.split() Qeustion

[wxjmfauth at gmail.com]

Le dimanche 18 août 2013 01:30:14 UTC+2, Gregory Ewing a écrit :
> wxjmfauth at gmail.com wrote:
> 
> > Na  + Cl   -->   NaCl
> 
> > 
> 
> > the chemist combines *one mole* of sodium and *one
> 
> > mole* of chlorine to get *one mole* of sodium chloride
> 
> > 
> 
> > It's independent of the number of "particles" in a mole.
> 
> 
> 
> The actual number chosen for the unit is arbitrary, but
> 
> number of particles is still the central issue. The
> 
> important thing is to have the *same* number of particles
> 
> of Na and Cl.
> 
> 
> 
> Weight only comes into it because it's totally impractical
> 
> to count particles. And the particular number 6.02e23 is
> 
> chosen because it happens to give a convenient relationship
> 
> between number of particles and grams. If chemists had
> 
> decided to use ounces instead, the number would be different.
> 
> 
> 
> -- 
> 
> Greg

--------


"The actual number chosen for the unit is arbitrary, but
number of particles is still the central issue."

No.


"The important thing is to have the *same* number of particles
of Na and Cl."

Yes.
And it is precisely for that reason, a chemist works in "mole
arithetic".

Same reaction as above

Na  + Cl   -->   NaCl

in pseudo math, with n = number of elements in a mole.


n * Na  + n * Cl  --> n * NaCl    <==>
n * (Na + Cl)  -->  n * NaCl      <==> division by n
Na + Cl   -->  NaCl


for any n.

----

The determination of n, the number of elements in
a mole, is an indipendent and separate problem.
(BTW, a very complicate task).


jmf