Re: The importance of being pedant

[Robert A Cohen <bbq@ESU.EDU>]

On Fri, 23 Jul 1999, Michael Edmiston wrote:

> But the overwhelming evidence, both printed and by personal testimony
> from chemists is that the words vapor and gas are used interchangeably.
>  I can cite published examples in very popular physical chemistry texts
> if anyone wishes to check them out.

I've been reading this thread with interest because I am one who thinks
that, while a vapor is not an aerosol of liquid droplets, there is a
difference between a vapor and a gas.  Could the interchanging be because
a vapor is a gas but a gas isn't necessarily a vapor?

For example, I've always used vapor to describe an evaporated liquid.
The vapor, having evaporated from the liquid, is a gas and the vapor
can coexist with the liquid.  On the other hand, I don't consider a gas
like atmospheric nitrogen a vapor because it isn't in equilibrium with
a liquid phase.

Is this usage misleading, incorrect or otherwise not appropriate?

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| Robert Cohen               Department of Physics       |
|                            East Stroudsburg University |
| bbq@esu.edu                East Stroudsburg, PA  18301 |
| http://www.esu.edu/~bbq/   (570) 422-3428              |
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