Methane, ethane, propane and butane are the alkanes that are gases at room temperature. These alkanes become gases at low temperatures due to the low number of carbon atoms in their structures.
All four of these alkanes have four or fewer carbon atoms. Alkanes with more carbon content are liquid or solid at room temperature. Hexane and octane are examples of alkanes that are liquid at room temperature. Hexane has six carbon atoms, and octane has eight carbon atoms. Complex alkanes with long chains of carbon are extracted from petroleum rather than found in nature.
The more carbon atoms exist in an alkane, the stronger its molecular bonds are. This is why the alkanes with the smallest number of carbon atoms have the lowest vaporization points; they have the weakest bonds holding them together. Alkanes with more than 12 carbon atoms have such strong bonds that they are solid at room temperature.
Methane, ethane, propane and butane are used as fuels. They power household appliances such as stoves, heaters and camping equipment. Liquid alkanes, such as octane, are components of gasoline and diesel fuels. Solid alkanes include wax, paraffin, greases and industrial lubricants. They are also used in motor oil and in the production of hydrocarbon compounds.