Methanol is manufactured by reacting carbon monoxide with hydrogen.
CO(g)+2H2(g)⇌CH3OH(g)\mathrm{CO(g)} + \mathrm{2H_{2}(g)} \rightleftharpoons \mathrm{CH_{3}OH(g)}CO(g)+2H2(g)⇌CH3OH(g)
The table shows the percentage of methanol in the equilibrium mixture under different conditions.
| Temperature / °C | Percentage of methanol at 50 atm (%) | Percentage of methanol at 100 atm (%) |
|---|---|---|
| 200 | 40 | 60 |
| 250 | 20 | 38 |
| 300 | 8 | 18 |
Deduce whether the forward reaction is exothermic or endothermic. Justify your answer using the table.
Explain why the percentage of methanol is higher at 100 atm than at 50 atm.
The industrial process uses a temperature of 250 °C and a copper-based catalyst. Suggest why 250 °C is used rather than 200 °C.
In the reactor, methanol is cooled and removed from the mixture as it forms. Explain the effect of this on the equilibrium.
A reactor is fed with 480 dm3\mathrm{dm^{3}}dm3 of carbon monoxide and 720 dm3\mathrm{dm^{3}}dm3 of hydrogen, both measured at room temperature and pressure. Determine which gas is the limiting reactant and calculate the maximum mass of methanol that could be made if all of the limiting reactant were converted into methanol. Relative formula mass: CH3OH=32\mathrm{CH_{3}OH} = 32CH3OH=32. One mole of any gas occupies 24 dm3\mathrm{dm^{3}}dm3 at room temperature and pressure.
45 exam-style questions on Edexcel GCSE Chemistry 5.2 Reversible reactions and equilibria, covering 5.2.1 Reversible reactions and dynamic equilibrium, 5.2.2 The Haber process, and 5.2.3 Changing the position of a dynamic equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.