Question

A sample of gas occupies a volume of 62.7 mL. As it expands, it does 146.3 J of work on its surroundings at a constant pressure of 783 torr. What is the final volume of the gas?

Answer 1

Work done = -Pext*dV = -Pext(V2-V1)

Pext = external pressure = 783torr

1 atm = 760torr

783 torr = 783/760atm = 1.03 atm

Pext = 1.03atm

Work done = 146.3J

1 L-atm = 101.3J

1J = 1/101.3Latm = 9.872*10^-3 Latm

146.3J = 146.3*9.872*10^-3 Latm = 1.444Latm

W = -1.444Latm (negative because work is being done by the system)

V1 = 62.7mL = 0.0627L

Keeping all the values->

-1.444Latm = -1.03atm*(V2-0.0627L)

1.402L = V2 - 0.0627L

V2 = 1.402L+ 0.0627L = 1.4646L = 1464.6mL