A sample consisting of 2.00 mol He is expanded isothermally at 22C from 22.8 dm to 31.

Question:

A sample consisting of 2.00 mol He is expanded isothermally at 22°C from 22.8 dm to 31. 7 dm 3
(a) Reversibly,
(b) Against a constant external pressure equal to the final pressure of the gas, and
(c) Freely (against zero external pressure). For the three processes calculate q, w, ∆U, and ∆H.