Exothermic and Endothermic Reactions

In this lab, we will explore the fundamental principles of chemical reactions that either absorb or release heat. However, this lab is not just about understanding the science behind these reactions, but it's also about applying green chemistry principles to minimize the environmental impact of chemical reactions. Many teachers use the calcium chloride and ammonium nitrate reaction to show exothermic and endothermic reactions. This method uses a catalase, a common enzyme found in nearly all living organisms. When catalase is exposed to oxygen, it catalyzes the decomposition of hydrogen peroxide to water and oxygen. Catalase has one of the highest turnover numbers of all enzymes; one molecule of catalase can convert millions of molecules of hydrogen peroxide to water and oxygen per second. In this procedure we will use liver, but you can easily substitute a yeast, potato, kiwi, peaches or many other forms of catalase in your classroom.