1. 1 pair of kicks (shoes)
1 dozen of eggs
One 2L of cola
reams of paper

2. So what unit do chemists use
to count particles?
Particles are so tiny, chemists use the unit of moles. A mole contains 6.02 x 1023 atoms.
602, 000, 000, 000, 000, 000, 000, 000

3. 602,000,000,000,000,000,000,000
One mole of popcorn would cover every dry surface of the Earth to a depth of six miles
One mole of stacked pennies would reach to the moon and back 16 times
One mole of marshmellows would cover the US to a depth of 650 miles

4. 1811- Avogadro- equal volumes of gases at the same temperature and pressure contained equal number of molecules
1861- Cannizzaro- developed atomic weights for known elements
1865- Loschmidt- determined the number of atoms present in given volume of air
1971- true value 6.02 x 1023 found

5. Recall the Law of Conservation of Mass
Mass of reactants = mass of products
Mass of starting substances = mass of ending substances
2 hydrogen atoms + 1 oxygen atom  1 water molecule

6. Law of Definite Proportions
Regardless of amount, a compound will always be composed of the same elements in the same proportions by mass
For example, two hydrogen atoms will always combine with one oxygen atom to produce one molecule of water

7. Moles  Particles Conversion (particles could be atoms or molecules)
If you have three and a half dozen roses, how many roses do you have?
What is the conversion factor?

8. Moles  Particles Conversion
Particles  Moles Conversion

9. Convert 3.5 moles to atoms Moles to atoms conversion factor
3.5 moles x 6.02x1023 atoms = 2.12 x 1024 atoms
1 mole

10. Convert 18.06x1023 atoms to moles
Atoms to moles conversion factor
18.06x1023 atoms x mole = 3 moles
6.02x1023 atoms

11. Convert from moles to particles
2.7 moles of lithium
2.7 moles x 6.02x1023 particles
1 mole
= x 1024 atoms
1.8 moles of sodium chloride
1.8 moles x 6.02x1023 particles
= 1.08 x 1024 molecules

12. Convert from moles to particles
5.3 moles of bromine
5.3 moles x 6.02x1023 particles
1 mole
= 3.19 x 1024 atoms
4.7 moles of potassium oxide
4.7 moles x 6.02x1023 particles
= 2.83 x 1024 molecules

13. BE CAREFUL WITH PARENTHESIS IN YOUR CALCULATOR!
particles  moles
4.32 x 1024 atoms of calcium
4.32 x 1024 atoms x 1 mole
6.02 x 1023 atoms
BE CAREFUL WITH PARENTHESIS IN YOUR CALCULATOR!
= (4.32 x 10(24)) / (6.02 x 10(23))
= 7.18 moles of calcium

14. particles  moles 2.7 x 1020 atoms of copper 2.7 x 1020 atoms x 1 mole
= (2.7 x 10(20)) / (6.02 x 10(23))
= moles of copper
=4.49 x 10-4 moles of copper

15. particles  moles 2.5 x 1024 molecules of sodium chloride
2.5 x 1024 atoms x 1 mole
6.02 x 1023 atoms
=4.15 moles of sodium chloride
5.32 x 1023 molecules of calcium chloride
5.32 x 1023 atoms x 1 mole
=0.88 moles of calcium chloride