The document discusses the mole concept in chemistry. It defines the mole as the amount of substance that contains as many elementary units (atoms, molecules, ions) as there are atoms in exactly 12 grams of carbon-12. The number of elementary units in one mole is Avogadro's number, which is approximately 6.022x1023. Examples are given to illustrate that one mole of any substance will contain this number of particles, though the masses in grams will vary depending on the molar masses of the substances. The mole can be used to convert between the number of particles, moles, and mass in grams for calculations involving chemical substances.

1. The Mole
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2. Use the mole concept to
express mass of
substances; and
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3. As you may have
guessed, D is the correct
answer!!
Although a mole might be
cute and fuzzy, we are going
to focus on the Chemistry
concept.

4. Counting Atoms
 Chemistry is a quantitative science -
we need a "counting unit."
 The MOLE
 1 mole is the amount of substance
that contains as many particles
(atoms or molecules) as there are
in 12g of Carbon-12.

5. A mole is a counting unit.
Just like:
 12 eggs equals a dozen eggs
 144 pencils equals one gross of
pencils
 2 socks equals a pair of socks.
 500 sheets of paper equals one
ream

6. One mole equals 6.022 x 1023
particles
 So one mole of eggs would be 6.022 x 1023 eggs
 One mole of pencils would be 6.022 x 1023 pencils
 And so on...

7. How Big is a Mole?
One mole of marbles would cover the entire Earth
(oceans included) for a depth of three miles!!!!
One mole of $100 bills stacked one on top of another
would reach from the Sun to Pluto and back 7.5 million
Times!!!!
It would take light 9500 years to travel from the
bottom to the top of a stack of 1 mole of $1 bills!!!!

8. Avogadro’s Number
 A MOLE of any substance contains as many elementary
units (atoms and molecules) as the number of atoms in
12 g of the isotope of carbon-12.
 This number is called AVOGADRO’s number NA = 6.02 x
1023 particles/mol
 The mass of one mole of a substance is called MOLAR
MASS
 Examples
H2 hydrogen 2 g/mol
He helium 4 g/mol
N2 nitrogen 28 g/mol
O2 oxygen 32 g/mol
CO2 carbon dioxide 44 g/mol

9. The Mole
 1 dozen cookies = 12 cookies
 1 mole of cookies = 6.02 X 1023 cookies
 1 dozen cars = 12 cars
 1 mole of cars = 6.02 X 1023 cars
 1 dozen Al atoms = 12 Al atoms
 1 mole of Al atoms = 6.02 X 1023 atoms
Note that the NUMBER is always the same,
but the MASS is very different!

10. A Mole of Particles
Contains 6.02 x 1023 particles
= 6.02 x 1023 C atoms
= 6.02 x 1023 H2O molecules
= 6.02 x 1023 NaCl “molecules”
6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
1 mole C
1 mole H2O
1 mole NaCl

11. 12
Using the mole concept is very much like using “dozen”.
Equivalence statement: 1 dozen eggs = 12 eggs
3.5 dozen eggs
1 dozen
12 eggs
( )
( ) = 42 eggs
How many eggs are in 3.5 dozen eggs?
3.5 mole Mg
( )
( ) = 2.1X1024
Mg atoms
How many Mg atoms are in 3.5 moles of Mg?
Equivalence statement: 1 mole Mg = 6.022X1023
Mg atoms
6.022X1023
Mg atoms
1 mole Mg

12. Mole Calculations I
 How many sodium atoms are in 0.120 mol Na?
• Step 1: we want atoms of Na
• Step 2: we have 0.120 mol Na
• Step 3: 1 mole Na = 6.02 × 1023 atoms Na
= 7.22 × 1022 atoms Na
0.120 mol Na ×
1 mol Na
6.02 × 1023 atoms Na

13. Mole Calculations I
 How many moles of potassium are in 1.25 × 1021
atoms K?
• Step 1: we want moles K
• Step 2: we have 1.25 × 1021 atoms K
• Step 3: 1 mole K = 6.02 × 1023 atoms K
= 2.08 × 10-3 mol K
1.25 × 1021 atoms K ×
1 mol K
6.02 × 1023 atoms K

14. Molar Mass
 The atomic mass of any substance expressed in
grams is the molar mass (MM) of that substance.
 The atomic mass of iron is 55.85 amu.
 Therefore, the molar mass of iron is 55.85 g/mol.
 Since oxygen occurs naturally as a diatomic, O2,
the molar mass of oxygen gas is 2 times 16.00 g
or 32.00 g/mol.

15. Learning Check
1. Number of atoms in 0.500 mole of Al
a) 500 Al atoms
b) 6.02 x 1023 Al atoms
c) 3.01 x 1023 Al atoms
2.Number of moles of S in 1.8 x 1024 S atoms
a) 1.0 mole S atoms
b) 3.0 mole S atoms
c) 1.1 x 1048 mole S atoms

16. Calculating Molar Mass
 The molar mass of a substance is the sum of the
molar masses of each element.
 What is the molar mass of magnesium nitrate,
Mg(NO3)2?
 The sum of the atomic masses is:
24 + 2(14 + 16 + 16 + 16) =
24 + 2(62) = 148 amu
 The molar mass for Mg(NO3)2 is 148 g/mol.

17. Mole Calculations II
 Now we will use the molar mass of a compound
to convert between grams of a substance and
moles or particles of a substance.
6.02 × 1023 particles = 1 mol = molar mass
 If we want to convert particles to mass, we must
first convert particles to moles and than we can
convert moles to mass.

18. Mass-Mole Calculations
 What is the mass of 1.33 moles of titanium, Ti?
 We want grams, we have 1.33 moles of titanium.
 Use the molar mass of Ti: 1 mol Ti = 47.88 g Ti
= 63.7 g Ti
1.33 mole Ti ×
47.88 g Ti
1 mole Ti

19. Mole Conversions

20. It’s time for some mole jokes!
How does Avogadro talk to his friends?
By E-Mole! Hahaha
Where did Avogadro go on Saturday?
The shopping mole.. Wow these are funny!
Why did Avogadro look forward to the year
2000?
It was the start of the new molennium!!!
What was Avogadro's favorite sport?
Golf - because he always got a mole-in-one.

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