Ammonia is manufactured by the Haber process.
N2(g)+3H2(g)⇌2NH3(g)\mathrm{N_{2}(g)} + \mathrm{3H_{2}(g)} \rightleftharpoons \mathrm{2NH_{3}(g)}N2(g)+3H2(g)⇌2NH3(g)
The mixture of gases leaving the reactor is cooled. The ammonia turns into a liquid and is removed. The unreacted nitrogen and hydrogen are sent back into the reactor.
Give one reason why the unreacted nitrogen and hydrogen are sent back into the reactor.
The table shows the percentage of ammonia in the equilibrium mixture at 450 °C at different pressures.
| Pressure / atm | Percentage of ammonia (%) |
|---|---|
| 50 | 9 |
| 100 | 16 |
| 200 | 28 |
| 300 | 36 |
| 400 | 42 |
Describe the trend shown in the table.
Estimate the percentage of ammonia in the equilibrium mixture at 250 atm.
Explain, in terms of molecules of gas, why increasing the pressure increases the percentage of ammonia.
Ammonia reacts with nitric acid to make ammonium nitrate, which is used as a fertiliser.
Write the word equation for this reaction.
Name one element, other than nitrogen, that fertilisers may contain to help plant growth.
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.