The SI definition of the mole is the
amount of a substance that contains as
many entities as there are in exactly 12 g
of carbon12.
Avogadro's number is 6.022
x
10
23
.
One
mole of anything is 6.022
x
10
23
units of
that substance.
The mass of 1 mole of an element is
equal to its atomic mass in grams.
Figure
3.4
Proceeding
clockwise
from
the top,
samples
containing
one
mole
each
of
copper,
aluminum,
iron, sulfur,
iodine,
and (in the
center)
mercury.
3.3
The MoLe
81
3.3 ~
The Mole
Because
samples
of matter typically
contain
so many atoms, a unit of measure
called the
mole
has been established
for use in counting atoms. For our purposes, it is most convenient
to define the mole (abbreviated
mol) as
the number
equal
to the number
of carbon
atoms
in exactly
12
grams of pure
12c.
Techniques
such as mass spectrometry,
which count atoms
very precisely, have been used to determine
this number
as 6.02214
X 10
23
(6.022
X 10
23
will be sufficient
for our purposes).
This number
is called Avogadro's
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 Organic chemistry, Atom, Mole, atoms

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