A device for measuring the diffusion coefficient of a gas mixture (Figure 2) consists of t...

A device for measuring the diffusion coefficient of a gas mixture (Figure 2) consists of two chambers connected by a small tube. Initially the chambers contain different proportions of two gases, A and B. The total pressure is the same in each chamber.

Figure 2

(a) Assuming that diffusion may be described by Fick's law, that the concentration in each flask is uniform, and that the concentration gradient in the tube is linear show that

State any other assumptions needed.

(b) B. G. Bray (Ph.D. Thesis, University of Michigan, 1960) used a similar device. The concentration of hydrogen in hydrogen-argon mixtures was determined from measurements of an ionizing current in each chamber. The ionizing current is proportional to concentration. The difference in ionizing currents between chambers one and two is measured (ΔIC). Compute the diffusion coefficient, DAB, for the following data.

769 psia, T = 35°C, CT = 2.033 mol/dm3, cell constant,