The simplest hydrocarbon, methane is a gas with a chemical formula of CH4.
Lewis Structure:
C | C-H-C | C
A principal component of natural gas, methane is a significant fuel. Burning one molecule of methane in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O (water):
- CH4 + 2O2 → CO2 + 2H2O
Methane is a greenhouse gas with a global warming potential of 22 (meaning that it has 22 times the warming ability of carbon dioxide).
Methane results from the decomposition of certain organic matters in the absence of oxygen. It is therefore also classified as a biogas.
Principal sources are
- decomposition of organic wastes
- natural sources (marshes) : 23 %
- fossil fuel extraction : 20 % See Coal bed methane extraction
- the processes of digestion of animals (cattle) : 17 %
- bacteria found in rice plantations : 12 %
- biomass anaerobic heating or combustion
See also methyl group, which is a functional group similar to methane.