Final answer:
In an endothermic reaction, potential energy is higher in the products than in the reactants, as the reaction absorbs energy. Consequently, the temperature decreases as the reaction absorbs heat from its surroundings. This change is depicted in a potential energy diagram where the reactants' energy level is lower than that of the products.
Step-by-step explanation:
The potential energy of the reactants and the products in an endothermic reaction can be understood through a potential energy diagram. In an endothermic reaction, the potential energy of the products is higher than the potential energy of the reactants. This is because endothermic reactions absorb energy from the surroundings, which is used to break the bonds of the reactants and form new bonds in the products, resulting in a net gain of potential energy.
As the reaction progresses, the temperature of the system will initially decrease, because the reaction absorbs heat from the surroundings to reach the activation energy. Once the activation energy is reached and the reaction starts, the absorbed energy is used to transform the reactants into products. The overall effect is that the temperature of the reaction environment may feel cooler, even though the potential energy within the chemical system has increased.