Haber Process

• 1. Purified H2 and N2 are passed over iron catalyst beds at 450 degrees and 200 atmospheres
• 2. The iron speeds up the rate of reaction so that a lower temperature could be used in the process
• 3. Some of the hydrogen and nitrogen react to form ammonia

  N2 + 3H2 = 2NH3
• 4. The reaction is reversible so ammonia breaks down again into nitrogen and hydrogen
• 5. On cooling, the ammonia liquifies and is removed. The remaining hydrogen and nitrogen are recycled. This means almost no material is wasted
• 6. Ammonia is used for production of nitrogen based fertilisers
• The reaction is exothermic. 450 degrees is used even though a lower temperature would give a higher yield because the production would be too slow otherwise
• 200 atmospheres are used even though a higher pressure would increase the yield because increasing the pressure would be too expensive