What is the heat of reaction if enthalpy of inputs and outputs at 25oC are 10 J and 8 J, the enthalpy of input and outputs at given temperature are 5 J and 20 J, enthalpy change of the reaction is 30 J?

Correct Answer: 13 J
Heat of reaction = (5 – 10) – (20 – 8) + 30 = 13 J.