1. Factor Label Method and the Mole
Chapter 8
Factor Label Method and the Mole

2. What is Avogadro’s Favorite Novel?

3. What is Avogadro’s Favorite Novel?
Molby Dick

4. An equality is a ratio is a conversion factor.
1.61 km = 1 mile
1 pound = kilograms
Density of Aluminum = 2.7 g/cm3
Land speed record = 763 miles/hr

5. What Do We Know About the Mole

6. What Do We Know About the Mole
1 mol = 6.02 x 1023 _________

7. What Do We Know About the Mole
1 mol = 6.02 x 1023 particles
Any equality or ratio can be made into a conversion factor and then used to solve problems with the factor label method.

8. Avogadro’s Number as a Conversion Factor
6.02 x 1023 “particles”
1 mole or
1 mole
Note that particles could be atoms, molecules, formula units, ions, etc.

9. A Mole of Particles Contains 6.02 x 1023 particles
= x 1023 C atoms
= x 1023 H2O molecules
= x 1023 NaCl “molecules”
(technically, ionic compounds are not molecules, they are called formula units)
1 mole C
1 mole H2O
1 mole NaCl

10. 1 mol Na+ = ? 1 mol SO42- = ?
6.02 x 1023 Na+ ions 6.02 x 1023 SO42- ions

11. What Do We Know About the Mole

12. What Do We Know About the Mole
1 mol of any substance = it’s gfm

13. What’s in a Name?
Atomic Mass/Atomic Weight/Molecular Mass/Molecular Weight/Formula Mass/Formula Weight: If you have a single atom or molecule or compound, mass is measured in amu’s.
Gram Atomic Mass/Gram Atomic Weight/Gram Molecular Mass/Gram Molecular Weight/Gram Formula Mass/Gram Formula Weight/Molar Mass: If you have a mole of atoms or molecules or a compound, mass is measured in grams.
But, the numerical value is the same whether you have 1 mole or one particle. Only the units are different. (This is the beauty of Avogadro’s Number!).
THE POINT: You may hear all of these terms which mean the SAME NUMBER… just different units.

14. Gram Atomic Mass (Molar Mass) of an atom
Equal to the atomic mass (get from chart)
The mass of 1 mole (in grams)
1 mole of C atoms = g

15. Gram Atomic Mass (Molar Mass) of an atom
1 mole of Mg atoms
6.02 x 1023 Mg atoms
24.3 g

16. Gram Atomic Mass (Molar Mass) of an atom
1 mole of Cu atoms
6.02 x 1023 Cu atoms
63.5 g

17. Gram Formula Mass (Molar Mass) of Molecules and Compounds

18. Gram Formula Mass (Molar Mass) of Molecules and Compounds
Mass in grams of 1 mole
Equal to the formula mass (sum of the atomic masses) expressed in grams

19. Gram Formula Mass (Molar Mass) of Molecules and Compounds
Mass in grams of 1 mole
Equal to the formula mass (sum of the atomic masses) expressed in grams
Gram Formula Mass of Ca3(PO4)2
3 x = 120.3
2 x =
8 x = 128.0
= g/mol
= 6.02 x 1023 Ca3(PO4)2 formula units

20. List “2” things you know about a mole of H.
1 mole H = 6.02 x 1023 H atoms
1 mole H = 1.0g
What could we use these equalities to do in a factor label problem?

21. List “2” things you know about a mole of H2O
1 mole H2O = 6.02 x 1023 H2O molecules
1 mole H2O = 18.0g

22. List “2” things you know about a mole of Na2O
1 mole Na2O = 6.02 x 1023 Na2O formula units
1 mole Na2O = 62.0g

23. Converting Moles and Grams
Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 8.62 moles of Al? a

24. 1 mole Al = ?

25. 1 mole Al = ?
1 mole Al = 27.0 g Al

26. What are the conversion factors?
1 mole Al = 27.0 g Al

27. What are the conversion factors?
1 mole Al = 27.0 g Al
27.0g Al or mol Al
1 mol Al g Al

28. What are the conversion factors?
1 mole Al = 27.0 g Al
27.0g Al or mol Al
1 mol Al g Al
Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 8.62 moles of Al?

29. Conversion factors for Al
1 mole Al = 27.0 g Al
Conversion factors for Al
27.0g Al or mol Al
1 mol Al g Al
8.62 moles Al

30. Conversion factors for Al
1 mole Al = 27.0 g Al
Conversion factors for Al
27.0g Al or mol Al
1 mol Al g Al
8.62 moles Al g Al
1 mole Al
= 233 g Al

31. How many Al atoms are in the bicycle frame?

32. How many Al atoms are in the bicycle frame?
8.62 moles Al

33. How many Al atoms are in the bicycle frame?
8.62 moles Al
1 mole Al

34. How many Al atoms are in the bicycle frame?
8.62 moles Al
6.02 x 1023 Al atoms
1 mole Al

35. How many Al atoms are in the bicycle frame?
8.62 moles Al
6.02 x 1023 Al atoms
1 mole Al
= 5.19 x 1024 Al atoms