Post on 15-Apr-2018
INTRODUCTION TO THE MOLE AND MOLAR MASS
(OWLS & MOLES LAB)
BACKGROUND
• When you buy eggs you usually ask for a _______
eggs.
• You know that one dozen of any item is ______.
Dozen
12
PAPER
• Paper is packaged in a _________.
• A ream of paper has ________ sheets.
• Why is it useful to use units like a dozen or a
ream?
Ream
500
•What determines how
many items should make
up a particular unit?
• If you were asked to design a new
unit to count pieces of candy, what
would you consider when choosing
how many items should be included in
your new counting unit?
ACTIVITY:
• WHAT YOU NEED:
• 3 packages,
• balance,
• worksheet,
• calculator,
• pencil.
PART 1
1. Follow your teacher’s instructions:
DATA TABLE 1
Name of the
Items in the
Package
Number of
items in
package
Mass of items
in the package
ANALYSIS AND INTERPRETATION
• As you know, a dozen represents 12 items.
• Since I did not have enough candy to put a dozen pieces in each bag, I decided to make a new counting unit. I called this unit an OWL.
• As you can tell, an Owl is _____ items.4
1. A OWL OF ORANGES WILL HAVE _____ ORANGES.
4
2. A OWL OF PRETZELS HAS ____ PRETZELS. 4
3. A OWL OF MOLECULES OF WATER HAS ____ MOLECULES OF WATER.
4
4. A OWL OF ATOMS OF IRON HAS _____ ATOMS OF IRON.
4
26
Fe
55.85
•Now that you understand the
meaning of an OWL, you should be
able to answer the following
questions:
1. HOW MANY HERSHEY’S KISSES ARE IN 2 OWLS? _______8
2. HOW MANY DUM DUM POPS ARE IN 400 OWLS? _______1600
3. HOW MANY STARBURSTS ARE IN 1/2 OWL? _____2
4. HOW MANY HYDROGEN ATOMS ARE IN 6OWLS? _______24
• Finding the Number of OWLS:
• If you are given the number of items you can tell the number of OWLS.
• For example, since one OWL is 4 items, 8 items make up 2 OWLS.
1. How many OWLS are 16
Hershey’s Kisses? ______4
2. How many OWLS are 100
pretzels? ____25
3. How many OWLS are 400
Starbursts? ____100
4. How many OWLS is 2
apples? ________ ½ or 0.5
OWLS VS. MOLES
• An OWL of molecules of water
would be too small to see.
• Scientists had to select a unit with a
MUCH greater value for counting
molecules because they are so small.
• The unit scientists use is called a
MOLE.
ONE MOLE OF ANYTHING HAS THIS MANY ITEMS:
602,200,000,000,000,000,000,000
•This number is written in
Scientific notation to avoid
mistakes:
6.022 x 1023
THIS IS KNOWN AS AVOGADRO’S NUMBER
•6.022 x 1023
•One MOLE of anything
has 6.022 x 1023 items.
1. HOW MANY HERSHEY’S KISSES MAKE UP 1 MOLE?
6.022 x 1023
2. HOW MANY CARAMELS MAKE UP 10 MOLES?
10 [6.022 x 1023]
60.22 x 1023
Or
6.022 x 1024
3. FIND THE NUMBER OF ATOMS OF SODIUM IN 2 MOLES.
2[6.022 x 1023 ]
12.044 x 1023
1.20 x 1024
11
Na
22.99
4. FIND THE NUMBER OF ATOMS OF CARAMELS IN 0.5 MOLES.
0.5[6.022 x 1023 ]
3.011 x 1023
5. HOW MANY MOLES ARE IN 6.022 X 1023 OF STARBURSTS?.
1 mole
6. HOW MANY MOLES ARE IN 1.204 X 1024
OF GOBSTOPPERS?.
2 moles
7. HOW MANY ATOMS OF POTASSIUM MAKE UP 1 MOLE?
1[6.022 x 1023 ]
6.022 x 1023
19
K
39.10
8. HOW MANY MOLECULES OF WATER MAKE UP 5 MOLES?
5[6.022 x 1023 ]
30.110 x 1023
3.01 x 1024
9. HOW MANY MOLES ARE IN 6.022 X 1023
OF SODIUM?
