What characterizes an exothermic reaction?

An exothermic reaction is characterized by its release of heat to the surroundings, leading to an increase in the temperature of the surroundings. This occurs because the energy contained in the reactants is greater than the energy of the products. As the reaction proceeds, excess energy is released, often in the form of heat, thus warming the nearby environment. This is a fundamental characteristic of exothermic processes and is often associated with combustion reactions, metabolism, and certain types of chemical reactions.

The nature of bond breaking and formation is also relevant in this context; however, exothermic reactions are defined by their heat release rather than merely by the breaking of bonds. The breaking of bonds is part of the overall chemical reaction process, but it is the bond formation in the products that releases energy. Therefore, the correct answer highlights the crucial aspect that these reactions elevate the temperature of the surroundings by expelling energy.