The energy levels for a reaction are shown in the table.
| Pathway | Energy of reactants in kJ/mol | Energy at the peak in kJ/mol | Energy of products in kJ/mol |
|---|---|---|---|
| Without a catalyst | 120 | 205 | 70 |
| With a catalyst | 120 | 160 | 70 |
Calculate the overall energy change, defined as the energy of the products minus the energy of the reactants.
Explain how the data show that the catalyst increases the rate of reaction but does not change the overall energy change.
127 exam-style questions on AQA GCSE Chemistry 6.1 Rate of reaction, covering 6.1.1a Calculating rates of reactions, 6.1.1b Gradient of a tangent as rate, 6.1.2 Factors which affect the rates of chemical reactions, 6.1.3 Collision theory and activation energy, and 6.1.4 Catalysts. Each one has a worked solution and a mark scheme showing where the marks go.