V. Air, Cylinder is insulated so adiabatic, Q = 0.
Continuity Eq.: m2 = m1 = m,
Energy Eq. m(u2 - u1) = 1Q2 - 1W2 = - 1W2
Entropy m(s2 - s1) = ∫ dQ/T + 1S2 gen = 0 + 1S2 gen
State 1: (T1, P1)
State 2: (P2, ?)
So one piece of information is needed for the ?, assume reversible process.