Unit 5 Topic1
The Mole
1
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
2
A Moles of Particles
Contains 6.02 x 1023 (Avogadro’s number)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 NaCl
= 6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
3
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
4
Ratio to use in unit conversion
6.02 x 1023 particles
1 mole
or
1 mole
6.02 x 1023 particles
5
Learning Check
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
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Solution
1. Number of atoms in 0.500 mol of Al
3) 3.01 x 1023 Al atoms
0.500 mol Al
6.02 x 1023 Al atoms
1 mol Al
2. Number of moles of S if a sample of S contains 4.50 x
1024 S atoms
2) 3.0 mole S atoms
4.50 x 1024 S atoms
1 mol S
6.02 x 1023 S atoms
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Practice Problems-R side
1. How many atoms are in 2.5 mol Zn?
2. How many molecules are in 0.7 mole water?
3. How many moles are in 5.75x10 24 atoms of
Al?
4. How many moles are in 2.50x10 20 atoms of
Fe?
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Unit 5 topic 2
Mole and molar mass conversion
9
Molar Mass
• Number of grams in 1 mole
• Equal to the atomic mass from the periodic table.
Just add the unit “gram.”
Mass of One C atom = 12.0 amu
Mass of 1 mole of C atoms
= 6.02 X 10 23 C atoms
=
12.0 g
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Learning Check
A. 1 mole of Br atoms
=
________gram
B. 1 mole of Sn atoms
=
________gram
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Molar Mass of Compounds
1 mole of CaCl2
(1 Ca x 40.1 g + 2 Cl x 35.5 g)
= 111.1 g/mole
1 mole of N2O4
(2 moles N x 14.0 g/mole + 4 moles O x 16.0 g/mole )
= 92.0 g/mole
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Learning Check-R side
A. 1 mole of K2O
= ______g
B. 1 mole of antacid Al(OH)3 = ______g
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Solution
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 1.01
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Learning Check
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
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Solution
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 (1.01) + 3F (19.0) + 1N (14.0) + 1 O
(16.0)
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Ratio to use in unit conversion
Molar mass (gram)
1mole
or
1 mole
molar mass (gram)
17
Molar mass (gram)
6.02 x 1023 Particles
or
6.02 x 1023particles
Molar Mass(gram)
18
Learning Check
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
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Solution
Acetic acid CH3COOH is the acid in vinegar . It has a
molar mass of 60.0 g/mole.
1 mole of acetic acid =
60.0 g acetic acid
1 mole acetic acid
60.0 g acetic acid
60.0 g acetic acid
or
1 mole acetic acid
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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
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1. Molar mass of Al
3. Setup
1 mole Al = 27.0 g Al
3.00 moles Al
Answer
27.0 g Al
1 mole Al
= 81.0 g Al
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Learning Check
The artificial sweetener aspartame (NutriSweet) 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
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
1mole of aspartame = 294 g aspartame
2. Setup
225 g aspartame
1 mole aspartame
294 g aspartame
= 0.765 mole aspartame
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Methane CH4 known as natural gas is used in gas cook
tops and gas heaters. How many grams are in 2.3 x
10 12 molecules of methane?
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