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Re: Vapor Pressure and Evaporation Rates
Not from the vapor pressure alone. The (equilibrium) vapor pressure of a
liquid is essentially the amount of vapor that will be in equilibrium with a
liquid in a closed container (that has some space in it) at a particular
temperature. It can be thought of as a tendency for the molecules to escape
from liquid as gas. Clearly it is a function of temperature and pressure
(or volume: pV=nRT -- and for you purists out there, I should really put the
van der Waals equation and not the ideal gas law, because we are not dealing
with an ideal gas, but it's a similar idea). Vapor pressure is an intrinsic
property of a substance. Evaporation rate, on the other hand, is an
extensive property and depends not only on temperature and pressure but on
the surface area of the liquid evaporating. I suggest you consult a
physical chemistry text, but evaporation rate is usually an empirical
measurement because it depends on several variables and is easier to measure
than to calculate.
Ruth Weiner
ruth_weiner@msn.com
-----Original Message-----
From: William Lorenzen <LORENZEN_W@A1.TCH.Harvard.edu>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Tuesday, August 01, 2000 4:41 PM
Subject: Vapor Pressure and Evaporation Rates
> Is it possible to determine the evaporation rate of an organic
> compound from it's vapor pressure?
>
> Regards,
>
> William A. Lorenzen
> Children's Hospital
> Boston, Ma 02115
> lorenzen_w@a1.tch.harvard.edu
>
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