An exergonic reaction is characterized by what type of energy change?

An exergonic reaction is characterized by a release of energy, which is why the choice indicating that energy is emitted is correct. In these types of reactions, the products have lower energy than the reactants, resulting in a decrease in free energy. This release of energy often manifests in the form of heat, light, or work, making it spontaneous under standard conditions.

During an exergonic reaction, the difference in free energy (ΔG) is negative, indicating that the system releases energy to the surroundings as the reaction proceeds towards equilibrium. This concept is critical in understanding metabolic processes, where energy is often harvested from exergonic reactions to drive endergonic reactions, which require energy input.

The incorrect options represent scenarios that do not align with the nature of exergonic reactions. For instance, reactions characterized by energy absorption would be classified as endergonic, while scenarios involving no energy exchange or constant energy would not describe the energetic movement typically seen in exergonic reactions.