cracking

when cracking short chains of what 2 hydrocarbons form

alkanes and alkenes

what two things are alkenes used for

fuel

in the petrochemical industry as starting materials to make new compounds

what is the purpose of cracking

cracking splits up long chain hydrocarbons into shorter chains so they are more flammable and easier to use for fuel

3 steps in catalytic cracking

1) heat long hydrocarbon chain until they vaporise

2) pass hydrocarbons over a hot powdered aluminium oxide catalyst

3) the hydrocarbon molecules will split up as little specks on top of catalyst

3 steps in steaming cracking

1) heat hydrocarbons until they vaporise

2) mix with steam

3) heat to high temp