The chemical equation for this combustion reaction is:
C8H18 + O2 --> CO2 + H2O
Balancing by adding whole number coefficients:
2 C8H18 + 25 O2 --> 16 CO2 + 18 H2O
Including the phases:
2 C8H18 (l) + 25 O2 (g) --> 16 CO2 (g) + 18 H2O (l)
where g is gas and l is liquid