The Haber Process The Haber Process combines nitrogen from the air with hydrogen derived mainly from natural gas (methane) into ammonia. The reaction is reversible and the production of ammonia is exothermic.

Fritz Haber Fritz Haber was the German scientist who developed an efficient way of producing ammonia from hydrogen and atmospheric nitrogen.  His discovery was a breakthrough. It meant that ammonia could be produced efficiently and cost effectively. Ammonia is the starting chemical used in the production of nitrate fertilisers and warfare explosives. For this reason Fritz Haber will go down in history as one of science’s greatest heroes and greatest villains.

Hydrocarbons The bigger the hydrocarbon molecule and the more carbon atoms it contains: the higher is its boiling point the less easily it turns into a vapour (i.e., it is less volatile) the less easily it flows (i.e., it is more viscous) and the less easily it ignites (i.e., it is less flammable)

More Hydrocarbons Here are some common simple hydrocarbons, with their molecular structures. Note that the last two have double bonds between their carbon atoms.

Fractional Distillation Fractional distillation differs from distillation only in that it separates the mixture into a number of different parts, called fractions. A tall column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with low boiling points condense at the top. Fractional distillation is used to separate the different hydrocarbons in crude oil.

Combustion Incomplete combustion When hydrocarbons burn in a limited supply of air, the amount of oxygen is not enough to oxidise all the carbon to carbon dioxide. Some of the carbon is released as black soot. Some of it reacts with oxygen to form carbon monoxide, which is a poisonous gas with no smell. Complete combustion When Hydrocarbons burn they react with oxygen in the air. Burning or combustion is an oxidation reaction. When hydrocarbons burn completely, the only products are water and carbon dioxide. In general: hydrocarbon + oxygen      water + carbon dioxide Water is an oxide of hydrogen.

Cracking is an example of a Thermal Composition reaction. Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful, hydrocarbon molecules. Fractions containing large hydrocarbon molecules are Vaporised and passed over a hot Catalyst. This breaks chemical bonds in the molecules, forming smaller hydrocarbon molecules. Cracking is an example of a Thermal Composition reaction.