The table shows information about two exothermic reactions.
| Reaction | Activation energy (kJ/mol\mathrm{kJ/mol}kJ/mol) | Energy change (kJ/mol\mathrm{kJ/mol}kJ/mol) |
|---|---|---|
| 1 | 40 | -200 |
| 2 | 150 | -300 |
Which statement is correct?
Reaction 2 needs less energy to start because it releases more energy overall.
Reaction 1 releases more energy overall because its activation energy is smaller.
Reaction 1 needs less energy to start, but reaction 2 releases more energy overall.
Reaction 2 needs less energy to start because its activation energy is larger.
51 exam-style questions on OCR GCSE Chemistry 3.2 Energetics, covering 3.2.1 Exothermic and endothermic reactions and reaction profiles and 3.2.2 Calculating energy change from bond energies. Each one has a worked solution and a mark scheme showing where the marks go.