) (d) State the direction of the electron flow in the hydrogen‑oxygen fuel cell shown. Justify your answer by reference to the redox processes in the cell. acidic electrolyte membrane hydrogen water oxygen cell load negative electrode positive electrode (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (e) State one advantage of the hydrogen‑oxygen fuel cell over the use of petrol as fuel in a vehicle. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 12 marks)

14   6 Amino acids can be separated using chromatography. (a) State how chromatography separates the components of a mixture. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) A sample of a tripeptide was hydrolysed and then placed on an ‘X’ at the bottom right‑hand corner of a piece of chromatography paper. A simplified diagram of a developed chromatogram is shown. baseline 1 solvent front 1 (i) Give a possible reason for the presence of only two spots for the tripeptide other than two amino acids have almost identical Rf values. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15   (ii) Some amino acid mixtures cannot be effectively separated in one chromatography ‘run’. The chromatography paper from the first run is dried but not developed. The chromatography paper is then rotated clockwise by 90° and placed in a different solvent. Complete the simplified diagram of the developed chromatography paper after a second ‘run’ for a tripeptide of alanine, glycine and valine by adding labelled spots for each amino acid. Amino acid Rf in solvent 1 Rf in solvent 2 alanine 0.38 0.43 glycine 0.33 0.26 valine 0.39 0.58 (3) baseline 1 baseline 2 solvent front 2 solvent front 1 16   (iii) Name a reagent that locates colourless amino acids by producing a coloured compound. (1) .................................................................................................................................................................................................................................................................................... (c) State the technique that is used in conjunction with gas chromatography (GC) when carrying out forensic testing. (1) .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 7 marks) Turn over 17   7 Hardness in water is measured in terms of the concentration of dissolved calcium compounds. Titration experiments can be carried out to determine the hardness of a water sample. (a) A pipette is used to measure a 50.0 cm3 water sample for titration. (i) Describe how to remove an air bubble from the tip of the pipette. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Calculate the maximum volume that would be obtained by using a 25.0 cm3 pipette twice to measure a total volume of 50.0 cm3. The uncertainty in each 25.0 cm3 pipette measurement is ±0.04 cm3. (1) (iii) Compare the percentage uncertainty in using a 25.0 cm3 pipette twice with using a 50.0 cm3 pipette once to measure 50.0 cm3 of water. The uncertainty in the 50.0 cm3 pipette measurement is ±0.05 cm3. (2) 18   (b) About 2 cm3 of a pH 10 buffer is added to each 50.0 cm3 water sample. (i) State whether or not a 100 cm3 measuring cylinder is suitable to measure this volume of buffer solution. Justify your answer. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) The pH 10 buffer can be made by adding solid ammonium chloride to an aqueous solution of ammonia of concentration 18.1 mol dm–3. The relevant equation is NH4 +  NH3 + H+ Ka = 5.62 × 10–10 mol dm–3 Calculate the mass of ammonium chloride that must be added to 100 cm3 of ammonia solution to make the pH 10 buffer. Assume that there is no change in the volume on the addition of ammonium chloride. (4) Turn over 19   (iii) State a necessary laboratory precaution, other than wearing a laboratory coat, gloves and goggles, that must be taken when using concentrated ammonia. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) The Eriochrome Black T indicator used in this titration forms an octahedral complex with the calcium ions in the water sample. The structure of Eriochrome Black T is shown with a calcium ion. (i) Complete the diagram to show how Eriochrome Black T forms three dative covalent or coordinate bonds with the calcium ion. (1) N O–Na+ N NO2 Ca2+ H S O O O H O (ii) State the number of water molecules needed to complete this complex. (1) .................................................................................................................................................................................................................................................................................... 20   (d) There are two types of water hardness: temporary hardness which is removed by boiling as a precipitate forms, permanent hardness which is unaffected by boiling. Levels of water hardness are expressed as the concentration of calcium ions in mg dm–3. A student carried out a series of experiments to determine the hardness of a sample of water. 50.0 cm3 samples of the water were titrated with EDTA. Further 50.0 cm3 samples of water were taken after boiling and then titrated with EDTA. (i) Name the process needed before titrating the sample of boiled water. (1) .................................................................................................................................................................................................................................................................................... (ii) The mean titre of 0.0100 mol dm–3 EDTA4– with a 50.0 cm3 water sample before boiling was 12.80 cm3. After boiling the mean titre was 5.15 cm3. There is a 1 : 1 ratio in the reaction between EDTA4– ions and Ca2+ ions. Calculate, in this water, the levels of permanent and temporary hardness in mg dm–3 of calcium ions. (6) (Total for Question 7 = 19 marks) Turn over 21   8 This question is about reaction kinetics and the Arrhenius equation. (a) Different iodine clock reactions are often used to investigate reaction kinetics. (i) The iodine clock reaction with hydrogen peroxide involves the reaction shown. H2O2 + 2I– + 2H+ → I2 + 2H2O Deduce two possible experimental techniques which could be used to monitor the progress of this reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) The iodate(V) reaction has the rate determining step IO3 – + 3HSO3 – → I– + 3HSO4 – Give a possible reason why this is the slowest step. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) The chlorate(V) reaction has the rate determining step ClO3 – + 2H+ + I– → HIO + HClO2 Deduce the rate equation for this iodine clock reaction. (1) 22   (b) The diagram shows a sketch of the Maxwell‑Boltzmann curve for the distribution of molecular energies of a reaction mixture at temperature 298 K. Number of molecules with energy E Energy E (i) Add a curve to show the distribution at a temperature of 308 K. (1) (ii) Explain why a temperature rise from 298 K to 308 K results in a large increase in the rate of reaction. Refer to the Maxwell‑Boltzmann distribution in your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 23   (c) The Arrhenius equation may be written in a logarithmic or an exponential form. ln k = – E RT a + ln A k = A e −E RT a A is a constant. (i) The rate constant, k, for the isomerisation of cyclopropane to propene was measured at various temperatures. The data obtained were used to draw the graph shown. 0 –2 –4 –6 –8 –10 1.1 × 10–3 1.2 × 10–3 1.3 × 10–3 1.4 × 10–3 ln k 1 1 T / K − Determine the activation energy, Ea , from the gradient of the graph. Include units in your answer. (3) 24   (ii) At a temperature T, the fraction of molecules with energy equal to or greater than the activation energy is given by the expression fraction of molecules = e −E RT a When a catalyst is added, the activation energy for a reaction is lowered. Explain, using calculations, why lowering the activation energy from 50 000 J mol–1 to 25 000 J mol–1 at 298 K results in a large increase in the rate of reaction. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 8 = 13 marks) Turn over 25   9 This is a question about isomers of C8H8O2 . (a) One of these isomers, methyl benzoate, is hydrolysed by alkali or by acid. (i) Hydrolysis with aqueous sodium hydroxide is followed by acidification to form benzoic acid. Give a reason why acidification is required after hydrolysis. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Write an equation, using structural formulae, for the acid hydrolysis of methyl benzoate. (1) 26   (b) Four other C8H8O2 isomers were investigated. • W and X are mono‑substituted aromatic compounds with the same functional group as methyl benzoate but only W is made from methanoic acid • Y is a mono‑substituted aromatic compound which reacts with sodium carbonate to give carbon dioxide • Z is a disubstituted aromatic compound with six peaks in its 13C NMR spectrum and forms a sweet‑smelling compound on reaction with ethanol Deduce the structures of isomers W, X, Y and Z. Justify your answers. (7) Turn over 27   .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 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.................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 28   (c) Piceol is found in the needles of Norway spruce trees. Its structure is shown. O H3C OH C (i) Piceol can be produced from the reaction of ethanoyl chloride and phenol. Assume the mechanism for the reaction with phenol is similar to that with benzene and involves the use of an aluminium chloride catalyst, which produces the electrophile [CH3C O]+. Complete the diagram, including curly arrows, to show the mechanism for this reaction to produce piceol. Include the regeneration of the catalyst. (4) O + H3C OH C (ii) Piceol can be distinguished from HOC6H4CH2CHO using simple chemical tests. Give the reagents for a chemical test, and the observation that would only be positive for piceol. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 9 = 15 marks) Turn over 29   10 The Mond Process is an industrial method of purifying nickel. (a) The first step involves the reaction of nickel oxide with hydrogen gas at 473 K. NiO(s) + H2(g) → Ni(s) + H2O(g) The nickel is not pure because the impurities also react with the hydrogen gas. Complete the electronic configuration of the Ni2+ ion. (1) 1s2 . ........................................................................................................................................................................................................................................................................... (b) The second step involves passing carbon monoxide over impure nickel at 323 K. The impurities do not react. The nickel reaction is Ni(s) + 4CO(g) → Ni(CO)4(g) ΔrH d = –191 kJ mol–1 (i) Calculate the total entropy change, ΔS d total , for this reaction. Include a sign and units in your answer. Substance S d / J mol–1 K–1 Ni(s) +29.9 CO(g) +197.6 Ni(CO)4(g) +313.4 (5) 30   (ii) Predict the sign of the Gibbs Free Energy change, ΔG, for this reaction and justify your choice. No calculation is required. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) 50.0 mol of carbon monoxide is mixed with excess impure solid nickel at 323 K in an industrial reactor. At equilibrium, 0.750 mol of carbon monoxide remains. The pressure is maintained at 1.5 atm throughout. Calculate the value of Kp at 323 K. Include units with your answer. (6) 31   (c) The final stage of the Mond Process is the thermal decomposition of the nickel carbonyl gas, Ni(CO)4 , to give pure nickel and carbon monoxide. The reaction mixture is heated to 523 K. Explain, in qualitative terms, why the entropy change of the system, ΔS d system , for this decomposition reaction is positive. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 10 = 15 marks) TOTAL FOR PAPER = 120 MARKS 32  

4   2 This question is about the double salt K2Mg(SO4)2.6H2O. A double salt is a salt containing more than one cation or more than one anion. (a) (i) Give the reason why the term relative formula mass is used, rather than relative molecular mass, when discussing K2Mg(SO4)2.6H2O. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Give the reason why relative formula mass has no mathematical units. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) What is the relative formula mass of K2Mg(SO4)2.6H2O? Use the Periodic Table as a source of data. (1) A 206.0 B 322.7 C 402.7 D 595.3 (iv) Calculate the amount of substance, in mol, in 25.0 g of K2Mg(SO4)2.6H2O. (1) Turn over 5   (b) Cations may be identified using a flame test on a solid or by the addition of aqueous sodium hydroxide to an aqueous solution containing the cation. Describe the expected results of performing these tests on K2Mg(SO4)2.6H2O. Include the observation for each cation in each test. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) The test used to show the presence of the anion in K2Mg(SO4)2.6H2O gives a white precipitate as the positive result. (i) What are the reagents used for this test? (1) A dilute hydrochloric acid and aqueous silver nitrate B dilute sulfuric acid and aqueous silver nitrate C dilute hydrochloric acid and aqueous barium chloride D dilute sulfuric acid and aqueous barium chloride (ii) Write an ionic equation, including state symbols, for the formation of the white precipitate in the test for the anion in the double salt. (1) (Total for Question 2 = 10 marks)

