The Haber Process
What is the Haber Process?
- Ammonia is manufactured using The Haber Process which occurs in five stages
- Stage 1: hydrogen is obtained from methane (natural gas) and nitrogen is obtained from the air. The gases are mixed and pumped into the compressor
- Stage 2: the gases are compressed to about 150-200 atmospheres inside the compressor
- Stage 3: the pressurised gases are pumped into a tank containing layers of an iron catalyst at a temperature of 350-450°C. Some of the hydrogen and nitrogen react to form ammonia:
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
nitrogen + hydrogen ⇌ ammonia
- Stage 4: unreacted hydrogen, nitrogen and product ammonia pass into a cooling tank. The ammonia is liquefied and removed to pressurised storage vessels
- Stage 5: the unreacted hydrogen and nitrogen gases are recycled back into the system and start over again
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
Examiners comment that students often know the raw materials for the Haber process, and what the purpose of the catalyst is, but not many know the name of the catalyst and confuse it with other catalysts like 'vanadium oxide' and 'enzymes'. You should know the conditions of the Haber process, which includes knowing the iron catalyst.
Make sure you know where the nitrogen and hydrogen come from, as students often don't know.
