Subject: Avogadro's number

From: Anatoli Korkin <[email-masked]>
Date: Thu, 11 Mar 1999 12:30:51 -0700

Dear Colleagues,

Last time I was visiting my dentist, he asked me how Avogadro
could come with his number at that time. Shame to me I was
not able to answer and I do not have a proper text book or
a time to do this small history research. However, since this
number links computational chemists to the "real world", I
would appreciate if someone takes his time to send me a short
story. I am sure someone has it in his lectures notes. It
is probably interesting for other people, since we have
many students on this list.

Thank you in advance,

Anatoli Korkin

---

From: Chris Harwell <[email-masked]>
Date: Thu, 11 Mar 1999 14:49:48 -0600 (CST)

On Thu, 11 Mar 1999, Anatoli Korkin wrote:

> could come with his number at that time. 
i think he only came up with the idea of a mole and relatvie proportions.

someone else actually came up with the number after boltzmann & maxwell
came up with the necessary stat. mech.

> story. I am sure someone has it in his lectures notes. It
for an excellent story.  see asimov's chemistry. it has lots of short
bio's and stories.

[email-masked]

---

From: "Robert E. Harris" <[email-masked]>
Date: Thu, 11 Mar 1999 16:01:37 -0600

Avogadro didn't come up with the number.  He asserted that equal volumes of
gases (under the same conditions) contqined equal numbers of molecules.
The first really good estimates of the Avogadro constant came from the
determination of the electron charge, which can be compared with Faraday's
number (the charge on a mole of +1 ions) to give the Avogadro constant as
the ratio.  I think the modern value comes from the lattice spacing in
high-ourity silicon compared with the density of the silicon.
Robert E. Harris

---

From: Ascanio DiPippo <[email-masked]>
Date: Thu, 11 Mar 1999 18:53:50 -0500 (EST)

Avogadro was long dead and buried when a quantity was assigned to
"equal volumes of gases contain equal numbers of particles'
I recall that at one time there was thirteen(13) differewnt ways of 
determining 6.02...x 10ee23.  The one I like best is from X-ray
crystallagraphy KBr in a unit cubic or similar calculations.
Students grasp this easily.