Combustion means the elements or compound can be burned, but burning which is a chemical process requires oxygen; combustion reaction typically takes place in the presence of air. The combustion of methane is as follows:
CH4(g) + 2 O2(g) -> CO2(g)+ 2 H2O(g) + energy
One mole of gaseous methane reacts with two oxygen molecules to form a carbon dioxide molecule, and two water molecules which is given off as water vapor. The reaction involves the release of heat.
