Write the balanced eqn. Of combustion of methane with the physical states

Complete combustion happens when the
hydrocarbon burns in an excess of air. An excess
of air means that there is more than enough oxygen
to cause all of the carbon to turn into carbon dioxide.
The methane gas burns with a clear blue flame.

methane + oxygen   =  carbon dioxide + water + energy
CH4(g)   +  2O2(g)   =     CO2(g)    +    2H2O(l)            

The reaction is exothermic (it gives out heat).
The heat released from burning natural gas is
used for central heating and to generate electricity.