This document provides an overview of the key concepts covered in 5 sections of a chapter on energy and chemical change: Section 15.1 defines energy and distinguishes between potential and kinetic energy. It relates chemical potential energy to heat released or absorbed in chemical reactions. Section 15.2 describes how calorimetry is used to measure energy changes and defines enthalpy and enthalpy changes. Section 15.3 explains how to write thermochemical equations and describes energy changes during state changes. Section 15.4 discusses calculating enthalpy changes using Hess's law and standard enthalpies of formation. Section 15.5 differentiates between spontaneous and nonspontaneous processes and explains how entropy