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. entropy has decreased disorder has decreased the kinetic energy of the reactants is less than that of the products the chemical energy of the products is greater than that of the reactants heat has been released to the environment