Methane

Figure 1. Space filling model of methane; the white is hydrogen and the black is carbon.

Methane is a hydrocarbon. At typical temperatures and pressures it is a gas and makes up around 95% of the content of liquefied natural gas, and around 80-90% of natural gas. It is a hydrocarbon, and its chemical makeup is CH₄. Methane is also a greenhouse gas, like carbon dioxide (CO₂). It has a shorter atmospheric lifetime than CO₂, at 12 years, but this is "balanced" by the fact that it is more effective at trapping heat than CO₂, as methane has a GWP (Global warming potential) of 21.

Methane combustion (see simulation at bottom of page) is a significant source of primary energy, and is used for home heating, cooking food, heating water, and electrical generation; it even provides some transportation. This means that it is also a significant contributor to climate change since using methane produces a fair amount of carbon dioxide (although less than other hydrocarbons).

Properties

Below is a table of some of the basic properties of methane.

Chemical formula	CH4
Molar mass	16.04 grams/mole
Energy density	55.5 MJ/kg
Melting Point	-183oC
Boiling Point	-164oC
GWP	21
Atmospheric lifetime	12 years

Combustion Animation

Methane is used as a combustible fuel. Below is an animation showing the net reaction that occurs during the hydrocarbon combustion of methane.