Chapter 12, Problem 103RQ

The osmotic pressure of a dilute solution of a slightly soluble polymer (a compound composed of large molecules formed by linking many smaller molecules together) in water was measured using the osmometer in Figure 12.22. The difference in the heights of the liquid levels was determined to be 1.26 cm at $\text{25 °C}\text{.}$

Assume the solution has a density of $\text{1}{\text{.00 g ml}}^{\text{-1}}\text{.}$

What is the osmotic pressure of the solution in torr?

What is the molarity of the solution? (c) At what temperature would the solution be expected to freeze? (d) On the basis of the results of these calculations, explain why freezing point depression cannot be used to determine the molecular masses of compounds composed of very large molecules.