Alkanes are a homologous series of saturated hydrocarbons that contain only carbon and hydrogen atoms. The term ‘saturated’ means that they contain the maximum number of hydrogen atoms possible in their molecular structure. This means that they do not have any double bonds, only single carbon-carbon bonds that connect the atoms together.
The general formula for alkanes is:
As the number of carbon atoms in an alkane chain increases, its physical properties change. For example, there is a gradual increase in boiling points.
Despite their varying physical properties, alkanes have similar chemical properties. They can undergo combustion and react with halogens. Also, alkanes can be cracked into smaller molecules.
The table below shows the molecular formulae and structures of the first three alkanes.
|Alkane||No. of carbon atoms||Molecular formula||Structural formula||Ball + stick diagram|