1.19a. Wilke-Chang method for liquid diffusivity.
Estimate the liquid diffusivity of carbon tetrachloride in dilute solution into ethanol at 298 K. Compare to the experimental value reported by Reid, et al. (1987) as 1.5 ´ 10-5 cm2/s. The critical volume of carbon tetrachloride is 275.9 cm3/mol. The viscosity of liquid ethanol at 298 K is 1.08 cP.

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1.20b. Diffusion in electrolyte solutions.
When a salt dissociates in solution, ions rather than molecules diffuse. In the absence of an electric potential, the diffusion of a single salt may be treated as molecular diffusion. For dilute solutions of a single salt, the diffusion coefficient is given by the Nernst-Haskell equation (Harned, H. S., and B. B. Owen, "The Physical Chemistry of Electrolytic Solutions," ACS Monogr. 95, 1950):
a) Estimate the diffusion coefficient at 298 K for a very dilute solution of HCl in water.

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b) Estimate the diffusion coefficient at 273 K for a very dilute solution of CuSO4 in water. The viscosity of liquid water at 273 K is 1.79 cP.
1.21a. Oxygen diffusion in water: Hayduk and Minhas correlation.
Estimate the diffusion coefficient of oxygen in liquid water at 298 K. Use the Hayduk and Minhas correlation for solutes in aqueous solutions. At this temperature, the viscosity of water is 0.9 cP. The critical volume of oxygen is 73.4 cm3/mol. The experimental value of this diffusivity was reported as 2.1 ´ 10Ð5 cm2/s (Cussler E. L., Diffusion, 2nd ed, Cambridge University Press, Cambridge, UK, 1997).
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