What is the general equation for combustion?

Answer 1

The general word equation for complete combustion is:

hydrocarbon + oxygen --> carbon dioxide + water

It depends on WHAT you want to burn with oxygen:

For alkanes like CH4 (methane, natural gas) or C8H18 (octane, petrol) the general balanced equation of complete combustion is as follows

CnH2n+2 + (3n+1)/2 O2 ==> n CO2 + (2n+2)/2 H2O for each uneven(*) natural value of n

(*) if n is even, then all coefficients should be doubled to prevent 'halve' values at the end.

Example butane:

• C4H10 + (13)/2 O2 ==> 4 CO2 + (10)/2 H2O

will become:

• 2 C4H10 + 13 O2 ==> 8 CO2 + 10 H2O

(because 6.5 O2 is not allowed)