The Haber process


The Haber process is used to manufacture ammonia, which can be used to produce nitrogen-based fertilisers.

The raw materials for the Haber process are nitrogen and hydrogen.

Students should be able to recall a source for the nitrogen and a source for the hydrogen used in the Haber process.

The purified gases are passed over a catalyst of iron at a high temperature (about 450°C) and a high pressure (about 200 atmospheres). Some of the hydrogen and nitrogen reacts to form ammonia. The reaction is reversible so some of the ammonia produced breaks down into nitrogen and hydrogen:

nitrogen + hydrogen ammonia

On cooling, the ammonia liquefies and is removed. The remaining hydrogen and nitrogen are recycled.

(HT only) Students should be able to:

  • interpret graphs of reaction conditions versus rate

WS 3.5 Interpreting observations and other data (presented in verbal, diagrammatic, graphical, symbolic or numerical form), including identifying patterns and trends, making inferences and drawing conclusions.

WS 3.8 Communicating the scientific rationale for investigations, methods used, findings and reasoned conclusions through paper-based and electronic reports and presentations using verbal, diagrammatic, graphical, numerical and symbolic forms.

MS 1a - Recognise and use expressions in decimal form

MS 1c Use ratios, fractions and percentages