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# vapor pressure of ethanol in a 40% alcoholic beverage

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At 48 degrees Celsius the vapor pressure of pure ethanol is 180 Torr. What is the vapor pressure of ethanol in a 40% by mass alcoholic beverage heated to 48 degrees Celsius? (In Torr)

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https://brainmass.com/chemistry/energetics-and-thermodynamics/vapor-pressure-ethanol-alcoholic-beverage-164416

## SOLUTION This solution is FREE courtesy of BrainMass!

Let's assume the other part of the beverage all pure water.
So basically, the beverage is a mixture of 40% ethanol and 60% water (in mass).
We can assume that there are 100 grams of beverage totally.
The mass of ethanol is then 40 grams. and the mass of water is 60 grams.
the moles of 40 grams of ethanol is
n = 40 / 46 mol

the moles of 60 grams water is
n1 = 60 /18 mol.

the mole fraction of ethanol in the beverage is
x = n/(n + n1) = 0.207.

According to Raoult's law, P = x * P0
where P0 = 180 Torr is the vapor pressure of the pure ethnaol and P is the vapor pressure of the ethanol in the beverage.
P = 0.207 * 180 = 37.2 Torr.
The vapor pressure is 37.2 torr for ethanol in the 40% beverage.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

© BrainMass Inc. brainmass.com October 2, 2022, 11:28 am ad1c9bdddf>
https://brainmass.com/chemistry/energetics-and-thermodynamics/vapor-pressure-ethanol-alcoholic-beverage-164416