Answer:
More energy will be released from the old substance than the new substance will need to form it's chemical bonds.
Explanation:
Given
Chemical A and Chemical B react in an exothermic reaction.
This means energy is released when they react to give products. The product formation also requires energy, which is got from the energy released when A and B reacts. The energy that is left after the formation of products is released as heat. So in order for a reaction to be exothermic, the energy released by the reactants should be more than the energy required for the new chemical bonds to be formed to give the products.
