A rigid vessel of 0.06 m3 volume contains an ideal gas. CV = (5/2) R. at 500

Question:

A rigid vessel of 0.06 m3 volume contains an ideal gas. CV = (5/2) R. at 500 K and I bar.
(а) If heat in the amount of 15,000 J is transferred to the gas, determine its entropy change.
(b) If the vessel is fitted with a stirrer that is rotated by a shaft so that work in the amount of 15.000 J is done on the gas. what is the entropy change of the gas if the process is adiabatic? What is Stotal? What is the irreversible feature of the process?