Re: [NTLK] OT humidity

From: Mark Ross (markr13_at_comcast.net)
Date: Tue Jul 02 2002 - 21:27:31 EDT


>Well, I think I see where the confusion came from... I *did* find one text
>last night that stated air is a solution of gasses. But I found another
>where the definition of a solvation required the solvent to exert some
>attractive force upon the solute in order to dissolve it. [In other words,
>if a mixture comes about by dissolving, then the substance that exerts the
>force is the solvent and the substance acted upon is the solute.] This is
>the definition that matches what I was taught in HS and college (although
>the text I found this definition in was not one I ever used). Using that
>definition, since water doesn't dissolve in air (i.e., air doesn't exert an
>*attractive* force to rip water molecules out of their liquid state), air
>cannot be a solvent and water is not a solute and therefore humid air is not
>a solution.
>
>So, it seems, there is a 'generic' usage of the term "solution" to mean any
>situation where there is a homogeneous mixture of substances. But there is
>also the rigorous definition that accounts for the physical process by which
>the mixture came about.
>
>Clear as mud, right? (Which, IIRC, is a suspension...)
>
>- Eric.

I just looked up the surface tension of water in the Chem and Physics
handbook. While it is high (75-53 dynes/cm at 20-100 C)) it still
indicates an interactive force. I suspect there is some hydrogen bonding
with molecular oxygen. In any event, this indicates the solvation effect,
even if it requires heat to obtain it.

Mark Ross
markr13_at_comcast.net

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