1 mole11
Na
22.99
10. HOW MANY MOLES ARE IN 1.204 X 1024 OF CARBON?
2 moles6
C
12.01
11. HOW MANY MOLES ARE 3.010 X 1024
MOLECULES OF WATER?
5 moles
PART 2
MASS
• In addition to being able to tell the number of items in an
OWL, you can now tell the mass of an OWL of Hershey’s
Kisses, Jolly Ranchers, caramels, or whatever.
DATA TABLE 1
Name of the
Items in the
Package
Number of items
in package
Mass of the
package
Candy #1
Candy #2
Candy #3
4
4
4
26.9
23.03
20.96
USE THE CLASS AVERAGE DATA IN DATA TABLE 1 TO FILL IN THE INFORMATION BELOW:
1. BASED ON YOUR MEASUREMENTS, THE MASS OF 1 OWL OF CANDY #1 IS ______ G.2. THE MEASURED MASS OF 2 OWLS OF CANDY #1 IS ______ G.3. THE MASS OF 1 OWL OF CANDY #2 IS _____ G.4. THE MASS OF 1 OWL OF CANDY #3 IS ____G5. THE MASS OF 100 OWLS OF CANDY #2 IS ____ G.6. THE MASS OF 1/2 OWL OF CANDY #3 IS ____ G.7. THE MASS OF 4 OWLS OF CANDY #2 IS ____ G.8. THE MASS OF 0.5 OWLS OF CANDY #3 IS ____ G.
MASS OF A MOLE:
As it turns out, the mass of one mole (6.022 X 1023
molecules or atoms of a substance) is THE SAME as
the atomic weight of the molecule of the element as
shown on the periodic table.
USE THE PERIODIC TABLE TO ANSWER THE FOLLOWING:
1. THE MASS OF 1 MOLE OF STRONTIUM (SR) IS ___ G.
38
Sr
87.62
87.62
2. THE MASS OF 1 MOLE OF LEAD (PB) IS ________ G.
82
Pb
207.2
207.2
3. THE MASS OF 1 MOLE OF NICKEL (NI) IS ____ G.
28
Ni
58.69
58.69
4. THE MASS OF 4 MOLES OF STRONTIUM (SR) IS _____G.
38
Sr
87.62
350.48
5. THE MASS OF 0.5 MOLES OF LEAD (PB) IS ____ G.
82
Pb
207.2
103.6
6. THE MASS OF 100 MOLES OF (NI) IS _____ G.
28
Ni
58.69
5869.00
MOLAR MASS
• Scientists also use the Periodic Table
to determine the molar mass (formula
weight) of compounds.
• The molar mass of the compound is
the sum of the molar masses of the
elements that make up the compound.
POTASSIUM CHLORIDE
• The molar mass of Potassium Chloride (KCl) is:
Potassium (K) 39.10 g/mole
Chloride (Cl) +34.45 g/mole
73.55 g/mole
POTASSIUM PERMANGANATE• The molar mass of KMnO4 is the sum of all the molar
masses times the number of atoms of each element for the
molecule (subscript).
POTASSIUM PERMANGANATE
• KMnO4
• Potassium (K) 39.10 g/mole
• Manganese (Mn) 54.94g/mole
• Oxygen (O) 4[16.00 g/mole] = 64.00g
158.04 g/mole.
1. THE MOLAR MASS OF 1 MOLE OF SODIUM CHLORIDE (NACL) IS____ 58.44 g
Na = 22.99 g
Cl = 35.45 g
2. THE MOLAR MASS OF 1 MOLE OF LEAD IODIDE (PBI2) IS _____ .461.0 g
Pb = 207.2
I = 126.9
3. THE MASS OF 100 MOLES OF NICKEL SULFIDE (NIS) IS ________ .9071.00 g
Ni = 58.65
S = 32.06
4. THE MASS OF 1 MOLE OF IS GLUCOSE (C6H12O6) IS ___________.180.16 g
5. THE MASS OF 1 MOLE OF IS SUCROSE (C12H24O12 ) _______.360.31 g
6. THE MASS OF 4 MOLES OF IS GLUCOSE (C6H12O6) IS ______ .720.62 g