Catalysts in industry
4 marks · NormalAn industrial process uses iron as a catalyst for the reaction between nitrogen and hydrogen to form ammonia (the Haber process):
The data below show the percentage yield of ammonia at two different temperatures, with and without the iron catalyst.
| Temperature/°C | Catalyst present? | Percentage yield of ammonia |
|---|---|---|
| 400 | No | 15 |
| 400 | Yes | 15 |
| 500 | No | 10 |
| 500 | Yes | 10 |
Use the information in the table to answer the questions.
Does the iron catalyst affect the percentage yield of ammonia at these temperatures? Explain your answer.
Explain why the use of the iron catalyst is still important in this industrial process.
Suggest one economic benefit of using a catalyst in the Haber process.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) No, the percentage yield is the same with and without the catalyst. · must show No change in yield
(b) The iron catalyst increases the rate of ammonia production, allowing the reaction to reach equilibrium faster even though the yield does not change. · must show increases rate, faster equilibrium
(c) It saves money by reducing energy costs/shortening reaction time. · must show lower cost, energy/resource saving
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States yield is unchanged with catalyst, with data support.
M1 (b) · 1 mark · Mentions catalyst increases rate/allows faster production.
A1 (b) · 1 mark · Mentions catalyst allows equilibrium to be reached more quickly.
B2 (c) · 1 mark · Suggests an economic benefit (e.g., energy saving, lower cost, faster process).
Worked solution
(a) No, the table shows the percentage yield is the same with or without the catalyst at both temperatures (15% at 400°C, 10% at 500°C).
(b) The iron catalyst is important because it increases the rate of the reaction. This means ammonia is produced faster and equilibrium is reached more quickly, increasing efficiency.
(c) The catalyst leads to lower energy costs and greater economic efficiency, as it allows the process to run at lower temperatures and pressures or produces ammonia more quickly.