Mole Triangle Review
Begin Stoichiometry
Chemistry GT 3/5/15
Drill
• How many moles are equivalent to:
– 450. g Ca(OH)2
– 935.2 g zinc chloride
• HW: Mole-Mole/Mass-Mass WS (finish)
Objectives
• IWBAT
– Convert from moles to grams and back
– Convert from moles to units and back
– Convert from moles to liters and back
– Use the mole triangle to do two step conversions
Mole Triangle
• We can convert between
– Mol  g and back
– mol  particle and back
– mol  L and back
• Ms. Bloedorn will show you how! 
The study of quantitative relationships
between amounts of reactants used and
products formed by a chemical reaction
What’s going on here?
• The candle burns freely in
air, but what happens
when it is covered with a
beaker?
– smothered, goes out
• What fuel runs out first?
– oxygen runs out
Mole Chemical
Relationships
• Mole-Mass Relationships in Chemical
Reactions:
– Law of Conservation of Mass:
• Mass cannot be created or destroyed by
ordinary chemical changes
– Look at:
• Fe(s) + O2(g)  Fe2O3(s)
• Is it balanced?
If not, balance it.
• 4 Fe(s) + 3 O2(g)  2 Fe2O3(s)
Interpret the equation
• Iron + oxygen  Iron (III) oxide
• 4Fe(s) + 3O2(g)  2Fe2O3(s)
• 4 atoms Fe + 3 molecules O2  2 molecules Fe2O3
• 4 mol Fe + 3 mol O2  2 mol Fe2O3
• 223.4 g Fe + 96.00 g O2  319.4 g Fe2O3
• These all tell you different information, but
also represent the same reaction.
Stoichiometric
Calculations
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•
1/2 cup butter
1/2 cup brown sugar
1/2 cup granulated sugar
1 egg
1/2 teaspoon vanilla
1 cup all-purpose flour
1/2 teaspoon salt
1/2 teaspoon baking soda
1/2 cup semisweet chocolate
chips
• Makes 42 cookies.
• What is the product of
this chemical reaction?
– 42 cookies
• How would you adjust
the ingredients to make
seven dozen cookies?
– Make twice as much (7 x
6, then 7 x 12)
The Mole “Bridge”
moles of B
moles of A
Moles of A
Moles of B
1 mol A
# grams B
# grams A
1 mol B
Grams of A
Grams of B
*** You MUST have a balanced equation! ***
Stoichiometry Conversion Flowchart
wA + xB  yC + zD
Liters B
Liters A
22.4L A
mol A
6.022 x 10231units
1 mol A
Atoms/
mol A
units A
1 mol A
6.022 x 1023 units A
1 mol A
Molar mass A
grams A
22.4L B
1 mol A
1 mol B
22.4L Aw mol A
1 mol B
22.4L B 1 mol B
6.022 x 1023 units B
x mol B
mol B
x mol B
mol B
w mol1 A
Molar mass B
Molar mass g A
1 mol A
grams B
Atoms/
units B
6.022 x 1023 units B
Molar mass g B
1 mol B
1 mol B
Stoich. Calculations,
cont.
• Sometimes, a chemist needs to make a certain
amount of a product, or only has a certain amount
of a starting material. How much reactant should
be used? How much product will be made?
• ex. How many moles of hydrogen will be produced
when 0.0400 mol potassium react with water?
• 2K(s) + 2H2O(l)  2KOH(aq) + H2(g)
– 0.0400 mol K • 1 mol H2 = 0.0200 mol H2
2 mol K
Mass to Mass
Conversion
• Ammonium nitrate (NH4NO3) decomposes into
N2O and water. Determine the mass of water
produced from the decomposition of 25.0 g solid
ammonium nitrate.
• NH4NO3  N2O + 2H2O
25.0 g NH4NO3 • 1 mol NH4NO3 • 2 mol H2O • 18.02 g H2O = 11.3 g H2O
80.04 g NH4NO3 1 mol NH4NO3 1 mol H2O
Practice
• Start on Mole-Mole side of WS
• Then, Mass-Mass side of WS
Closure
• Calculate, in 2.3 mol Na3PO4,
– How many grams?