1. Math Of Chemistry
In the laboratory you will be dealing with masses and volumes, but in chemistry problems you will be dealing with moles, and molecules. You need a way to connect the two!
This unit is about finding the “# of things” (molecules/moles) by using macroscopic means:
Volume and mass!
How does this relate to real life:
Lets take the following example. I ask you to bake me 10 apple pies. Each apple pie requires 6 whole apples. You must get the correct amount of apples but without counting them at the supermarket!!! How do you do it??? HINT: Each apple weighs 100grams

2. We can use the same approach with elements in compounds
We can use the same approach with elements in compounds. Since we can’t count individual elements we need to have a system that will allow us to determine how much of each element/compound we have without direct counting.
We can use the concept of a MOLE!!!
Just like we set 1 dozen = 12 Just like we set 16 ounces = 1 lbs
Just like we set 1 year = 365 days
Just like we set 1 day = 24 hours
You get the point. A mole is equal to a certain quantity of something. Let’s get more specific…

3. What is a mole?
How does it relate the following quantities:
Volume of a gas
Molecules/atoms of a substance
Gram formula mass (this one is tricky, and we need to go into more detail on what GFM is!)

4. Gram formula mass
In the laboratory we measure mass in grams. We are UNABLE to measure individual masses of atoms in our high school laboratory. When we measure the mass of compounds/elements we are actually measuring 1020 to 1023 units of these substances.
There is a standard for measurement for each element:
6.02 x 1023 units of a substance = gram formula mass
6.02 x 1023 units of a substance = 1 mole of a substance
Therefore: 1 mole of a substance = gram formula mass
Definition of Gram Formula Mass:
How do I find the gram formula mass of a substance (compound or element)?

5. Practice finding gram atomic masses of Different substances

6. Review So Far: Key points
One set of problems you will see in this unit will ask you to find the number of moles, the volume, the mass, or the number of molecules of a substance based on a piece of information given. For example you may be asked to find the volume of 1 mole of a gas. Or the mass of 3 moles of a substance. Finally you may be asked to find the number of moles of 5 x 1015 molecules. (These are just a few examples). There are two methods to do this. One of them is on the next page. YOU MUST MEMORIZE THIS OR THE CONCEPT BEHIND THIS CHART IN ORDER TO MASTER THE REST OF THIS UNIT!

7. Mole Conversions
Grams   Moles
Liters   Moles
Molecules   Moles
Grams   Liters
Molecules   Grams

8. You must always go through the mole center to get anywhere!!!!!
Mole Crutch
Volume
In Liters
Volume
In Liters
Multiply by
22.4 Liters
Divide by
22.4 Liters
Divide by formula mass
Multiply
by formula mass
Mass in
grams
MOLE
Central
station
Mass in
grams
multiply by
6.02 x 1023
Divide by
6.02 x 1023
molecules
molecules
You must always go through the mole center to get anywhere!!!!!

9. Using gram formula mass for percent composition problems
Percent Composition and hydrates

10. Finding the Empirical Formula of a Substance

11. Finding the Molecular formula of a Substance

12. The mole ratio in balanced equations, never forget it!!!
Use mole
Ratio in
Balanced
equation
Moles of A
Moles of B

13. Using the mole ratio and the mole crutch: Putting everything together!
Grams of A
Grams of B
Use mole conversion
Use mole conversion
Use mole
Ratio in
Balanced
equation
Moles of A
Moles of B

14. Limiting Reagent Problems

15. Limiting Reagent Problems

16. Percent Yield

17. Molarity and Solution Terms

18. Solution Stoichiometry