6   3 This question is about elements in Group 7. (a) Group 7 elements react with many metals. (i) What happens to the atoms of a metal and the Group 7 element when they react together? (1) A B C D (ii) Which is not true when calcium reacts with bromine? (1) A bromine reacts less vigorously than chlorine B during the reaction bromine oxidises the calcium C the percentage by mass of calcium in the product is 33 % D the product gives a brick‑red flame test (iii) The equation for the reaction between aluminium and bromine is shown. 2Al + 3Br2 → Al2Br6 The compound is a dimer made up of two covalently bonded monomers joined by dative covalent bonds. Complete the dot‑and‑cross diagram, showing outer shell electrons only, of this dimer. Use • for bromine electrons and × for aluminium electrons. (2) Br Al Br Br Br Br Br Al Metal Group 7 element gains electrons to form a positive ion loses electrons to form a negative ion increases in oxidation number gains electrons to form a negative ion loses electrons to form a negative ion decreases in oxidation number loses electrons to form a positive ion increases in oxidation number Turn over 7   (iv) Platinum metal reacts with fluorine to give a compound of platinum with an oxidation number of +6. Give the formula of this compound of platinum. (1) .................................................................................................................................................................................................................................................................................... (v) Chromium reacts with iodine. The only product contains 12.0 % chromium by mass. Calculate the empirical formula of the chromium iodide formed. You must show your working. (2) (b) Chlorine, bromine and iodine are three of the Group 7 elements. The bond length and bond enthalpies in molecules of these elements are shown in the table. Bond Bond length / nm Bond enthalpy / kJ mol–1 Cl Cl 0.199 243.4 Br Br 0.228 192.9 I I 0.267 151.2 (i) Explain how the trend in bond length relates to the trend in bond strength on descending the group. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 8   (ii) The relative reactivity of chlorine and iodine can be demonstrated using the reaction between one of these elements and the potassium salt of the other halogen. Describe an experiment to show how this is deduced and give the expected observation for the reaction that occurs. Include an ionic equation for this reaction. State symbols are not required. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 3 = 12 marks) Turn over 9   4 The reaction between magnesium and chlorine can be carried out using the apparatus shown. concentrated hydrochloric acid (11.5 mol dm–3) flask containing potassium manganate(VII) tube containing coil of magnesium ribbon hole The coil of magnesium ribbon is first heated strongly until it just melts. Chlorine gas is then produced by a chemical reaction in the conical flask. The chlorine gas is passed over the heated magnesium, resulting in the formation of magnesium chloride. (a) In order to melt the magnesium, it must be heated strongly. Explain why the structure of magnesium gives it a high melting temperature. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 10   (b) The equation for the reaction to produce chlorine is shown. 2KMnO4 + 8HCl → 3Cl2 + 2KCl + 2MnO2 + 4H2O The concentration of the hydrochloric acid is 11.5 mol dm–3. The equation for the reaction between the chlorine and the magnesium is shown. Mg + Cl2 → MgCl2 Calculate the minimum volume of concentrated hydrochloric acid, in cm3, required to produce 4.00 g of magnesium chloride, MgCl2. Give your answer to an appropriate number of significant figures. (4) Turn over 11   (c) Bottles of potassium manganate(VII), KMnO4 , have three hazard warning labels. One of these is shown. This hazard symbol means that potassium manganate(VII) is liable to (1) A burn easily in the presence of oxygen B explode C react dangerously with oxygen D react vigorously with reducing agents (Total for Question 4 = 7 marks)

12   5 The question is about electronegativity and its influence on bonding. (a) State what is meant by the term electronegativity. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) Explain the trend in electronegativity for the Group 7 elements. 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(c) Describe what you understand by the term ‘continuum of bonding type’ in relation to electronegativities. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 13   (d) The table gives data for chlorine and chlorine compounds of some Period 3 elements. The data show evidence that the type of bonding in compounds is a continuum across Period 3. Empirical formula Melting temperature / °C Electrical conductivity Sodium chloride NaCl 801 Yes, when molten Magnesium chloride MgCl2 714 Yes, when molten Aluminium chloride AlCl3 180 (sublimes) No Silicon tetrachloride SiCl4 –70 No Phosphorus(III) chloride PCl3 –112 No Chlorine Cl2 –102 No Discuss the extent to which the data in the table demonstrate a continuum of bonding type. Include reference to the data of three of the substances in the table with different types of bonding. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 5 = 9 marks)

14   6 Redox reactions can be understood in terms of electron transfer or in terms of changes of oxidation number. (a) The equation for a redox reaction is shown. 8KI + 5H2SO4 → 4I2 + 4K2SO4 + H2S + 4H2O (i) State, in terms of electron transfer, what you understand by the terms oxidation and reduction. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain, in terms of electron transfer, which of the species is the oxidising agent and which is the reducing agent. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 15   (b) Bromine reacts with sodium hydroxide solution in a disproportionation reaction to form BrO3 –. Complete the equation for this disproportionation. Justify the balancing of the equation in terms of the changes in oxidation number. (4) ...................Br2 + ...................OH– → ...................BrO3 – + ................... + ................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 7 marks)

16   7 This question is about ions. (a) Draw a dot‑and‑cross diagram of the ionic compound potassium chloride. Show outer shell electrons only. (1) (b) Deduce the order of increasing size of the ions: Br–, Ca2+, Cl–, K+ Justify your answer. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 17   (c) A saturated aqueous calcium hydroxide solution contains 17.3 g in 10.0 dm3 of solution. Under these conditions the calcium hydroxide is fully dissociated into ions. What is the concentration of the calcium ions in this solution, in mol dm–3 ? (1) A 0.0233 B 0.0303 C 0.0431 D 0.0597 (Total for Question 7 = 6 marks)

18   8 Reactions between calcium carbonate and acids produce carbon dioxide gas. CaCO3(s) + 2H+(aq) → Ca2+(aq) + CO2(g) + H2O(l) This reaction can be used in an experiment to determine the molar volume of carbon dioxide. Procedure Step 1    Place 50 cm3 of 1 mol dm–3 nitric acid in a conical flask. Step 2    Set up the apparatus as shown in the diagram. Step 3    Place approximately 0.4 g of calcium carbonate in a test tube and weigh the test tube and its contents accurately. Step 4    Remove the bung from the conical flask. Step 5    Tip the calcium carbonate into the conical flask. Step 6    Replace the bung in the conical flask. Step 7    Once all the calcium carbonate has reacted, measure the volume of gas collected in the measuring cylinder. Step 8    Reweigh the test tube that had contained the calcium carbonate. Step 9    Repeat the experiment decreasing the mass of calcium carbonate added each time. delivery tube 100 cm3 measuring cylinder water bung nitric acid Turn over 19   (a) A major source of inaccuracy in this experiment occurs between Steps 5 and 6 when carbon dioxide gas is lost before the bung is replaced. (i) Identify a change to the acid in Step 1 that would reduce the volume of gas lost between Steps 5 and 6. Justify your answer. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Identify a change to the procedure in Steps 5 and 6 that would prevent loss of gas. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) A second source of inaccuracy results from the significant solubility in water of carbon dioxide. Give two improvements which together prevent this problem. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 20   (c) After appropriate improvements, the procedure was carried out and the results were plotted on a graph. A line of best fit was drawn. Volume of CO2 / cm3 0.00 0.10 0.20 0.30 0.40 100 90 80 70 60 50 40 30 20 10 0 Mass of CaCO3 / g 0.05 0.15 0.25 0.35 (i) Use the graph to find the molar volume of carbon dioxide, in dm3. You must show your working on the graph. [Assume molar mass of CaCO3 = 100 g mol–1] (3) Turn over 21   (ii) The procedure was carried out at a temperature of 22 °C and a pressure of 1.01 × 105 Pa. Calculate the theoretical molar volume, giving units with your answer. [The ideal gas equation is pV = nRT. Gas constant (R) = 8.31 J mol–1 K–1] (3) (Total for Question 8 = 12 marks)

22   9 This question is about ionisation energy. (a) The first four ionisation energies, in kJ mol–1, of four elements are shown. Which element is in Group 3? (1) A   738 1451 7753 10 541 B   578 1817 2745 11 578 C   789 1577 3232    4356 D 1012 1903 2912    4957 (b) The second ionisation energy of beryllium is more endothermic than the first ionisation energy. (i) Write an equation for the second ionisation of beryllium. Include state symbols. (2) Turn over 23   *(ii) Explain how the nuclear structure and the electronic structure of the Group 2 elements affect ionisation energies. Include: • an explanation of the trend of the first ionisation energies down the group • a comparison of the first two ionisation energies for an element. 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.................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 25   (iii) The value of the sum of the first and second ionisation energies changes on descending Group 2. Explain how this changing value might contribute to the relative reactivity of the elements with chlorine. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 9 = 11 marks) TOTAL FOR PAPER = 80 MARKS 26   BLANK PAGE 27   BLANK PAGE 28  

12   4 This question is about halogenoalkanes and some of their reactions. (a) X, Y and Z are three different halogenoalkanes. X is 1‑chloropropane Y is 1‑bromopropane Z is 1‑iodopropane An experiment is carried out to compare the rates of hydrolysis of these compounds. Outline procedure: 1 cm3 of each of the three halogenoalkanes, X, Y and Z, is added to separate test tubes, each containing 5 cm3 of ethanol and 5 cm3 of aqueous silver nitrate solution, in a water bath at 50 °C. The time taken for a precipitate to form in each test tube is measured. (i) Give three reasons why these reaction conditions are specified. (3) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (ii) Explain why a precipitate forms. 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Turn over 13   (iii) The three halogenoalkanes were placed in order of increasing rate of reaction. Which is the correct sequence? (1) A X, Y, Z B X, Z, Y C Y, X, Z D Z, Y, X (b) The results table shows the time taken to produce a precipitate when three bromoalkanes react with aqueous ethanolic silver nitrate solution. Halogenoalkane Time to produce a precipitate / s 1‑bromobutane 58 2‑bromobutane 33 2‑bromo‑2‑methylpropane 2 Give a reason why the times taken to produce a precipitate for these isomeric bromoalkanes are different. (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 14   (c) (i) Which equation shows the first step of the mechanism for the reaction of 1‑bromopropane with ammonia? (1) A CH3 CH2 CH2 Br δ+ δ– CH3 CH2 CH2 NH2 + HBr • •NH3 B CH3 CH2 CH2 Br δ+ δ– CH3 CH2 CH2 NH3 + Br • •NH3 + – C CH3 CH2 CH2 Br δ+ δ– CH3 CH2 CH2 NH2 + Br • •NH3 + – D CH3 CH2 CH2 Br δ+ δ– CH3 CH2 CH2 NH3 + Br • •NH3 (ii) Write the formula of the final inorganic product of the reaction of 1‑bromopropane with excess ammonia. (1) .................................................................................................................................................................................................................................................................................... Turn over 15   (iii) The infrared spectrum of ethylamine is shown. 4000 3000 2000 1500 1000 500 Wavenumber / cm–1 100 50 0 Transmittance / % P S R Q Which absorption peak confirms this as an amine? (1) A absorption P B absorption Q C absorption R D absorption S (d) 1-bromopropane undergoes reactions when heated with different reagents. (i) Give two reasons why organic reactions are often heated for a long time but the yield is frequently low. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 16   (ii) Give the name or formula of the reagent and the condition, other than heat, used to increase the carbon chain length by one carbon atom, starting from 1-bromopropane. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) 1-bromopropane, CH3CH2CH2CH2Br, can be converted into but-1-ene, CH3CH2CH CH2 . Give the name or formula of the reagent and the condition, other than heat, used for this reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 4 = 16 marks) Turn over 17   BLANK PAGE

18   5 A student found a bottle of a colourless liquid that was thought to be an alcohol. However, the label was missing and the identity of the alcohol was unknown. The student decided to attempt to identify this alcohol (Q) by measuring its enthalpy change of combustion, and comparing the result with values in a data book. The student used the equipment shown in the diagram to determine the enthalpy change of combustion of alcohol Q. thermometer beaker water spirit burner alcohol Q Data Mass of spirit burner + alcohol Q before combustion = 20.24 g Mass of spirit burner + alcohol Q after combustion = 19.48 g Mass of water in the beaker = 500 g Temperature of the water before the experiment = 17.8 °C Temperature of the water at the end of the experiment = 28.7 °C Specific heat capacity of water = 4.18 J g–1 °C–1 Turn over 19   (a) (i) Calculate the enthalpy change, in kJ g–1, when 1.00 g of alcohol Q is burned. Include a sign in your final answer. (3) (ii) At the end of the experiment there was a black deposit of carbon on the bottom of the beaker. Explain the effect of formation of the carbon deposit on your answer to (a)(i). (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 20   (b) Give one theoretical and one practical reason why this procedure is insufficient to identify the alcohol. (2) Theoretical reason .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Practical reason .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (c) The student concluded that alcohol Q was either propan‑1‑ol or propan‑2‑ol because the mass spectrum had the molecular ion peak at m / z = 60. Explain one peak that you would expect to be present in the mass spectrum of propan‑1‑ol but not in the mass spectrum of propan‑2‑ol. 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(Total for Question 5 = 9 marks) Turn over 21   6 Ammonium carbamate has the formula NH2COONH4 . When a sample of ammonium carbamate is placed in a sealed tube and heated, it partially decomposes to the compounds used to synthesise it. The equation for this reversible reaction is NH2COONH4(s)  2NH3(g) + CO2(g) Which is the expression for the equilibrium constant, Kc , for this reaction? All concentration terms are at equilibrium. A NH CO NH COONH4 3 2 2 B 2NH CO NH COONH4 3 2 2 C NH CO 3 2 2 D NH CO NH COONH4 3 2 2 2 (Total for Question 6 = 1 mark)

