The synthesis of ammonia from nitrogen and hydrogen is a reversible reaction:
N2(g)+3H2(g)⇌2NH3(g) \text{N}_2\text{(g)} + 3\text{H}_2\text{(g)} \rightleftharpoons 2\text{NH}_3\text{(g)} N2(g)+3H2(g)⇌2NH3(g)The forward reaction is exothermic.
If nitrogen and hydrogen are reacted at a pressure of 200 atm and a low temperature of 250 °C without a catalyst, a high equilibrium yield of ammonia can eventually be achieved, but the reaction takes a very long time.
In the commercial Haber process, a pressure of 200 atm and a temperature of 450 °C are used in the presence of an iron catalyst.
Explain why the conditions used in the industrial Haber process are preferred for the profitable manufacture of ammonia compared to the low-temperature, catalyst-free conditions.
Practise Edexcel GCSE Chemistry Reversible reactions and equilibria with exam-style questions for Foundation and Higher tier. 38 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
