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