Synthesis of Ammonia

Monitoring and Management‎ > ‎2. Maximising Production‎ > ‎

Identify that ammonia can be synthesised from its component gases, nitrogen and hydrogen

Describe that synthesis of ammonia occurs as a reversible reaction that will reach equilibrium

Identify the reaction of hydrogen with nitrogen as exothermic

  • Ammonia is synthesised from nitrogen gas and hydrogen gas.
  • Haber Process: The industrial synthesis of ammonia.
  • The nitrogen gas used in the Haber process can be obtained through either:
    • The catalytic reaction between natural gas and air, which removes oxygen and leaves nitrogen.
    • The fractional distillation of liquid air.
  • The hydrogen used in the Haber process can be obtained through one of the following:
    • The catalytic reaction between natural gas and steam, and natural gas and air.
    • The electrolysis of water.
  • Generally, catalytic reactions are used to obtain both nitrogen and hydrogen gas.

The main method of preparation of hydrogen and nitrogen gases for the Haber process

  • The synthesis of ammonia is a reversible exothermic equilibrium:

  • For every mole of ammonia formed, 46 kJ of energy is released.
  • At room temperature and atmospheric pressure, the equilibrium lies well to the left.
  • By altering temperature and pressure, the equilibrium can be shifted in the forward direction.
Structure of ammonia