A student reacts magnesium ribbon with dilute hydrochloric acid and measures the volume of hydrogen made (Experiment 1). The student then changes one thing and repeats the experiment (Experiment 2). The acid is in excess in both experiments.
| Time (s) | 0 | 20 | 40 | 60 | 80 | 100 |
|---|---|---|---|---|---|---|
| Volume in Experiment 1 (cm3\mathrm{cm^{3}}cm3) | 0 | 30 | 48 | 58 | 60 | 60 |
| Volume in Experiment 2 (cm3\mathrm{cm^{3}}cm3) | 0 | 15 | 24 | 29 | 30 | 30 |
Which change did the student make in Experiment 2?
Used the acid at a lower temperature
Used more dilute hydrochloric acid
Used half the mass of magnesium ribbon
Used larger pieces of magnesium
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.