Substances R and S react reversibly in a sealed container. The conditions are kept constant. The table shows how the amounts of R and S change.
| Time (s) | Amount of R (mmol) | Amount of S (mmol) |
|---|---|---|
| 0 | 7.8 | 2.2 |
| 15 | 6.4 | 3.6 |
| 30 | 5.8 | 4.2 |
| 45 | 5.6 | 4.4 |
| 60 | 5.6 | 4.4 |
| 75 | 5.6 | 4.4 |
Which statement is correct?
At 45 s, the reaction is continuing until all of substance R has been used.
At 60 s, particles continue to react in both directions at equal rates.
At 15 s, the change from S to R is faster than the change from R to S.
At 30 s, the forward and reverse reactions are happening at the same rate.
124 exam-style questions on OCR GCSE Chemistry 5.3 Equilibria, covering 5.3.1 Reversible reactions and dynamic equilibrium and 5.3.2 Changing the position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.