A crystal of Copper sulfate CuSO4.5 HO falls through a large tank of pure water at 20C. Estimate the rate at which the crystal dissolves by calculating the flux of CuSO4 from the crystal surface to the bulk solution. Molecular diffusion occurs through a film of water uniformly 0.0305 mm thick surrounding the crystal. At the inner side of the film, adjacent to the crystal surface, the concentration of CuSO4 is 0.0229 mole fraction CuSO4 (Density of solution = 1193 Kg/m). The outer surface of the film is pure water. The diffusivity of CuSO4 is 7.29 x 10- m/s. (10) (May/June '06)