What term is used to refer to the amount of free energy that can be utilized to do work in a system?

The term that refers to the amount of free energy that can be utilized to do work in a system is known as Delta G, or Gibbs free energy. Gibbs free energy is a thermodynamic potential that helps predict the direction of chemical reactions and the balance between reactants and products in a system at constant temperature and pressure.

A negative change in Gibbs free energy indicates that a reaction can occur spontaneously, and such energy can be harnessed to perform work. This makes Delta G an essential concept in understanding not just the feasibility of reactions but also their equilibrium.

Delta H represents the change in enthalpy, or total heat content, of a system. While it is important for understanding the heat absorbed or released during a reaction, it doesn't directly indicate the energy available for work in the way that Delta G does.

Delta S describes the change in entropy, or the degree of disorder or randomness in a system. Although it relates to the spontaneity of a reaction as well, it doesn’t quantify the usable energy in the same way as Gibbs free energy.

Activation energy is the minimum energy required for a reaction to occur, which is important for understanding reaction kinetics but does not refer to the free energy available for work. Overall, Delta G is the key term