Chapter 10
The Mole
National Standards for Chapter 10
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UCP.1 Systems, order, and organization
A.1 Abilities necessary to do scientific inquiry
A.2 Understandings about scientific inquiry
B.1 Structure of atoms
B.2 Structure ad properties of matter
B.3 Chemical reactions
B.6 Interactions of energy and matter
E.1 Abilities of technological design
E.2 Understandings about science and technology
F.5 Natural and human-induced hazards
F.6 Science and technology in local, national, and global challenges
G.1 Science as a human endeavor
G.2 Nature of scientific knowledge
G.3 Historical perspectives
Vocabulary/Study Guide
• Define each term using the Glossary
• Either write on the handout, or use your own
paper
• This is due on Test Day (tentatively, Monday,
March 31)
Section 1: Measuring Matter
• National Standards:
– UCP.1 Systems, order, and organization
– A.1 Abilities necessary to do scientific inquiry
– B.2 Structure ad properties of matter
– E.2 Understandings about science and
technology
– G.2 Nature of scientific knowledge
– G.3 Historical perspectives
Objectives – Section 1
• Explain how a mole is used to indirectly count the
number of particles of matter.
• Relate the mole to a common everyday counting
unit.
• Convert between moles and number of
representative particles.
REVIEW VOCABULARY:
molecule: two or more atoms that covalently bond together to form a
unit
New Vocabulary
mole
Avogadro’s number
Chemists use the mole to count atoms,
molecules, ions, and formula units.
Lab: How much is a mole? (pg. 318)
Counting Particles
• Chemists need a convenient method for
accurately counting the number of atoms,
molecules, or formula units of a substance.
• The mole is the SI base unit used to measure the
amount of a substance.
• 1 mole is the amount of atoms in 12 g of pure
carbon-12, or 6.02  1023 representative particles,
which is any kind of particle – an atom, a
molecule, a formula unit, an electron, an ion, etc.
• The number is called Avogadro’s number.
Converting Between Moles and
Particles
• Conversion factors must be used.
• Moles to particles
• Number of molecules in 3.50 mol of sucrose
Converting Between Moles and
Particles
• Particles to moles
• Use the inverse of Avogadro’s number as the
conversion factor.
Converting Between Moles and
Particles
• Practice Problems #1-4, page 323
• Practice Problems #5-6, page 324
Mole Day Facts
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Fact 1- It is believed that one mole of paper if stacked can reach the moon more
than 80 billion times.
Fact 2- The second fact about one mole of grain of sand would be much more than
that what is there at Miami Beach.
Fact 3- The next fact about one mole is that one mole of blood cells would be
more than the number of blood cells in every human-being on earth.
Fact 4- It is also believed that one liter of water contains 55.5 moles of water.
Fact 5- An astonishing fact about one mole is that one mole is approximately
1,616,434 light years or it can also be easily 8 times around our galaxy.
Fact 6- Another interesting fact about one mole is that one mole of seconds is
approximately 19 quadrillion years. It is 954,150 times the age of the universe or
4,240,666 times earth’s age.
Fact 7- An important fact about one mole is that one mole of cents would be good
enough to repay the debt of United States of America 86 million times.
Homework, Section 1
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SECTION 1 REVIEW, Page 324
Questions #7-14
Answer with complete sentences
Due tomorrow
Section 2: Mass and the Mole
• National Standards:
– UCP.1 Systems, order, and organization
– B.1 Structure of atoms
– B.2 Structure ad properties of matter
– E.2 Understandings about science and
technology
Objectives – Section 2
• Relate the mass of an atom to the mass of a mole of
atoms.
• Convert between number of moles and the mass of
an element.
• Convert between number of moles and number of
atoms of an element.
Review Vocabulary:
conversion factor: a ratio of equivalent values used to express
the same quantity in different units
New Vocabulary
molar mass
A mole always contains the same number of
particles; however, moles of different
substances have different masses.
The Mass of a Mole
• 1 mol of copper (6.02 x 1023 atoms of copper)
and 1 mol of carbon (6.02 x 1023 atoms of
carbon) have different masses.
• One copper atom has a different mass than 1
carbon atom.
The Mass of a Mole
• Molar mass is the mass in grams of one mole
of any pure substance.
• The molar mass of any element is numerically
equivalent to its atomic mass and has the
units g/mol.
Lab: Formulate a Model (pg. 326)
Using Molar Mass
• Moles to mass
3.00 moles of copper has a mass of 191 g.
