Alkenes are hydrocarbons with the functional group C=C
It is the gererality of reactions of functional groups that determine the reactions of organic compounds
Alkenes react with oxygen in combustion reactions in the same way as other hydrocarbons but they tend to burn in air with smoky flames because of incomplete combustion
Alkenes react with hydrogen, wayward, and the halogens, by that addition of atoms across the carbon-carbon double bond ao that the double bond becomes a single carbon-carbon bon