A concentration difference of a certain solute of 1.0 Ã- 10â€"2 kg/m3 is maintained between the ends of a tube with a length of 3.5 m and a cross-sectional area of 0.25 m2. When 0.0040 g of the solute is introduced to the tube, it takes 350 minutes for this solute to diffuse through the solvent to the opposite end of the tube. What is the diffusion constant for the solute?