Which value is defined as the difference between the potential energy of the products and the potential energy of the reactants during a chemical change?

Heat of reaction or enthalpy of reaction (ΔH)

Explanation:

The heat of reaction or enthalpy of reaction (ΔH) is the amount of heat energy that the system must release or absorb so that the temperature remains constant throughout the chemical reaction process. In other words, the heat of reaction or enthalpy of reaction (ΔH) is the change in the enthalpy of a chemical reaction (the energy  absorbed or released into it) that occurs at a constant pressure.

Then, this energy can be observed in the following way:

Every substance has a quantity of energy stored in its links. When the energy contained in the reagents is greater than that contained in the products, the reaction is exothermic because energy release occurs. When the energy contained in the reagents is less than that contained in the products, an endothermic reaction occurs because energy absorption occurs.

That energy contained in the substances is called enthalpy (H).  

Then the enthalpy can be defined as the difference between the sum of the enthalpies of the products and the sum of the enthalpies of the reactants.

this means that the temperature of both substances will be equal