What is a MOLE?

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What is a MOLE?
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There are 12 items in a dozen
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There are 144 items in a gross of any substance
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There are 6.02 x 1023 atoms or molecules in a
mole of any substance
Im going to need a bigger shovel!
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6.02 x 1023 602, 000,000,000,000,000,000,000
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A mole of standard soft drink cans would cover
the surface of the Earth to a depth of over 200
miles.
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If you had a mole of unpopped popcorn kernels,
and spread them across the United States of
America, the country would be covered in popcorn
to a depth of over 9 miles.
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Molar mass is the weight of one mole (or 6.02 x
1023 molecules) of any chemical compounds.
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Molar Masses
Waters molar mass is 18 grams
PVCs molar mass is 150,000 grams
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How can I find the molar mass of an element?

• Use the elements mass on the periodic table

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Example What is the molar mass of Carbon?

• Carbons atomic mass is

12.01
Therefore, Carbons molar mass is..
12.01g
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Example What is the molar mass of Magnesium?

• Magnesiums atomic mass is

24.31
Therefore, Magnesiums molar mass is..
24.31g
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Example What is the molar mass of Krypton?

• Kryptons atomic mass is

83.80
Therefore, Kryptons molar mass is..
83.80g
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Practice Time!
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Element Molar Mass Element Molar mass
Helium (He) Argon (Ar)
Chlorine (Cl) Neon (Ne)
Sodium (Na) Phosphorus (P)
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Now, lets kick it up a notch!
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To calculate the molar mass of a compounds

• First you find the molar mass of the parts of the
  compound and then you add.
• If there are more than one of a type of atom in
  the compound, you multiply the number of atoms
  time the molar mass of the one atom, and then add
  all parts together.

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Whats the molar mass of a compound like NaCl?
Molar mass of Na
22.99
Molar mass of Cl
35.45
22.99 35.45
So, the Molar mass of NaCl
58.44g
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Whats the molar mass of C6H12O6?
6 x 12.01 72.06
Molar mass of C6
12 x 1.008 12.096
Molar mass of H12
6 x 16.00 96
Molar mass of O6
72.06 12.096 96
So, the Molar mass of C6H12O6
180.156 g
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Practice Time!
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Compound Molar Mass Compound Molar mass
Carbon dioxide (CO2) Ammonia (NH3)
Ethanol (C2H6O) Sulfuric acid (H2SO4)
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Calculate the Molar Mass

• Ca(NO3)2

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Percent Composition

• A percent is a ratio.
• Sometimes we want to know how much of an element
  is in the compound.

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Steps to determine percent composition

• Calculate the molar mass from the formula.
• 2. Determine how many grams the atom of interest
  contributes to the compound
• Divide the mass of the atom by the molar mass and
  multiply by 100 to get a percentage.
• Composition Mass of the element in cmpd
  x 100
• Molar Mass of cmpd

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Example Find the of Na and Cl in NaCl

• Sodium Chloride, NaCl
• Na 22.99g
• Cl 35.45g Molar Mass 58.44g
• Na 22.99 x 100
• 58.44 39.34 Na
• Cl 35.45 x 100
• 58.44 60.7 Cl

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Find the of each element in Na2SO4
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Give the composition of all the elements in

• Magnesium sulfite Formula

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Relating Moles Mass
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What you already know.

• How big is a mole?

6.02 x 1023 atoms or molecules
Its the same as atomic mass.
How do you determine molar mass of an atom?
Its the same as the sum of the atomic masses of
the parts.
How do you determine molar mass of a molecule?
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• Chemist use moles to understand relationships
  between reactants and products. In the lab we
  dont have a balance that measures moles. We
  must relate grams to the number of moles.

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What you dont know

• How many moles are in this glass of water?

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What else you dont know

• Can you add 3.25 moles of water to the beaker?

