Calculate the enthalpy of formation for sulfur dioxide, s02, from its elements, sulfur and oxygen. Use the balanced chemical equation

To check, it should be (−296.81±0.20) kJ/mol . You should use NIST more often. I actually got −310.17 kJ/mol though.

the balanced chemical equation stipulates the formation of two moles of sulfur trioxide when two moles of sulfur dioxide and one mole of oxygen react do now is determine how much heat is given off when one mole of sulfur.