And,
yes, we who celebrate such a chemical constant are
geeks! Thanks for asking!
But...why is a day celebrating Avogadro's number called Mole Day?
Well,
Avogadro's number has to with “moles,” which is an amount. For
any sort of molecule, one mole is a mass in grams whose number is
equal to the atomic mass of the molecule. A water molecule, as you
may know, is H2O,
and it has an atomic mass of 18. So one mole of water weighs 18
grams. But
oxygen gas (two oxygen atoms) has an atomic mass of 32, and so one
mole of oxygen gas weighs 32 grams.
In
general, one mole of any substance contains Avogadro's Number of
molecules or atoms of that substance. Another way of saying that is
that 18 grams of water has 6.02 x 10^23 molecules of water, and 32
grams of oxygen gas has 6.02 x 10^23 molecules of oxygen gas.
On
this day in chemistry history....
On
October 23, 1803...
Chemist
John Dalton read aloud to the Manchester Literary and Philosophical
Society his essay about how water absorbs gases, and he gave atomic
weights for 21 different elements and compounds. From this work on
absorption of gases and atomic weights, Dalton came up with a much of
the modern atomic theory eventually adopted by physics.
A
very appropriate essay to have read on Mole Day!
To
learn more about Mole Day, and to find links to a funny song and
official website, check out last year's post!
By
the way, did you notice...?
National
Mole Day has nothing to do with moles-the-mammals-that-dig?
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