When Ethanol and Oxygen combine, a combustion reaction occurs, which means that the result will always be CO2 and H2O.
The chemical equation of this reaction looks like this:
C2H5OH + O2 => CO2 + H2O
In order to balance your chemical equation, you must place coefficients in front of chemicals to balance the number of each elements.
C2H5OH + 3 O2 => 2 CO2 + 3 H2O
