Question

Be sure to answer all parts. Calculate the vapor pressure of a solution made by dissolving 87.8 g of urea (molar mass = 60.06 g/mol) in 224.5 mL of water at 35°C. (Hint: The vapor pressure of pure water at 35°C is given in the table below. Assume the density of the solution is 1.00 g/mL.) I nHg What is the magnitude of vapor-pressure lowering? D nHg

Answer 1

P Solution = X Sowent PSOLVENT Psolwent = 42.2 mm Hg AT 35°C No. of moles of WATER = 224.5 g 18g moet = 12.472 more mass of UREA No. of moles Of URFA = - i Hh of UREA 87.89 60.06 gmoet = 1.462 mol molt FRACTION OF SOLENT, X Solvent = 12.472 12.472 + 1.462 = 0.895 VAPOR PRESSURE OF SOWTION, Powrion = 0.895x 42.2 mm Hg 1 37 76 mm Hg mass of WATER = 224.5 ml x 1.00 g ml = 224.59

MAGNITUDE OF VAPOR PRESSURE LOWERING = Powens - Psowurow = 42.2-37. To - 4.4.21 mm ang