The table shows energy values for a reaction with and without a catalyst. All values are in kJ/mol\mathrm{kJ/mol}kJ/mol and are measured from the same reference level.
| Part of reaction | Without catalyst | With catalyst |
|---|---|---|
| Reactants | 40 | 40 |
| Products | 12 | 12 |
| Highest point on pathway | 110 | 78 |
Calculate the activation energy for each pathway and the overall energy change. Explain what the results show about the effect of the catalyst on the rate of reaction and on the overall energy change.
122 exam-style questions on OCR GCSE Chemistry 5.2 Controlling reactions, covering 5.2.1 Measuring and interpreting rate of reaction, 5.2.2 Factors affecting rate and collision theory, and 5.2.3 Catalysts, activation energy and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.