A manufacturer uses a solid reactant to make a gas. Two 4.0 g samples of the same solid are reacted separately with the same volume and concentration of a solution at the same temperature. The solution is in excess in both experiments.
| Sample | Form of solid | Total exposed surface area in cm² | Volume of gas after 20 s in cm³ | Final volume of gas in cm³ |
|---|---|---|---|---|
| P | pellets | 24 | 18 | 72 |
| Q | powder | 160 | 55 | not measured |
Use the data to explain the difference between the volumes of gas collected after 20 s. Include in your answer the final volume of gas expected from sample Q.
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.