A student investigates a reaction between two solutions. The mixture changes from blue to colourless during the reaction.
The student records the time taken for the mixture to reach the same shade of pale blue. The same volumes and concentrations of the solutions are used each time.
| Temperature (∘C^\circ\mathrm{C}∘C) | Time in trial 1 (s) | Time in trial 2 (s) | Time in trial 3 (s) |
|---|---|---|---|
| 20 | 79 | 80 | 81 |
| 30 | 39 | 41 | 65 |
One result is anomalous.
Calculate how many times greater the mean relative rate is at 30 ∘C30\,^\circ\mathrm{C}30∘C than at 20 ∘C20\,^\circ\mathrm{C}20∘C.
Do not use the anomalous result.
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.