A sample of nitrogen gas expands in volume from 1.3 to 5.7 L at constant temperature. Calculate the work done in joules if the gas expands (a) against a vacuum: J (b) against a constant pressure of 0.60 atm: * 10 J Enter your answer in scientific notation. (c) against a constant pressure of 4.7 atm: * 10 J Enter your answer in scientific notation.

a) 0 J

b) - 2.67x10² J

c) - 2.09x10³ J

Explanation:

For an isothermic expansion (with constant temperature) the work (W) is:

W = - pΔV, where p is the pressure and ΔV the volume variation. The minus signal is used because the compression is positive and ΔV is negative (Vf < Vi).

a) In vacuum, the relative pressure is 0 atm, so the work:

W = - 0x (5.7 - 1.3)

W = 0 J

b) For a constant pressure of 0.60 atm

W = - 0.6atmx (5.7 - 1.3) L = - 2.64 L. atm

1 L. atm = 101.3 J

W = - 2.64x101.3 = - 2.67x10² J

c) For a pressure of 4.7 atm

W = - 4.7atmx (5.7 - 1.3) L = - 20.68 atm. L

1 atm. L = 101.3 J

W = - 20.68x101.3 = - 2.09x10³ J