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. (2) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... (Total for Question 6 = 16 marks)