Consider the following.

(a) Find the work done by an ideal gas as it expands from point A to point B along the path shown in the figure.
MJ

(b) How much work is done by the gas if it compressed from B to A along the same path?
MJ

I an curious as to how we are to know the pathway from point A to point B?

To find the work done by an ideal gas as it expands or compresses along a given path, we need to use the first law of thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the heat (Q) added to the system minus the work (W) done by the system.

(a) To find the work done by the gas as it expands from point A to point B, we can use the equation:

W = -(ΔU + Q)

In this case, as the gas expands, it does work on the surroundings, and as a result, its internal energy decreases. Assuming the expansion is adiabatic (no heat transfer), we can simplify the equation to:

W = -ΔU

Therefore, to find the work done, we need to calculate the change in internal energy (ΔU).

(b) Similarly, to find the work done by the gas if it compresses from point B to point A along the same path, we can use the same equation:

W = -(ΔU + Q)

In this case, as the gas is compressed, work is done on the gas by the surroundings, and its internal energy increases. Assuming the compression is adiabatic, we can simplify the equation to:

W = -ΔU

Again, we need to calculate the change in internal energy (ΔU) to find the work done.

To calculate the change in internal energy, we need additional information about the system, such as the initial and final states, the specific heat capacity, and any other relevant parameters. Once we have this information, we can use the appropriate equations or thermodynamic processes to determine the change in internal energy and subsequently the work done by the ideal gas.

Note: Without specific data or equations, it is not possible to calculate the exact work done by the gas from point A to point B or from point B to point A.