A blue reactant changes into a colourless product. Two experiments use identical quantities of reactants at the same temperature. Solid X is added only in experiment 2.
| Experiment | Mass of X added in g | Time for the colour to stop changing in s | Mass of product formed in g | Mass of X recovered in g |
|---|---|---|---|---|
| 1 | 0.00 | 180 | 3.60 | 0.00 |
| 2 | 0.20 | 72 | 3.60 | 0.20 |
Explain, using the results and collision theory, why X can be described as a catalyst.
The reaction is repeated with the same quantities of reactants and 0.40 g of X. Give the mass of product formed when the reaction has finished. Explain your answer.
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.