ANSWERS: Crystal Ball questions on Combustion QUESTION: Write balanced equations for the complete and incomplete complete combustion of the following molecules organic molecule equation for complete combustion equation for incomplete combustion octane 2C8H18(g) + 25O2(g) ? 16CO2(g) + 18H2O(g) 2C8H18(g) + 13O2(g) ? 8CO(g) + 8C(s) + 18H2O(g) there are other possibilities by changing moles of CO and C propene 2C3H6(g) + 9O2(g) ? 6CO2(g) + 6H2O(g) 2C3H6(g) + 5O2(g) ? 4CO(g) + 2C(s) + 6H2O(g) there are other possibilities by changing moles of CO and C ethane 2C2H6(g) + 7O2(g) ? 4CO2(g) + 6H2O(g) C2H6(g) + 2O2(g) ? CO(g) + C(s) + 3H2O(g) there are other possibilities by changing moles of CO and C heptane