What is alkenes and examples? What is the general formula for an alkene? AlkenesAlkenes form another family of hydrocarbons. The general formula for the alkene family is CnH2n, where n = 2, 3, 4, ...Alkenes are unsaturated hydrocarbons. Every alkene has a carbon-carbon double bond. The carbon-carbon double bond is the functional group of … [Read more...] about What is an alkene in chemistry?