The vapor pressure of pure ethanol at 60 °C is 0.459 atm. Raoult's Law predicts that a solution prepared by dissolving 10.0 mmol naphthalene (nonvolatile) in 90.0 mmol ethanol will have a vapor pressure of atm.
A) 0.367
B) 0.0918
C) 0.498
D) 0.790
E) 0.413

Question

Quizplus · Accepted Answer

Raoult's Law states that the vapor pressure of a solution is the product of the mole fraction of the solvent and the vapor pressure of the pure solvent. The mole fraction of ethanol is 90.0 mmol / (90.0 mmol + 10.0 mmol) = 0.9. Therefore, the vapor pressure is 0.9 * 0.459 atm = 0.413 atm.

The Vapor Pressure of Pure Ethanol at 60 °C Is