Homework Help: Chemistry

Posted by Arnold on Thursday, March 18, 2010 at 12:27am.

The vapor pressures of ethanol (C2H5OH) and 1-propanol (C3H7OH) are 100 mmHg and 37.6 mmHg, respectively. Assume ideal behavior and calculate the partial pressures of ethanol and 1-propanol at 35 degrees Celsius over a solution of ethanol in 1-propanol, in which the mole fraction of ethanol is .300 .

I used the equation Pi = Xi * Ptotal. Where Pi is the partial pressure and Xi is the mole fraction.

So for ethanol I got Pi = .3 * 100mmHg = 30 mmHg (correct answer)

However for 1-propanol:
Pi = .3 * 37.6mmHg = 11.28 mmHg

But the book is telling me the answer is 26.3 mmHg.

Hellpp pleasee!

Chemistry - DrBob222, Thursday, March 18, 2010 at 12:39am
And the book is right.
If the mole fraction for ethanol is 0.3, then the mole fraction for 1-propanol is 0.7 since mole fractions must add to 1.00.
Chemistry - ZAKES, Sunday, August 26, 2012 at 10:07am
THE MOLE FRACTION OF THE SOLUTES YIELD AT 1. THEREFORE IF ETHANOL HAS THE MOLE FRACTION OF 0.300, THE MOLE FRACTION OF 1-PROPANOL SHOULD BE 0.700 THEN USE THE EQUETION:Pi=Xi*P
=0.700*37.6mmHg
=26.32mmHg
Chemistry - ZEKHHETHELO SIBIYA, Sunday, August 26, 2012 at 10:08am
THE MOLE FRACTION OF THE SOLUTES YIELD AT 1. THEREFORE IF ETHANOL HAS THE MOLE FRACTION OF 0.300, THE MOLE FRACTION OF 1-PROPANOL SHOULD BE 0.700 THEN USE THE EQUETION:Pi=Xi*P
=0.700*37.6mmHg
=26.32mmHg

Answer this Question

Related Questions

Chemistry - An example of a solution that exhibits a positive deviation from ...
Chem - You measure two different pressures of the sealed vial containing air and...
chemistry - The Vapor pressures of pure propyl alcohol and isopropyl alcohol are...
Chemistry - Two liquids A and B have vapor pressures of 71.3 and 131 mmHg, ...
CHEMISTRY- vapour pressure - Bromobenzene, C6H5Br, and chlorobenzene, C6H5Cl, ...
Ap Chemistry - 2-propanol has a delta Hvp of 701 J/g and a vapor pressure of 31....
chemistry - Pressure of pure A at 85 (degrees)C is 500 mmHg, what is the vapor ...
Chemistry - A gas mixture with a total pressure of 750 mmHg contains each of the...
Chemistry - The vapor pressure of pure ethanol at 20 degrees C is 44 mmHg, and ...
AP CHEM - 2-propanol has a delta Hvp of 701 J/g and a vapor pressure of 31.6 ...

For Further Reading

First Name:
School Subject:
Answer: