A student adds marble chips to dilute hydrochloric acid in a flask on a balance. The table shows the mass of the flask and its contents.
| Time (s) | 0 | 30 | 60 | 90 | 120 | 150 |
|---|---|---|---|---|---|---|
| Mass (g) | 150.00 | 149.52 | 149.20 | 149.04 | 149.00 | 149.00 |
Statement 1: The mean rate of reaction in the first 30 s is 0.016 g/s.
Statement 2: The reaction had stopped by 90 s.
Statement 3: The mean rate of reaction between 60 s and 90 s is one third of the mean rate in the first 30 s.
Which statements are correct?
1 only
1 and 2 only
1 and 3 only
1, 2 and 3
56 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.