What is true about exothermic reactions?

Exothermic reactions are characterized by their ability to release heat into the environment. This occurs during the process when the total energy of the reactants is higher than that of the products, resulting in a net release of energy, typically in the form of heat. This release often leads to an increase in temperature of the surroundings, which is a key feature of exothermic processes.

For example, combustion reactions, such as the burning of fuels, are classic exothermic reactions. When a substance like wood or gasoline burns, it releases heat and light energy, indicating an exothermic nature. Therefore, the response that exothermic reactions release heat into the environment accurately captures the essential nature of these reactions.

In contrast, while some of the other choices mention the processes associated with energy transfer, they do not correctly describe the defining characteristic of exothermic reactions. Thus, option C stands out as the most accurate description of exothermic reactions.