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These two questions can be solved by using
conveRsi?ns!
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A Conversion is just a math equation in which you
1. START with the data and units they give you
in the problem, and then2. MULTIPLY by
CONVERSION FACTORS until you have the right
units at the end.
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Whats a Conversion Factor?

• Its a FRACTION in which the TOP number and
  BOTTOM number mean the same thing but have
  different units.

12 eggs 1 dozen
3 feet 1 yard
1 week 7 days
6 points 1 touchdown
1 cup 8 ounces
100 yards 1 football field
Write 3 of your own!
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Mole Conversion

• Molar Mass or 1 Mole
• 1 Mole Molar Mass

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How do you know which part to put on top and
which part to put on bottom?

• Because

12 eggs 1 dozen
Is the same thing as
1 dozen 12 eggs
How do you know which one to use?
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RULE!!!!

• Use the conversion factor with the UNITS of the
  info they give you in the problem on the BOTTOM
  and the UNITS of what youre LOOKING FOR on the
  TOP!!

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So, if they tell you there are 8 dozen and ask
you how many eggs there are
By a conversion factor that connects eggs to
dozens. How many eggs in ONE dozen?
START with what they give you 8 dozen
MULTIPLY X
12 eggs 1 dozen
96 eggs
NOTE The dozen in the first number and the
dozen in the bottom of the conversion factor
will cancel each other out, leaving eggs!!!
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For example

• How many grams are in 3 moles of Carbon?

By a conversion factor that connects moles to
grams. How many grams in ONE mole of hydrogen?
START with what they give you 3 moles
MULTIPLY X
12.00 grams 1 mole C
36.00 g
NOTE The moles in the first number and the moles
in the bottom of the conversion factor will
cancel each other out, leaving grams!!!
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Another example, this time a little trickier

• How many grams are in 5 moles of
• carbon dioxide (CO2)?

By a conversion factor that connects moles to
grams. How many grams in ONE mole of carbon
dioxide?
START with what they give you 5 moles CO2
MULTIPLY X
44.01 grams 1 mole CO2
220.05 g
NOTE The moles in the first number and the moles
in the bottom of the conversion factor will
cancel each other out, leaving grams!!!
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Steps to conversions

• Write the given.
• Draw a times and a line
• Write the units you were given on the bottom
• Write the units you want on top
• Fill in the conversion factor (remember 1 is
  always with the mole)
• Multiply all the numbers on the top and divide it
  by the numbers on the bottom.

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Practice Time!
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• How many grams are there in 350 moles of iron
  (Fe)?
• How many grams are there in 3 moles of Lithium
  (Li)?
• How many grams are there in 46 moles of water
  (H2O)?
•  How many grams are there in 12.7 moles of
  magnesium chloride (MgCl2)?
• A chemist needs 12.5 moles of sulfuric acid
  (H2SO4). How many grams does he need?

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• How many grams are there in 350 moles of iron
  (Fe)? 19547.5 g
• How many grams are there in 3 moles of Lithium
  (Li)? 20.82 g
• How many grams are there in 46 moles of water
  (H2O)? 828.92 g
•  How many grams are there in 12.7 moles of
  magnesium chloride (MgCl2)?
• 1209.04 g
• A chemist needs 12.5 moles of sulfuric acid
  (H2SO4). How many grams does he need? 1226 g

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We could, on the other hand, give you GRAMS and
ask you to find MOLES. That would be a GRAMS TO
MOLES problem.
Those problems you just finished were all MOLES
TO GRAMS problems because they GAVE you moles
and asked you to find grams.
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For example

• How many moles are in 250 grams of Carbon?

By a conversion factor that connects moles to
grams. How many grams in ONE mole of carbon?
START with what they give you 250 grams
MULTIPLY X
1 mole C 12.00 grams
20.83 moles
NOTE The grams in the first number and the grams
in the bottom of the conversion factor will
cancel each other out, leaving moles!!!
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Another example, this time a little trickier

• How many moles are in 930 grams of
• carbon dioxide (CO2)?

