A cylinder with an initial volume of 10.0 L is fitted with a frictionless piston and is filled with 1.00 mole of an ideal gas at 25
C. Assume that the surroundings are large enough so that if heat is withdrawn from or added to it, the temperature does not change.

a. The gas expands isothermally and reversibly from 10.0 L to 20.0 L. Calculate the work and the heat.
b. The gas expands isothermally and irreversibly from 10.0 L to 20.0 L as the external pressure changes instantaneously from 2.46 atm to 1.23 atm. Calculate the work and the heat.