A balanced equation for the combustion of octane with oxygen to obtain carbon dioxide and water

Octane is C8H18, Carbon Dioxide is CO2, Oxygen is O2, and water is H2O. Thus, the reaction will be in the form:

C8H18+O2 - > CO2+H2O

However, it is not balanced. We start with just one C8H18. This requires 8 CO2s to account for the 8 carbon atoms and 9 H2Os to account for the 18 hydrogen atoms. This is a total of 8*2+9=25 oxygen atoms. We can't have 25/2 of a molecule, so we multiply all coefficients by two. Therefore, our balanced equation is:

2 C8H18 + 25 O2 - > 16 CO2 + 18 H2O