A reaction takes place in an insulated container. The table gives the relative energy of the reacting chemicals and the measured temperature of the surroundings, before and after the reaction.
| Measurement | Before reaction | After reaction |
|---|---|---|
| Relative energy of reacting chemicals | 640 kJ/mol | 410 kJ/mol |
| Temperature of surroundings | 18 ∘C18\ ^\circ\text{C}18 ∘C | 24 ∘C24\ ^\circ\text{C}24 ∘C |
Calculate the energy change for the reaction and explain whether the temperature readings are consistent with your answer.
85 exam-style questions on AQA GCSE Chemistry 5.1 Exothermic and endothermic reactions, covering 5.1.1 Energy transfer during exothermic and endothermic reactions, 5.1.2 Reaction profiles, and 5.1.3 The energy change of reactions. Each one has a worked solution and a mark scheme showing where the marks go.