A student burned four liquid alcohols to compare the amount of heat energy they released, in order to determine which is the best fuel. The energy released was used to raise the temperature of 100 g of water. For each fuel, the student recorded the mass of fuel burned and the temperature increase of the water. The results are shown in the table below:
| Fuel | Relative formula mass | Mass of fuel burned in g\text{g}g | Amount of fuel burned in mol\text{mol}mol | Increase in temperature in ∘C^{\circ}\text{C}∘C |
|---|---|---|---|---|
| propanol | 60 | 1.0 | 0.017 | 11 |
| butanol | 74 | 2.0 | 0.027 | 20 |
| pentanol | 88 | 3.0 | 0.034 | 27 |
| hexanol | 102 | 4.0 | 0.039 | 32 |
One student suggests that propanol is the best fuel. Explain why, using the information in the table.
Another student suggests that hexanol is the best fuel. Explain why, using the information in the table.
In another trial, the student calculated the experimental energy released per mole of propanol to be 1100 kJ/mol. The accepted data book value is 2021 kJ/mol. Suggest two reasons why the experimental value is lower than the data book value.
