10 Ammonia

What are the optimal conditions for the Haber Process

A pressure of 250 atm, a temperature of 450C, a finely divided iron catalyst and a ratio of H2 to N2 of 3 to 1

Why must the pressure be 250 atm

Higher pressure favours the side of the reversible reaction with fewer moles, but higher pressure is more expensive to maintain

Why must the temperature be 450C

The forward reaction is exothermic so a lower temperature would favour the forward reaction but lower temperature means slower reaction

Why must the catalyst be finely divided iron

It is finely divided as it increases the surface area present for the reactants to adsorb, iron is cheap, durable and effective at high pressures

What are the sources of hydrogen and nitrogen for the production of ammonia

Steam methane reforming and cracking of hydrocarbons from crude oil for hydrogen, fractional distillation of liquid air for nitrogen.

How does steam methane reforming work.

In the primary reformer, first the natural gas methane is heated together with steam to about 800 degree centigrade and is thereby converted into a mixture of carbon monoxide, carbon dioxide and hydrogen.

How does the cracking of hydrocarbons work

butane → ethene + hydrogen gas

What are the reactions involving ammonia

Ammonium salt + alkali → ammonia + water + salt

Ammonia + acid → ammonium salt

What are the used for ammonia

Starter for explosives, dyes, production of nitric acid, household cleaning products, fertiliser

What are some examples of ammonia fertilisers

ammonium nitrate, phosphate and sulfate