A sample consisting of 3.00 mole of argon gas at an initial temperature of 22.0°C expands in a cylinder with adiabatic walls from 22.7 L to 32.5 L under the following conditions. What are the values of the work (w), heat (q), and change of internal energy (ΔU) in each case?
(a) Against a constant external pressure of 1.00 bar.
(b) Against a vacuum (free expansion).