Is the molar enthalpy of combustion of pentane the same as the molar enthalpy of formation of pentane?
No. The molar enthalpy for the combustion is for the reacton
C5H10 + (15/2)O2 ==> 5CO2 + 5H2O
The molar enthalpy for the formaton is
5C(graphite) + 5H2(g) ==> C5H10(l)
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