Cracking

Long hydrocarbon are __________ useful than shorter ones like petrol. We can 'crack' these longer chains into shorter ones.

In the exam use the chemical symbols to represent atoms rather than circles eg:

This process involves heating the hydrocarbons to vaporise them and passing the vapours over a hot catalyst. A catalyst is a chemical that speeds up a reaction without being used up or changed itself and allows the reaction to happen at a cooler temperature.

The actual cracking process is a thermal decomposition reaction in which a __________ molecule splits into __________ molecules, when __________. In the lab, cracking can be done using the following equipment:

Cracking Paraffin
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In this example the porcelain chips are the __________.

When we do this we end up with a mixture of both alkanes and alkenes (see What's in crdue oil? from C1a).

The alkanes are used as __________, while the alkenes can also be used to make __________ (plastics).