Moles Notes
Counting Units
• Dozen doughnuts
• Cents in a dollar
• Gallon of milk
Counting Atoms
Counting atoms requires
a standard unit of
measurement.
The Mole

Amedeo Avogadro
• Actual name: Lorenzo
Romano Amedeo Carlo
Bernadette Avogadro di
Quaregna e Cerreto
• Born August 9, 1776 in
Turin, Italy
• Lawyer who dabbled in
natural philosophy in his
later life
Amedeo Avogadro
• Avogadro became important for
some of his discoveries that he
made
• Avogadro discovered that gases
were not alone, but a molecule
containing 2 atoms of the gas
• Like: O2, N2, I2
Avogadro’s Number
• Was NOT discovered by Avogadro, but
attributed to him by the scientists who
discovered the number.
• Avogadro’s number refers to the number
of atoms in a specific amount of a
substance. This amount is called a mole.
The Mole
• 1 mole is symbolized by
(the unit) mol
• 1 mol = 6.02 x 1023 atoms
• 1 mole of any substance
will contain 6.02 x 1023
atoms
Moles
• 1 mole of a substance will not always be the
same size. However…..
• 1 mol of any gas at STP will fill 22.4L
1 mol of
• Popcorn kernals would cover the continental 48
states to a depth of 310 miles
• Sodapop cans would cover the Earth to a depth of
200 miles
• If we were able to count atoms at the rate of 10
million per second, it would take about 2 billion years
to count the atoms in one mole!
• If Uncle Chintzy had left you a mole of dollars, and
you could count 24hrs a day it would take you
19,100,000,000,000,000 years (19 quadrillion)
• http://www.youtube.com/watch?v=TEl4jeETVmg
Molar Masses
• What is the molar mass of sodium (Na)?
• What is the molar mass of chlorine (Cl)?
• What is the molar mass of calcium (Ca)?
• These numbers are found directly on the periodic
table – rounded to one decimal place.