A cylinder which is in a horizontal position contains an unk

A cylinder which is in a horizontal position contains an unknown noble gas at 5.05 × 104 Pa and is sealed with a massless piston. The piston is slowly, isobarically moved inward 0.176 m, while 1.50 × 104 J of heat is removed from the gas. If the piston has a radius of 0.261 m, calculate the change in internal energy of the system.

Solution

dV = AdX

= piR^2*dX

= 3.14*0.261^2*0.176 = 0.0376 m^3

=> W on the system = PdV = 5.05*10^4*0.0376 = 1898.8 J

=> dE = Q + W

=> dE = -1.50*10^4 + 1898.8 = -13101.2 J