A solution is prepared by adding 40.00 g of lactose (milk sugar)to 110.0 g of water at 55 °C The partial pressure of water above the solution is ________ torr. The vapor pressure of pure water at 55 °C is 118.0 torr. The MW of lactose is 342.3 g/mol.
A)2.216
B)125.5
C)225.9
D)115.8
E)86.5

Question

Quizplus · Accepted Answer

The partial pressure of water above the solution can be calculated using Raoult's Law: P_solution = X_solvent * P_pure. First, calculate the moles of lactose (40.00 g / 342.3 g/mol) and water (110.0 g / 18.015 g/mol). Then, find the mole fraction of water (X_solvent) and multiply by the vapor pressure of pure water (118.0 torr) to get the partial pressure.

A Solution Is Prepared by Adding 40