Final answer:
In an exothermic reaction, the total energy of the products is lower than the total energy of the original reactants. This indicates that energy is released during the reaction, usually in the form of heat. The decrease in energy occurs because the bonds in the products are stronger than the bonds in the reactants.
Step-by-step explanation:
In a chemical reaction where the total energy of the products is lower than the total energy of the original reactants, it indicates an exothermic reaction. In an exothermic reaction, the energy of the products is lower than the energy of the reactants. This means that energy is released during the reaction, usually in the form of heat.
This decrease in energy occurs because the bonds in the products are stronger (higher bond energy) than the bonds in the reactants. The excess energy is given off as the reactants are converted to products, resulting in a decrease in total energy.
For example, when wood burns, the energy stored in the chemical bonds of the wood is released as heat and light energy, and the products (ash, smoke, and gases) have lower energy than the original wood.