RE: FW: Isopentane Substitute /making N2 slush
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From: | jim <jim@proscitech.com.au> |
To: | "'RUSS ALLISON'" <Allison@Cardiff.ac.uk> |
Reply-To: | |
Content-Type: | text/plain; charset="us-ascii" |
The trouble with "shorthand" is lack of precision. Boiling cools, does sound
funny. So I'll try again for anybody I might have confused and for Russ Allison
in particular:
When boiling water, we add heat (energy) until (at normal pressure) water
reaches 100 degrees and boils. Additional heat yields not further increase in
temperature, but the additional energy is released through the boiling action.
Next time somebody asks to boil water, just sit some in a vacuum belljar and
pump. It soon will boil (water is not very good for a mechanical pump) and it
has not been heated. Russ - English is imprecise: when you say "boil that
water, you actually mean "heat that water to boiling point". Boiling cools - I
am sorry about that fact.
In relation to making nitrogen slush.
Lowering air pressure (evacuating) lowers the boiling point. So liquid nitrogen
boils vigorously and since little heat is lost the boiling actually cools the
liquid nitrogen until it reaches its freezing point - nitrogen slush.
Any further complaints to Russ please Allison@Cardiff.ac.uk
Cheers
Jim Darley
ProSciTech Microscopy PLUS
PO Box 111, Thuringowa QLD 4817 Australia
Ph +61 7 4774 0370 Fax:+61 7 4789 2313 service@proscitech.com
Great microscopy catalogue, 500 Links, MSDS, User Notes
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On Monday, May 22, 2000 6:35 PM, RUSS ALLISON [SMTP:Allison@Cardiff.ac.uk]
wrote:
>
> "Boiling cools" - that's the nicest quote I've heard in a long time,
> Jim.
> Russ Allison,
> Dental School
> Cardiff
> Wales
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