A fertiliser producer is comparing two designs for an ammonia reactor.
The equation for the reaction is:
N2+3H2⇌2NH3\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3N2+3H2⇌2NH3
The forward reaction is exothermic.
The table shows the conditions, the equilibrium yield and the mass of ammonia produced each hour for each design.
| Design | Pressure / atmospheres | Temperature / ∘C^\circ\text{C}∘C | Equilibrium yield of ammonia / % | Ammonia produced / tonnes per hour |
|---|---|---|---|---|
| A | 150 | 400 | 31 | 17 |
| B | 200 | 450 | 28 | 24 |
Explain why design A has a higher equilibrium yield than design B, even though design A operates at a lower pressure.
Design B produces more ammonia each hour than design A, but its equilibrium yield is lower. Explain why.
71 exam-style questions on AQA GCSE Chemistry 10.4 The Haber process and the use of NPK fertilisers, covering 10.4.1a The Haber process, 10.4.1b Equilibrium and rate in the Haber process, and 10.4.2 Production and uses of NPK fertilisers. Each one has a worked solution and a mark scheme showing where the marks go.