Cracking
Chemistry: Cambridge International GCSE Supplement, topic 11.5.5
Cracking
Cracking is the process that breaks down long-chain hydrocarbons into shorter-chain molecules that have a higher commercial value. Cracking is an example of a thermal decomposition reaction. Cracking can be done in two ways:
Catalytic cracking
- Vapourised heavy hydrocarbons are passed over the top of a heated catalyst.
- Alkanes and alkenes are produced by this reaction.
- E.g. hexane → butane + ethene
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Steam cracking
- Vapourised heavy hydrocarbons are mixed with steam in a high temperature environment.
- The products include alkanes and alkenes.
- E.g. decane → octane + ethene
Test yourself on Cracking
Methods of cracking hydrocarbons
What type of chemical reaction is cracking?
In which method of cracking are vapourised heavy hydrocarbons passed over a hot catalyst?
What are the products of cracking?