Exothermic Reactions: These are the opposite of endothermic reactions; they release heat into their surroundings.
Activation Energy: This is the minimum amount of energy required to start a chemical reaction. For endothermic reactions, this is typically higher than for exothermic ones.
Thermodynamics: This is the study of energy and its transformations, which includes understanding concepts like endothermic and exothermic reactions.