[Om3] [Om] units

[Alberto Gonz ález Palomo]

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On Wed, 11 Jul 2007 10:38:11 -0700 (PDT)
John Ogilvie <ogilvie at cecm.sfu.ca> wrote:

>[...]
>    It would be helpful for the development of civilisation if the knowledge 
> of mathematicians and 'computer scientists' included a greater awareness 
> of basic aspects of natural science (natural philosophy).

      It would indeed. For instance, while my understanding of the mol was
correct, after seeing this discrepancy between Davenport and you I had to
look it up because I wasn't sure.

> On Wed, 11 Jul 2007, Professor James Davenport wrote:
> 
> > On Tue, 10 Jul 2007, John Ogilvie wrote:
> >[...]
> >> SI unit is 'mol' is 'amount of [chemical] substance', with appropriate
> >> technical connotations for 'substance'.
> > Um. Is the 'mol' an SI unit as such? A 'mol' of O2 is not a 'mol' of N2,
> > for example.

      I suspect this misconception comes from a mole of O2 having a different
*mass* (obviously, by definition) from a mole of N2, a point that would have
been stressed by our high school chemistry teachers. I guess this is what
casted a shadow on my shaky recollections about the mole.

      About the other point, the mole (symbol 'mol') is a SI unit, and I
propose that in this dicussion we refer to the Bureau International des
Poids et Measures which has a surprisingly useful website, with clear
definitions of the SI units:

http://www.bipm.org/en/si/base_units/

      The link labelled "SI brochure" for each unit is a good explanation
for each of them, complete with historical notes.

      Cheers,
--
	Alberto González Palomo
	Toledo, España / Saarbrücken, Deutschland
	http://www.matracas.org