Le vendredi 16 août 2013 15:23:37 UTC+2, Roy Smith a écrit : > In article <2d88bc0f-fdcb-4685-87ed-c17998dd3...@googlegroups.com>, > > wxjmfa...@gmail.com wrote: > > > > > A chemist has to work and is always working in mole; as his > > > balance can only measure a mass, the calculation mole <-> mass > > > is always mandatory. > > > > That's because chemists are lazy. > > > > The recipe says, "Add one mole of carbon atoms". So, does the chemist > > follow the recipe and count out 6.022 x 10^23 atoms like he's supposed > > to? No. He says, "I don't have time for that. I'll just weigh out 12 > > grams. Good enough for government work." Sheesh.
-------- You don't understand the concept of "mole". In this formal reaction Na + Cl --> NaCl the chemist combines *one mole* of sodium and *one mole* of chlorine to get *one mole* of sodium chloride (cooking salt). It's independent of the number of "particles" in a mole. It's not a question of laziness, the chemist can only weight 22.98 g of sodium to work with one mole of sodium, because the nature is like this. The work with relative quantities has a name: stoichiometry. jmf -- http://mail.python.org/mailman/listinfo/python-list
