Mass transport question

. Consider a polymer sphere of radius R whose inside is allowed to dissolve steadily in a large bath of solvent. The sphere outer shell has a low solubility in the solvent so its size does not change signicantly. However, the inside material that does dissolve does so very quickly so that the bath concentration at the sphere's surface is saturated, Cam. With the large size of bath, the polymer concentration far from the sphere surface is negligible (i.e. zero). A) Find a relationship for the steady-state dissolution ux of the sphere. B) What happens to the dissolution rate if the spheres diameter is doubled