The Haber process
- Ammonia is manufactured using the Haber Process which occurs in five stages
- The reactants are hydrogen and nitrogen which are extracted from methane and the air respectively
- 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
Worked example
Ammonia is produced during the Haber Process. The reaction is summarised in the diagram below.
a)
Give the name of gas A.
b)
Name the catalyst B used and state why it is used
Answer
a)
Hydrogen
b)
Iron. Speeds up the reaction/ increases the rate of reaction
Examiner Tip
The air contains 78% nitrogen and it is removed by fractional distillation. Hydrogen is derived from methane (CH4) in a process called steam reforming.
