Four additives were tested in a reaction used to make a food ingredient. The same mass of each additive was used. All four additives made the reaction finish sooner than it did without an additive.
After the reaction, the products were removed from any remaining additive. The remaining additive was washed, dried and weighed.
| Additive | Mass before the reaction / g | Mass after the reaction / g |
|---|---|---|
| A | 0.40 | 0.20 |
| B | 0.40 | 0.00 |
| C | 0.40 | 0.40 |
| D | 0.40 | 0.10 |
Use the mass results to select the additive whose behaviour is consistent with a catalyst.
Additive B is the catalyst
Additive D is the catalyst
Additive A is the catalyst
Additive C is the catalyst
127 exam-style questions on AQA GCSE Chemistry 6.1 Rate of reaction, covering 6.1.1a Calculating rates of reactions, 6.1.1b Gradient of a tangent as rate, 6.1.2 Factors which affect the rates of chemical reactions, 6.1.3 Collision theory and activation energy, and 6.1.4 Catalysts. Each one has a worked solution and a mark scheme showing where the marks go.