Enthalpy change for the following reaction?

Question

C8H18(l)+12.5O2(g) --------------8CO2 (g) +9H2O (g)

Change in Hof C8H18(l)= -2.69.7 kJ
Change in Hof CO2 (g)= -3.93.5 kJ
Change in Hof H2O (g)= -241.8 kJ

Answer 1

ΔH° = (9*-241.8) + (8*-393.5) + (269.7)

ΔH° = -5054.5 kJ


*** For all the things where you wrote "Change in Hof," the units should be kJ/mol, not kJ.