A researcher tests four insoluble solids, P, Q, R and S. Each solid increases the rate of the same reaction.
The researcher starts each test with 0.80 g of solid. After each reaction, the solid is filtered, washed, dried and reweighed.
| Solid | Mass after the reaction in g |
|---|---|
| P | 0.62 |
| Q | 0.80 |
| R | 0.86 |
| S | 0.74 |
Which solid was not used up in the reaction?
Solid P, because it could still be recovered after the reaction.
Solid Q, because its dry mass was the same before and after.
Solid R, because it had the greatest dry mass after the reaction.
Solid S, because it lost less mass than solid P did.
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.