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The Mole
1. The mole is the amount of substance of a system which contains
as many elementary entities as there are atoms in 0.012
kilogram of carbon 12; its symbol is “mol.”
2. When the mole is used, the elementary entities must be
specified and may be atoms, molecules, ions, electrons, other
particles, or specified groups of such particles.
The number of entitites in 1 mol is expressed as
6.022 141 29 ×1023 mol−1 . This number is called Avogadro’s
constant, and is abbreviated NA
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The Mole
1. The mole is the amount of substance of a system which contains
as many elementary entities as there are atoms in 0.012
kilogram of carbon 12; its symbol is “mol.”
2. When the mole is used, the elementary entities must be
specified and may be atoms, molecules, ions, electrons, other
particles, or specified groups of such particles.
The number of entitites in 1 mol is expressed as
6.022 141 29 ×1023 mol−1 . This number is called Avogadro’s
constant, and is abbreviated NA
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Relationship between amount (mol), mass (g) and
number of chemical entities
mass(g) = amount(mol) × molar mass(g · mol −1 )
mass(g)
amount(mol) =
molar mass(g · mol −1 )
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Relationship between amount (mol), mass (g) and
number of chemical entities
mass(g) = amount(mol) × molar mass(g · mol −1 )
mass(g)
amount(mol) =
molar mass(g · mol −1 )
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Relationship between amount (mol), mass (g) and
number of chemical entities
mass(g) = amount(mol) × molar mass(g · mol −1 )
mass(g)
amount(mol) =
molar mass(g · mol −1 )
number of entitites = amount(mol) × Avogadro0 s constant(mol −1 )
number of entitites
amount(mol) =
Avogadro0 s constant(mol −1 )
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Relationship between amount (mol), mass (g) and
number of chemical entities
mass(g) = amount(mol) × molar mass(g · mol −1 )
mass(g)
amount(mol) =
molar mass(g · mol −1 )
number of entitites = amount(mol) × Avogadro0 s constant(mol −1 )
number of entitites
amount(mol) =
Avogadro0 s constant(mol −1 )
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Mass-amount-number relationships for elements
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Calculating the Mass of a
Given Amount of an Element
PROBLEM: Silver (Ag) is used in jewelry and tableware but no longer
in U.S. coins. What is the mass of silver in 0.0342 mol of the metal?
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Calculating the Mass of a
Given Amount of an Element
PROBLEM: Silver (Ag) is used in jewelry and tableware but no longer
in U.S. coins. What is the mass of silver in 0.0342 mol of the metal?
PLAN: To convert amount of Ag (mol) to mass of Ag (g) we need the
molar mass of Ag.
SOLUTION:
0.0342 mol Ag ×
107.9 g Ag
= 3.699 g Ag
1 mol
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Calculating the Mass of a
Given Amount of an Element
PROBLEM: Silver (Ag) is used in jewelry and tableware but no longer
in U.S. coins. What is the mass of silver in 0.0342 mol of the metal?
PLAN: To convert amount of Ag (mol) to mass of Ag (g) we need the
molar mass of Ag.
SOLUTION:
0.0342 mol Ag ×
107.9 g Ag
= 3.699 g Ag
1 mol
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