The Haber Process (OCR GCSE Chemistry A (Gateway)): Revision Note

The Haber Process

• Ammonia is manufactured using the Haber Process 

• More than 80% of the ammonia produced is used to produce fertiliser 

• It is also used to make explosives and dyes

• The reactants are hydrogen and nitrogen which are extracted from methane and the air respectively

• The process occurs in five stages:

• Stage 1: H₂ and N₂ gases are pumped into the compressor through pipes

• Stage 2: The gases are compressed to about 200 atmospheres inside the compressor

• Stage 3: The pressurised gases are pumped into a tank containing layers of catalytic iron beads at a temperature of 450°C. Some of the hydrogen and nitrogen react to form ammonia in the following reversible reaction

N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)

• Stage 4: Unreacted H₂ and N₂ and product ammonia pass into a cooling tank.

• The ammonia is liquefied and removed to pressurised storage vessels

• Stage 5: The unreacted H₂ and N₂ gases are recycled back into the system

The production of ammonia by the Haber Process