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 products of cracking include alkanes and alkenes, members of a different homologous series.

What type of reaction is cracking?

Cracking is an example of a thermal decomposition chemical reaction.

Is cracking an exothermic reaction?

The "spent" catalyst then flows into a fluidized-bed regenerator where air (or in some cases air plus oxygen) is used to burn off the coke to restore catalyst activity and also provide the necessary heat for the next reaction cycle, cracking being an endothermic reaction.