1. Chapter 5 Chemical Reactions and Quantities
5.5
The Mole
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Publishing as Benjamin Cummings

2. Collection Terms A collection term states a specific number of items.
1 dozen donuts
= 12 donuts
1 ream of paper
= 500 sheets
1 case = 24 cans
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

3. A Mole of Atoms A mole is a collection that contains
the same number of particles as there are carbon atoms in 12.0 g of carbon.
6.02 x 1023 atoms of an element (Avogadro’s number).
1 mole element Number of Atoms
1 mole C = x 1023 C atoms
1 mole Na = x 1023 Na atoms
1 mole Au = x 1023 Au atoms

4. A Mole of a Compound A mole
of a covalent compound has Avogadro’s number of molecules.
1 mole CO2 = x 1023 CO2 molecules
1 mole H2O = x 1023 H2O molecules
of an ionic compound contains Avogadro’s number of formula units.
1 mole NaCl = 6.02 x 1023 NaCl formula units
1 mole K2SO4 = 6.02 x 1023 K2SO4 formula units

5. Samples of One Mole Quantities
1 mole C = 6.02 x 1023 C atoms
1 mole Al = 6.02 x 1023 Al atoms
1 mole S = 6.02 x 1023 S atoms
1 mole H2O = 6.02 x 1023 H2O molecules
1 mole CCl4 = 6.02 x 1023 CCl4 molecules

6. Avogadro’s Number Avogadro’s number 6.02 x 1023 can be written as an
equality and two conversion factors.
Equality:
1 mole = x 1023 particles
Conversion Factors:
6.02 x 1023 particles and mole
1 mole x 1023 particles

7. Using Avogadro’s Number
Avogadro’s number is used to convert
moles of a substance to particles.
How many Cu atoms are in 0.50 mole Cu?
0.50 mole Cu x x 1023 Cu atoms
1 mole Cu
= 3.0 x 1023 Cu atoms
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

8. Using Avogadro’s Number
Avogadro’s number is used to convert
particles of a substance to moles.
How many moles of CO2 are in
2.50 x 1024 molecules CO2?
2.50 x 1024 molecules CO2 x mole CO2
6.02 x 1023 molecules CO2
= mole CO2

9. Learning Check 1. The number of atoms in 2.0 mole Al is
A Al atoms.
B x 1023 Al atoms.
C x 1024 Al atoms.
2. The number of moles of S in 1.8 x 1024 atoms S is
A mole S atoms.
B mole S atoms.
C x 1048 mole S atoms.

10. Solution C. 1.2 x 1024 Al atoms 2.0 mole Al x 6.02 x 1023 Al atoms
B. 3.0 mole S atoms
1.8 x 1024 S atoms x mole S
6.02 x 1023 S atoms

11. Subscripts and Moles The subscripts in a formula show
the relationship of atoms in the formula.
the moles of each element in 1 mole of compound.
Glucose
C6H12O6
In 1 molecule: 6 atoms C 12 atoms H 6 atoms O
In 1 mole: 6 mole C 12 mole H 6 mole O

12. Subscripts State Atoms and Moles
9 mole C 8 mole H 4 mole O

13. Factors from Subscripts
The subscripts are used to write conversion factors for
moles of each element in 1 mole compound. For aspirin
C9H8O4, the following factors can be written:
9 mole C mole H mole O
1 mole C9H8O mole C9H8O4 1 mole C9H8O4
and
1 mole C9H8O mole C9H8O mole C9H8O4
9 mole C mole H mole O

14. Learning Check A. How many mole O are in 0.150 mole aspirin C9H8O4?
B. How many O atoms are in mole aspirin C9H8O4?

15. Solution A. How many mole O are in 0.150 mole aspirin C9H8O4?
0.150 mole C9H8O4 x 4 mole O = mole O
1 mole C9H8O4
subscript factor
B. How many O atoms are in mole aspirin C9H8O4?
0.150 mole C9H8O4 x 4 mole O x x 1023 O atoms
1 mole C9H8O4 1 mole O
subscript Avogadro’s
factor Number
= x 1023 O atoms