Both alkanes and alkenes are hydrocarbons, meaning they are made up of hydrogen and carbon only. However, alkanes are saturated hydrocarbons consisting of single bonds only whereas alkenes are unsaturated hydrocarbons which include a carbon-carbon double bond. Additionally, alkanes and alkenes have different general formula. The general formula for alkanes is C(n)H(2n+2) whereas the general formula for alkenes is C(n)H(2n).