Organic chemistry - (CCEA)Cracking

An organic chemical contains the element carbon. There are four different homologous series of organic compounds discussed here: alkanes, alkenes, alcohols and carboxylic acids.

Part ofCombined ScienceFurther chemical reactions, rates and equilibrium, calculations and organic chemistry

Cracking

is a reaction in which larger saturated hydrocarbon molecules are broken down into smaller, more useful hydrocarbon molecules, some of which are unsaturated:

  • the original starting are alkanes
  • the products of cracking include alkanes and alkenes, members of a different homologous series
  • For example, hexane can be cracked to form butane and ethene:

hexane → butane + ethene

C6H14 → C4H10 + C2H4

The starting compound will always fit the rule for an alkane, CnH2n+2. The first product will also follow this rule. The second product will contain all the other C and H atoms. The second product is an alkene, so it will follow the rule CnH2n.