Question

The vapor pressure of ethanol is 1.00 x 102 mmHg at 34.90oC. What is its vapor...

The vapor pressure of ethanol is 1.00 x 102 mmHg at 34.90oC. What is its vapor pressure at 51.73 oC? (ΔHvap for ethanol is 39.3 Kj/mol.)

Given the vapor pressure at one temperature, P1, we can calculate the vapor pressure at a second temperature, P2.

In (P1/P2) = ΔHvap/R (1/T2 - 1/T1)

Where,

ΔHvap for ethanol must have the units of J/mol.

R = 8.314 J/K.mol .. The temperatures must be in Kelvins.

Solve for P2, What is the vapor pressure of ethanol at 51.73 oC?

0 0
Add a comment Improve this question Transcribed image text
Answer #1
Concepts and reason

The relation between the vapor pressure and temperature can be expressed by an equation called Clausius–Clapeyron equation. Vapor pressure of substances can be calculated by using this equation.

Fundamentals

Clausius–Clapeyron equation:-

1 1
-дн,
P
In
Р.
vap
Т, т,
R

Here

P = Initial pressure
P2 Final pressure
AH Molarenthalpy of vapourization

R 8.314J/mol K
T, Initial temperature
T Final temperature

Conversion factor;

T(к) -т(°c) +273.15

Given,

Initial temperature T, =34.90°C
= 34.90+273.15
-308.05K

Final temperature T, =51.73°C
51.73+273.19
324.88K

Given,

Vapor pressure of ethanolat34.90°C(P,)=100mmHg
AH39.3x10 J/mol
vap

Gas constant R 8.314J/molK
T 308.05K
T 324.88K

Substitute the given values in Clausius–Clapeyron equation for finding Р,
,

-AH
(Т, т,
-ΔΗ,
vap
In
1 1
-39.3x10J/mol
8.314J/mol K 324.88 K 308.05K
Р,
In
100mm Hg
Р,
In
=0.803
100mm Hg
P2 223.35mmHg

Ans:

The vapor pressure of the ethanol at 51.73°C
is 223.35mmHg.

Add a comment
Know the answer?
Add Answer to:
The vapor pressure of ethanol is 1.00 x 102 mmHg at 34.90oC. What is its vapor...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT