Are all Alkenes hydrocarbons?
A hydrocarbon contains only carbon and hydrogen atoms. Alkenes that do not have functional groups such as bromine are hydrocarbons. However, you can say that an alkene HAS a hydrocarbon chain, even if it has a functional group. For example, propene is a hydrocarbon. However, bromopropene is not but you can say that bromopropene has a hydrocarbon CHAIN. Hope this cleared things up!