Making ammonia The Haber process

1. Making ammoniaThe Haber process

2. The Haber processThe optimum conditions • High pressure (200atm) • High temperature (450oC) • Iron catalyst

3. Pressure

4. 200atm Pressure • A high pressure will push the equilibrium to the right and increase the % yield of ammonia. The equilibrium moves to the side of the reaction with fewer molecules.

5. 200atm Pressure • Achieving a very high pressure is expensive as the equipment will need to be very strong. • 200atm is a good compromise …the yield is still high but the factory is cheaper and safer.

6. Temperature

7. Exo Endo 450oC Temperature A low temperature will push the equilibrium to the right and increase the % yield of ammonia. A low temperature favours the exothermic reaction.

8. Exo Endo 450oC Temperature At a low temperature the rate of reaction is too slow. The particles collide less often and with less energy. Time is money! A high temperature would push the equilibrium to the left (Endo)

9. Exo Endo 450oC Temperature A temperature of 450oC is a good compromise…the equilibrium is not too far over to the left and the rate of reaction is still reasonable.

10. The iron catalyst also increases the rate of the reaction…but it has no effect on the position of equilibrium as it increases the rate of forward and backward reaction equally…we just reach equilibrium faster Iron catalyst