The Mole
Chap. 11
No, not that mole!
I. Counting Particles
I. Counting Particles
A. There are common
units to count things
I. Counting Particles
A. There are common
units to count things
1. Pair
I. Counting Particles
A. There are common
units to count things
1. Pair = 2
2. Dozen
I. Counting Particles
A. There are common
units to count things
1. Pair = 2
2. Dozen = 12
3. Ream
I. Counting Particles
A. There are common
units to count things
1.
2.
3.
4.
Pair = 2
Dozen = 12
Ream = 500 sheets
Gross
I. Counting Particles
A. There are common
units to count things
1.
2.
3.
4.
5.
Pair = 2
Dozen = 12
Ream = 500
Gross = 144
‘Scop’ (not really)
I. Counting Particles
A. There are common
units to count things
1.
2.
3.
4.
5.
6.
Pair = 2
Dozen = 12
Ream = 500
Gross = 144
‘Scop’ (not really) = 64
Mole
I. Counting Particles
A. There are common
units to count things
1.
2.
3.
4.
5.
6.
Pair = 2
Dozen = 12
Ream = 500
Gross = 144
‘Scop’ (not really) = 64
Mole = Avogadro’s #
Avogadro’s number
A value equal to
23
6.0221367 x 10 .
We’ll round it to: 6.02 x 1023
I. Counting Particles
B. Converting with moles
1. Finding the number of
particles from moles.
Self Check – Ex. 1
How many atoms are in
2 moles of helium?
Self Check – Ex. 2
How many molecules
are in 7.5 moles of
carbon dioxide?
I. Counting Particles
B. Converting with moles
1. Finding the number of
particles from moles.
2. Finding the number of
moles from particles.
Self Check – Ex. 3
A sample of lead
24
contains 1.5 x 10
atoms. How many moles
of lead atoms are there?
Self Check – Ex. 4
A sample of zinc chloride
18
contains 2.150 x 10
formula units. How many
moles of zinc chloride are
there?
II. Massing a Mole
A. Different atoms have
different masses.
1 atom of carbon would
weigh ____
3 times more
than 1 atom of helium.
dozen atoms
1 atom of carbon would
weigh ____
3 times more
dozen atoms
than 1 atom of helium.
mole of
1 atom of carbon would
weigh ____
3 times more
mole of
than 1 atom of helium.
II. Massing a Mole
A. Different atoms have
different masses.
B. The mass on the P.T.
represents. . .
II. Massing a Mole
A. Different atoms have
different masses.
B. The mass on the P.T.
represents. . .
1. The mass of 1 atom (in amu)
II. Massing a Mole
A. Different atoms have
different masses.
B. The mass on the P.T.
represents. . .
1. The mass of 1 atom (in amu)
2. The mass of 1 mole of atoms
(in grams)
II. Massing a Mole
A. Different atoms have
different masses.
B. The mass on the P.T.
represents. . .
C. This value is called the
molar mass.
The mass of 1 mole of particles
If you weigh out 40
grams of argon you have
essentially counted
______________ atoms.
If you weigh out 40
grams of argon you have
essentially counted
23
______________
6.02 x 10
atoms.
II. Massing a Mole
D. Calculating with
molar mass
1. Using molar mass you can
convert from
to
.
II. Massing a Mole
D. Calculating with
molar mass
1. Using molar mass you can
convert from grams to moles.
Self Check – Ex. 5
If a sample of aluminum
has a mass 81.0 g how
many moles are present?
II. Massing a Mole
D. Calculating with
molar mass
1. Using molar mass you can
convert from grams to moles.
2. You can also convert from
_____ to
.
II. Massing a Mole
D. Calculating with
molar mass
1. Using molar mass you can
convert from grams to moles.
2. You can also convert from
moles to grams.
Self Check – Ex. 6
What is the mass of 0.25
moles of chromium?
II. Massing a Mole
D. Calculating with
molar mass
E. Calculating the molar
mass of compound
Example
One mole of CH4 contains:
1 mole of
carbon
moles of
hydrogen
Example
One mole of CH4 contains:
1 mole of
carbon
4 moles of
hydrogen
Example
One mole of CH4 contains:
1 mole of
carbon
4 moles of
hydrogen
weighs
12 g
weighs
______
Example
One mole of CH4 contains:
1 mole of
carbon
4 moles of
hydrogen
weighs
12 g
weighs
4 x (1) g
Example
One mole of CH4 contains:
1 mole of
carbon
4 moles of
hydrogen
weighs
12 g
weighs
4 x (1) g
= 16 g/mol
II. Massing a Mole
D. Calculating with
molar mass
E. Calculating the molar
mass of compound
1. Add the masses of each of the
atoms in the compound.
II. Massing a Mole
D. Calculating with
molar mass
E. Calculating the molar
mass of compound
1. Add the masses of each of the
atoms in the compound.
2. Remember to multiply each
atom’s mass by the number
atoms in the compound.
Self Check – Ex. 7
What is the molar mass
of lithium nitrate,
LiNO3?
Self Check – Ex. 8
What is the molar mass
of calcium acetate,
Ca(C2H3O2)2?
III. Molar Volume of Gas
The volume of 1 mole of gas particles
when measured at STP
III. Molar Volume of Gas
A. This is determined at
specific conditions.
STP – standard temperature (0ºC) and
standard pressure (1 atm)
III. Molar Volume of Gas
A. This is determined at
specific conditions.
B. It’s the same for all
gases.
1 mole of gas at STP = 22.4 L
III. Molar Volume of Gas
A. This is determined at
specific conditions.
B. It’s the same for all
gases.
C. Conversions
Self Check – Ex. 9
What is the volume of 3
moles of carbon dioxide
gas at STP?
Self Check – Ex. 10
How many moles of air
are in a 64 L that is at 1
atm and 0ºC.
IV. Multiple step conversions
Just remember the mole is the central
unit
Mass
(grams)
Volume
(liters)
particles
(atoms,
molecules,
formula units)
MOLE
Self Check – Ex. 11
What is the mass of 11.2
L of carbon dioxide
gas?
Self Check – Ex. 12
How many molecules of
ammonia, NH3 are in a
68-g sample?
IV. Mole ratios in chemical
formulas
IV. Mole ratios in chemical
formulas
A. The subscripts can give
a ratio of atoms in a
compound.
1 mole of
ammonia, NH3
1 mole of N
mole of N
1 mole of
ammonia, NH3
1 mole of N
3 mole of N
1 mole of
ammonia, NH3
1 mole of N
3 mole of N
1 mole NH3 : 1 mole N
1 mole NH3 : 3 mole H
1 mole of
ammonia, NH3
1 mole of N
3 mole of N
1 mole NH3 : 1 mole N
1 mole NH3 : 3 mole H
1 mole NH3
1 mole N
1 mole NH3
1 mole N
IV. Mole ratios in chemical
formulas
A. The subscripts can give
a ratio of atoms in a
compound.
B. Conversions
Self Check – Ex. 13
How many moles of
hydroxide ions are in
1.2 moles of magnesium
hydroxide, Mg(OH)2?
Self Check – Ex. 14
What is the mass of the
oxygen atoms in 4 moles
of sodium sulfate?
The end.