A student investigates whether a powder, Z, acts as a catalyst for a reaction that gives off a gas. Both experiments use the same volume and concentration of the reacting solution at the same temperature.
| Experiment | Mass of Z added in g | Time to collect 50 cm3 of gas in s | Mass of Z recovered at the end in g |
|---|---|---|---|
| A | 0.00 | 240 | — |
| B | 0.50 | 45 | 0.50 |
State two pieces of evidence from the results that support the conclusion that Z acted as a catalyst.
122 exam-style questions on Edexcel GCSE Chemistry 8.1 Rates of reaction, covering 8.1.1 Measuring and interpreting rates of reaction, 8.1.2 Collision theory and the factors affecting rate, and 8.1.3 Catalysts and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.