A solution is prepared from 53.8 g of a nonvolatile,nondissociating solute and 85.0 g of water.The vapor pressure of the solution at 60°C is 132 torr.The vapor pressure of water at 60°C is 150.torr.What is the molar mass of the solute?
A)61.1 g/mol
B)11.4 g/mol
C)34.6 g/mol
D)186 g/mol
E)83.6 g/mol

Question

Quizplus · Accepted Answer

The vapor pressure lowering can be used to find the mole fraction of the solute, which can then be used to calculate the molar mass. Using Raoult's Law: P_solution = X_solvent * P_solvent. The mole fraction of the solvent (water) is 132/150. Using the mole fraction and the mass of water, the molar mass of the solute is calculated to be approximately 83.6 g/mol.

A Solution Is Prepared from 53