How are alkenes different from alkanes?

Alkanes are hydrocarbons (compounds containing only C and H) that have single covalent bonds connecting carbon atoms. The molecular formula of all alkanes corresponds to the expression CnH2n + 2, where n is the number of carbon atoms.

Alkenes are hydrocarbons (compounds containing only C and H) that have one or more C = C double bonds (two C atoms are linked by four common electrons). The general formula is CnH2n, which is two hydrogen atoms less than the corresponding alkane. Compared to alkanes, alkenes can undergo a wider range of chemical reactions such as combustion and addition reactions (hydrogenation, additive polymerization, hydration, etc.).