22   7 This question is about the primary alcohol butan‑1‑ol. (a) Which are the intermolecular force(s) between butan‑1‑ol molecules in the liquid phase? (1) A hydrogen bonding only B hydrogen bonding and permanent dipole‑dipole forces only C hydrogen bonding, permanent dipole‑dipole forces and London forces D London forces only (b) The equation for the complete combustion of butan‑1‑ol is shown. CH3CH2CH2CH2OH(l) + 6O2(g) → 4CO2(g) + 5H2O(l) ΔcH d = –2675.6 kJ mol–1 Draw a labelled enthalpy level diagram for this reaction, using the axes provided. You may use the labels ‘reactants’ and ‘products’ in place of the formulae shown in the equation. (2) Enthalpy Progress of reaction Turn over 23   (c) Butan‑1‑ol can be oxidised to produce butanal or butanoic acid. (i) Which is a suitable test and result for butan‑1‑ol? (1) A B C D Test reagent Observation phosphorus(V) chloride PCl5(s) white smoke phosphorus(V) chloride PCl5(s) steamy fumes sodium carbonate Na2CO3(aq) carbon dioxide given off sodium carbonate Na2CO3(aq) effervescence (ii) State how to produce butanal in high yield when butan‑1‑ol reacts with acidified potassium dichromate(VI). (1) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (iii) Describe a chemical test, including the expected results, that would confirm the presence of an aldehyde such as butanal. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... 24   *(iv) Describe, including practical details, how a sample of butanoic acid (boiling temperature 166 °C) could be prepared from butan‑1‑ol (boiling temperature 117 °C) using acidified potassium dichromate(VI). Include labelled diagrams of the apparatus you would use for the reaction, and for collecting the product. You may assume that all necessary safety precautions are observed. 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(Total for Question 7 = 13 marks)

26   8 A data book gave the following information. H2(g) + ½O2(g) → H2O(l) ΔH d = –285.8 kJ mol–1 (a) State the two conditions denoted by the standard symbol d for this reaction. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (b) (i) Draw a Hess’s Law cycle that would enable you to use the data provided to calculate the enthalpy change of formation of gaseous water, ΔrH. (2) H2(g) + ½O2(g) → H2O(g) Data: H2(g) + ½O2(g) → H2O(l) ΔH 1 d = –285.8 kJ mol–1 H2O(l) → H2O(g) ΔH 2 d = +2.261 kJ g–1 27   (ii) Calculate the enthalpy change for the reaction shown. H2(g) + ½O2(g) → H2O(g) (3) (Total for Question 8 = 7 marks) TOTAL FOR PAPER = 80 MARKS 28  

18 (A410U10-1) 18 © WJEC CBAC Ltd. 10. Chlorine forms a range of oxides and oxyanions. Many of these are reactive species that can oxidise or chlorinate a range of elements and compounds. (a) Dichlorine heptoxide, Cl2O7, is a colourless liquid that can be formed by reaction of ozone with chlorine in the presence of ultraviolet light. Substance Standard enthalpy change of formation, ΔfH θ / kJ mol–1 Cl2(g) 0 O3(g) 142 7O3(g) ΔH θ = −199 kJ mol–1 3Cl2(g) 3Cl2O7(g) + (A410U10-1) 19 19 © WJEC CBAC Ltd. Examiner only Energy / kJ mol –1 Reaction progress Reaction progress – 250 – 200 –150 –100 – 50 0 100 150 200 250 50 Turn over. (i) The activation energy for this reaction is 18 kJ mol–1. Draw the energy profile for this reaction on the axes provided. [3] 20 (A410U10-1) 20 Examiner only © WJEC CBAC Ltd. (ii) The reaction is carried out at a temperature of 223 K and the rate constant is found to have a value of 2.24 × 103. The unit of the rate constant is not stated. Calculate the temperature required to double the rate of reaction. [4] T = ...................................................... K (iii) The rate equation for this reaction is first order with respect to each reactant and the rate is measured in units of mol dm–3 s–1. I. Write the rate equation. [1] II. Give the unit of the rate constant. [1] ..................................................................................................... (iv) Explain why the standard enthalpy of formation for chlorine gas is zero but that of ozone is not. [2] (A410U10-1) 21 21 Examiner only © WJEC CBAC Ltd. (v) Dichlorine heptoxide decomposes readily to form Cl2(g) and O2(g). Calculate the volume of gas produced when 2.70 g of Cl2O7 decomposes at a temperature of –12°C and 1 atm pressure. [4] Volume = ...................................................... dm3 2Cl2(g) 2Cl2O7(g) 7O2(g) + Turn over. 22 (A410U10-1) 22 Examiner only © WJEC CBAC Ltd. (b) Chlorine dioxide, ClO2, is an unstable oxide of chlorine. It is often stored in aqueous solution and in some countries solutions can only be transported if the concentration is lower than 0.30 g in 100 cm3 of water. Calculate the concentration of this solution in mol dm–3. [2] Concentration = ...................................................... mol dm–3 (c) Chlorine perchlorate, ClOClO3, is an oxide with the two chlorine atoms in different oxidation states. (i) If one chlorine atom has an oxidation state of +1, find the oxidation state of the other. [1] ............................................................ (ii) Predict the appearance of the molecular ion peaks seen in the mass spectrum of chlorine perchlorate. Give reasons for your answer. You should refer to both the positions and heights of the peaks. [4] (A410U10-1) 23 23 Examiner only © WJEC CBAC Ltd. (d) The chlorite ion,  , has a non-linear shape. Explain why this ion is not linear. [2] 24 O Cl O– Turn over.

24 (A410U10-1) 24 © WJEC CBAC Ltd. 11. A student carried out two acid-base titrations using two acids, HA and HB. A 25.0 cm3 sample of each acid was titrated against a sodium hydroxide solution of concentration 0.150 mol dm–3 giving the titration curves shown. The initial pH values are missing from both graphs. One acid is a strong acid and one is a weak acid. 0 2 4 6 8 10 12 14 0 5 10 15 20 25 30 35 40 Volume of sodium hydroxide added / cm3 HA pH 0 2 4 6 8 10 12 14 0 5 10 15 20 25 30 35 40 Volume of sodium hydroxide added / cm3 HB pH (A410U10-1) 25 25 © WJEC CBAC Ltd. Turn over. Examiner only (a) Describe and explain the differences between the two curves. • You should identify which acid is strong and which is weak, explaining fully how you have reached your conclusion. • You should identify which acid is more concentrated and which is more dilute, explaining how you have reached your conclusion. [6 QER] (b) Calculate Ka for the weak acid. [2] Ka = ................................................................................... mol dm–3 26 (A410U10-1) 26 Examiner only © WJEC CBAC Ltd. (c) Both these titrations can be performed using appropriate acid-base indicators, but similar experiments using a weak acid and a weak base cannot use acid-base indicators successfully. Explain this difference. [2] (d) The students made 250 cm3 of aqueous sodium hydroxide of concentration 0.150 mol dm–3 for these experiments. (i) Calculate the mass of NaOH required to make this solution. [2] Mass = ....................................................... g (ii) Outline how this solution could be made. [3] (A410U10-1) 27 27 © WJEC CBAC Ltd. Examiner only Turn over. (iii) Calculate the pH of this aqueous sodium hydroxide at 298 K. [3] pH = ....................................................... 18 28 (A410U10-1) 28 © WJEC CBAC Ltd. Examiner only 12. (a) Five ionisation energies are represented by the letters A–E as shown below. A 1st ionisation energy of helium B final ionisation energy of nitrogen C final ionisation energy of oxygen D 1st ionisation energy of sodium E 2nd ionisation energy of magnesium The values of these five ionisation energies are given in the table. Value of ionisation energy / kJ mol–1 Letter representing the ionisation energy 84 078 .................................... 64 360 .................................... 2372 .................................... 1450 .................................... 496 .................................... Complete the table using letters A–E to show which ionisation energy corresponds to each value. Give reasons for your choices. [5] (A410U10-1) 29 29 Examiner only © WJEC CBAC Ltd. Turn over. (b) Three boiling temperatures are listed below. –33°C –111°C –132°C These are the boiling temperatures of NH3, PH3 and AsH3. Identify which value corresponds to each compound. Give reasons for your choices. [3] Boiling temperature of NH3 ..................................................... °C Boiling temperature of PH3 ..................................................... °C Boiling temperature of AsH3 ..................................................... °C 30 (A410U10-1) 30 © WJEC CBAC Ltd. (c) A student is provided with four solutions labelled W, X, Y and Z and is told that these contain common cations and anions that they have studied. He observes that one solution is pale blue and the others are colourless. Flame tests on the solutions give apple-green and golden yellow flames with two solutions and unfamiliar colours with the others. The student mixes pairs of solutions together and obtains the following results. He did not complete all the experiments. Solution 1 Solution 2 Observation(s) W X white precipitate that dissolves when excess solution W is added W Y mixture of pale blue precipitate and white precipitate in a colourless solution W Z no visible change X Y white precipitate in a pale blue solution X Z Y Z white precipitate in a brown solution (A410U10-1) 31 31 © WJEC CBAC Ltd. Turn over. Examiner only Identify the four compounds and give reasons for your decisions. [6] Compound W ................................................................................................................... Compound X ................................................................................................................... Compound Y ................................................................................................................... Compound Z ................................................................................................................... END OF PAPER 14 (A410U10-1) 32 © WJEC CBAC Ltd. 32 Examiner only Question number Additional page, if required. Write the question number(s) in the left-hand margin. BE*(S23-A410U10-1A) © WJEC CBAC Ltd. GCE A LEVEL A410U10-1A MONDAY, 12 JUNE 2023 – MORNING CHEMISTRY – A level component 1 Data Booklet Avogadro constant NA = 6.02 × 1023 mol –1 molar gas constant R = 8.31 J mol –1 K –1 molar gas volume at 273 K and 1 atm Vm = 22.4 dm3 mol –1 molar gas volume at 298 K and 1 atm Vm = 24.5 dm3 mol –1 Planck constant h = 6.63 × 10 –34 J s speed of light c = 3.00 × 108 m s –1 density of water d = 1.00 g cm –3 specific heat capacity of water c = 4.18 J g –1 K –1 ionic product of water at 298 K Kw = 1.00 × 10 –14 mol 2 dm – 6 fundamental electronic charge e = 1.60 × 10 –19 C temperature (K) = temperature (°C) + 273 1 dm3 = 1000 cm3 1 m3 = 1000 dm3 1 tonne = 1000 kg 1 atm = 1.01 × 105 Pa Multiple Prefix Symbol 10 –9 nano n 10 –6 micro μ 10 –3 milli m Multiple Prefix Symbol 10 3 kilo k 10 6 mega M 10 9 giga G S23-A410U10-1A (A410U10-1A) 2 © WJEC CBAC Ltd. 500 to 600 650 to 800 1000 to 1300 1620 to 1670 1650 to 1750 2100 to 2250 2800 to 3100 2500 to 3200 (very broad) 3200 to 3550 (broad) 3300 to 3500 C Br C Cl C O C C C O C N C H O H (carboxylic acid) O H (alcohol / phenol) N H 10 to 70 5 to 40 20 to 50 25 to 60 50 to 90 90 to 150 110 to 125 110 to 160 160 to 185 190 to 220 N C R C C C O C C R Cl or Br C O C R C O (carboxylic acid / ester) C R (aldehyde / ketone) O C R N R C 13C NMR chemical shifts relative to TMS = 0 Type of carbon Chemical shift, δ (ppm) Infrared absorption values Bond Wavenumber / cm –1 Turn over. (A410U10-1A) 3 © WJEC CBAC Ltd. *variable figure dependent on concentration and solvent 1H NMR chemical shifts relative to TMS = 0 Type of proton Chemical shift, δ (ppm) 0.9 0.1 to 2.0 3.1 to 4.3 1.3 2.0 2.0 to 3.0 2.0 to 2.5 2.2 to 2.3 R CH3 R CH2 R CH3 C N CH3 C O CH3 CH3 CH2 C O 4.5 * 4.5 to 6.3 6.5 to 7.5 6.5 to 8.0 R OH 3.3 to 4.3 HC Cl or HC Br C CH HC O C CH H 7.0 * OH 9.8 * 11.0 * R C O H R C O OH 5.8 to 6.5 C CH CO (A410U10-1A) 4 © WJEC CBAC Ltd. 6.94 Li Lithium 3 9.01 Be Beryllium 4 10.8 B Boron 5 12.0 C Carbon 6 14.0 N Nitrogen 7 16.0 O Oxygen 8 19.0 F Fluorine 9 20.2 Ne Neon 10 23.0 Na Sodium 11 24.3 Mg Magnesium 12 27.0 Al Aluminium 13 28.1 Si Silicon 14 31.0 P Phosphorus 15 32.1 S Sulfur 16 35.5 Cl Chlorine 17 40.0 Ar Argon 18 39.1 K Potassium 19 40.1 Ca Calcium 20 45.0 Sc Scandium 21 47.9 Ti Titanium 22 50.9 V Vanadium 23 52.0 Cr Chromium 24 54.9 Mn Manganese 25 55.8 Fe Iron 26 58.9 Co Cobalt 27 58.7 Ni Nickel 28 63.5 Cu Copper 29 65.4 Zn Zinc 30 69.7 Ga Gallium 31 72.6 Ge Germanium 32 74.9 As Arsenic 33 79.0 Se Selenium 34 79.9 Br Bromine 35 83.8 Kr Krypton 36 85.5 Rb Rubidium 37 87.6 Sr Strontium 38 88.9 Y Yttrium 39 91.2 Zr Zirconium 40 92.9 Nb Niobium 41 95.9 Mo Molybdenum 42 98.9 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 112 Cd Cadmium 48 115 In Indium 49 119 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 133 Cs Caesium 55 137 Ba Barium 56 139 La Lanthanum 57 179 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 (210) Po Polonium 84 (210) At Astatine 85 (222) Rn Radon 86 (223) Fr Francium 87 (226) Ra Radium 88 (227) Ac Actinium 89 THE PERIODIC TABLE 1 2 Group 3 4 5 6 7 0 1 2 3 4 5 6 7 1.01 H Hydrogen 1 4.00 He Helium 2 d block s block Period p block 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 (147) Pm Promethium 61 150 Sm Samarium 62 (153) Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 163 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 (231) Pa Protactinium 91 238 U Uranium 92 (237) Np Neptunium 93 (242) Pu Plutonium 94 (243) Am Americium 95 (247) Cm Curium 96 (245) Bk Berkelium 97 (251) Cf Californium 98 (254) Es Einsteinium 99 (253) Fm Fermium 100 (256) Md Mendelevium 101 (254) No Nobelium 102 (257) Lr Lawrencium 103 f block Actinoid elements Ar Symbol Name Z relative atomic mass atomic number Key Lanthanoid elements ▴ ▴▴ ▴ ▴▴

