# Interpretation of non-spontaneous Gibbs free energy

Good day guys,

I was reading some books on physical thermodynamics, they explain that for system undergoing a chemical reaction whose $$\Delta G < 0$$ indicating that the reaction can then provide us with a max non-PV work of $$W_{max} = - \Delta G$$

However, what happens when the reaction is not spontaneous, is $$\Delta G$$ the minimum work we need to supply? The books I have do not explicitly mention this statement, they only state it for work obtained from spontaneous reactions.

• It's the amount of work you/surroundings must do to the system so that the (non-spontaneous) process goes forward. That is, $W=\Delta G$ Commented Nov 28, 2023 at 6:02
• Is it the total amount of work we must supply or the minimum ? One of my book presents this equation as an inequality: $W \le \delta G$.
– RMS
Commented Nov 28, 2023 at 6:22
• the difference $\Delta G -W$ is the dissipated heat. Commented Nov 28, 2023 at 14:51
• here are two similar questions for the Helmholtz free energy $F$ with obvious changes to your question on $G$ physics.stackexchange.com/questions/761649/… and physics.stackexchange.com/questions/755441/… Commented Nov 28, 2023 at 15:56
• @RMS it’s the minimum. Commented Nov 28, 2023 at 22:07