A student investigates the reaction between zinc and dilute sulfuric acid. A gas is made.
The student does three experiments. In each experiment the student uses:
the same volume and concentration of dilute sulfuric acid
the same mass of zinc.
The student measures the time taken to collect 40 cm3\mathrm{cm^{3}}cm3 of gas.
The table shows the results.
| Experiment | Form of zinc | Temperature of acid (°C) | Time to collect 40 cm3\mathrm{cm^{3}}cm3 of gas (s) |
|---|---|---|---|
| 1 | granules | 20 | 240 |
| 2 | granules | 40 | 60 |
| 3 | powder | 40 | 16 |
Name the gas made. Describe the test for this gas.
Calculate how many times faster Experiment 2 is than Experiment 1.
Use the results to describe the effect of temperature and the effect of the size of the pieces of zinc on the rate of reaction.
Explain both effects using the reacting particle model.
Suggest how the student could improve the investigation.
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.