[Om] [Om3] units
ogilvie at cecm.sfu.ca
Wed Jul 11 19:38:11 CEST 2007
A 'mole', abbreviated 'mol' (which is minimal abbreviation), is
defined as the amount of chemical substance that contains a number of
molecules equal to Avogadro's constant, or perhaps a number of formula
units for cases in which an individual molecule is poorly defined, such as
carbon in diamond or sodium chloride in a crystal of common salt. In any
case for dinitrogen and for dioxygen, yes -- definitely, a mole of O2 is
exactly equivalent to a mole of N2, as each contains by definition
(6.02214179+-0.00000030)x10^23 molecules, within the accuracy of the
value of Avogadro's constant. One mole of N2 thus reacts with one mole
of O2 to yield two moles of nitrogen oxide NO as product, according to
the chemical equation
N2 + O2 = 2 NO
in which mass and charge AND (in this particular case) numbers of moles
are conserved, and which conforms to the law of multiple proportions.
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).
J. F. Ogilvie
(M.A., Ph.D., formerly research fellow of Emmanuel College)
On Wed, 11 Jul 2007, Professor James Davenport wrote:
> On Tue, 10 Jul 2007, John Ogilvie wrote:
>> In the list below of dimensions, mass appears twice. Clearly this double
>> appearance is incorrect. The correct name of the quantity for which the
>> 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.
>> It would be worth while and appropriate to add the SI units radian,
>> for angle within a plane, and steradian, for solid angle, but neither
>> degree nor grad.
> Why not? I grant they are not SI, and might belong in a different CD, but
> they are common units. Whilst I often say that my Vice-Chancellor has
> executes a \pi turn, most people refer to them as 180-degree turns.
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