# A solution of methanol and water has a vapor pressure of 213 torr. What would you predict as the...

## Question:

A solution of methanol and water has a vapor pressure of {eq}213 \, \mathrm{torr} {/eq}. What would you predict as the mole fractions of each component, assuming ideal behavior? The vapor pressures of methanol and water are {eq}256 \, \mathrm{torr} {/eq} and {eq}55.3 \, \mathrm{torr} {/eq}, respectively.

## Raoult's law

We apply the Raoult's law to find the mole fraction of methanol. According to Raoult's law, the mole fraction of methanol is equal to the vapor pressure of the solution divided by the vapor pressure of pure methanol. Remember that the total mole fraction is a solution is equal to 1.

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Given:

• Vapor pressure of the solution {eq}213 \, \mathrm{torr}{/eq}
• Vapor pressure of methanol {eq}256 \, \mathrm{torr}{/eq}

To solve for the mole...

Vapor Pressure: Definition, Equation & Examples

from

Chapter 19 / Lesson 6
21K

This lesson explains the definition of vapor pressure, describes how vapor pressure changes as a function of temperature according to the Clausius-Clapeyron equation, and shows how to determine the vapor pressure of a single component in a mixture of liquids using Raoult's Law.