Question

Help please. The combustion of pentane, C5H12, occurs via the reaction

C5H12(g)+8O2(g)_5CO2(g)+6H2O(g)
with heat of formation values given by the following table:
Substance _H_f
(kJ/mol)
C5H12(g) _35.1
CO2(g) _393.5
H2O(g) _241.8

Answer 1

If I were you, I'd try to go with this one :
`[(6)(-241.8)+(5)(-393.5)]-[-35.1] =-481.6`. I think that is a solution you have to find. Just use the sum of standard enthalpies of products and of reactants. Hope you will find it helpful!