page 02 SECTION 1 — 25 marks Attempt ALL questions 1. Which of the following electronic configurations shows the ground state arrangement of electrons in the 3d and 4s subshells of an atom? A B C D 3d 4s 2. Which of the following shapes can only be formed by compounds that contain non‑bonding electron pairs? A Linear B Tetrahedral C Trigonal pyramidal D Trigonal bipyramidal 3. In which block of the periodic table is the shaded element? A s B p C d D f

page 03 4. Which line in the table is correct for transition metal catalysts? Heterogenous catalyst Homogeneous catalyst A adsorption onto active sites same state as reactants B full d subshell different state to reactants C same state as reactants can change oxidation state D different state to reactants adsorption onto active sites 5. The titration curve above shows how the pH changes when a A weak acid is added to a strong alkali B strong alkali is added to a weak acid C strong acid is added to a weak alkali D weak alkali is added to a strong acid. 6. Which line in the table is correct for an acidic buffer? Species absorbing excess H3O+ ions Species providing H3O+ ions A weak base conjugate acid B conjugate base conjugate acid C weak base weak acid D conjugate base weak acid [Turn over volume added pH 14 12 10 8 6 4 2 0

page 04 7. Which of the following statements is correct for a feasible reaction under standard conditions? A The standard free energy change is negative and the equilibrium favours products. B The standard free energy change is negative and the equilibrium favours reactants. C The standard free energy change is positive and the equilibrium favours products. D The standard free energy change is positive and the equilibrium favours reactants. 8. At 298 K, 1 2N2(g)  +  O2(g)  ↓  NO2(g) ΔG° = +51.8 kJ mol−1 N2(g)  +  2O2(g)  ↓  N2O4(g) ΔG° = +97.7 kJ mol−1 What is the free energy change ΔG°, in kJ mol−1, for the conversion of nitrogen dioxide to one mole of dinitrogen tetroxide? A −45.9 B −5.9 C +5.9 D +45.9 9. Which of the following processes is endothermic and has a positive ΔS value? A Carbon burning B Snowflakes forming C Ethoxyethane evaporating D Ammonia gas and hydrogen chloride gas forming solid ammonium chloride 10. The reaction X  +  2Y  ↓  Z has the rate equation shown below. rate = k[X][Y] Which of the following could represent the rate determining step? A X  +  Y  ↓  intermediate B Y  +  Y  ↓  intermediate C X  +  Y  ↓  Z D XY  +  Y  ↓  Z

page 05 11. Which line in the table is correct for a carbon‑carbon single bond in an alkane? Overlap of atomic orbitals Symmetry of molecular orbital A end‑on symmetrical B end‑on asymmetrical C side‑on symmetrical D side‑on asymmetrical 12. Which line in the table is correct for a chromophore that absorbs blue‑green light? Movement of electrons Colour observed A HOMO to LUMO blue‑green B LUMO to HOMO blue‑green C HOMO to LUMO red D LUMO to HOMO red 13. Which of the following compounds does not exhibit hydrogen bonding between its molecules? A Ethanol B Ethylamine C Ethanoic acid D Ethoxyethane 14. A haloalkane can be converted into a ketone by reaction with A aqueous sodium hydroxide followed by oxidation B ethanolic potassium cyanide followed by hydrolysis C ethanolic sodium hydroxide followed by addition D potassium in ethanol followed by substitution. [Turn over page 06 15. CH3CH2CH(CH3)CHO LiAlH4 X The organic product X is A 2‑methylbutanal B 2‑methylbut‑1‑ene C 2-methylbutan-1-ol D 2-methylbutanoic acid. 16. CH3CH2CH2COOH NH3 X heat Y  +  H2O The formula for Y will be A CH3CH2CH2CN B CH3CH2CH2CONH2 C CH3CH2CH2CH2NH2 D CH3CH2CH2COONH4 17. Which of the following compounds is not an isomer of methoxypropane? A CH3CH2COCH3 B CH3CH2OCH2CH3 C CH3CH(OH)CH2CH3 D CH3CH(CH3)CH2OH 18. Which of the following compounds can exhibit geometric isomerism? A CH2CHBr B CHClCHCH3 C CH3CH2CHCCl2 D CH3C(CH3)CHCH3 19. In which of the following techniques will the test compound always be destroyed? A Mass spectrometry B Infrared spectroscopy C Melting point analysis D Proton NMR spectroscopy

page 07 20. Which line in the table correctly describes the action of a drug? Type of drug Binding site Response A antagonist receptor binding site produces a response similar to the body’s natural response B antagonist enzyme active site blocks the body’s natural response C enzyme inhibitor receptor binding site produces a response similar to the natural action of the enzyme D enzyme inhibitor enzyme active site blocks the action of the enzyme [Turn over

page 08 21. The structural formulae of three antihistamine drugs are shown. N N Cl Cl N N N H O O O loratadine doxepin desloratadine Which of the following is the largest structural fragment that is common to all three molecules? N N N Cl A B C D

page 09 22. A compound was found to have the percentage composition by mass as shown below. vanadium 61.4% oxygen 38.6% This compound has the formula A VO B VO2 C V2O D V2O3 23. Which of the following compounds could be used as a primary standard? A Calcium carbonate B Hydrochloric acid C Sodium carbonate D Sodium hydroxide 24. The total mass of the Earth’s atmosphere has been determined to be 5.1 × 1018 kg. What mass, in kg, of carbon dioxide is in the Earth’s atmosphere if the concentration of carbon dioxide is 420 ppm? A 1.2 × 1013 B 2.1 × 1015 C 1.2 × 1016 D 2.1 × 1018 25. The concentration of Pb2+ ions in a solution can be determined using the following sequence of reactions: Pb2+(aq)  +  CrO4 2−(aq)  ↓  PbCrO4(s) PbCrO4(s)  +  2Cl−(aq)  ↓  PbCl2(s)  +  CrO4 2−(aq) 2CrO4 2−(aq)  +  6I−(aq)  +  16H+(aq)  ↓  2Cr3+(aq)  +  3I2(aq)  +  8H2O(ℓ) How many moles of iodine are formed from one mole of Pb2+ ions in the solution? A 0.75 B 1.5 C 3.0 D 6.0 [END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OF YOUR QUESTION AND ANSWER BOOKLET.] page 10 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 11 [BLANK PAGE] DO NOT WRITE ON THIS PAGE page 12 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

page 02 Total marks — 25 Attempt ALL questions 1. Which of the following compounds has the least ionic character? A Sodium iodide B Sodium fluoride C Potassium iodide D Potassium fluoride 2. In which of the following compounds would hydrogen bonding not occur? H H C C H H H N H H H H C C H H H O H H H C N H H C H H H H H C O H C H H H A B C D 3. Fats are formed from glycerol molecules and fatty acid molecules. The mole ratio of glycerol molecules to fatty acid molecules is A 1 : 2 B 2 : 1 C 1 : 3 D 3 : 1

page 03 4. A reaction was carried out as shown in the energy diagram. reaction path potential energy (kJ mol-1) 250 200 150 100 50 0 Which of the following has a value of 150 kJ mol-1? A Activation energy of the reverse reaction B Enthalpy change of the reverse reaction C Activation energy of the forward reaction D Enthalpy change of the forward reaction [Turn over

page 04 5. The graph shows how the rate of a reaction varies with the concentration of one of the reactants. 1.25 1.00 0.75 0.50 0.25 0 concentration (mol l−1) 0.5 0.4 0.3 0.2 0.1 0 rate (1/t) (s−1) What was the concentration, in mol l-1, when the reaction time was 10 s? A 0.04 B 0.10 C 0.25 D 0.40

page 05 6. The diagram represents the change in concentration of a reactant against time during a reversible chemical reaction. time concentration In which diagram below does the dotted line show the result of repeating the reaction using a catalyst? A B C D time time time time concentration concentration concentration concentration [Turn over

page 06 7. The enthalpy of combustion of methanol (GFM = 32.0 g) is -726 kJ mol-1. What mass of methanol has to be burned to produce 145.2 kJ? A 3.2 g B 6.4 g C 32.0 g D 160.0 g 8. Which of the following statements is true? A The sodium atom is larger than the sodium ion. B The chloride ion is smaller than the chlorine atom. C The magnesium ion is larger than the magnesium atom. D The oxygen atom is larger than the oxide ion. 9. Which of the following structures is never found in compounds? A Covalent molecular B Covalent network C Monatomic D Ionic 10. Which of the following carbon containing compounds is an isomer of hexanal? A 2-methylbutanal B 3-methylpentan-2-one C 2,2-dimethylbutan-1-ol D 3,3-dimethylpentanal

page 07 11. When two amino acids react in a condensation reaction, water is eliminated and a peptide link is formed. Which of the following represents this process? O H H OH CH3 C C H N O OH C2H5 C C H N H H O OH C2H5 C C H N H H O H H OH CH3 C C H N O H H OH C2H5 C C N H O H H OH CH3 C C H N O H H OH CH3 C C H N H H C2H5 N C H C H O O A B C D [Turn over

page 08 12. Which of the following equations represents an enthalpy of combustion? A 2CH4(g)  +  3O2(g)  ↓  2CO(g)  +  4H2O(ℓ) B CH4(g)  +  1 1 2O2(g)  ↓  CO(g)  +  2H2O(ℓ) C 2C2H6(g)  +  7O2(g)  ↓  4CO2(g)  +  6H2O(ℓ) D C2H6(g)  +  3 1 2O2(g)  ↓  2CO2(g)  +  3H2O(ℓ) 13. Two flasks, A and B, were placed in a water bath at 40°C. B A ethanol and ethanoic acid ethyl ethanoate and water water at 40°C After several days, the contents of the flasks were analysed. Which results would be expected? A Flask A contains ethyl ethanoate, water, ethanol and ethanoic acid; flask B is unchanged. B Flask A contains only ethyl ethanoate and water; flask B is unchanged. C Flask A contains only ethyl ethanoate and water; flask B contains only ethanol and ethanoic acid. D Flask A and flask B contain ethyl ethanoate, water, ethanol and ethanoic acid.

