ELC Table 5.21 gives a value for the diffusion coefficient of urea in water at high dilution as a function of urea concentration (1.380.0782c1+0.00464c12),c1 is in moles /L. a) Estimate the effective diameter of the urea molecule assuming that it is a sphere and applying the Stokes-Einstein equation. Does this result make sense in light of the structure of urea? b) One possible explanation for the decreased diffusivity of urea at high concentration is that the urea forms clusters within the water, thus increasing the effective size of diffusant. Assess this explanation based on your results from (a)