C7: Cracking and alkenes

what can hydrocarbons be broken down into?

smaller, more useful molecules

what is cracking?

splitting up long chain hydrocarbons

what type of reaction is cracking?

thermal decomposition

what is thermal decomposition?

the breaking down of a substance by heating

what are the 2 types of cracking?

catalytic cracking and steam cracking

how does steam cracking work?

vaporise hydrocarbons, mix them with steam, and then heat them to a very high temperature

how does catalytic cracking work?

vaporise the hydrocarbons and pass them over a powdered catalyst

what catalyst is usually used in cracking?

powdered aluminium oxide

what are long chain hydrocarbons cracked into?

shorter alkane and an alkene

what is an alkene?

an unsaturated hydrocarbon

what's the difference between alkanes and alkenes?

alkenes have a c=c double bond

which are more reactive: alkanes or alkenes?

alkenes

what do alkenes react with?

bromine water

what is the test for alkenes?

bromine water

what colour is bromine water?

orange

what colour does bromine water go when reacted with an alkene?

colourless

what are short chain hydrocarbons used for and why?

fuels, they're easily flammable

what can alkenes be used for?

making polymers, starting materials for the production of other chemicals

what is there a high demand for?

fuels with small molecules

what can some of the products of cracking be useful for?

fuels