page 09 14. During a redox process in acid solution, iodate ions are converted into iodine. 2IO3 -(aq)  +  12H+(aq)  +  xe-  ↓  I2(aq)  +  6H2O(ℓ) What value of x is required to balance the equation? A 12 B 11 C 10 D 6 15. A step in the synthesis of vitamin B3 is shown. HC HC C N CH C O CH H H H HC HC C N CH C O O CH H What name is given to this type of reaction? A Condensation B Hydration C Reduction D Oxidation [Turn over

page 10 16. A chemist analysed a mixture of four dyes, A, B, C and D, using gas-liquid chromatography. The time taken to travel through the column (retention time) depends on the polarity of the molecule. The more polar the molecule the longer the retention time. The following chromatogram was obtained. concentration Z increasing retention time Which of the following compounds corresponds to peak Z? O O OH O OH OH HO O HO OH O O OH HO OH O OH HO O D C B A Structure Dye

page 11 17. The apparatus was used to measure the enthalpy of combustion of ethanol. thermometer 100 cm3 water ethanol copper can Which of the following would not improve the accuracy of the result? A Using a draught shield B Moving the thermometer C Using a glass beaker instead of a copper can D Stirring the water [Turn over

page 12 18. Which line in the table best describes the ball-like structures formed when soap is added to an oil and water mixture? Diagram Description A B C D ionic head dissolves in water, non-polar tail dissolves in oil droplet ionic head dissolves in oil droplet, non-polar tail dissolves in water non-polar head dissolves in oil droplet, ionic tail dissolves in water non-polar head dissolves in water, ionic tail dissolves in oil droplet water water water water 19. In an experiment, nickel oxide is added to sulfuric acid until no more nickel oxide reacts. The products are nickel sulfate and water. The correct method to separate and collect a dry, pure sample of nickel sulfate is A evaporation B filtration C filtration followed by evaporation D evaporation followed by filtration. 20. Which of the following compounds would react with sodium hydroxide solution to form a salt? A CH3CHO B CH3COOH C CH3COCH3 D CH3CH2OH

page 13 21. Which structural formula represents a primary alcohol? C H OH C H H C C H OH C C H H H H H H C H C H H C H H H H H C H H H H H C H H H C C H H H H C OH CH3 H C H H C CH3 CH3 OH A B C D 22. Reduction of 4-methylpentan-2-one to the corresponding alcohol results in the molecule A gaining 2 g per mole B losing 2 g per mole C losing 16 g per mole D not changing in mass. 23. Which of the following gas samples has the same volume as 16.0 g of oxygen? (All volumes are measured at the same temperature and pressure) A 21.0 g of carbon monoxide B 44.0 g of carbon dioxide C 46.0 g of nitrogen dioxide D 46.0 g of dinitrogen tetroxide [Turn over

page 14 24. The number of moles of positive ions in 0.25 moles of aluminium sulfate is A 0.5 B 1.0 C 2.0 D 3.0 25. Addition of hydrogen chloride, HCl, to an alkene can give a mixture of two products. The product produced in the greatest amount in the reaction is called the major product. The major product is formed when the hydrogen atom of HCl attaches to the carbon atom of the double bond that has the greatest number of hydrogen atoms attached. C CH3 C H H H C H C H H C H H H 2-methylpent-2-ene The major product in the reaction of HCl with the 2-methylpent-2-ene is C CH3 C H H H C H C H H C H H H Cl H C CH3 C H H H C H C H H C H H H Cl Cl C CH3 C H H H C H C H H C H H H H Cl C CH3 C H H H C H C H H C H H H H H A B C D [END OF QUESTION PAPER] page 15 SPACE FOR ROUGH WORK page 16 [BLANK PAGE] DO NOT WRITE ON THIS PAGE

14 (2410U10-1) 10. (a) A student investigated the thermal stability of Group 2 carbonates. She used the following apparatus and method. © WJEC CBAC Ltd. 14 Group 2 carbonate heat delivery tube limewater 1. Start a stopwatch at the moment you begin to heat the carbonate and continue to heat for 4 minutes or until the limewater turns cloudy. 2. After the limewater turns cloudy lift the delivery tube out of the limewater then remove the flame from under the boiling tube. 3. Repeat the heating procedure for each carbonate in turn. 4. Use a spatula-measure of the appropriate carbonate, fresh limewater and heat with the hottest Bunsen burner flame each time. Her results are shown below. Carbonate Time taken for limewater to turn cloudy / s MgCO3 20 CaCO3 40 SrCO3 230 BaCO3 does not turn cloudy (2410U10-1) Turn over. 15 Examiner only (i) Suggest an improvement to the method to ensure that the experiment is a fair test. [1] (ii) Suggest why the delivery tube should be lifted out of the limewater before the flame is removed from under the boiling tube. [1] (iii) State what conclusion she can draw about the thermal stabilities of the Group 2 carbonates from these results. [1] (iv) The student was told that the temperature at which barium carbonate decomposes is 1360 °C. The maximum temperature of a typical Bunsen burner flame is around 800 °C. State whether the limewater would have turned cloudy if she had used two Bunsen burners to heat the barium carbonate. Give a reason for your answer. [1] © WJEC CBAC Ltd. 15 16 (2410U10-1) Examiner only (b) Barium nitrate also decomposes on heating. 2BaO(s) 4NO2(g) 2Ba(NO3)2(s) O2(g) + + (i) In an experiment 0.960 g of barium nitrate was heated strongly for 2 minutes. Calculate the maximum volume, in cm3, of gas that could be produced at a temperature of 25 °C and a pressure of 1 atm. [3] Volume = ........................................................ cm3 (ii) The volume of a gas is directly proportional to its temperature at constant pressure. A student said that if the gas formed in this experiment were collected at a temperature of 50 °C and at 1 atm pressure, the volume formed would be double that calculated in part (i). Do you agree? Justify your answer. [1] © WJEC CBAC Ltd. 16 (2410U10-1) Turn over. 17 Examiner only (c) State the conditions necessary for each of barium oxide and barium metal to conduct electricity. Explain this property in terms of structure and bonding in each case. [3] (d) The atomic radius of a barium atom is 0.217 nm. From the list below, choose the value for the ionic radius of a barium ion. Give a reason for your choice. [2] 0.135 nm 0.210 nm 0.217 nm 0.265 nm (e) A sample of barium contains two isotopes. The first isotope has a relative isotopic mass of 134.9 and the second a relative isotopic mass of 137.9. The relative atomic mass of the sample of barium is 137.3. Calculate the percentage abundance of the first isotope. [2] Abundance = ........................................................ % © WJEC CBAC Ltd. 17 15

18 (2410U10-1) Examiner only 11. Seawater contains a number of dissolved salts. Although composition varies with location, 1 000 cm3 of seawater contains about 20 g of chloride ions, Cl–, and about 3 g of sulfate ions, SO4 2–. A student is given a sample of seawater from Rhossili Bay and asked to determine the chloride ion content by volumetric analysis and the sulfate ion content by gravimetric analysis. (a) Determination of chloride ion content by volumetric analysis. © WJEC CBAC Ltd. 18 The method is similar to an acid-base titration. A silver nitrate solution of known concentration is used to precipitate chloride ions as silver chloride. CI–(aq) AgCI(s) Ag+(aq) + The seawater is diluted by a factor of five before it is used in the titration. The endpoint of this titration is difficult to determine directly, so potassium chromate(VI), K2CrO4, is used as an indicator. When all of the chloride ions have been used up, the chromate(VI) ions react with silver ions and produce silver chromate(VI), which forms a red precipitate. The instant a permanent red tinge appears in the solution, the endpoint has been reached. Volume of diluted seawater in the conical flask = 25.0 cm3 Concentration of silver nitrate solution in the burette = 0.100 mol dm−3 Mean titre = 26.40 cm3 (i) Before starting the titration, the student rinses the burette with silver nitrate solution. Suggest why he does this. [1] (ii) Suggest why the student dilutes the seawater. [1] (2410U10-1) Turn over. 19 Examiner only (iii) Describe how the student should dilute the seawater by a factor of five. [3] (iv) Describe and explain one action the student might take just before the endpoint of the titration, to ensure that the volume of silver nitrate added at the endpoint is accurate. [2] (v) Write an ionic equation for the precipitation of silver chromate(VI). [1] (vi) Calculate the mass of chloride ions in 1 000 cm3 of the original seawater, giving your answer to an appropriate number of significant figures. [4] Mass of chloride ions = ….............................................…….. g © WJEC CBAC Ltd. 19 20 (2410U10-1) Examiner only (b) Determination of sulfate ion content by gravimetric analysis. © WJEC CBAC Ltd. 20 100 cm3 of undiluted seawater and 0.100 mol dm−3 barium nitrate solution were used. The mass of the barium sulfate precipitate was 0.65 g. You may assume that all of the sulfate ions in the seawater were precipitated. (i) Describe how the student carried out the gravimetric analysis to find the mass of the barium sulfate precipitated. [5] (2410U10-1) Turn over. 21 © WJEC CBAC Ltd. 21 21 Examiner only (ii) Calculate the minimum volume, in cm3, of barium nitrate solution needed to precipitate all of the sulfate ions in 100 cm3 of the seawater. [3] Volume = ........................................................ cm3 (iii) Suggest why the volume of barium nitrate needed was different to the volume of seawater used. [1] END OF PAPER 22 (2410U10-1) © WJEC CBAC Ltd. 22 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (2410U10-1) 23 © WJEC CBAC Ltd. 23 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only 24 (2410U10-1) © WJEC CBAC Ltd. 24 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

8 (2410U20-1) 10. (a) The enthalpy of neutralisation of an acid is defined as the enthalpy change when 1 mol of aqueous H+ ions is neutralised by aqueous OH– ions according to the equation shown. The reaction is exothermic. © WJEC CBAC Ltd. 08 OH–(aq) H+(aq) H2O(I) + Some students followed the instructions below to determine the enthalpy change of neutralisation of methanoic acid, HCOOH. 1. Weigh 24.7 g of methanoic acid and mix with water to make 250 cm3 of solution. Record the temperature of the solution. 2. Transfer eight 25.0 cm3 portions of this solution into eight insulated cups. 3. Using a burette add 5.0 cm3 of aqueous sodium hydroxide to the solution in the first cup. Stir and record the maximum temperature reached. 4. Add the following volumes of aqueous sodium hydroxide to each of the remaining cups in turn: 10.0 cm3 15.0 cm3 20.0 cm3 25.0 cm3 30.0 cm3 35.0 cm3 40.0 cm3 Stir and record the maximum temperature reached in each cup. 5. Plot a graph of maximum temperature reached against volume of sodium hydroxide added. Their results are plotted in the graph. 20 25 30 35 40 0 10 20 30 40 50 Maximum temperature / °C Volume of NaOH added / cm3 (2410U20-1) Turn over. 2410 U201 0 9 9 Examiner only (i) Name the apparatus used to transfer exactly 25.0 cm3 of methanoic acid solution into the insulated cups. [1] ..................................................................................... (ii) State why a higher maximum temperature is recorded when increasing volumes of sodium hydroxide are added. [1] (iii) Explain why the maximum temperature recorded decreases when more than 30 cm3 of sodium hydroxide is added. [2] (iv) On the graph, draw one straight line through the points that show an increase in maximum temperature and another straight line through the points that show a decrease in maximum temperature. [1] (v) From the graph, deduce the volume of sodium hydroxide needed to neutralise 25.0 cm3 of the methanoic acid solution and the temperature increase at that point. Assume that the initial temperature of every 25.0 cm3 of methanoic acid solution is 22.0 °C. [2] Volume = ........................................................ cm3 Temperature increase = ........................................................ °C © WJEC CBAC Ltd. 09 10 (2410U20-1) Examiner only (vi) Use your answers to part (v) to calculate the amount of heat released by the neutralisation reaction. [2] Heat released = ........................................................ J (vii) Calculate the number of moles of methanoic acid in 25.0 cm3 of the solution and hence the enthalpy change of neutralisation of methanoic acid. [3] Enthalpy change of neutralisation = ........................................................ kJ mol–1 © WJEC CBAC Ltd. 10 (2410U20-1) Turn over. 2410 U201 11 11 Examiner only (b) The experiment is repeated using hydrochloric acid instead of methanoic acid and a more negative value of the enthalpy change of neutralisation is calculated. Suggest and explain a reason for this difference. [2] (c) (i) Write the equation for the reaction that occurs when solid copper(II) carbonate is added to aqueous methanoic acid to form aqueous copper(ll) methanoate, (HCOO)2Cu. Include state symbols. [2] (ii) State what is observed during the reaction in part (i). [2] © WJEC CBAC Ltd. 11 18 12 (2410U20-1) 11. (a) Compound X contains carbon, hydrogen and oxygen only. It has no reaction with acidified potassium dichromate. Simplified versions of its mass spectrum, IR spectrum and 13C NMR spectrum are shown. © WJEC CBAC Ltd. 12 0 20 40 60 80 Intensity Mass spectrum m/z 500 1000 1500 2000 3000 4000 Wavenumber / cm–1 IR spectrum Transmittance 200 180 160 140 120 100 80 60 40 20 0 δ / ppm 13C NMR spectrum Intensity (2410U20-1) Turn over. 13 Examiner only Identify compound X. You must use information from all the sources given and explain how you used it. [8] Compound X © WJEC CBAC Ltd. 13 14 (2410U20-1) Examiner only (b) On the axes below, complete the low resolution 1H NMR spectrum you would expect for the compound you identified in part (a). You should indicate where you would expect to see peaks and the relative intensities of the peaks. [2] © WJEC CBAC Ltd. 14 10 11 10 9 8 7 6 5 4 3 2 1 0 δ / ppm Intensity (2410U20-1) Turn over. 15 © WJEC CBAC Ltd. 15 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

