Posted by Joseph on .
Ethanol has a heat of vaporization of 38.56 KJ/Mol. And a normal boiling point of 78.4 degrees celcius.
WHAT is the vapor pressure of ethanol at 18 degrees celcius??
Okay...I don't really get out to solve for it actually.
ln (P2/760 torr)= 38560/8.3145 * (1/291.15  1/351.15).
I got ln x/760 = 2.87 ( I must have made an error) and I got stuck right here.
Can someone find me the answer to this??? Answer has to be in 2 sig figs.

Chem. 
DrBob222,
I would not use the negative sign for delta Hvap and 1/T2 should be 1/351.55. Try those changes and get back to me. That may be the only problem you're having.

Chem. 
Joseph,
I solved it and got 42.94 torr, so by 2 sig figs i rounded it up to 43 torr. What did you get?

Chem. 
Joseph,
nevermind. i got it. thank you dr. bob for showing me how to do it tho