An investigator burned four different liquid ketones to evaluate their efficiency as fuels. The energy released from each combustion was used to heat 150 g150\text{ g}150 g of water. For each ketone, the investigator recorded the mass of the fuel burned and the temperature rise of the water. The results are summarized 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 |
|---|---|---|---|---|
| propanone | 58 | 1.5 | 0.026 | 18 |
| butanone | 72 | 2.5 | 0.035 | 28 |
| pentan-2-one | 86 | 3.5 | 0.041 | 36 |
| hexan-2-one | 100 | 4.5 | 0.045 | 42 |
One student suggests that propanone is the best fuel. Explain why, using the information in the table.
Another student suggests that hexan-2-one 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 propanone to be 1050 kJ/mol1050\text{ kJ/mol}1050 kJ/mol. The accepted data book value is 1790 kJ/mol1790\text{ kJ/mol}1790 kJ/mol. Suggest two reasons why the experimental value is lower than the data book value.