16 (2410U20-1) Examiner only 12. (a) Y is a halogenocompound in which each molecule contains one atom of chlorine, bromine or iodine. (i) Describe a chemical test to determine which halogen is present in Y. [3] (ii) Y contains four carbon atoms in each molecule. The percentage by mass of halogen present in Y is less than 40%. Identify Y. Explain how you reached your conclusion. [2] © WJEC CBAC Ltd. 16 (2410U20-1) Turn over. 17 Examiner only (b) (i) Halogenoalkanes react with aqueous sodium hydroxide. Draw the mechanism to show the reaction of 1-chloropropane with aqueous sodium hydroxide. You should include all charges, partial charges and lone pairs, and curly arrows to show electron movement. [4] (ii) Name the type of reaction shown in part (i). [1] ................................................................................................................ (c) Halogenoalkanes can also take part in an elimination reaction. 2-Chloropentane undergoes elimination in a similar way to 1-chloropropane. (i) Give the reagent and conditions needed for 2-chloropentane to undergo elimination. [1] (ii) When 2-chloropentane undergoes elimination, two structural isomers are formed. Give the structures of these two isomers. [2] © WJEC CBAC Ltd. 17 13

18 (2410U20-1) Examiner only 13. (a) In cold weather the wings of an aeroplane can become covered in ice. For safety reasons the wings must be de-iced. The liquid ethane-1,2-diol, CH2OHCH2OH, is used, mixed with water, since this lowers the freezing temperature of water and causes the ice to melt. (i) Use the diagram below to show the intermolecular forces that allow ethane-1,2-diol to dissolve in water. [3] © WJEC CBAC Ltd. 18 (ii) Suggest a reason why the addition of ethane-1,2-diol lowers the freezing temperature of water. [1] C C O H H O H H H H (2410U20-1) Turn over. 19 Examiner only © WJEC CBAC Ltd. 19 (b) Ethane-1,2-diol can be oxidised to ethanedioic acid, (COOH)2. (i) Suggest an oxidising agent suitable to carry out this reaction. [1] .......................................................................................................................................... (ii) Write the equation for this reaction. Use [O] for the oxidising agent. [2] (iii) To ensure complete oxidation the reagents are refluxed. Draw and label the apparatus as it is being used in this reaction. [2] (iv) A sample of the reacting mixture was taken during the reflux process and a mass spectrum was produced. One of the peaks recorded was at m/z 58. Suggest the identity of the molecular ion that gave this peak. [1] ................................................................................... (v) The reaction can be used to prepare a sample of solid ethanedioic acid. This is generally hydrated as (COOH)2.xH2O where x is an integer. 2.00 g of ethane-1,2-diol was oxidised and 3.94 g of hydrated ethanedioic acid was produced. Calculate the relative molecular mass of hydrated ethanedioic acid and hence the value of x in its formula. [4] x = ........................................................ 20 (2410U20-1) Examiner only © WJEC CBAC Ltd. 20 (2410U20-1) Turn over. 21 © WJEC CBAC Ltd. 21 17 Examiner only (vi) I. Complete the equation for the reaction which occurs when ethanedioic acid is heated with excess methanol in acidic conditions. Clearly show the structure of the organic product. [2] COOH COOH 2CH3OH + + II. Name the type of functional group present in the organic product. [1] END OF PAPER 22 (2410U20-1) © WJEC CBAC Ltd. 22 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only (2410U20-1) 23 © WJEC CBAC Ltd. 23 Question number Additional page, if required. Write the question number(s) in the left-hand margin. Examiner only 24 (2410U20-1) © WJEC CBAC Ltd. 24 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE

11983.05R 6 Which of the following describes a dynamic equilibrium? concentration of reactants and products forward and reverse reaction rates A constant equal B constant not equal C not constant equal D not constant not equal 7 A mixture of potassium bromide and potassium carbonate contains 0.6 moles of bromide ion and 0.2 moles of carbonate ion. How many moles of potassium ions are present? A 0.4 B 0.5 C 0.8 D 1.0 8 The total pressure is increased in each of the following reactions. For which reaction would the yield of product(s) not change? A CO(g) + H2O(g) ? CO2(g) + H2(g) B CO(g) + 2H2(g) ? CH3OH(g) C 2H2(g) + O2(g) ? 2H2O(g) D 3H2(g) + CO(g) ? CH4(g) + H2O(g)

11983.05R [Turn over 9 One molecule of cuprimine contains one sulfur atom. The percentage, by mass, of sulfur in cuprimine is 21.47%. The relative molecular mass of cuprimine is A 85. B 101. C 125. D 149. 10 The general formula of an alkyl group is A CnHn + 1 B CnHn − 1 C CnH2n + 1 D CnH2n − 1 11983.05R Section B Answer all four questions in this section 11 Group II metal nitrates are formed when either the metal, the metal oxide or the metal carbonate are reacted with nitric acid. Metal nitrates are very soluble in water and all of the reactions proceed normally, apart from magnesium with nitric acid, because nitric acid is an oxidising agent and causes other reactions to take place. (a) Write equations for the reactions of calcium, calcium oxide and calcium carbonate with dilute nitric acid. (i) calcium: [1] (ii) calcium oxide: [1] (iii) calcium carbonate: [1] (b) Magnesium does not react with most concentrations of nitric acid to give hydrogen. Instead, nitrogen(IV) oxide together with magnesium nitrate and water are produced. Write the equation for the reaction. [1] 11983.05R [Turn over (c) Group II metal nitrates increase in thermal stability as the Group is descended. (i) Explain what is meant by the term thermal stability. [1] (ii) Explain why thermal stability increases down the Group. [1] (d) When heated, the Group II nitrates, M(NO3)2, decompose according to the following equation: 2M(NO3)2 → 2MO + 4NO2 + O2 (i) Explain why the residue left after the reaction gives an alkaline solution when dissolved in water. [1] (ii) If 3.6 g of strontium nitrate is heated and completely decomposes, what is the total volume of gases collected at 20 °C and a pressure of one atmosphere? [3] 11983.05R (iii) The diagram below shows the gases from the decomposition of a nitrate passing through Universal Indicator (UI) solution and one gas being collected in a test tube. Explain why the UI solution goes red and name the gas collected in the test tube. test tube heat UI solution [2] 11983.05R [Turn over (e) Group II metal nitrates are soluble in water. The solubility curve for the Group I nitrate, rubidium nitrate, is shown below. 100 80 60 40 20 0 0 10 20 30 40 50 60 70 80 90 100 temperature/°C solubility/ g/100 g water The following data refers to the solubility of strontium nitrate with temperature. Solubility/ g/100 g water 40  55  71  88  91  93  94  97  99  101 Temperature/°C 0  10  20  30  40  50  60  70  80    90 (i) Plot the solubility curve for strontium nitrate on the axes above. [1] (ii) Determine the temperature at which rubidium nitrate and strontium nitrate have the same solubility. [1]

11983.05R 12 Hypochlorous acid has the formula HOCl. It adds to alkenes to form chlorohydrins. CH2 CH2 + HOCl → CH2ClCH2OH (a) (i) Calculate the enthalpy change for the reaction between ethene and hypochlorous acid using the following average bond enthalpies. bond enthalpy/ kJ mol−1 C C 612 C C 347 Cl O 272 C Cl 346 C O 358 [3] (ii) Construct a simple labelled enthalpy level diagram for the reaction between ethene and hypochlorous acid. Insert the enthalpy value calculated in part (i) onto the diagram. enthalpy reaction co-ordinate [2] 11983.05R [Turn over (b) Hypochlorous acid adds to alkenes because it has a polar bond, HO Cl. (i) Explain what is meant by the term polar bond. [2] (ii) Draw the polarity of a hypochlorous acid molecule. [1] (iii) Draw the mechanism, using curly arrows, for the reaction of hypochlorous acid with propene to form CH2ClCHOHCH3. [4] (iv) Name the compound CH2ClCHOHCH3. [2] 11983.05R (v) The compound CH2ClCHOHCH3 is the major product. Draw the structure of the minor product and explain why it is the minor product. [2] (vi) If the reaction in part (iii) is carried out in the presence of sodium nitrite, NaNO2, some CH2ClCHNO2CH3 is formed. Suggest how this compound is formed. [1] (c) Chlorohydrins are useful in synthetic chemistry because they are bifunctional. (i) Suggest the meaning of the term bifunctional. [1] 11983.05R [Turn over (ii) Complete the following reaction scheme for CH2ClCHOHCH3 by drawing the organic products. HBr NaOH(aq) CH2ClCHOHCH3 KCN PCl5 [4]

11983.05R 13 α-Terpineol is a terpene which is the main ingredient in pine oil. OH α-terpineol It is a colourless liquid with a smell of violets. The boiling point of α-terpineol is 214–216 °C and its density is 0.93 g cm−3. α-Terpineol is slightly soluble in water; 2.42 g dissolves in 1 dm3 of water at room temperature. (a) (i) Describe and explain, using calculated values, what you would observe if you added 1.1 g of α-terpineol to 200 cm3 of water in a beaker at room temperature and stirred the mixture. [4] 11983.05R [Turn over (ii) Explain, with full experimental detail, how you would separate α-terpineol from a mixture of 50 cm3 of α-terpineol and 10 cm3 of water. Your method should include separating with a funnel, distillation and drying. In this question you will be assessed on your written communication skills including the use of specialist scientific terms. [6] 11983.05R (b) The purity of the α-terpineol obtained from part (a) may be determined by the infrared spectrum which is shown below. transmittance wavenumber (cm−1) 3000 2000 1000 0.8 0.6 0.4 0.2 (i) Explain why molecules absorb infrared radiation producing infrared spectra. [2] (ii) Identify the peaks, by stating the range of wavenumbers in the spectrum, which correspond to the functional groups in the molecule. [2] "Data from NIST Standard Reference Database 69: NIST Chemistry WebBook © National Institute of Standard and Technology. U.S. Department of Commerce" 11983.05R [Turn over (iii) Explain how you could use infrared spectrometry to determine that a sample of α-terpineol is pure and free from all impurities. [1] (c) (i) Explain, using the structure of α-terpineol, whether the alcohol is primary, secondary or tertiary. [2] (ii) State what would be observed when a few drops of α-terpineol are added to acidified potassium dichromate(VI) and the mixture is heated. [1] 11983.05R (d) When α-terpineol is dehydrated it forms a mixture of limonene and δ-terpinene. limonene Suggest the structure of δ-terpinene. [1] (e) Limonene is an unsaturated hydrocarbon which reacts with bromine and hydrogen. (i) Define the term unsaturated. [1] 11983.05R [Turn over (ii) Explain, giving experimental detail, how you would use bromine water to test for unsaturation. [3] (iii) Explain, naming the catalyst, what is meant by catalytic hydrogenation. [2] (iv) Cadinene, C15H24, reacts with hydrogen and becomes completely saturated. 0.34 g of cadinene reacts with 80 cm3 of hydrogen at 20 °C and a pressure of one atmosphere. Calculate the number of double bonds in a molecule of cadinene. [3]

