By using the following reactions, calculate the heat of combustion of pentane: C5H12(g)+8O2(g)→5CO2(g)+6H2O(l) . C(s)+O2(g)→CO2(g), △H=−395 kJ H2(g)+12O2(g)→H2O(l), △H=−285 kJ 5C(s)+6H2(g)→C5H12(g), △H=−147 kJ −5.42×103 kJ −3.54×103 kJ −2.85×103 kJ −6.80×103 kJ