Which of the following defines the term 'Gibbs energy'?

Gibbs energy, also known as Gibbs free energy, is defined as the energy that can be used to do reversible work at constant temperature and pressure. This concept is crucial in thermodynamics because it allows us to determine the spontaneity of a reaction. When the change in Gibbs energy (ΔG) for a process is negative, the reaction can occur spontaneously.

This definition highlights the ability of Gibbs energy to predict whether a reaction will proceed in the forward direction under specified conditions. Unlike the potential energy available for doing work, which is a broader concept that can apply to various energy forms in a system, Gibbs energy specifically focuses on the energy available for performing work in a thermodynamic context.

Additionally, while the energy stored in chemical bonds is part of the system's internal energy, it does not encapsulate the balance of enthalpy and entropy that Gibbs energy represents. The idea that Gibbs energy is specifically related to the energy released during spontaneous reactions only doesn’t encompass the full utility of the Gibbs energy concept, as it can also apply to non-spontaneous reactions under certain conditions. Therefore, understanding Gibbs energy as a measure of useful work potential in a system at equilibrium provides crucial insight into chemical thermodynamics.