Find the mass of urea (CH4N2O) needed to prepare 48.5 g of a solution in water in which the mole fraction of urea is 7.68×10-2.
What mass of sucrose (C12H22O11) should be combined with 5.01×102 g of water to make a solution with an osmotic pressure of 8.55 bar at 300 K ? (Assume a density of 1.0 gmL-1 for the solution.)