Question

If 0.540 moles of a gas are compressed from 2.10 L to 0.875 L at 273 K, what is the change in work at a) a constant pressure of 1.00 atm, and b) variable pressure?

Answer 1

a) a constant pressure :

work = - p (V2 - V1)

           = - 1.00 x (0.875 - 2.10)

           = 1.225 L-atm

           = 124 J

work = 124 J

b) variable pressure :

work = - n R T ln (V2 / V1)

          = -0.540 x 8.314 x 273 x ln (0.875 / 2.10)

          = 1073 J