Consider 4 moles of a perfect gas with initial volume= 20dm^3, initial temp= 300K, and final volume= 60dm^3. What is the change in entropy for the system, surroundings, AND total for the following processes:
(a) isothermal expantion into vaccume
(b) isotheral expansion against a constant external pressure of 1bar
(c) isothermal expansion which gives max work