1. THE MOLE CONCEPT Let’s Remember…
Where is atomic mass?
What isotope are masses based upon?

2. Let’s Remember… What’s the unit for atomic mass?
How do you calculate the mass of a compound?

3. Let’s Remember…
What’s the difference between a molecule and a formula unit?
Molecule:
Formula unit:

4. Let’s Calculate…
Determine the formula mass for the following compounds, and decide whether each compound is a molecule or formula unit.
Diphosphorus pentoxide, P2O5
Calcium bromide, CaBr2

5. Measuring Quantities
How many donuts will we get if we ask for 1 dozen?
How about a baker’s dozen?

6. Measuring Quantities
How many donuts will we get if we ask for a mole of donuts?
Since atoms are SOOOOO small we must count them in moles

7. The Mole A.K.A. the Avogadro Constant
Named in honor of Amadeo Avogadro
SI unit for measuring quantities
Abbreviation is mol
It is simply a WORD that represents a NUMBER

8. Converting Units 1 mole of NaCl formula units = 58.44 grams
1 mole of copper atoms = grams
1 mole of lead atoms = grams
These are molar masses
Measured in g/mol
Equalities!
Use as conversion factors!

9. Converting Units
Ex: How many moles are in g of KCl?

10. Converting Units 6.02 x 1023 particles = 1 mol
Equality!
Use as conversion factor!
Ex: How many atoms are in 5.0 mol of tin (Sn)?

11. Let’s try together…
A 12.0-gram sample of iron (III) oxide, Fe2O3, contains how many formula units?

12. Summary Use Avogadro’s number to convert between moles and particles
1 mol = 6.02 x 1023 particles
Use molar mass to convert between moles and grams
1 mol = X grams (X depends on substance)