Methanol, CH3OH\mathrm{CH_{3}OH}CH3OH, is made from carbon monoxide and hydrogen.
CO(g)+2H2(g)⇌CH3OH(g) \mathrm{CO(g) + 2H_{2}(g) \rightleftharpoons CH_{3}OH(g)} CO(g)+2H2(g)⇌CH3OH(g)The forward reaction is exothermic.
A chemist compares four sets of conditions, A, B, C and D.
| Set of conditions | Temperature (°C) | Pressure (atm) |
|---|---|---|
| A | 200 | 10 |
| B | 200 | 100 |
| C | 400 | 10 |
| D | 400 | 100 |
Which set of conditions gives the highest percentage of methanol in the equilibrium mixture?
Write the letter.
Explain your choice of temperature in (a).
Explain your choice of pressure in (a).
In the factory, methanol is removed from the reaction mixture as it forms.
Predict the effect of this on the position of equilibrium. Explain your answer.
The chemist adds more hydrogen to an equilibrium mixture. The temperature and pressure stay the same.
State what happens to the amount of carbon monoxide in the mixture.
47 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.