A reversible reaction takes place in a sealed vessel:
X(g)+Y(g)⇌Z(g) \mathrm{X(g) + Y(g) \rightleftharpoons Z(g)} X(g)+Y(g)⇌Z(g)The concentrations are measured at different times.
| Time / min | Concentration of X / mol dm−3^{-3}−3 | Concentration of Y / mol dm−3^{-3}−3 | Concentration of Z / mol dm−3^{-3}−3 |
|---|---|---|---|
| 0 | 0.80 | 0.60 | 0.00 |
| 10 | 0.60 | 0.40 | 0.20 |
| 20 | 0.50 | 0.30 | 0.30 |
| 30 | 0.50 | 0.30 | 0.30 |
| 40 | 0.50 | 0.30 | 0.30 |
Use the results to determine the first recorded time at which the reaction mixture has reached dynamic equilibrium. Explain your answer.
The experiment is repeated in an open vessel.
Explain why the mixture cannot reach dynamic equilibrium.
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.