A piston cylinder device sketch contains 4 kg of the ideaI g

A piston cylinder device (sketch) contains 4 kg of the ideaI gas, argon, initially at 20 kPa and 35 degree C. During the process, 15 kj of boundary work is done on the piston by the argon, and in addition. 3 kJ of paddle wheel work is done on the argon. If the final argon temperature Is 35 degree C. determine the heat transfer to the system, in kJ.Sketch the system and the p-v diagram.

Solution

Given

m = 4 kg

P1 = 20 kPa

T1 = 35 C = 308 K

T2 = 35 C = 308 K

Since the inital and final temerature are same

change in internal energy = 0

Net work done by argon = 15-3 = 12 kJ

Therefore from the first law

The heat transfer

Q = 12 kJ