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Unit 5 Test Review
1.
Consider the following balanced chemical equation:
2 Na + Cl2
 2 NaCl
How many molecules of NaCl will be produced from the reaction of 36 molecules of Cl2?
a. 9
b. 18
c. 36
d. 72
e. 144
2.
Consider the following balanced chemical equation:
C5H12(l) + 8 O2(g)  5 CO2(g) + 6 H2O(g)
How many moles of CO2 will be produced from the reaction of 31.6 moles of C5H12?
a. 5.27
b. 6.32
c. 31.6
d. 158
e. 190
3.
Consider the following balanced chemical equation:
2 Al + 3 CuCl2
 2 AlCl3 + 3 Cu
How many atoms of Cu will be produced from the reaction of 12 atoms of Al?
a. 6
b. 8
c. 12
d. 18
4.
e. 36
Consider the following unbalanced chemical equation:
Al + O2

Al2O3
How many molecules of Al2O3 will be produced from the reaction of 6 atoms of Al?
a. 2
b. 3
c. 6
d. 12
e. 18
5.
Determine the number of molecules of H2O that can be produced by the combustion of 2 molecules of
methane (CH4)?
a. 1
b. 2
c. 3
d. 4
e. 8
6.
Consider the synthesis of aluminum oxide from its elements. How many molecules of aluminum
oxide are produced by the reaction of 24 atoms of aluminum?
a. 6
b. 12
c. 16
d. 36
e. 48
7.
Consider the following reaction.
4 Al + 3 O2
 2 Al2O3
Pick two conversion factors that would be needed in order to determine the mass of Al that must react
to produce 19.3 mole of Al2O3. Bubble in two answers.
1 mol Al
4 mol Al
102 g Al 2 O 3
27 g Al
2 mol Al 2 O 3
a.
b.
c.
d.
e.
27 g Al
2 mol Al 2 O 3
1 mol Al 2 O 3
1 mol Al
4 mol Al
8.

Consider the following reaction.


4 Al + 3 O2
 2 Al
2O3

Pick two conversion factors that would be needed in order to determine the moles of Al that must
react to produce 276 grams of Al2O3. Bubble in two answers.
4 mol Al
1 mol Al 2 O 3
102 g Al 2 O 3
27 g Al
2 mol Al 2 O 3
a.
b.
c.
d.
e.
2 mol Al 2 O 3
102 g Al 2 O 3
1 mol Al 2 O 3
1 mol Al
4 mol Al
9.

Which method is correct for determining the mass of carbon dioxide that can be made by the
combustion of 3.219
grams of ethanol with excess oxygen?




C2H5OH(l) + 3O2(g)  2CO2(g) + 3H2O(l)
 1 mole   2 mole CO2   44.01 g CO2 
3.219 g C2 H5OH 


