S(g)+O2 (g)=SO2(g) ΔH= -297kJ/mol4FeS2(s)+11O2(g)=2Fe2O3(g)+8SO2(g) ΔH=-853kJ/mol2SO2(g)+O2(g) = 2SO3(g) ΔH= -98.3kJ/molSO3(g)+H2O(l)=H2SO4(l) ΔH= -130.3kJ/mol