... process is called polymerisation." (Source 1) Cracking Hydrocarbons with large molecules have higher boiling points than those with smaller molecules. They also burn less easily. To get more useful fuel, a large hydrocarbon molecule can be cracked by heating with steam or a catalyst. Two smaller molecules are formed. One is still an alkane - a hydrocarbon with only single bonds. The other is an alkene - a hydrocarbon with at least one double bond in its chain. This is said to be unsaturated because extra atoms can add when the double bonds break down to a single bond again. By contrast, alkanes are saturated. Below molecules are shown using structural formulae. Diagram page 112 (Source 1) Addition Polymerisation "The short unsaturated molecules (monomers) can join up with each other when their double bonds break open. This is called addition polymerisation. The very long chain molecule formed is a polymer (commonly known as plastic). Diagram page 112 (Source 1) The diagram ...

See this essay or coursework document in full right now