The Haber process
Making ammonia
Ammonia is an important industrial product used to make A nutrient added to the soil to increase the soil fertility., explosives and dyes. It is manufactured using the The industrial chemical process that makes ammonia by reacting nitrogen and hydrogen together.. This involves a A chemical reaction which can go both ways. between nitrogen and hydrogen:
N2(g) + 3H2(g) ⇌ 2NH3(g)
The reaction can reach a dynamic In chemical reactions, a situation where the forward and backward reactions happen at the same rate, and the concentrations of the substances stay the same..
In the Haber process:
- nitrogen (extracted from the air) and hydrogen (obtained from A naturally occurring hydrocarbon gas mixture.) are pumped through pipes
- the Force exerted over an area. The greater the pressure, the greater the force exerted over the same area. of the mixture of gases is increased to 200 A unit of pressure.
- the pressurised gases are heated to 450°C and passed through a tank containing an iron A chemical or other agent that brings about a change in something else without necessarily changing itself. It can also mean a person or thing that causes an event.
- the reaction mixture is cooled so that ammonia To turn from a gas to a liquid, usually by cooling or by being put under pressure. and can be removed
- unreacted nitrogen and hydrogen are Used materials that have been reprocessed to make new materials.
Worked example
Question
Explain why iron is used in the Haber process.
Iron is a catalyst for the reaction. It increases the rate of the reaction without being used up in the reaction.
Question
Explain why the unreacted hydrogen and nitrogen are recycled.
Recycling the unused reactants saves money and increases the effective (overall) yield.