The Haber process

The Haber process

The Haber process is about the production of ammonia (NH3) – the reversible reaction is:

N2 + 3H2 <- -> 2NH3 + (heat)

Volume will be higher on the left as there is two sets of molecules (volume includes space between them) – also the reaction is exothermic towards the direction of ammonia

Industrially you need 200 atmospheres of pressure and 450 degrees C of temperature and an iron catalyst

  1. The high pressure favours the forward reaction – the pressure encourages the ammonia to stay together and makes it harder for them to separate back Nitrogen and hydrogen because of the pressure on them
  2. If the pressure was higher then you could get even more yield – but it becomes very expensive to make the pressure higher
  3. The forward reaction is exothermic – but you need the higher temperature to get the reaction going fast enough – (higher temperature increases the rate of reaction) – however decreases the yield of ammonia because the reaction in exothermic

Ammonia is used in creating fertiliser

The iron catalyst helps speed up the catalyst – thus allowing us to keep the temperature slightly lower but doesn’t affect the yield