Question

21 Which mathematical expression represents the heat of reaction for a chemical reaction?(1) (the heat of fusion) – (the heat of vaporization)

(2) (the heat of vaporization) – (the heat of fusion)
(3) (the potential energy of the products) – (the potential energy of the reactants)
(4) (the potential energy of the reactants) – (the potential energy of the products)

Answer 1

The answer is (3) the potential energy of the products - the potential energy of the reactants. The reaction energy production can be represented by the change of energy of products and reactants.

Answer 2

Correct Answer: Option 3 i.e. (the potential energy of the products) – (the potential energy of the reactants)

Reason:
Heat of reaction for a chemical reaction is the change in the enthalpy of a chemical reaction that occurs at a constant pressure. This can be measured on the basis of potential energy of reactants and products. Mathematically, it is expressed as:

Heat of reaction = ΔH = ΣH products - ΣHr reactants.