posted by Laura .
A stoppered flask at 25 C contains 250 mL water, 200 mL octanol, and 50 mL of air. An unknown mass of o-xylene is added to the flask and allowed to partition among the phases. After equilibrium has been established, 5.0 mg of o-xylene are measured in the water. What is the total mass (g) of o-xylene present in the flask?