The following osmotic pressures were measured for solutions of a macromolecular material in water at 25C. Concentration (g/dm) Osmotic pressure (cm solution) 0.35 0.60 0.80 0.95 20 38 55 70 Assume solution density = 1.05 g/cm in each case. Note that solutions are not ideal. Calculate an average molecular mass of the material. (500 g/mole)