A student investigates the rate of reaction between solid calcium carbonate (CaCO3\text{CaCO}_3CaCO3) and dilute hydrochloric acid (HCl\text{HCl}HCl) to produce calcium chloride, carbon dioxide, and water.
The reaction is carried out under two different sets of conditions, Trial 1 and Trial 2, as shown in the table below:
| Condition | Trial 1 | Trial 2 |
|---|---|---|
| Temperature (∘C^\circ\text{C}∘C) | 60 | 20 |
| State of CaCO3\text{CaCO}_3CaCO3 | Large lumps | Fine powder |
Explain, in terms of collision theory, why it is not possible to predict whether the rate of Trial 2 will be faster or slower than the rate of Trial 1.
127 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.