Answer: (4) the energy released or absorbed during the reaction
Explanation: Potential energy diagram is the representation of energy with the course of reaction. It shows the energy of reactants, activation energy which is the energy required by the reactants to cross the energy barrier and the energy of the products.
Thus the difference of energy of products and energy of reactants gives us the energy released or absorbed during the reaction.
\(\Delta H=E_P-E_R\)
where \(\Delta H\) = enthalpy of reaction
\(E_P\) = energy of products
\(E_R\) = energy of reactants
If \(E_P\) > \(E_R\) , energy is absorbed and reaction is endothermic
\(E_P\) < \(E_R\) , energy is released and the reaction is exothermic.
