Two reactions, R and S, form the same cloudy product. A light sensor measures the percentage of light transmitted through each mixture. The decrease in the sensor reading is proportional to the amount of cloudy product formed.
| Time in s | Light transmitted for R in % | Light transmitted for S in % |
|---|---|---|
| 0 | 100 | 100 |
| 20 | 70 | 80 |
| 40 | 50 | 65 |
| 80 | 50 | 50 |
Calculate the mean rate of decrease in the sensor reading during the first 20 s for each reaction.
Explain which reaction finished first. Use the data in the table.
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.