Consider a system consisting of 2.0 mol CO2 (assumed to be a perfect gas) at 298K confined to a cylinder of cross-section 10cm^2 at 10 atm. The gas is allowed to expand adiabatically and reversibly against a constant pressure of 1 atm. Calculate W, Q, ΔU, ΔH, and ΔT when the piston has moved 200cm.
(Ans: W=-1.6KJ, Q=0, ΔU=-1.6KJ, ΔT=-28, ΔH=-2.1KJ)
The thermodynamics equations
The Attempt at a Solution
as it is adiabatic, Q=0.
and i found that my W and ΔU are wrong
what's wrong with my answer?
should Pgas=Pex if the system is in equilibrium?
i just found that it isn't
but in my book :
"To achieve reversible expansion we must match Pex to P at each state: dw=-Pex dV=-P dV"
i am so confused.