Calculate the internal energy change for each of the following.

Question

A piston is compressed from a volume of 8.48 L to 2.87 L against a constant pressure of 1.79 atm. In the process, there is a heat gain by the system of 350. J.

Answer 1

w = -P∆V

w = work

P = pressure = 1.79 atm

∆V = change in volume = 2.87 L - 8.48 L = - -5.61 L

w = -(1.79 atm x -5.61 L) = +10 Latm

converting to J we have 10 Latm x 101.325 J/Latm = +1013 J of work done ON THE SYSTEM

∆U = q + w = 350 J + 1013 J = 1023 J