Question

What mass of sucrose (C12H22O11) should be combined with 548g of water to make a solution with an osmotic pressure of 8.50atm at 270K ? (Assume the density of the solution to be equal to the density of the solvent.)

Answer 1

Osmotic Pressure is P=MRT. Solving for the mass we get M=P/(RT). Given information is:

P=8.50 atm, m_H2O=548 g, T=270 K, R=0.08206 L atm / mol K

Substituting the respective values we have M=0.384 moles/L. The molar mass of sucrose is 342.3 g/mol.

Molarity=(moles of solute)/(liters of solution)

Don't forget that the sucrose you're going to add has a volume to it that must be accounted for in addition to the 0.548 liters of H₂O. So from here we need to express the mass of sucrose