Part of completing problems in thermostoichiometry involves knowing if the reaction is endothermic or exothermic. Endothermic reactions absorb heat and energy, while exothermic reactions give off heat and energy. How many objects or products can you list that either give off heat or absorb heat? In this Warm-Up, list as many objects as you can that either absorb or radiate heat and energy. One example is shown in the image on this page. The hot beverage is giving off heat. This makes the beverage exothermic.