In this reaction a scheme of a chemical reaction. the reactants are two molecules, one of which consists of a and b, and the other consists of c and d. the products are two molecules, one of which consists of a and c, and the other consists of b and d. the energy of molecules ab and cd is higher than the energy of molecules ac and bd. in this reaction a scheme of a chemical reaction. the reactants are two molecules, one of which consists of a and b, and the other consists of c and d. the products are two molecules, one of which consists of a and c, and the other consists of b and d. the energy of molecules ab and cd is higher than the energy of molecules ac and bd. cd is a product entropy has decreased the products have less potential energy than the reactants ac is a reactant the products have been rearranged to form reactants.