A research chemist is investigating the thermal efficiency of various liquid biofuels. The chemist combusts samples of different straight-chain alcohols under standard laboratory conditions to determine the energy released per gram.
| Alcohol | Chemical formula of alcohol molecule | Energy released in kJ/g\text{kJ/g}kJ/g |
|---|---|---|
| Ethanol | C2H5OH\text{C}_2\text{H}_5\text{OH}C2H5OH | 29.8 |
| Propanol | C3H7OH\text{C}_3\text{H}_7\text{OH}C3H7OH | 33.5 |
| Butanol | C4H9OH\text{C}_4\text{H}_9\text{OH}C4H9OH | 36.0 |
| Pentanol | C5H11OH\text{C}_5\text{H}_{11}\text{OH}C5H11OH | 37.8 |
| Hexanol | C6H13OH\text{C}_6\text{H}_{13}\text{OH}C6H13OH | 39.0 |
| Heptanol | C7H15OH\text{C}_7\text{H}_{15}\text{OH}C7H15OH | 40.2 |
Calculate the mass of ethanol that must be completely burned to release the same amount of thermal energy as burning 4.80 g4.80\text{ g}4.80 g of hexanol. Give your answer to 3 significant figures.
12 exam-style questions on AQA GCSE Chemistry 7.2 Reactions of alkenes and alcohols, covering 7.2.1 Structure and formulae of alkenes, 7.2.2 Reactions of alkenes, 7.2.3 Alcohols, and 7.2.4 Carboxylic acids. Each one has a worked solution and a mark scheme showing where the marks go.