Energy is a vital component of the world around us. Nearly every physical and chemical process, including all the chemical reactions discussed in previous chapters, occurs with a simultaneous energy change. In this chapter, we will explore the nature of energy and how energy and chemistry are related. 8.0: Prelude to Energy and Chemical Processes Metabolism is the collective term for the chemical reactions that occur in cells and provide energy to keep cells alive. Some of the energy from metabolism is in the form of heat, and some animals use this heat to regulate their body temperatures. Such warm-blooded animals are called endotherms. In endotherms, problems with metabolism can lead to fluctuations in body temperature. When humans get sick, for instance, our body temperatures can rise higher than normal; we develop a fever. 8.1: Energy and Its Units Energy is the ability to do work. Heat is the transfer of energy due to temperature differences. Energy and heat are expressed in units of joules. 8.2: Heat Heat transfer is related to temperature change. Heat is equal to the product of the mass, the change in temperature, and a proportionality constant called the specific heat. 8.3: Phase Changes There is an energy change associated with any phase change. There is an energy change associated with any phase change. 8.4: Bond Energies Atoms are held together by a certain amount of energy called bond energy. Chemical processes are labeled as exothermic or endothermic based on whether they give off or absorb energy, respectively. 8.5: The Energy of Biochemical Reactions Energy to power the human body comes from chemical reactions. 8.E: Energy and Chemical Processes (Exercises) Problems and Solutions to accompany the chapter. 8.S: Energy and Chemical Processes (Summary) To ensure that you understand the material in this chapter, you should review the meanings of the following bold terms in the following summary and ask yourself how they relate to the topics in the chapter.