<unk>  is a chemical compound with the molecular formula<unk> . It is the simplest alkane, and the principal component of natural gas.<unk> 's bond angles are 109.5 degrees. Burning one molecule of<unk>  in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O:<unk> 's relative abundance and clean burning process makes it a very attractive fuel.  However, because it is a gas (at normal temperature and pressure  - see, STP) and not a liquid or solid,<unk>  is difficult to transport from the areas that produce it to the areas that consume it.  Converting<unk>  to derivatives that are more easily transported, such as <unk> l, is an active area of research. Certain microorganisms can effect this selective oxidation using enzymes called<unk>  monooxygenases.<unk>  is a relatively potent greenhouse gas with a high global warming potential (i.e., warming effect compared to carbon dioxide).  When averaged over 100 years each kg of<unk>  warms the Earth 
25
times as much as the same mass of CO2. The total warming effect of<unk>  is smaller than that of CO2, since there is approximately 220 times as much CO2 in the Earth's atmosphere as<unk> . However,<unk>  in the atmosphere is eventually oxidised, producing carbon dioxide and water.<unk>  in the atmosphere has a half life of seven years, meaning that every seven years, half of the<unk>  present is converted to carbon dioxide and water.
The Earth's crust contains huge amounts of<unk> . Large amounts of<unk>  are produced anaerobically by<unk> genesis. Other sources include mud volcanoes which are connected with deep geological faults.
Methane
Acetylene
Ether
Benzene
Acrolein
Bromoform
Butane
Xylene