You have previously learned about energy and its relationship to chemical processes (enthalpy). There are some processes that require the input of heat (endothermic) while others release heat (exothermic), but how do we know if any of these processes will proceed under certain conditions? Enthalpy is only part of the answer, so we must delve  further into chemical thermodynamics.

In this chapter, we will examine the concept of spontaneity: whether a process will occur without external influences. As well, we will focus on the thermodynamic state function known as entropy, a measure of “randomness” or the amount of energy dispersal in molecules. Finally, we will discuss Gibbs free energy, a thermodynamic quantity used to predict spontaneity, which incorporates both enthalpy and entropy.