A chemist investigated the rate of reaction between copper(II) carbonate and dilute nitric acid by monitoring the total mass of the reaction flask. Carbon dioxide gas was allowed to escape through a cotton wool plug.
Their results are shown in the table below:
| Time (t t\,t in seconds) | Mass of flask (m m\,m in grams) |
|---|---|
| 0 | 250.00 |
| 20 | 248.65 |
| 40 | 247.70 |
| 60 | 247.10 |
| 80 | 246.75 |
| 100 | 246.55 |
| 120 | 246.45 |
| 140 | 246.45 |
| 160 | 246.45 |
Explain why the chemist could have stopped recording measurements at 120 seconds.
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.