Amedeo Avogadro
In order to state that
equal volumes of all
gases at the same
temperature and
pressure contain the
same number of
molecules, Amedeo
Avogadro used the ideas
of Gay-Lussac in the
year 1811.
Avogadro's Principle
If we assume that equal volumes of all gases
contain the same number of molecules, then by
measuring the mass of the same volume of
different gases, we can determine the relative
weights of each element. It follows then that a
sample of any element,weighing an amount in
grams numerically equal to it’s atomic weight,
contains the same number of atoms as any other
element meeting the same requirement.
The number of atoms in any given
element is known as Avogadro's
number and has been determined
to be equal to:
6.02 x 10^23
Avogadro’s Number
The atomic weight of any element
that is being expressed in grams
contains 6.02 x 10^23 atoms of the
element.
The Mole
The molecular weight of a
substance expressed in grams.
6.02 x 10^23 H atoms= 1 mol H
and
6.02 x 10^23 Al atoms= 1 mol of Al