Find the enthalpy of formation

Question

Under certain nonstandard conditions, oxidation by O2(g) of 1 mol of SO2(g) to SO3(g) absorbs 89.6 kJ

The heat of formation of SO3(g) is -204.1 kJ/mol under these conditions.

Find the enthalpy of formation of SO2(g)

I tried to get the solution but I keep getting the wrong one. Please let me know how we can solve this. Thanks.

Answer 1

The balanced thermochemical equation for this reaction would be

89.6 kJ + SO₂(g) + 1/2 O₂(g) ==> SO₃(g)

∆Hf_SO3 - ∆Hf_SO2 = ∆Hrxn

-204.1 - ∆Hf_SO2 = +89.6

∆Hf_SO2 = -293.7 kJ/mole