Osmosis and Reverse Osmosis: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

An aqueous solution containing 2.5 g of a protein dissolved in 600 cm3 solution at 20°C was placed in a container that has a water-permeable membrane. Water permeated through the membrane until the level of the solution was 0.90 cm above the pure water. What is the molecular weight of the protein?

Example Problem 2

A solution is made by dissolving 13.0 g of sucrose, C12H22O11, in 117 g of water, producing a solution with a volume of 125 mL at 20.°C. What is the expected osmotic pressure at 20.°C?