=
46.07 g  1 mole C2 H5OH   1 mole 

a.
 1 mole   1 mole CO2   44.01 g CO2 
3.219 g C2 H5OH 


=
46.07 g  2 mole C2 H5OH   1 mole 

b.
 1 mole   1 mole CO2   44.01 g CO2 
3.219 g C2 H5OH 


=
46.07 g  1 mole C2 H5OH   1 mole 

c.
 46.07 mole   2 mole CO2   44.01 g CO2 
3.219 g C2 H5OH 


=
1g
1 mole C2 H5OH   1 mole 


d.
 46.07 mole   1 mole CO2   44.01 g CO2 
3.219 g C2 H5OH 


=
1g
2 mole C2 H5OH   1 mole 


e.
10.
Suppose that a student wishes to solve a problem involving the determination of the mass of product
produced if a given amount of moles of reactant was reacted. Which quantities would be essential in
order to solve such a problem? Bubble in all that apply - but only those that are essential to this
calculation.
a. The molar mass of the reactant
b. The molar mass of the product
c. The coefficients of the balanced chemical equation
d. The density of the reactant
e. The density of the product
11.
Which of the following statements best describes what a limiting reactant is for any given reaction?
a. It is the reactant that is used up first while other reactants remain.
b. It is the reactant that has the highest coefficient in the balanced chemical equation.
c. It is the reactant that has the lowest coefficient in the balanced chemical equation.
d. It is the reactant that is available with the least amount of mass.
12.
The combustion of methane occurs according to the reaction
CH4 + 2 O2  CO2
+ 2 H2O
Methane and oxygen are combined in a reaction vessel in amounts of 16 grams and 32 grams
respectively. What amounts of reactants and products will be present in the reaction vessel once the
reaction is complete?
a. 0 grams CH4, 0 grams of O2, 44 grams of CO2, 36 grams of H2O
b. 8 grams CH4, 0 grams of O2, 22 grams of CO2, 18 grams of H2O
c. 0 grams CH4, 0 grams of O2, 44 grams of CO2, 18 grams of H2O
d. 8 grams CH4, 0 grams of O2, 22 grams of CO2, 9 grams of H2O
e. 0 grams CH4, 16 grams of O2, 22 grams of CO2, 10 grams of H2O
13.
Consider the reaction for the combustion of benzene (C 6H6).
2 C6H6
+
15 O2
==>
12 CO2 + 6 H2O
Suppose that 4 moles of benzene are mixed with 15 moles of oxygen. What amounts of reactants and
products will be present in the reaction vessel once the reaction is complete?
a. 0 moles C6H6, 15 moles of O2, 24 moles of CO2, 12 moles of H2O
b. 0 moles C6H6, 15 moles of O2, 12 moles of CO2, 6 moles of H2O
c. 2 moles C6H6, 0 moles of O2, 24 moles of CO2, 12 moles of H2O
d. 2 moles C6H6, 0 moles of O2, 12 moles of CO2, 6 moles of H2O
e. 2 moles C6H6, 15 moles of O2, 12 moles of CO2, 6 moles of H2O
14.
Consider the reaction for the combustion of methane (CH4).
CH4 + 2 O2  CO2
+ 2 H2O
Suppose that 4 moles of benzene are mixed with 10 moles of oxygen. Which one of the following
statements is true?
a. Methane is the limiting reactant and there is an excess of 1 mole of oxygen.
b. Methane is the limiting reactant and there is an excess of 2 moles of oxygen.
c. Oxygen is the limiting reactant and there is an excess of 1 moles of methane.
d. Oxygen is the limiting reactant and there is an excess of 2 moles of methane.
e. None of these statements are correct.
15.
Nitrogen reacts with hydrogen to produce ammonia (NH3). In a certain reaction, a chemist found that
235 g of ammonia were produced. What other piece of information would be required to determine
the percent yield?
a. the density of ammonia
b. the volume of ammonia
c. the theoretical yield of ammonia
d. the mass of excess reactant remaining
16.
A lab group performs a four-step copper cycle lab. They begin with 0.31 grams of Cu. In the final step
of the cycle, they produce 0.23 g of Cu. What percent yield has this lab group obtained?
a. 26%
b. 30.%
c. 35%
d. 74%
e. 87%
Two students perform a lab in order to experimentally
determine the mole ratio of silver to copper in a single
replacement reaction between copper and silver nitrate.
A copper wire is massed and placed in a 100 mL beaker
with a known amount of silver(I) nitrate. Once the
reaction is complete, the mass of the silver product and
the unreacted copper is determined. The following data
was collected:
Experimental Data
Mass of Cu Wire Before Reaction
Mass of Empty 100 mL Beaker
Mass of 100 mL Beaker + AgNO3
Mass of Empty 50 mL Beaker
Mass of 50 mL Beaker + Ag
Mass of Cu Wire After Reaction
1.86 g
52.85 g
59.08 g
31.92 g
35.74 g
0.71 g
17.
Determine the mass and the number of moles of copper that reacted in this experiment, accurate to
three significant figures. PSYW
18.
Determine the mass and the number of moles of silver produced by this reaction, accurate to three
significant figures. PSYW
19.
Determine the experimental mole ratio of silver to copper (mol Ag/mol Cu), accurate to at least two
decimal places. PSYW