Using an illustrated example, the difference between an endothermic and an exothermic reaction is described. The concept of enthalpy, or heat energy change, is explained, and the energy diagrams of reactions are presented.

For this lesson on endothermic and exothermic reactions, students explore chemical reactions, energy transfer, and energy diagrams.

This lesson focuses on heat energy changes in chemical reactions. Exothermic reactions transfer energy to the surroundings. Endothermic reactions take in energy from the surroundings. It also offers links to a video and a test.

Given descriptions, diagrams, scenarios, or chemical symbols, students will calculate the energy changes and identify exothermic and endothermic reactions.