Using Molar Mass
• Convert mass to moles with the inverse molar
mass conversion factor.
• Convert moles to atoms with Avogadro’s
number as the conversion factor.
Using Molar Mass
• Practice Problems #15-18, page 328
Math Skills Transparency 13
Using Molar Mass
• This figure shows the steps to complete
conversions between mass and atoms.
Using Molar Mass
• Practice Problems #19-21, page 331
Homework, Section 2
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SECTION 2 REVIEW, Page 332
Questions #22-28
Answer with complete sentences
Due tomorrow
Section 3: Moles of Compounds
• National Standards:
– UCP.1 Systems, order, and organization
– B.2 Structure and properties of matter
– E.2 Understandings about science and
technology
Objectives – Section 3
• Recognize the mole relationships shown by a
chemical formula.
• Calculate the molar mass of a compound.
• Convert between the number of moles and mass of a
compound.
• Apply conversion factors to determine the number of
atoms or ions in a known mass of a compound.
Review Vocabulary:
representative particle: an atom, molecule, formula unit, or ion
New Vocabulary
The molar mass of a compound can be
calculated from its chemical formula and can
be used to convert from mass to moles of that
compound.
Chemical Formula and the Mole
• Chemical formulas indicate the numbers and
types of atoms contained in one unit of the
compound.
• One mole of CCl2F2 contains one mole of C
atoms, two moles of Cl atoms, and two moles
of F atoms.
Chemical Formulas and the Mole
• Practice Problems #29-33, page 335
The Molar Mass of Compounds
• The molar mass of a compound equals the
molar mass of each element, multiplied by the
moles of that element in the chemical
formula, added together.
• The molar mass of a compound demonstrates
the law of conservation of mass.
Molar Mass of Compounds
• Practice Problems #34-36, page 335
Math Skills Transparency 14: Calculating
the Molar Mass of a Compound
Converting Moles of a Compound to
Mass
• For elements, the conversion factor is the
molar mass of the compound.
• The procedure is the same for compounds,
except that you must first calculate the molar
mass of the compound.
Converting Moles of a Compound to
Mass
• Practice Problems #37-39, page 336
Converting the Mass of a Compound
to Moles
• The conversion factor is the inverse of the
molar mass of the compound.
Converting the Mass of a Compound
to Moles
• Practice Problems #40-41, page 337
Converting the Mass of a Compound
to Number of Particles
• Convert mass to moles of compound with the
inverse of molar mass.
• Convert moles to particles with Avogadro’s
number.
Converting the Mass of a Compound
to Number of Particles
• Practice Problems #42-46, page 339
Converting the Mass of a Compound
to Number of Particles
• This figure summarizes the conversions
between mass, moles, and particles.
Transparency 34: Mass-to-Mole and Moleto-Particles Conversions for Compounds
Lab: Estimating the Size of a Mole
Homework, Section 3
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SECTION 3 REVIEW, Page 340
Questions #47-53
Answer with complete sentences
Due tomorrow
Section 4: Empirical and Molecular
Formulas
• National Standards:
– UCP.1 Systems, order, and organization
– A.1 Abilities necessary to do scientific inquiry
– A.2 Understandings about scientific inquiry
– B.2 Structure ad properties of matter
– E.2 Understandings about science and
technology
– G.1 Science as a human endeavor
Objectives – Section 4
• Explain what is meant by the percent composition of
a compound.
• Determine the empirical and molecular formulas for
a compound from mass percent and actual mass
data.
Review Vocabulary:
percent by mass: the ratio of the mass of each element to the
total mass of the compound expressed as a percent
New Vocabulary
percent composition
empirical formula
molecular formula
A molecular formula of a compound is a wholenumber multiple of its empirical formula.
Percent Composition
• The percent by mass of any element in a
compound can be found by dividing the mass
of the element by the mass of the compound
and multiplying by 100.
Percent Composition
• The percent by mass of each element in a
compound is the percent composition of a
compound.
• Percent composition of a compound can also
be determined from its chemical formula.
Mini-Lab: Analyze Chewing Gum, pg.
342
Percent Composition
• Practice Problems #54-57, page 344
Empirical Formula
• The empirical formula for a compound is the smallest
whole-number mole ratio of the elements.
• You can calculate the empirical formula from percent
by mass by assuming you have 100.00 g of the
compound. Then, convert the mass of each element to
moles.
• The empirical formula may or may not be the same as
the molecular formula.
