Chemical reactions are accompanied by energy changes, which often appear in the form of heat. In fact, energy absorbed or released by a chemic al system may take different forms. Basic concepts of chemical energetics and enthalpy terms are introduced in this topic. Practical work on the simple calorimetric method and quantitative treatment of Hess’s law can help students to better understand th e concepts of energetics. However, the use of equipment such as the bomb calorimeter is not expected at this level of study.