A student measures the volume of oxygen made when the same volume of the same hydrogen peroxide solution decomposes, with and without a catalyst.
| Time (s) | 0 | 10 | 20 | 30 | 40 | 50 | 60 |
|---|---|---|---|---|---|---|---|
| Volume without catalyst (cm3\mathrm{cm^{3}}cm3) | 0 | 6 | 12 | 17 | 22 | 26 | 30 |
| Volume with catalyst (cm3\mathrm{cm^{3}}cm3) | 0 | 24 | 42 | 54 | 60 | 60 | 60 |
Statement 1: The catalyst increases the total volume of oxygen made, because twice as much oxygen is collected in 60 s.
Statement 2: The mean rate of reaction in the first 10 s is 4 times greater with the catalyst.
Statement 3: The reaction with the catalyst had stopped by 40 s.
Which statements are correct?
1 only
1 and 2 only
2 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.