WHAT IS A MOLE?

1
WHAT IS A MOLE?

• 602214199000000000000000
• 6.02 x 1023

2
Mole Facts

• 6.02 X 1023  Pennies Would make at least 7
  stacks that would reach the moon.
• 6.02 X 1023  Watermelon Seeds Would be found
  inside a melon slightly larger than the moon.
• 6.02 X 1023  Blood Cells Would be more than the
  total number of blood cells found in every human
  on earth.
• 1 Liter bottle of Water contains 55.5 moles H20

3
A Brief History

• Amadeo Avogadro was an Italian physics professor
  who proposed in 1811 that equal volumes of
  different gases at the same temperature contain
  equal numbers of molecules
• Josef Loschmidt, an Austrian high school
  teacher,in 1865, calculated the number of
  molecules in one cm3 of gaseous substance to be
  somewhere around 2.6 x 1019
• J.Perrin (1908) estimated the value to be between
  6.5 x 1023 and 6.9 x 1023
• Rutherford and Geiger used radioactive methods
  6.2 x 1023
• The best modern values for what we now call
  "Avogadro's Number" are the result of the x-ray
  diffraction measurement of lattice distances in
  metals and salts.

4
Definition of a Mole

• The amount of atoms in 12.0 grams of Carbon 12
  (6.02 x 1023 atoms known as Avogadros number).
• A sample of any element with a mass equal to that
  element's atomic weight (in grams) will contain
  precisely one mole of atoms (6.02 x 1023 atoms).

5
How do we determine MOLAR MASS?

• Molar Mass Mass in grams of one mole of that
  substance
• What is the molar mass of H2O?
• 2 Hydrogen atoms 2 x 1g 2g
• 1 Oxygen atom 1x 16g 16g
• 1 mole H2O 18g
• What is the molar mass of CO2?
• Fe2O3?

6
Why is the mole an important unit in chemistry?

• Atoms and molecules react with one another
  particle by particle
• The mole is the translation factor between
  weights and numbers of particles

7
How do we convert mass to particles?

• How many moles in 10 g of O2?
• 10g O2 x 1 mole
• 32g 0.3125 mol
• How many molecules in 55 g of H2O?
• 55g H2O x 1mole x 6.02 1023
• 18g 1mole
• 18.4 1023 1.84 1024 molecules