# How can I identify alkenes?

Alkenes are hydrocarbons that possess a double bond and have the general formula ${C}_{n} {H}_{2} n$, where n refers to the number of carbon.
For example if we look at the simplest alkene - ethene, for example - the formula is ${C}_{2} {H}_{4}$, which follows the general formula above, and has the following structure:
It is possible for compounds to have multiple double bonds, and the general formula for these will be represented as ${C}_{n} {H}_{2} n {-}_{2} y$ where y is the number of additional double bonds in the compound.