1. 6.3/6.4 The Mole and Molar Mass

2. The Mole (n)
The mole (mol) is the SI base unit for the amount of substance
Amount could be referring to atoms, ions or molecules
The mole base unit was determined by the amount of atoms in 12g or carbon-12
It was created to deal with the fact that we cannot easily see an atom

3. Recall all that balancing equations business… 2H2 + O2  2H2O
What the number out in front now tells us is how many moles of something we have.
Thus in the previous equation we have:
2 moles of hydrogen gas
1 moles of oxygen gas
2 moles of water

4. Mole… So what does it represent?
Avogadro’s number (NA) = the number of entities (pieces) in one mole
 1023 to be exact! Big number :)
thus one mole = 6.02  1023 entities (atoms, ions, molecules
the mole works for chemists because it is amount that is actually visually observable

5. one mole of sodium atoms is 6.02 × 1023 sodium atoms
one mole of chlorine molecules is 6.02 × chlorine molecules
one mole of sodium chloride is 6.02 × formula units of NaCl
one mole of elephants is 6.02 × elephants

6. Terminology
Atomic Mass: the mass of one atom of an element, expressed in atomic mass units (u)
Molecular Mass: the mass of one molecule, expressed in atomic mass units (u)
Formula Mass: the mass of one formula of an ionic compound, expressed in atomic mass units (u)
Molar Mass: The mass of 1 mol of a substance (g/mol)

7. List the atomic and molar mass of the following chemicals with the appropriate unit
Calcium
Helium
Neon
Gold
Iron

8. To obtain the formula mass or molecular mass of a compound we do the following:
1. Know the formula of the molecule i.e. Cu2SO4  
2. Look up the atomic mass of all elements involved 
i.e. *note: depending on the periodic
table, the number may
differ due to decimal places
3. Calculate m

9. Ex. 1 Calculate the molar mass of sodium chloride.
Na- Cl - MNaCl =
Ex. 2 Calculate the molar mass of mercury (II) chlorate?

10. Mass to moles In chemistry we can use molar mass as conversion factor.
It allows us to go from a mass (ie. Grams, kilograms) to the mole Or
It allows us to find out a required mass of chemical based on an amount (moles)
The term amount is commonly used in chemistry to refer to the mole.

11. Converting Amount to Mass
How many grams are in 1.89 moles of palladium?

12. Converting Amount to Mass
How many grams are in 1.89 moles of carbon tetrachloride?

13. Converting Amount to Mass
How many moles are in 2.99 moles of lead (II) sulfate?

14. Converting Mass to Amount
How many moles are in 65.6g of gold?

15. Converting Mass to Amount
How many moles are in 72g of cadmium (II) nitrate?

16. Class work!
Pg 277 # 4-11