The temperature of 0.150 mol of an ideal gas is held constant at 77.0oC while its volume

Question:

The temperature of 0.150 mol of an ideal gas is held constant at 77.0oC while its volume is reduced to 25.0% of its initial volume. The initial pressure of the gas is 1.25 atm.
(a) Determine the work done by the gas.
(b) What is the change in its internal energy'?
(c) Does the gas exchange heat with its surroundings? If so, how much? Does the gas absorb or liberate heat?