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Stoichiometry - deals with mole, mass and
volume relationships in chemical reactions
Limiting reactant - controls the amount of
product formed
 There is no more at the end of the reaction

From the balanced equation, we can
predict the amount of product if given the
amount of reactant
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From the balanced equation, we can
predict the amount of reactant needed if
given the desired amount of product
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Mole Ratio – will help convert moles of one
compound in a balanced chemical equation
into moles of another compound.
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Example:
Reaction between magnesium and oxygen to
form magnesium oxide. ( fireworks)
2 Mg + O2  2 MgO
 Mole Ratios:
2 mole : 1 mole :
2 mole
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Stoichiometry is used in chemical
engineering in order to understand/predict
chemical reactions.
 Production of items include: soap, tires, fertilizer,
gasoline, deodorant, and chocolate bars

Real-life applications in chemical
engineering as well as research
 Therefore, stoichiometry is one of the most
important and fundamental topics in chemistry.

Write the balanced equation
 Determine which is the starting chemical (A)
and which is chemical we want to end up with
(B)
 Use coefficients of balanced equation to
convert moles of chemical A to moles of
chemical B
▪ Mole ratio!
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How many moles of water can be obtained
from the reaction of 4 moles of O2?
2 H2 +
4 mol O2
1
x
1 O2 →
2 mol H2O
1 mol O2
2 H2O
= 8 mol H2O
Mole Ratio
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In order to produce 15 moles of water, how
many moles of oxygen must be reacted?
2 H 2 + 1 O2 → 2 H 2O
Allows you to calculate the mass of product produced or the mass of
reactant needed.

Write the balanced equation
 Determine which is the starting chemical (A) and which is
chemical we want to end up with (B)

Steps :
 Convert gA to molA
▪ Use Molar Mass (GFW = Gram Formula Weight)
 Convert molA to molB
▪ Use stoichiometry rules
 Convert molB to gB
▪ Use Molar Mass (GFW = Gram Formula Weight)
Moles of “A”
Grams of “A”
Mole Ratio
Moles of “B”
Grams of “B”

How many grams of SnF2 can be produced
from the reaction of 30.00 g of HF with Sn?
Sn + 2 HF → SnF2 + H2
30.00 g HF 1 mole HF
1
x
20.01 g HF
x
1 molSnF2
2 mol HF
x
156.71 g SnF2
1 mol SnF2
Ratio
=Mole
117.5
g SnF2GFWSnF2
GFWAnswer
HF
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The combustion of a sample of butane, C4H10
(lighter fluid), produced 2.46 grams of water.
2 C4H10 + 13 O2 -------> 8 CO2 + 10 H2O
How many grams of butane were used?

Iodine chloride, ICl, can be made by the following
reaction between iodine, I2, potassium iodate, KIO3, and
hydrochloric acid.
2 I2 + KIO3 + 6 HCl -> 5 ICl + KCl + 3 H2O
Calculate how many grams of iodine are needed to
prepare 10.3 grams of ICl by this reaction.