Enthalpy Change

Question

Given the following reactions:
S(s) + O2(g) → SO2(g) ΔH = -297 kJ/mol
SO2(g) + ½ O2(g) → SO3(g) ΔH = -141 kJ/mol

Calculate the ΔH for the reaction:
S(s) + 3/2O2(g) → SO3(g)

Answer 1

ΔH= (-297)+ (-141)
-438kJ/mol