2. [20] 2.0mol of an perfect gas undergoes isothermal expansion along three different paths: (1) reversible expansion from pi=25.0 bar and Vi=4.5L to pc=4.5 bar, (2) a single-step irreversible expansion against a constant external pressure of 4.5 bar, and (3) a two-step irreversible expansion consisting initially of an expansion against a constant external pressure of 11.0 bar until p=pextenal, followed by an expansion against a constant external pressure of 4.5 bar until p= pexernal. Calculate and compare the work for each of these processes. Gas constant, R=8.314J/molK=8.314102 L bar /molK.1 bar =105Pa,1L=103m3,1J=1Pam3