1. Launch: 11/30
 Grab your binder and immediately take a seat!
 Place homework (practice questions), binder paper, and
a pen/pencil on your desk.
Today’s Objective: I can convert between grams and
moles using molecular mass as a conversion
factor
Tonight’s HW: Finish practice question worksheet

2. Launch 11/30
1. Calculate the molecular mass of H2 (include units!).

3. Launch 11/30
2. Calculate the molecular mass of NO3 (include units!).

4. Launch 11/30
3. Calculate the molecular mass of Mg(ClO2)2 .

5. Announcements
 Quiz on Friday
 The mole
 Conversions
 Unit exam in 2 weeks
 Block 5 earned the party this Friday

6. How many moles? - Part II
Mr. Heffner
11/30/09

7. How many moles?
 Molar mass
 used to convert between grams and moles
 units = grams/mole
 can be shown as a fraction
Molar mass of H2 = 2.02 g/mol
2.02 grams 1 mole
or
1 mole 2.02 grams

8. How many moles?
 There is a 3-step process:
1. Write down the starting unit.
2. Calculate molecular mass and turn it into a
conversion factor with the starting units on the
bottom.
3. Cancel units and multiply across the top and
bottom.

9. Example #1: mol  g
How many grams of H2 are there in 2 moles of H2?
 Step #1: Write down the starting unit.
2 moles

10. Example #1: mol  g
How many grams of H2 are there in 2 moles of H2?
 Step #2: Calculate molecular mass and turn it into a conversion
factor with the starting units on the bottom.
2.02 grams
2 moles X =
1 mole

11. Example #1: mol  g
How many grams of H2 are there in 2 moles of H2?
 Step #3: Cancel units and multiply across the top and bottom.
2.02 grams 2 X 2.02 grams
2 moles X =
1 mole 1
= 4.04 grams
units!

12. Example #2: g  mol
How many moles of CO are there in 14.00 grams of CO?
 Step #1: Write down the starting unit.
14.00 grams

13. Example #2: g  mol
How many moles of CO are there in 14.00 grams of CO?
 Step #2: Calculate molecular mass and turn it into a conversion
factor with the starting units on the bottom.
1 mole
14.00 grams X =
28.01 grams

14. Example #2: g  mol
How many moles of CO are there in 14.00 grams of CO?
 Step #3: Cancel units and multiply across the top and bottom.
1 mole 14.00 X 1 mole
14.00 grams X =
28.01 grams 28.01
= ~.5 moles
units!

15. Partner Teaching
 Partner A teaches Partner B
 Partner A writes and narrates
 Partner B listens
 Partner B completes the problem on own paper
 Switch!
1. How many moles of O2 are there in 64.00 grams of
O2?
2. How many grams of NO2 are there in 4 moles of
NO2?

16. Foldable
 Define the following terms:
 Mole
 Avogadro’s number
 Molecular mass
 Conversion factor
 Starting unit

17. Practice Questions
 Practice question worksheet

18. Exit Slip
1. What is the molar mass of Al(OH)3?
a. 43.99 g/mol
b. 78.01 g/mol
c. 300.03 g/mol
d. 303.00 g/mol

19. Exit Slip
2. Which of the following is not a correct way to
represent the molecular mass of CH4?
16.05 moles
a. 1 gram
16.05 grams
b.
1 mole
c. 1 mole
16.05 grams
d. 16.05 g/mol

20. Exit Slip
3. Which of the following shows the correct way to
calculate the number of moles in 16.00 grams of O2?
32.00 grams
a. 16.00 moles X
1 mole
1 mole
b. 16.00 grams X 16.00 grams
1 mole
c. 16.00 grams X 32.00 grams
16.00 grams
d. 16.00 moles X
1 mole

21. Exit Slip
4. How many grams of NH3 are there in 2 moles of NH3?
a. 1.00 moles
b. 14.01 grams
c. 17.04 grams
d. 34.08 grams

22. Exit Slip
5. How many moles of N2 are there in 14.01g of N2?
a. .5 moles
b. 2 mole
c. 14.01 moles
d. 28.02 moles

23. Homework
 Finish practice questions