1. 1
   A student carries out the core practical investigation into the combustion of alcohols. She burns a measured mass of ethanol, then propanol, then butanol, each in turn under a copper calorimeter containing 100 g of water, and records the temperature rise of the water for each alcohol burned.

   (a)

   (a) Which functional group is present in all alcohols?

   [1 mark]

   • A–OH
   • B–COOH
   • C–CHO
   • D–NH2

   (b)

   (b) The student's data shows that, per mole burned, butanol raises the temperature of the water by more than ethanol does. What is the best explanation for this trend?

   [1 mark]

   • AButanol evaporates more slowly than ethanol during the experiment
   • BButanol is denser than ethanol, so it weighs more for the same volume burned
   • CButanol contains a different functional group to ethanol
   • DButanol molecules have longer carbon chains, so each mole contains more carbon-hydrogen and carbon-carbon bonds, releasing more energy when broken and reformed during combustion

   (c)

   (c) Suggest two reasons why the temperature rise measured in this experiment is likely to be lower than the true energy released by combustion of the alcohol.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A bottle of wine has been left open and exposed to air for several weeks. Bacteria in the air have converted some of the ethanol in the wine into ethanoic acid, giving the wine a sour, vinegar-like taste.

   (a)

   What type of reaction converts ethanol into ethanoic acid in the wine?

   [1 mark]

   • ANeutralisation
   • BReduction
   • COxidation
   • DFermentation

   (b)

   (b) Which functional group is responsible for the acidic properties of the ethanoic acid now present in the wine?

   [1 mark]

   • A–OH
   • B–COOH
   • C–CH3
   • D–O–

   (c)

   (c) The spoiled wine is tested by adding a small amount of sodium carbonate powder to a sample. Describe what would be observed and name the gas produced.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A small brewery produces ethanol by mixing crushed grain with water and yeast in a large sealed vessel, kept at a warm temperature and away from air, for several days. The resulting liquid contains only a dilute concentration of ethanol mixed with water and other substances, so it is then heated in a tall column to separate out a much more concentrated ethanol solution.

   (a)

   (a) Describe how the yeast produces ethanol from the sugars in the crushed grain, and explain why the sealed vessel is kept away from air.

   [3 marks]

   (b)

   (b) Explain how heating the fermentation mixture in the tall column produces a more concentrated ethanol solution, referring to the boiling points of the substances involved.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A student is comparing the alcohol homologous series (methanol, ethanol, propan-1-ol, butan-1-ol) with the carboxylic acid homologous series (methanoic acid, ethanoic acid, propanoic acid, butanoic acid).

   (a)

   (a) Describe, in words, the structures of ethanol and ethanoic acid, stating every atom present and how the atoms are covalently bonded to each other. Explain what is meant by a homologous series and why members of the alcohol series all react in similar ways to each other.

   [6 marks]

   (b)

   (b) Propan-1-ol can be dehydrated to form an alkene. Explain what is meant by dehydration in this context, name the alkene product, and predict, with reasoning, the alkene product formed when butan-1-ol undergoes the same reaction.

   [6 marks]

   Total for question 4: 12 marks

End of questions