A portable camping stove is tested using different liquid alcohol fuels. The table below shows the experimental energy density (energy released per gram of fuel combusted under standard conditions) for several straight-chain alcohols.
| Alcohol | Molecular formula | Energy released in kJ g−1\text{kJ g}^{-1}kJ g−1 |
|---|---|---|
| Methanol | CH3OH\text{CH}_3\text{OH}CH3OH | 22.722.722.7 |
| Ethanol | C2H5OH\text{C}_2\text{H}_5\text{OH}C2H5OH | 29.729.729.7 |
| Propan-1-ol | C3H7OH\text{C}_3\text{H}_7\text{OH}C3H7OH | 33.633.633.6 |
| Butan-1-ol | C4H9OH\text{C}_4\text{H}_9\text{OH}C4H9OH | 36.136.136.1 |
| Pentan-1-ol | C5H11OH\text{C}_5\text{H}_{11}\text{OH}C5H11OH | 37.837.837.8 |
| Octan-1-ol | C8H17OH\text{C}_8\text{H}_{17}\text{OH}C8H17OH | 41.241.241.2 |
Determine the mass of methanol that must be completely combusted to release the same quantity of energy as the complete combustion of 4.25 g4.25\text{ g}4.25 g of octan-1-ol.
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.