11983.05R 14 The Maxwell–Boltzmann distribution curve below shows the distribution of molecular energies in a mixture of the gases sulfur dioxide and oxygen at 25 °C. energy Ea number of molecules The x-axis can either be labelled as energy or speed. The distribution curve starts at the point 0,0 and at the end approaches the x-axis but does not touch it. The symbol Ea is the activation energy. (a) Draw, on the axes above, the Maxwell–Boltzmann distribution curve for a mixture of sulfur dioxide and oxygen, at a lower temperature. [2] (b) Explain why the x-axis can either be labelled as energy or speed. [1] 11983.05R [Turn over (c) Explain what it means if the distribution curve starts at the point 0,0. [1] (d) Explain what it would mean if the Maxwell–Boltzmann curve touched the x-axis at a final energy value. [1] (e) Activation energy varies from reaction to reaction. (i) Explain the term activation energy. [2] (ii) Comment on the reaction speed between silver ions and chloride ions in aqueous solution and how it relates to activation energy. [2] (iii) State the effect of a catalyst on the activation energy of a reaction. [1] 11983.05R (f) The reaction between sulfur dioxide and oxygen is part of the process to manufacture sulfuric acid. (i) What is the name of this industrial process? [1] (ii) Describe and explain the conditions used in this process for the reaction between sulfur dioxide and oxygen referring to temperature, pressure and catalyst. temperature [2] pressure [2] catalyst [1] 11983.05R BLANK PAGE DO NOT WRITE ON THIS PAGE THIS IS THE END OF THE QUESTION PAPER Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 240427 DO NOT WRITE ON THIS PAGE Data Leaflet Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry New Specification © CCEA 2017 For first teaching from September 2016 For first award of AS Level in Summer 2017 For first award of A Level in Summer 2018 Subject Code: 1110 General Information 1 tonne = 106 g 1 metre = 109nm One mole of any gas at 293K and a pressure of 1 atmosphere (105Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 Js Specific Heat Capacity of water = 4.2 J g–1K–1 Speed of Light = 3 × 108 ms–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 (I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx)

13108 [Turn over 12 Magnesium oxide is formed from its elements as follows: Mg(s)  + 1 2O2(g)  →  MgO(s)         ΔfHO — = −602 kJ mol−1 (a) (i) Use the values in the table to calculate the entropy change for the reaction. Substance MgO(s) O2(g) Mg(s) Entropy /J K−1 mol−1 26.9 205 32.7 [2] (ii) Write the equation for free energy change. [1] (iii) Calculate the free energy change for the formation of magnesium oxide at 298 K. State the units. Give your answer to 3 significant figures. [3] (iv) Explain why this reaction is feasible at 298 K. [1] 13108 (b) The following enthalpy changes can be used to calculate the lattice enthalpy of magnesium oxide. Mg(s)  →  Mg(g) + 148 kJ mol−1 Mg(g)  →  Mg2+(g)  +  2e− + 2189 kJ mol−1 O2(g)  →  2O(g) + 498 kJ mol−1 O(g)  +  2e−  →  O2–(g) + 657 kJ mol−1 Mg(s)  + 1 2O2(g)  →  MgO(s) − 602 kJ mol−1 (i) Define lattice enthalpy. [2] (ii) Calculate the lattice enthalpy of magnesium oxide. [2] (iii) Write an equation for the second electron affinity of oxygen. Explain whether this process is exothermic or endothermic. [2] 13108 [Turn over (c) A theoretical value for the enthalpy of solution of magnesium oxide may be calculated using a Hess’s Law diagram. (aq) Mg2 (g) O2 (g) A B MgO(s) Mg2 (aq) O2 (g) enthalpy of solution C Mg2 (aq) O2 (i) Name the enthalpy changes labelled A and B. A B [2] (ii) Suggest why an actual value for the enthalpy of solution of magnesium oxide is not found in any data books. [1]

13108 13 Benzene was first isolated by Faraday in 1825. (a) Both benzene and propene will react with bromine but in different ways. (i) Write equations for the reactions of bromine with benzene and bromine with propene. benzene: propene: [2] (ii) Complete the table below. Reaction of bromine with benzene Reaction of bromine with propene Name of mechanism IUPAC name of product [4] (iii) Explain why the mechanisms for the reactions in (a)(ii) are different. [2] 13108 [Turn over (b) (4-bromophenyl)methanal can be formed by the sequence of reactions shown below. CH3 CH3 Br CH2Br Br CH2OH Br Br C O H Step 1 Step 2 Step 3 Step 4 Step 5 (i) Name the reagent and catalyst used in the formation of methylbenzene in Step 1. reagent: catalyst: [2] (ii) Methylbenzene reacts with bromine in Step 2 in the same way that benzene reacts with bromine. Including any appropriate equations, outline the mechanism for the catalysed reaction of methylbenzene and bromine in Step 2, using curly arrows. [5] 13108 (iii) Suggest the name for the reaction mechanism which occurs during Step 3 of the reaction sequence. [1] (iv) Name the reagent and the reaction conditions needed to carry out Step 5. reagent: conditions: [2] (v) The sample of (4-bromophenyl)methanal obtained contains an organic impurity. The relative molecular mass of the impurity was determined to be 201. Draw the structure of this organic impurity and state its IUPAC name. IUPAC name [2] 13108 [Turn over (c) (i) (4-bromophenyl)methanal reacts with 2,4-dinitrophenylhydrazine. Write an equation for this reaction. [2] (ii) State how the purified organic product formed from the reaction in c(i) could be used to confirm the identity of (4-bromophenyl)methanal. [2]

13108 14 3-methylbutan-1-ol is one of eight alcohols with the molecular formula C5H12O. (a) (i) Complete the table below for some of the isomers of C5H12O. C C C C CH3 O H H H H H H H H H C C C C OH H H CH3 H H H H H H C C C C C OH H H H H H H H H H H H H C C C C OH H H H CH3 H H H H Structural formula Classification IUPAC name primary 3-methylbutan-1-ol primary pentan-2-ol tertiary secondary [5] 13108 [Turn over (ii) Some of the alcohol isomers are optically active. Define the term optically active. [2] (iii) Name the alcohols shown in the table in (a)(i) which exhibit optical activity. [2] (iv) Name the alcohol shown in the table in (a)(i) which can be oxidised to produce an optically active compound. Draw the structural formula of the optically active compound. Name: [2] 13108 (b) 3-methylbutan-1-ol undergoes an esterification reaction with ethanoic acid to form ‘banana oil’ which is used as a food flavouring. (i) Write an equation for this esterification reaction. [2] (ii) An impure sample of ‘banana oil’ was obtained in a round-bottomed flask by reacting 3-methylbutan-1-ol with ethanoic acid in the presence of a concentrated sulfuric acid catalyst. The impure sample of the ‘banana oil’ was collected by distillation. Describe how the sample could be further purified by removing acidic impurities and water. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] 13108 [Turn over (c) Coconut oil contains a large proportion of the triglyceride, glyceryl trilaurate. The fatty acid in this triglyceride is lauric acid, CH3(CH2)10COOH. (i) Draw the structure of glyceryl trilaurate. [1] (ii) Explain why glyceryl trilaurate is a solid at room temperature. [2] (iii) Biodiesel can be produced from oils such as coconut oil by a transesterification reaction. Define the term transesterification. [2] 13108 (iv) An oil, with the general formula shown below, can be used in the formation of biodiesel. CH2 CH CH2 R1COO R2COO R3COO Write the equation for the formation of biodiesel by heating the oil with an excess of ethanol in the presence of a catalyst. [2]

13108 [Turn over 15 Succinic acid is a dicarboxylic acid. It is a white solid at room temperature and melts at 184 °C. It has a solubility in water of 0.0580 kg dm−3 at 20 °C. C H2 C H2 COOH COOH succinic acid (a) (i) Explain why succinic acid has a relatively high melting point. [2] (ii) Calculate the molarity of a saturated solution of succinic acid at 20 °C. Give your answer to 3 significant figures. [2] 13108 (b) Succinic acid undergoes two successive acid ionisation reactions with pKa1 = 4.30 and pKa2 = 5.60. (i) Write an expression for the first acid dissociation constant for succinic acid. [1] (ii) Using the pKa1 value, calculate the pH of a 0.100 mol dm−3 solution of succinic acid. Give your answer to 2 decimal places. [3] 13108 [Turn over (c) Dimethyl succinate (C6H10O4) is a fruit-flavoured additive for ice-cream and chewing gum. It can be hydrolysed to form succinic acid and methanol. C6H10O4  +  2H2O  ⇌  C4H6O4  +  2CH3OH A mixture of 2.0 moles of dimethyl succinate in 5.0 moles of water is left to reach equilibrium in the presence of an acid catalyst at 50 °C. At equilibrium 1.4 moles of dimethyl succinate are present. Calculate the value for Kc in this equilibrium at 50 °C. Give your answer to 2 significant figures. [4] 13108 (d) Sodium ethanoate, used in the production of dimethyl succinate, can also be used in buffer solutions. Solid sodium ethanoate (relative formula mass = 82) is added to 250 cm3 of a 0.1 mol dm−3 solution of ethanoic acid to form a buffer with pH 4.80. The Ka of ethanoic acid is 1.74 × 10−5 mol dm−3. Calculate the mass of sodium ethanoate required and give your answer to 3 significant figures. [4] 13108 (e) Give the structures of the organic products for the reaction of succinic acid with an excess of each reagent. C H2 C H2 COOH COOH excess NH3 excess LiAlH4 excess PCl5 excess NaOH excess NaOH excess LiAlH4 excess PCl5 excess NH3 [4] THIS IS THE END OF THE QUESTION PAPER 13108 BLANK PAGE DO NOT WRITE ON THIS PAGE 13108 BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. DO NOT WRITE ON THIS PAGE ACH14/7 262168 Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

13012 10 Which one of the following statements is the definition of the base peak in a mass spectrum? A The highest mass ion B The peak of greatest abundance C The lowest m/z peak D The molecular ion peak Answer                 [1] 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over 13012 Section B Answer all five questions in this section 11 The ethanedioate ion, C2O2− 4  , may act as a bidentate ligand. Ethanedioate ions, C2O2− 4  , can be titrated using manganate(VII) ions in solution. (a) Explain the term bidentate ligand. [2] (b) The reaction below occurs when a solution containing ethanedioate ions is added to a solution containing hexaaquanickel(II) ions. [Ni(H2O)6]2+  +  3C2O2− 4  →  [Ni(C2O4)3]4-  +  6H2O (i) Suggest why the enthalpy change for this reaction is approximately zero. [2] (ii) Explain, with reference to the equation, why this reaction occurs despite the enthalpy change being approximately zero. [2] 13012 [Turn over (iii) State the co-ordination number and oxidation state of nickel and the shape of the [Ni(C2O4)3]4- complex. co-ordination number: oxidation state of nickel: shape of complex: [3] (c) Hexaaquachromium(III) ions react with ethanedioate ions in solution. The complex formed is shown below. This complex exhibits isomerism. The cis (Z) isomer is shown below and is blue-grey in solution. The trans (E) isomer is purple in solution. Cr O O OH2 O OH2 O C O C O C C O O (i) Write an equation for the formation of this complex from hexaaquachromium(III) ions. [2] (ii) Suggest the structure of the trans (E) isomer. [1] 13012 (d) A 25.0 cm3 portion of a solution of iron(II) ethanedioate was acidified using an excess of sulfuric acid and titrated with 0.0150 mol dm-3 potassium manganate(VII) solution. The overall equation for the reaction is: 10FeC2O4 + 6KMnO4 + 24H2SO4 →  6MnSO4 + 5Fe2(SO4)3 + 3K2SO4 + 24H2O + 20CO2 (i) Explain in terms of oxidation states why this is a redox reaction. [4] (ii) Write three half-equations to show the oxidation and reduction reactions occurring in this overall reaction. [3] 13012 [Turn over (iii) State the colour change which would be observed at the end point during this titration. [1] (iv) The mean titre was found to be 12.45 cm3. Calculate the concentration of the iron(II) ethanedioate solution in mol dm-3. Give your answer to an appropriate number of significant figures. [4] (v) The iron(II) ethanedioate solution was originally made by dissolving 0.561 g of hydrated iron(II) ethanedioate (FeC2O4.xH2O) in 250 cm3 of deionised water. Calculate the value of x in FeC2O4.xH2O. [3]

13012 12 Benzene-1,4-dicarboxylic acid may be used to synthesise polyamide and polyester polymers. COOH COOH benzene-1,4-dicarboxylic acid (a) (i) Name the polyester formed from benzene-1,4-dicarboxylic acid and ethane-1,2-diol. [1] (ii) Draw one repeating unit of the polyester named in (a)(i). [1] 13012 [Turn over (b) The polyamide Kevlar is made from the reaction of 1,4-diaminobenzene with benzene-1,4-dicarboxylic acid. The melting point of Kevlar is over 500 °C. The diagram below shows two Kevlar polymer chains. O N H N H O O N H N H O N H N H O O N H N H O O (i) Suggest the type of bond represented by the dotted lines in the diagram above. [1] (ii) Explain, using the diagram above, why Kevlar has such a high melting point. [1] (c) Explain why polyamides and polyesters are biodegradable. [2]

