Chemical Reactions and
Quantities
The Mole
Calculations Using Molar Mass
Timberlake LecturePLUS
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Collection Terms
1 trio
=
3 singers
1 six-pack Cola
=
6 cans Cola drink
1 dozen donuts
=
12 donuts
1 gross of pencils
=
144 pencils
Timberlake LecturePLUS
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A Mole of Particles
Contains 6.02 x 1023 particles
1 mole C
= 6.02 x 1023 C atoms
1 mole H2O
= 6.02 x 1023 H2O molecules
1 mole NaCl
= 6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
Timberlake LecturePLUS
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More Examples of Moles
Moles of elements
1 mole Mg
= 6.02 x 1023 Mg atoms
1 mole Au
= 6.02 x 1023 Au atoms
Moles of compounds
1 mole NH3
= 6.02 x 1023 NH3 molecules
1 mole C9H8O4 = 6.02 x 1023 aspirin molecules
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Avogadro's Number
6.02 x 1023 particles
1 mole
or
1 mole
6.02 x 1023 particles
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Learning Check M1
Suppose we invented a new collection unit
called a mep. One mep contains 8 objects.
A. How many paper clips in 1 mep?
1) 1
2) 4
3) 8
B. How many oranges in 2.0 meps?
1) 4
2) 8
3) 16
C. How many meps contain 40 gummy bears?
1) 5
2) 10
Timberlake LecturePLUS
3) 20
6
Solution M1
Suppose we invented a new collection unit
called a mep. One mep contains 8 objects.
A. How many paper clips in 1 mep?
3) 8
B. How many oranges in 2.0 meps?
3) 16
C. How many meps contain 40 gummy bears?
1) 5
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Learning Check M2
1. Number of atoms in 0.500 mole of Al
1) 500 Al atoms
2) 6.02 x 1023 Al atoms
3) 3.01 x 1023 Al atoms
2.Number of moles of S in 1.8 x 1024
S atoms
1) 1.0 mole S atoms
2) 3.0 mole S atoms
3) 1.1 x 1048 mole S atoms
Timberlake LecturePLUS
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Solution M2
1. Number of atoms in 0.500 mol of Al
3) 3.01 x 1023 Al atoms
2. Number of moles of S if a sample of S
contains 4.50 x 1024 S atoms
2) 3.0 mole S atoms
Timberlake LecturePLUS
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Molar Mass

Number of grams in 1 mole

Equal to the numerical value of the atomic
mass
1 mole of C atoms
=
12.0 g
1 mole of Mg atoms
=
24.3 g
1 mole of Cu atoms
=
63.5 g
Timberlake LecturePLUS
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Learning Check M3
Give the molar mass to 0.1 g
A. 1 mole of Br atoms
=
________
B. 1 mole of Sn atoms
=
________
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Solution M3
Give the molar mass to 0.1 g
A. 1 mole of Br atoms =
79.9 g/mole
B. 1 mole of Sn atoms =
118.7 g/mole
Timberlake LecturePLUS
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Molar Mass of Compounds
Mass in grams of 1 mole equal numerically to
the sum of the atomic masses
1 mole of CaCl2
= 111.1 g/mole
1 mole Ca x 40.1 g/mole
+ 2 moles Cl x 35.5 g/mole
1 mole of N2O4
= 74.0 g/mole
2 moles N x 14.0 g/mole
+ 4 moles O x 16.0 g/mole
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Learning Check M4
A. 1 mole of K2O
= ______g
B. 1 mole of antacid Al(OH)3
= ______g
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Solution M4
A. 1 mole of K2O
= 94.2 g
2 K x 39.1 g/mole + 1 O x 16.0 g/mole
B. 1 mole of antacid Al(OH)3
= 78.0 g
1 Al x 27.0 g/mole + 3 O x 16.0 g/mole
+ 3 x 1.0
Timberlake LecturePLUS
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Learning Check M5
Prozac, C17H18F3NO, is a widely used
antidepressant that inhibits the uptake of
serotonin by the brain. It has a molar mass
of
1) 40.0 g/mole
2) 262 g/mole
3) 309 g/mole
Timberlake LecturePLUS
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Solution M5
Prozac, C17H18F3NO, is a widely used
antidepressant that inhibits the uptake of
serotonin by the brain. It has a molar mass
of
3) 309 g/mole
17C (12.0) + 18H (1.0) + 3F (19.0) + 1N (14.0)
+ 1 O (16.0)
Timberlake LecturePLUS
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Learning Check M6
What is the percent carbon in C5H8NO4
(MSG monosodium glutamate), a
compound used to flavor foods and
tenderize meats?
1) 8.22 %C
2) 24.3 %C
3) 41.1 %C
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Solution M6
Molar mass = 146.0 g/mole
% = total g C
x 100
total g compound
= 60.0 g C
146.0 g MSG
x 100 = 41.1% C
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Molar Mass Factors for CH4
Methane CH4 known as natural gas is used
in gas cook tops and gas heaters. Express
the molar mass of methane in the form of
conversion factors.
Molar mass of CH4 =
16.0 g CH4
1 mole CH4
and
16.0 g
1 mole CH4
16.0 g CH4
Timberlake LecturePLUS
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Learning Check M7
Acetic acid CH3COOH is the acid in vinegar . It
has a molar mass of 60.0 g/mole.
1 mole of acetic acid
1 mole acetic acid
g acetic acid
=
or
____________
g acetic acid
1 mole acetic acid
Timberlake LecturePLUS
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Solution M7
Acetic acid CH3COOH is the acid in vinegar . It
has a molar mass of 60.0 g/mole.
1 mole of acetic acid
1 mole acetic acid
60.0 g acetic acid
=
or
60.0 g
60.0 g acetic acid
1 mole acetic acid
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Calculations with Molar Mass
molar mass
Grams
Moles
Timberlake LecturePLUS
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Moles and Grams
Aluminum is often used for the structure of
light-weight bicycle frames. How many grams
of Al are in 3.00 moles of Al?
3.00 moles Al
? g Al
Timberlake LecturePLUS
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1. Molar mass of Al
1 mole Al = 27.0 g Al
2. Conversion factors for Al
27.0g Al
or
1 mol Al
1 mol Al
27.0 g Al
3. Setup
3.00 moles Al x
Answer
27.0 g Al
1 mole Al
= 81.0 g Al
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Learning Check M9
The artificial sweetener aspartame
(Nutri-Sweet) formula C14H18N2O5 is
used to sweeten diet foods, coffee and
soft drinks. How many moles of
aspartame are present in 225 g of
aspartame?
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Solution M9
1. Molar mass of Aspartame C14H18N2O5
(14 x 12.0) + (18 x 1.01) + (2 x 14.0) + (5 x 16.0)
= 294 g/mole
2. Setup
225 g aspartame x 1 mole aspartame
294 g aspartame
= 0.765 mole aspartame
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