Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution.

Mass of solvent = 1000 g Molar mass of urea (NH2CONH2) = 60 g mol-10.25 mole of urea = 0.25 x 60 = 15 gTotal mass of solution = (1000 + 15) g = 1.015 kg∵1.015 kg of solution contain urea = 15 g∴2.5kg of solution will contain urea =151.015×2.5=37 g