Cambridge Secondary (7-9). Stage 9. Science. Learner's Book - Unit 8: Rates of reaction - Question 4

This table shows results from magnesium reacting with dilute sulfuric acid in the gas-syringe apparatus. How can you tell from the table that the reaction has finished at 270 seconds?

| Time (s) | Total hydrogen volume (cm³) |
|---|---|
| 0 | 0 |
| 30 | 10 |
| 60 | 20 |
| 90 | 26 |
| 120 | 40 |
| 150 | 48 |
| 180 | 54 |
| 210 | 60 |
| 240 | 64 |
| 270 | 66 |
| 300 | 66 |
| 330 | 66 |