Question

A certin gas expans in volume from 2.0 L to 0.6 L at a constant tempature. Caculate the work done under the following conditions:

a. expansion agasint external pressure of 1.2 atm

b. expansion aganist a vacuum

Answer 1

a)

external pressure = 1.2 atm

work done = - pdv

                 = - 1.2 x (6 - 2)

                 = - 4.8 L.atm

work done = - 4.8 x 101.325 = - 486.5 J

work done = - 486.5 J

b)

in vaccum , the external pressure = 0

work done = 0 J

Note : expands from 2.0 to 6.0 L not 0.6 L