Stoichiometry Practice Worksheet
Solve the following stoichiometry grams-grams problems:
1)
Using the following equation: 2 NaOH + H2SO4  2 H2O + Na2SO4
How many grams of sodium sulfate will be formed if you start with 200 grams of
sodium hydroxide and you have an excess of sulfuric acid?
2)
Using the following equation: Pb(SO4)2 + 4 LiNO3  Pb(NO3)4 + 2 Li2SO4
How many grams of lithium nitrate will be needed to make 250 grams of lithium
sulfate, assuming that you have an adequate amount of lead (IV) sulfate to do
the reaction?
Limiting Reagent Worksheet
For the following reactions, find the following:
a)
Which of the reagents is the limiting reagent?
b)
What is the maximum amount of each product that can be formed?
c)
How much of the other reagent is left over after the reaction is complete?
3)
Consider the following reaction:
3 NH4NO3 + Na3PO4  (NH4)3PO4 + 3 NaNO3
Answer the questions above (a,b,c), assuming we started with 30 grams of
ammonium nitrate and 50 grams of sodium phosphate.
4)
Consider the following reaction:
3 CaCO3 + 2 FePO4  Ca3(PO4)2 + Fe2(CO3)3
Answer the questions above (a,b,c) assuming we start with 100 grams of
calcium carbonate and 45 grams of iron (III) phosphate.
5) When copper (II) chloride reacts with sodium nitrate, copper (II) nitrate and sodium
chloride are formed.
a)
Write the balanced equation for the reaction given above:
b)
c)
If 15 grams of copper (II) chloride react with 20 grams of sodium nitrate, how
much sodium chloride can be formed?
What is the limiting reagent for the reaction in #2? __________________
d)
How much of the nonlimiting reagent is left over in this reaction?
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e)
If 11.3 grams of sodium chloride are formed in the reaction described in
problem #2, what is the percent yield of this reaction?
Solutions!
When doing stoichiometry problems, people are frequently worried by statements
such as “if you have an excess of (compound X)”. This statement shouldn’t worry
you… what it really means is that this isn’t a limiting reagent problem, so you can
totally ignore whatever reagent you have an excess of. Don’t even give it a second
thought, because if you do, you’ll run into trouble.
1)
355.3 grams of Na2SO4
2)
386.3 grams of LiNO3
Limiting Reagent Answers
3
a) ammonium nitrate
b) 18.6 grams of ammonium phosphate, 31.9 grams of sodium nitrate
c) 29.5 grams of sodium phosphate
4
a) iron (III) phosphate
b) 46.3 grams of calcium phosphate, 43.8 grams of iron (III) carbonate
c) 54.0 grams of calcium carbonate
5
a) CuCl2 + 2 NaNO3  Cu(NO3)2 + 2 NaCl
b)To solve this problem determine how much sodium chloride can be
made from each of the reagents by themselves. When you work out how
much sodium chloride can be made with 15 grams of copper (II) chloride,
you find that 13.0 grams will be formed. When starting with 20 grams of
sodium nitrate, 13.6 grams will be formed. Since 13.0 grams is the
smaller number, that’s our answer. Please note that rounding differences
may cause your answers to be slightly different, so if they are, don’t
panic.
c)
copper (II) chloride
d)
Nonlimiting reagent remaining = 20 grams – 20 grams (13.0 / 13.6)
= 0.88 grams
e)
11.3/13.0 x 100% = 86.9%
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