1. Warm Up #1
If we were curious about finding the molar mass of a substance (say, NaCl), how can we find it?
You have Iron (III) Oxide. Knowing the name of this substance, how many Iron atoms do you have, what about oxygen atoms? What is the molar mass of this compound?
1 mole of a substance = _________ atoms? What is this number called again?
Yeah, we’re bringing this back.

2. Chapter 10.1, 10.2
The Return of the Mole

3. Molar Mass and Moles Molar Mass (g) of compound = 1 mol
Periodic Table (bottom #)
1 mol Fe = g Fe
1 mol Fe2O3 = 2(55.85) + 3(16.00) = g Fe2O3

4. Try These Find the masses (in grams) of 1 mole of…. Sulfur Trioxide
Sodium Carbonate (CO3-2)
Nitrogen gas

5. Chemistry Conversions Chart
Grams
Mass # of element
Bottom # on periodic table
Moles
ALWAYS 1 mol when converting
HEART of chemistry

6. Atoms and Moles 6.022x1023 atoms = 1 mole (Avogadro’s #)
True for ALL elements/compounds/molecules
1 mol Fe = 6.022x1023 atoms Fe
1 mol Fe2O3 = 6.022x1023 formula units Fe2O3

7. Units You Will See 6.022x1023 _______
Examples:
Just one single element (N) = atoms
Covalent bonds (N2, H2O, C6H12O6) = molecules
Ionic Bonds (NaCl) = formula units
Ions (Ca+2, SO4-2) = ions

8. Chemistry Conversions Chart
Grams
Mass # of element
Bottom # on periodic table
Moles
ALWAYS 1 mol when converting
HEART of chemistry
Atoms
6.022 x atoms
Avogadro's number
# NEVER changes

9. Quick Quiz #1 60.0 grams Na2CO3 = ____ mol Na2CO3?
9.0 mol Na2CO3 = _____ formula units Na2CO3?
Why is Na2CO3 expressed in formula units?
60.0 grams Na2CO3 = ____ formula units Na2CO3?