[06.04]on a potential energy diagram, the activation energy is greatest under which of the following conditions? the potential energy of the products is greater than that of the reactants and the change in enthalpy is positive.  the potential energy of the products is less than that of the reactants and the change in enthalpy is positive.  the potential energy of the products is greater than that of the reactants and the change in enthalpy is negative.  the potential energy of the products is less than that of the reactants and the change in enthalpy is negative.