Final answer:
The maximum additional work and Gibbs energy are related by AG = W_add,max. The change in Gibbs energy represents the maximum amount of work that a system can perform on the surroundings during a spontaneous change. The Gibbs energy measures the maximum amount of energy that can be freed from the system to perform useful work.
Step-by-step explanation:
The relationship between the maximum additional (non-expansion) work, W_add,max, and the Gibbs energy, AG, is given by the equation AG = W_add,max. This means that the maximum amount of work that a system can perform on the surroundings during a spontaneous change is equal to the change in Gibbs energy. The Gibbs energy, also known as the free energy, measures the maximum amount of energy that can be freed from the system to perform useful work.