Transcript Limiting and Excess Reactant

Limiting Reagent/Reactant
Miss Knick
HAHS
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Reacting Amounts
In a table setting, there is 1
plate, 1 fork, 1 knife, and
1 spoon.
How many table settings are
possible from 5 plates, 6 forks,
4 spoons, and 7 knives?
 What is the limiting item?
 What are the excess items?
 How much of the excess
2 remain?
items will

What happens in a
chemical reaction, if
there is an
insufficient amount
of one reactant?
http://ossfabricators.com/photos/reactor2.jpg
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Limiting Reagent: the reagent
that is completely used up in a
chemical reaction.
Excess Reagent: reagent not
completely used up in a chemical
reaction.
Example:
Find the limiting reagent when 1.22g
O2 reacts with 1.05g H2 to produce
H2O. How many grams of water will be
produced?
Method
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Use the moles of each of the reactant
to calculate the product of interest.
The reactant that yields the smaller
calculated value of product is the
limiting reagent.
This calculated amount is also known
as the theoretical yield.
Example: Find the limiting reagent
when 1.22g O2 reacts with 1.05g H2 to
produce H2O. How many grams of
water will be produced?
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Calculate H2O moles produced by using each
of the reactants.
The actual amount H2O produced is the
smaller one of the two values.
Use the smaller mole value to convert to
grams.
This is the theoretical yield.