1. Launch: 12/1
 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 moles and
atoms using Avogadro’s number as a conversion
factor
Tonight’s HW: Finish the back of the practice
question worksheet

2. Launch 12/1
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

3. Launch 12/1
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

4. Announcements
 Quiz on Friday
 The mole
 Conversions
 Unit exam in 2 weeks

5. How many atoms?
Mr. Heffner
12/1/09

6. Review: 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

7. How many atoms?
 Avogadro’s number… ..or particles, or molecules
 is equal to 6.02 X 1023 atoms/mol
 can be used to convert between moles and atoms
6.02 X 1023 atoms 1 mole
or
1 mole 6.02 X 1023 atoms
..or particles, or molecules

8. How many atoms?
 There is a 3-step process for conversions:
1. Write down the starting unit.
2. Write the conversion factor with the starting units on
the bottom.
3. Cancel like terms and multiply across the top and
bottom.

9. Example #1
How many atoms are there in 2 moles of carbon (C)?
 Step #1: Write down the starting unit.
2 moles

10. Example #1
How many atoms are there in 2 moles of carbon (C)?
 Step #2: Write conversion factor with the starting units on the
bottom.
6.02 X 1023 atoms
2 moles X =
1 mole

11. Example #1
How many atoms are there in 2 moles of carbon (C)?
 Step #3: Cancel like terms and multiply across the top and
bottom.
Ignore
6.02 X 1023 atoms 2 X 6.02 X 1023 atoms
2 moles X =
1 mole 1 +1
= 12.04 X 1023 atoms
= 1.204 X 1024 atoms

12. Example #2
How many atoms are there in 1.5 moles of CO2?
 Step #1: Write down the starting unit.
1.5 moles

13. Example #2
How many atoms are there in 1.5 moles of CO2?
 Step #2: Write conversion factor with the starting units on the
bottom.
6.02 X 1023 atoms
1.5 moles X =
1 mole

14. Example #2
How many atoms are there in 1.5 moles of CO2?
 Step #3: Cancel like terms and multiply across the top and
bottom.
Ignore
6.02 X 1023 atoms 1.5 X 6.02 X 1023 atoms
1.5 moles X =
1 mole 1
= 9.03 X 1023 atoms

15. Example #3
How many moles are there in 3.01 X 1023 molecules of CO2?
 Step #1: Write down the starting unit.
3.01X1023 molecules

16. Example #3
How many molecules are there in 1.5 moles of CO2?
 Step #2: Write conversion factor with the starting units on the
bottom.
1 mol
3.01X1023 molecules X =
6.02X1023 molecules

17. Example #3
How many molecules are there in 1.5 moles of CO2?
 Step #3: Cancel like terms and multiply across the top and
bottom.
1 mol 3.01 X 1 mol
3.01X1023 molecules X =
6.02X10 23 molecules 6.02
= .5 mol

18. Whiteboards
 Work in pairs
 Trade-off marker every question
 You have 60 seconds to solve the question
 Show all of your work!
 Don’t forget units!
 Lift board only when prompted

19. How many atoms are there
in 1 mole of potassium (K)?

20. How many molecules are
there in .5 moles of HCl?

21. How many moles of NO are
there in 9.03 X 1023 particles?

22. How many moles of
fluorine (F) are there in
12.04 X 1023 atoms?

23. Practice Questions
 Practice question worksheet

24. Exit Slip
1. What is Avogadro’s number?
a. 6.02 X 1024 atoms
b. 6.02 X 1023 atoms
c. 3.01 X 1023 atoms
d. 1.2 X 1024 atoms

25. Exit Slip
2. Which of the following shows the correct way to
calculate the number of atoms in 2 moles of O2?
32.00 grams
a. 16 moles X
1 mole
1 mole
b. 2 moles X 16.00 grams
1 atoms
c. 2 moles X 6.02 X 1023 moles
6.02 X 1023 atoms
d. 2 moles X
1 mole

26. Exit Slip
3. How many atoms of sodium (Na) are in 1 mole?
a. 3.01 X 1023 atoms
b. 6.02 X 1023 atoms
c. 12.04 X 1023 atoms
d. 1.204 X 1024 atoms

27. Exit Slip
4. How many molecules of C3OH are in .5 moles?
a. 3.01 X 1023 molecules
b. 6.02 X 1023 molecules
c. 9.03 X 1023 molecules
d. 1.204 X 1024 atoms

28. Exit Slip
5. If there are 1.204 X 1024 particles of gold (Au), how
many moles are there?
a. .5 moles
b. 1 mole
c. 2 moles
d. 4 moles

29. Homework
 Finish practice questions