 Molecular formula of hydrogen peroxide = H2O2
 Empirical formula of hydrogen peroxide = HO
Empirical Formula
• Practice Problems #58-61, page 346
Molecular Formula
• The molecular formula specifies the actual
number of atoms of each element in one
molecule or formula unit of the substance.
• Molecular formula is always a whole-number
multiple of the empirical formula.
Molecular Formula
Molecular Formula
• Practice Problems #62-66, page 350
Lab: Mole Ratios
Molecular Formula
• Worksheet: Supplemental Problems
Homework, Section 4
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SECTION 4 REVIEW, Page 350
Questions #67-73
Answer with complete sentences
Due tomorrow
Section 5: Formulas of Hydrates
• National Standards:
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UCP.1 Systems, order, and organization
A.1 Abilities necessary to do scientific inquiry
A.2 Understandings about scientific inquiry
B.2 Structure ad properties of matter
B.3 Chemical reactions
B.6 Interactions of energy and matter
E.1 Abilities of technological design
E.2 Understandings about science and technology
F.5 Natural and human-induced hazards
F.6 Science and technology in local, national, and global
challenges
Objectives – Section 5
• Explain what a hydrate is and relate the name
of the hydrate to its composition.
• Determine the formula of a hydrate from
laboratory data.
Review Vocabulary:
crystal lattice: a three-dimensional geometric
arrangement of particles
New Vocabulary
hydrate
Hydrates are solid ionic compounds in which
water molecules are trapped.
Naming Hydrates
• A hydrate is a compound that has a specific
number of water molecules bound to its
atoms.
• The number of water molecules associated
with each formula unit of the compound is
written following a dot.
• Sodium carbonate decahydrate =
Na2CO3 • 10H2O
Naming Hydrates
Analyzing a Hydrate
• When heated, water molecules are released
from a hydrate leaving an anhydrous
compound.
• To determine the formula of a hydrate, find
the number of moles of water associated with
1 mole of hydrate.
Analyzing a Hydrate
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Weigh hydrate.
Heat to drive off the water.
Weigh the anhydrous compound.
Subtract and convert the difference to moles.
The ratio of moles of water to moles of
anhydrous compound is the coefficient for
water in the hydrate.
Analyzing a Hydrate
• Practice Problems #74-75, page 353
Lab: Determine the Formula of a
Hydrate, page 356
Use of Hydrates
• Anhydrous forms of hydrates are often used to
absorb water, particularly during shipment of
electronic and optical equipment.
• In chemistry labs, anhydrous forms of hydrates
are used to remove moisture from the air and
keep other substances dry.
Homework, Section 5
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SECTION 5 REVIEW, Page 354
Questions #76-82
Answer with complete sentences
Due tomorrow
Key Concepts
• The mole is a unit used to count particles of matter
indirectly. One mole of a pure substance contains
Avogadro’s number of particles.
• Representative particles include atoms, ions,
molecules, formula units, electrons, and other similar
particles.
• One mole of carbon-12 atoms has a mass of exactly
12 g.
• Conversion factors written from Avogadro’s
relationship can be used to convert between moles and
number of representative particles.
Key Concepts
• The mass in grams of 1 mol of any pure substance
is called its molar mass.
• The molar mass of an element is numerically
equal to its atomic mass.
• The molar mass of any substance is the mass in
grams of Avogadro’s number of representative
particles of the substance.
• Molar mass is used to convert from moles to
mass. The inverse of molar mass is used to
convert from mass to moles.
Key Concepts
• Subscripts in a chemical formula indicate how
many moles of each element are present in 1
mol of the compound.
• The molar mass of a compound is calculated
from the molar masses of all of the elements
in the compound.
• Conversion factors based on a compound’s
molar mass are used to convert between
moles and mass of a compound.
Key Concepts
• The percent by mass of an element in a
compound gives the percentage of the
compound’s total mass due to that element.
• The subscripts in an empirical formula give the
smallest whole-number ratio of moles of
elements in the compound.
• The molecular formula gives the actual number
of atoms of each element in a molecule or
formula unit of a substance.
• The molecular formula is a whole-number
multiple of the empirical formula.
Key Concepts
• The formula of a hydrate consists of the formula
of the ionic compound and the number of water
molecules associated with one formula unit.
• The name of a hydrate consists of the compound
name and the word hydrate with a prefix
indicating the number of water molecules in 1
mol of the compound.
• Anhydrous compounds are formed when
hydrates are heated.