C2e

C2e: Manufacturing Chemicals and Making Ammonia

Ammonia

Ammonia (NH3) is an alkaline gas made from nitrogen and hydrogen. It is used to make nitric acid and fertilisers (fertilisers are important in helping to produce enough food for the growing world population)

The reaction that makes ammonia is a REVERSIBLE REACTION. Nitrogen and hydrogen can form ammonia, and ammonia and hydrogen can decompose to make hydrogen and nitrogen.

The Haber Process

Ammonia is made on a large scale in the Haber process. The reactants are:

• nitrogen (from the air)
• hydrogen (from natural gas/ the cracking of crude oil)

nitrogen + hydrogen <---> ammonia

N2 + 3H2 <---> 2NH3

Optimum conditions aren't used as they would be very expensive to maintain, so a compromise is reached:

• the nitrogen and hydrogen mixture is under a HIGH PRESSURE of 200 atmosphere
• the gases are passed over an iron catalyst at 450 degrees

Only about 15% of the reactant gases make ammonia. The reactant gases are…