Define a hydrocarbon and explain the difference between alkenes and alkanes.

A Hydrocarbon is an organic molecule containing only hydrogen and carbon atoms. Alkanes are saturated hydrocarbons, meaning they are only made up of single bonds. The carbons are 'saturated' with hydrogen atoms. The general formula for an alkane is CnH2n+2.Alkenes are unsaturated hydrocarbons and they contain one or more C=C double bond within their structure. Alkenes with one double bond have the general formula CnH2n. The presence of the double bond will decrease the number of hydrogen atoms within the molecule meaning it is unsaturated.