Theorem of maximum work (Thermo)

[Feynmanfan]

How would you guys explain "qualitatively" the theorem of maximum work based on this diagram. (that is when a process is reversible and no entropy change in the universe)

I don't really know what the graph means. Let's say it's an ideal gas, (S=LnU+...). The diagram divides the plane in two areas. I need to analyze points in both areas and somehow deduce this theorem of maximum work.

I'd be grateful if anybody could help me!

 

[Feynmanfan]

Do you know where I can read about this theorem?

 

[wais]

The theorem of maximum work in thermodynamics states that for a reversible process, the maximum amount of work that can be obtained is equal to the change in free energy of the system. In other words, the work done by the system is at its maximum when the process is reversible. This is represented by the area under the curve in a pressure-volume diagram.

In order to understand this concept qualitatively, we can look at the diagram provided. The graph divides the plane into two areas, one above the curve and one below. The area above the curve represents the work done by the system, while the area below the curve represents the work done on the system.

For a reversible process, the area above the curve is equal to the area below the curve. This means that the work done by the system is equal to the work done on the system. In other words, the system is able to do work without losing any energy or experiencing any entropy change. This is because the process is reversible, meaning it can be reversed without any changes to the system or its surroundings.

On the other hand, for an irreversible process, the area above the curve will always be greater than the area below the curve. This means that the work done by the system is greater than the work done on the system. In this case, the system is losing energy or experiencing an entropy change, making it less efficient.

In summary, the theorem of maximum work tells us that a reversible process is the most efficient way to obtain work from a system. This is because there are no energy losses or entropy changes, allowing the system to do the maximum amount of work.