By a conversion factor that connects moles to
grams. How many grams in ONE mole of carbon
dioxide?
START with what they give you 930 grams
MULTIPLY X
1 mole CO2 44.01 grams
21.13 moles
NOTE The grams in the first number and the grams
in the bottom of the conversion factor will
cancel each other out, leaving moles!!!
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Practice Time!
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• How many moles are in 2.4 grams of sulfur (S)?
•  How many moles are in 18.7 grams of argon (Ar)?
• How many moles are in 88.1 grams of potassium
  chloride (KCl)?
• How many moles are in 2.3 grams of nitric acid
  (HNO3)?
• How many moles are in 11.9 grams of calcium
  hydroxide - Ca(OH)2? (Dont forget! The 2
  subscript applies to the O and to the H!!)

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• How many moles are in 2.4 grams of sulfur (S)?
  0. 0748 mol S
•  How many moles are in 18.7 grams of argon (Ar)?
  0.468 mol Ar
• How many moles are in 88.1 grams of potassium
  chloride (KCl)? 1.18 mol
• How many moles are in 2.3 grams of nitric acid
  (HNO3)? 0.036 mol
• How many moles are in 11.9 grams of calcium
  hydroxide - Ca(OH)2? (Dont forget! The 2
  subscript applies to the O and to the H!!) 0.16
  mol

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Moles and Molecules

• 1 mole 6.02 x 1023 particles (atoms,
  molecules, ions)
• A way of counting the number of atoms in a
  substance.
• The one always goes with mole!
• Solve using the same steps for conversions

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Steps to conversions

• Write the given.
• Draw a times and a line
• Write the units you were given on the bottom
• Write the units you want on top
• Fill in the conversion factor (remember 1 is
  always with the mole)
• Multiply all the numbers on the top and divide it
  by the numbers on the bottom.

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Using your calculator

• Graphing Calculators use parentheses around (6.02
  x 1023 )
• Enter 6.02
• Find the EE or EXP button
• This button tells your calculator x 10
• Enter the exponent 23

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Examples

• How many moles are in 2.5 x 1015 molecules of
  water?

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• 2. How many moles are in 3.9 x 1034 atoms of
  iron?

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• 3. How many atoms are in 5 moles of Ne?

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Stoichiometry

• The study of quantitative relationships between
  reactants and products
• Balanced chemical equations relate moles of
  reactants to moles of product
• N2 3H2 ? 2NH3
• The coefficients are the mole ratio
• 1 mole of N2 and 3 moles of H2 make 2 moles of NH3

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Sample Problems

• 2 KClO3 ? 2KCl 3O2
• 2 moles of KClO3 can produce __ moles of KCl.
• 4 moles of KClO3 can produce __ moles of KCl.

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Theoretical Yield

• Yield the amount of product
• Goal make as much of the product as possible
• Theoretical Yield the most you should make as
  predicted by the chemical reaction using
  stoichiometry N2 3H2 ? 2NH3

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Actual Yield

• the amount of product actually produced in the
  lab
• Usually lower due to collection techniques and
  apparatus used
• If the amount is higher than predicted then there
  may be impurities in the product

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Percent Yield

• Measures how well you did the lab
• Percent yield Actual yield x 100
• theoretical yield

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Do Now

• Balance the reaction
• ____ NaCl ____ F2 ? ____ NaF ____ Cl2
• For every 2 moles of NaCl, ___ moles of NaF are
  produced.
• For every 2 moles of NaCl, ___ moles of Cl2 are
  produced.
• For every 4 moles of NaCl, ____ moles of NaF are
  produced.

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• Work on assignment 8
• Try the practice quiz
• Do NOT copy

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Limiting Reactant

• The reactant that is used up first
• Making a bicycle requires
• 1 frame 2 wheels ? 1 bicycle
• If you have 10 frames and 12 wheels, how
• many bicycles can you manufacture?
• What is the limiting reactant?