- In I/GCSE Chemistry, the Haber process is used to manufacture ammonia, which can be used to make fertilisers and other chemicals.
- Nitrogen from the air and hydrogen, which is usually obtained from natural gas, are purified and mixed in the correct proportions.
- The gases are passed over an iron catalyst at a temperature of about 450°C and a pressure of about 200 atmospheres.
- In I/GCSE Chemistry, these conditions are chosen to give a fast rate of reaction and a reasonable yield of ammonia.
- The reaction is reversible.
- Some of the ammonia that’s produced breaks down into nitrogen and hydrogen and the yield of ammonia is only about 15%.
- Unreacted gases are recycled so they’re not wasted.
The economics of the Haber process
- In I/GCSE Chemistry, the Haber process uses a pressure of around 200 atmospheres to increase the amount of ammonia produced.
- Although a higher pressure would produce more ammonia, they would make the chemical plant too expensive to build and run.
- A temperature of about 450°C is used for the reaction. Although lower temperatures would increase the yield of ammonia, it would be produced too slowly.
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