Hess's law help chemistry

Fe2O3(s) + 3 CO(g) = 2 Fe(s) + 3 CO2(g)
Given:
2 Fe2O3(s) = 4 Fe(s) + 3O2(g)

H = 1602.6 kJ/mol
CO(g) = C(s) +(1/2) O2


H = 110.5 kJ/mol
C(s) + O2(g) = CO2(g)

H = −393.5 kJ/mol
Answer in units of kJ/mol.

Divide first equation by 2
Multiply second equation by 3
Multiply third equation by 3

Then, add 'em up!

More Hess' law examples here:

http://www.chemteam.info/Thermochem/Hess…