The pressure dependence of the vacancy concentration in a metal at 800C has been determined in a high-pressure experiment for two pressures: At p_1 = 1 atm, xv = 1.6010^-4 and at p_2 = 1,000 atm, x_v = 1.4710^-4. The self-diffusion coefficients of this metal at 800C have been determined at the same pressures: D_Me = 3.0510^-8 cm^2/s at p_1 = 1 atm and D_Me = 2.6510^-8 cm^2/s at p1 = 1,000 atm.

a) Calculate the volume of vacancy formation in this metal.

b) At what pressure will xv = 1.3010^-4?

c) What is the value of the activation volume of motion?