STOICHIOMETRY REVIEW
ANSWERS
• 1. The calculation of quantities in chemical
equations is called
• Stoichiometry
• 2. The first step in most stoichiometry
problems is to convert given quantities to
• Moles
• 3. When two substances react to form
products, the reactant which is used up is
called the
• Limiting Reagent
• 4. The amount of product that forms when a
reaction is carried out in the laboratory is the
• Actual Yield
• 5. The maximum amount of products that could
be formed from given amounts of reactants is
the
• Theoretical Yield
• 6. When an equation is used to calculate the
amount of product that will form during a
reaction, then the value obtained is called the
• Theoretical Yield
• 7.
2Al(s) + 3Pb(NO3)2(aq)  2Al(NO3)3(aq) + 3Pb(s)
•
A.) 2 moles Al + 3 molecules Pb(NO3)2  2 molecules Al(NO3)3 + 3 moles Pb
•
F
•
•
B.) 2 grams Al + 3 grams Pb(NO3)2  2 grams Al(NO3)3 + 3 grams Pb
F
•
•
C.) 2 moles Al + 3 moles Pb(NO3)2  2 moles Al(NO3)3 + 3 moles Pb
T
• 8. In every chemical reaction ___________ stay the same.
• The Mass
• 9. In the reaction 2CO + O2  2CO2, what is the
ratio of moles of oxygen used to moles of CO2
produced?
• 1:2
• 10. For C5H12 + 8O2  5CO2 + 6H2O
• ______ moles of reactants chemically
change into ______ moles of product.
• 9 moles of reactant to 11 moles of product
11. How many moles of oxygen are
required to react completely with
14.8 mol Al when given
4Al + 3O2  2Al2O3?
14.8 ----------mol Al x
3 mol O2
----------------4 mol
--------Al
=
11.1 mol O2
12. Given the balanced equation
16HCl + 2KMnO4  2KCl + 2MnCl2 + 5Cl2 + 8H2O
if 2.0 mol of KMnO4 reacts, how many moles of
H2O are produced?
8.0 mol H2O
13. Based on…
16HCl + 2KMnO4  2KCl + 2MnCl2 + 5Cl2 + 8H2O
…how many grams of KCl are produced
when 3.0 mol of KmnO4 reacts?
------------3.0 mol
KMnO4
2 mol
--------KCl
74.5 g KCl
x ---------------- X --------------------2 mol
------------KMnO4
1 mol
--------KCl
= 220 g KCl
14. If CuO + H2  Cu + H2O, how
many moles of H2O are produced
when 240 grams of CuO react?
1 mol
--------CuO
1 mol H2O
--------240 g
CuO x ---------------- X --------------------80 g--------CuO
1 mol
--------CuO
= 3.0 mol H2O
15. In the reaction
Zn + H2SO4  ZnSO4 + H2
how many grams of
H2SO4 are required to produce
2.3 gram of H2?
1 mol
H2
----------2.3 g------H2 x
-----------------
2 g------H2
1 mol
H2SO4
----------------
98 g H2SO4
x ------------------- x ----------------------------1 mol
H2
1 mol
H2SO4
-----------------
113 g H2SO4
=
16. LiOH + HBr  LiBr + H2O
If you start with 15.0 grams of
lithium hydroxide, how many grams of
lithium bromide will be produced?
54.4 g LiBr
17. How many molecules of oxygen
are required to react completely
with 2.96 X 1023 molecules Al
when given 4Al + 3O2  2Al2O3?
3 molecules O2
---------------------2.96 x 1023 molecules
Al x -----------------
4 ---------------------molecules Al
2.22 x
23
10
=
molecules O2
18. How many molecules of oxygen
are produced by the
decomposition of 6.54 g of
potassium chlorate (KClO3)?
2KClO3  2KCl + 3O2
-----------1 mol
KClO3
--------3 mol
O2
6.02 x 1023 molecules O2
6.54 g-----------KClO3 x --------------- x --------------- x -----------------122.5 g-----------KClO3
4.82 x
22
10
-----------2 mol
KClO3
--------1 mol
O2
molecules O2
=
• 19.
LiOH + KCl  LiCl + KOH
• A) I began this reaction with 20 grams of
lithium hydroxide.
What is my theoretical yield of lithium chloride?
Convert 20 grams of LiOH  Grams of LiCl
35 g LiCl
• B) I actually produced 6 grams of lithium
chloride. What is my percent yield?
Actual
_________
Theoretical
X 100 =
17%
• 20.C3H8 + 5 O2  3 CO2 + 4 H2O
• A) If I start with 5 grams of C3H8, what is my
theoretical yield of water?
Convert 5 grams C3H8  Grams of H2O
8.2 g H2O
• B) I made 6.1 g of water. What was my percent
yield?
Actual
_________
Theoretical
X 100 =
74%
21. Be + 2 HCl  BeCl2 + H2
My theoretical yield of beryllium
chloride was 10.7 grams. If my
actual yield was 4.5 grams, what
was my percent yield?
Actual
___
Theoretical
X 100
=
42%
22. CaSO4
+
NaI

CaI2
+ Na2SO4
If 34.7 g of calcium sulfate and 58.3 g
of sodium iodide are placed in a
reaction vessel, what will be the
limiting reagent?
NaI
Note: Refer to Limiting Reagent Notes to see how to work it out.