13012 13 α-amino acids are compounds which have a carboxylic acid group and an amino group bonded to the same carbon atom. (a) Draw the structure of the amino acids, glycine and alanine. glycine alanine [2] (b) The Strecker synthesis involves the reaction of aldehydes or ketones with ammonia and hydrogen cyanide to form an α-aminonitrile which is hydrolysed to form an amino acid. C O R1 R2 C NH2 CN R1 R2 C NH2 COOH R1 R2 NH3 HCN hydrolysis α-aminonitrile amino acid (i) State the IUPAC name of the amino acid which is formed via the Strecker synthesis from propanone. [2] 13012 [Turn over (ii) Draw the structure and state the IUPAC name of the aldehyde or ketone needed to form the amino acid valine, (CH3)2CHCH(NH2)COOH, via the Strecker synthesis. [2] (iii) Write an equation for the reaction of ethanal with ammonia and hydrogen cyanide to form the α-aminonitrile. [1] (iv) Write an equation for the hydrolysis of the α-aminonitrile formed in (b)(iii) above using hydrochloric acid. [2] 13012 (c) The structures of the amino acids lysine and valine are shown below. C COOH (CH )4 H NH2 H2N C COOH CH3 H H2N C H CH3 lysine valine (i) Draw the structure of lysine in solution at pH 1. [1] (ii) Draw the structures of two possible dipeptides formed between one molecule of lysine and one molecule of valine. Circle the peptide link in one of the structures you have drawn. [3] 13012 [Turn over (d) Chains of amino acids, bonded by peptide links, form the primary structure of proteins. Describe the secondary structure of proteins. [3] (e) Two-way paper chromatography can be used to separate and identify lysine and valine from a mixture of amino acids. (i) Describe how two-way paper chromatography is used to separate lysine and valine from the mixture of amino acids. [5] 13012 (ii) Describe how lysine and valine may be located and identified from the chromatogram. [4] (iii) Explain why two-way paper chromatography is a more effective method of separating amino acids than one-way paper chromatography. [1] 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13012 14 Vanadium is a transition metal. (a) State what is meant by the term transition metal and explain using electronic configuration why vanadium is a transition metal. [2] (b) Complete the table below by giving the half-equations and the colour changes for the reduction reactions given. Reduction reaction Half-equation Colour change VO+ 2 to VO2+ VO2+ to V3+ V3+ to V2+ V3+ +  e- →  V2+ [5] 13012 [Turn over (c) V2+ is a powerful reducing agent and is oxidised by oxygen in the presence of acid to V3+. The half-equations with their standard electrode potentials are shown below. EO —/ V V3+(aq)  +  e-  ⇌  V2+(aq) - 0.26 O2(g)  +  4H+(aq)  +  4e-  ⇌  2H2O(l) + 1.23 (i) Write the ionic equation for the oxidation of V2+ using oxygen in the presence of acid. [2] (ii) Write the conventional cell representation for the cell which would be set up using the half cells associated with these two half-equations. [2] (iii) State and explain, in terms of electrons, which half cell is the negative electrode in the cell. [2] (iv) Calculate the emf of the cell. [1] 13012 [Turn over (d) Describe how you would set up a standard hydrogen electrode and use it to measure the standard electrode potential of VO+ 2(aq)/ VO2+(aq). In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE (Questions continue overleaf) [Turn over

13012 15 The azo dye magneson I is also called azo violet as it is violet in colour. It is prepared from 4-nitrophenylamine and resorcinol. NH2 NO2 OH OH 4-nitrophenylamine resorcinol (a) In this preparation, 4-nitrophenylamine is converted into its diazonium ion and reacted with resorcinol. (i) State the reagents and conditions required for the formation of the diazonium ion from 4-nitrophenylamine. [3] (ii) Suggest the IUPAC name for resorcinol. [2] 13012 (iii) Suggest the structure of the azo dye magneson I formed when the diazonium ion of 4-nitrophenylamine reacts with resorcinol. [2] (iv) Explain why magneson I is coloured. [3] [Turn over 13012 (b) 4-nitrophenylamine cannot be prepared by nitration of phenylamine because the amino group is oxidised by nitric acid. The amino group is therefore protected by converting it to an amide group before the nitration is carried out. The amide group is then hydrolysed. The following diagram shows the steps in the synthesis N-phenylethanamide Step 1 Step 2 Step 3 phenylamine NH2 N – C – CH3 A NO2 4-nitrophenylamine NH2 NO2 H O N – C – CH3 H O (i) Name a reagent ­which could be used to carry out Step 1. [1] (ii) Write the molecular formula for A. [1] 13012 [Turn over (iii) 4-nitrophenylamine is a solid at room temperature. Describe, giving experimental details, how the 4-nitrophenylamine obtained in Step 3 can be purified. State how the purity of the solid could be confirmed. In this question you will be assessed on using your written communication skills including the use of specialist scientific terms. [6] 13012 (c) 4-nitrophenylamine may be reduced to 1,4-diaminobenzene using tin in concentrated hydrochloric acid. The mixture is heated under reflux for 30 minutes. Sodium hydroxide solution is then added. (i) Write an equation, using [H] to represent the reducing agent, for the reduction of 4-nitrophenylamine to 1,4-diaminobenzene. [2] (ii) Explain why sodium hydroxide is added. [1] THIS IS THE END OF THE QUESTION PAPER 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE 13012 BLANK PAGE DO NOT WRITE ON THIS PAGE Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. ACH24/8 263175 DO NOT WRITE ON THIS PAGE Data Leafl et Including the Periodic Table of the Elements For the use of candidates taking Advanced Subsidiary and Advanced Level Examinations Copies must be free from notes or additions of any kind. No other type of data booklet or information sheet is authorised for use in the examinations gce a/as examinations chemistry © CCEA 2017 General Information 1 tonne = 106 g 1 metre = 109 nm One mole of any gas at 293 K and a pressure of 1 atmosphere (105 Pa) occupies a volume of 24 dm3 Avogadro Constant = 6.02 × 1023 mol–1 Planck Constant = 6.63 × 10–34 J s Specifi c Heat Capacity of water = 4.2 J g–1 K–1 Speed of Light = 3 × 108 m s–1 Characteristic absorptions in IR spectroscopy Wavenumber/cm–1 Bond Compound 550–850 C–X (X = Cl, Br, I) Haloalkanes s p u o r g ly kla ,s e n a kl A C – C 0 0 1 1 – 0 5 7 s dic a cily x o b r a c ,sr e ts e ,slo h o cl A O – C 0 0 3 1 – 0 0 0 1 1450–1650 C ̿ s e n e r A C 1600–1700 C ̿ s e n e kl A C 1650–1800 C ̿ ,s e d y h e dla ,sr e ts e ,s dic a cily x o b r a C O s e dir olh c ly c a ,s e di m a ,s e n o t e k 2200–2300 C s elirti N N s dic a cily x o b r a C H – O 0 0 2 3 – 0 0 5 2 s e d y h e dl A H – C 0 5 8 2 – 0 5 7 2 s e n e r a ,s e n e kla ,s p u o r g ly kla ,s e n a kl A H – C 0 0 0 3 – 0 5 8 2 slo h o cl A H – O 0 0 6 3 – 0 0 2 3 s e di m a ,s e ni m A H – N 0 0 5 3 – 0 0 3 3 Proton Chemical Shifts in Nuclear Magnetic Resonance Spectroscopy (relative to TMS) Structure 0.5–2.0 –CH s e n a kla d e t a r u t a S 0.5–5.5 –OH slo h o cl A 1.0–3.0 –NH s e ni m A 2.0–3.0 –CO–CH Ketones C – N – H Amines C 6H5–CH c on ring) 2.0–4.0 X–CH X = Cl or Br (3.0–4.0) ) 0.3 – 0.2 ( I = X 4.5–6.0 –C ̿ CH Alkenes 5.5–8.5 RCONH Amides 6.0–8.0 –C6H5 Arenes (on ring) 9.0–10.0 –CHO Aldehydes 10.0–12.0 –COOH Carboxylic acids on and temperature dependent and may be outside the ranges indicated above. 11331.03 227 89 139 57 256 101 223 87 226 88 261 104 262 105 266 106 264 107 277 108 268 109 271 110 272 111 140 58 141 59 144 60 145 61 150 62 152 63 157 64 159 65 162 66 165 67 167 68 169 69 173 70 175 71 232 90 231 91 238 92 237 93 242 94 243 95 247 96 245 97 251 98 254 99 253 100 254 102 257 103 133 55 137 56 178 72 181 73 184 74 186 75 190 76 192 77 195 78 197 79 201 80 89 39 91 40 103 45 85 37 88 38 93 41 96 42 98 43 101 44 106 46 108 47 112 48 131 54 222 86 210 85 210 84 209 83 207 82 204 81 84 36 79 34 73 32 40 20 39 19 45 21 48 22 51 23 52 24 55 25 56 26 59 27 59 28 64 29 65 30 11 5 12 6 14 7 16 8 19 9 20 10 4 2 40 18 35.5 17 32 16 31 15 28 14 27 13 70 31 75 33 80 35 115 49 119 50 122 51 128 52 127 53 23 11 24 12 7 3 9 4 THE PERIODIC TABLE OF ELEMENTS Group * † 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 II I III IV VI VII 0 V 285 112 Copernicium * 58 – 71 Lanthanum series † 90 – 103 Actinium series a = relative atomic mass x = atomic symbol b = atomic number a bx (approx) 11331.03

12885.03 [Turn over INSTRUCTIONS TO THE SUPERVISOR OF THE PRACTICAL EXAMINATION General 1. The instructions contained in this document are for the use of the Supervisor and are strictly confidential. Under no circumstances may information concerning apparatus or materials be given before the examination to a candidate or other unauthorised person. 2. In a centre with a large number of candidates it may be necessary for two or more examination sessions to be organised. It is the responsibility of the schools to ensure that there should be no contact between candidates taking each session. 3. A suitable laboratory must be reserved for the examination and kept locked throughout the period of preparation. Unauthorised persons not involved in the preparation for the examination must not be allowed to enter. Candidates must not be admitted until the specified time for commencement of the examination. 4. The Supervisor must ensure that the solutions provided for the candidates are of the nature and concentrations specified in the Apparatus and Materials List. 5. The Supervisor is to be granted access to the Teacher’s Copy of Practical Booklet A on Monday 9 May 2022. The Supervisor is asked to check, at the earliest opportunity, that the experiments and tests in the question paper may be completed satisfactorily using the apparatus, materials and solutions that have been assembled. This question paper must then be returned to safe custody at the earliest possible moment after the Supervisor has ensured that all is in order. No access to the question paper should be allowed before Monday 9 May 2022. 6. Centres may need to carry out multiple sessions to accommodate all their candidates sitting Practical Booklet A in a laboratory. Supervision must take place from 30 minutes after the scheduled starting time of the examination, as set out in the timetable, until the time when the candidate(s) begin(s) their examination(s). This is in order to ensure that there is no contact with other candidates. The centre must appoint a member of staff from the centre to supervise the candidate(s) at all times while they are on the premises. 7. All apparatus should be checked before the examination, and there should be an adequate supply of spare apparatus in case of breakages. The Apparatus and Materials List should be regarded as a minimum and there is no objection to candidates being supplied with more than the minimum amount of apparatus and materials. 8. Candidates may not use text books and laboratory notes for reference during the examination, and must be informed of this beforehand.

12885.03 [Turn over 9. Clear instructions must be given by the Supervisor to all candidates at the beginning of the examination concerning appropriate safety procedures and precautions. Supervisors are also advised to remind candidates that all substances in the examination must be treated with caution. Only those tests specified in the question paper should be attempted. Candidates must not attempt any additional confirmatory tests. Anything spilled on the skin should be washed off immediately with plenty of water. The use of appropriate eye protection is essential. 10. Supervisors are reminded that they may not assist candidates during the examination. However if, in the opinion of the Supervisor, a candidate is about to do something which may endanger themselves or others, the Supervisor should intervene. A full written report must be sent to CCEA at once. 11. Upon request, a candidate may be given additional quantities of materials (answer paper, reagents and unknowns) without penalty. No notification needs to be sent to CCEA. 12. The examination room must be cleared of candidates immediately after the examination. 13. No materials will be supplied by CCEA. 14. All JCQ procedures for conducting examinations should be followed for this practical examination including displaying JCQ posters with examination information in the laboratory and removal of mobile phones. Posters should be available from your Examinations Officer. 12885.03 [Turn over Northern Ireland Council for the Curriculum, Examinations and Assessment General Certificate of Education Advanced Chemistry Practical Booklet A [ACH31] Thursday 12 May 2022 This report must be completed by the Supervisor during the examination. The complete report should include all candidates taking this Practical Examination. This Supervisor’s Report should be copied and attached to Each Advice Note bundle and returned to CCEA in the normal way. Comments: Supervisor’s Signature . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . 71 Centre Number Candidate Number