Stoichiometry
Name:
1.
2.
3.
Date:
Element A and element B chemically combine to
form substance C. Substance C must be
A.
a solution
B.
C.
an element
D. a mixture
5.
a compound
ammonia
B.
C.
iron
D. helium
4.
2
C.
B.
4.
C.
2N2 H4 + N2 O4 ! 3N2 + 4H2 O
3
8.
NH3 (g) +
N2 (g) +
O2 (g) !
H2 O(g)
2.
B.
3.
C.
4.
D. 6.
When methane (CH4 ) gas is burned in the presence
of oxygen, the following chemical reaction occurs.
CH4 + 2O2 ! CO2 + 2H2 O
If 1 mole of methane reacts with 2 moles of
oxygen, then
D. 4
This chemical equation represents the combustion
of propane. When correctly balanced, the
coecient for water is
2.
C.
A.
C3 H8 + O2 ! CO2 + H2 O
A.
2N2 H4 + N2 O4 ! 2N2 + 4H2 O
When the reaction above is completely balanced,
the coecient for NH3 will be
Which equation shows that the total mass during a
chemical reaction stays the same?
B.
B.
6.
7.
1
N2 H4 + N2 O4 ! N2 + H2 O
argon
The following equations represent chemical
reactions.
A.
A.
D. 2N2 H4 + 3N2 O4 ! 5N2 + 6H2 O
Which substance can be decomposed by a chemical
change?
A.
Hydrazine, N2 H4 , and dinitrogen tetroxide, N2 O4 ,
react to form gaseous nitrogen and water. Which
of these represents a properly balanced equation
for this reaction?
A.
6.02  1023 molecules of CO2 and 6.02  1023
molecules of H2 O are produced.
B.
1.2  1024 molecules of CO2 and 1.2  1024
molecules of H2 O are produced.
C.
6.02  1023 molecules of CO2 and 1.2  1024
molecules of H2 O are produced.
D. 1.2  1024 molecules of CO2 and 6.02  1023
molecules of H2 O are produced.
D. 16.
page 1
8.
In the reaction of solid zinc with hydrochloric acid
(HCl), the products of hydrogen gas and aqueous
zinc chloride are produced.
10.
Which of these is the balanced equation from the
reaction?
A.
Zn(s) + HCl(aq) ! ZnCl2 (aq) + H(g)
B.
2Zn(s) + 4HCl(aq) ! Zn2Cl4 (aq) + H2 (g)
C.
Zn(s) + 2HCl(aq) ! ZnCl2 (aq) + H2 (g)
The law of conservation of mass can be
demonstrated by a chemical reaction. Which of
the following models of a chemical reaction best
represents the law of conservation of mass?
A.
B.
D. Zn2 (s) + HCl(aq) ! 2ZnCl(aq) + H2 (g)
C.
D.
9.
The tires on most cars are not made of natural
rubber because it becomes brittle in the cold
and sticky in the heat. Instead, natural rubber
is vulcanized by adding sulfur and heat, making
it stronger and more elastic. This process is
represented chemically in the diagram below.
The complete combustion or burning of natural
rubber will produce
.
A.
hydrogen and oxygen
B.
oxygen and water
C.
hydrogen gas and water
D. carbon dioxide and water.
page 2
Stoichiometry
11.
Students in a biology laboratory are monitoring
the rate at which hydrogen peroxide breaks down
to produce water and oxygen gas. They begin
monitoring a sample of hydrogen peroxide and
then add catalase, an enzyme that speeds up its
breakdown. Their data are shown in the table
below.
Time
(min)
0.0
13.
Pb(NO3 )2 +
PbCrO4 +
0
0.030
1.5
4,970,000
2.5
4,985,300
1.0
2.0
3.0
A.
2, 4, 4, 6
B.
2, 4, 4, 3
C.
1, 1, 1, 2
D. 1, 6, 6, 2
0.032
5,001,000
5,021,700
14.
Based on the data in this table, during which of
the following time periods did the students add the
catalase to the hydrogen peroxide?
A.
between 0.0 and 0.5 min
B.
between 1.0 and 1.5 min
C.
between 2.0 and 2.5 min
A.
15.
Fe + CuSO4 ! FeSO4 + Cu
What type of reaction is shown above?
decomposition
B.
synthesis
C.
single displacement
K2 CO3 + 3H2 O
When this equation is balanced, what is the
coecient for potassium carbonate?
Copper in the compound CuSO4 can be isolated
in the following reaction with iron.
A.
Potassium carbonate (K2 CO3 ) is an important
component of fertilizer. The partially balanced
equation for the reaction of 6 moles of potassium
hydroxide (KOH) and 3 moles of carbon dioxide
(CO2 ) to produce potassium carbonate and water
is given below.
6KOH + 3CO2 !
D. between 2.5 and 3.0 min
12.
K2CrO4 !
KNO3
Which coecients are needed to balance this
equation?
Rate of Hydrogen
Peroxide Breakdown
(molecules per min)
0.5
An unbalanced chemical equation is shown below.
2
B.
3
C.
6
D. 9
Aluminum reacts vigorously and exothermically
with copper(II) chloride. Which of the following
is the balanced equation for this reaction?
A.
Al + CuCl2 ! AlCl3 + Cu
B.
Al + 3CuCl2 ! 2AlCl3 + Cu
C.
2Al + 3CuCl2 ! 2AlCl3 + 3Cu
D. 3Al + 2CuCl2 ! 3AlCl3 + 2Cu
D. double displacement
page 3
Stoichiometry
16.
Which of the following represents a double
displacement reaction?
A.
ABC ! AB + C
B.
A + B ! AB
C.
AB + CD ! AD + CB
19.
Butane (C4 H10 ) is used as the fuel in many
portable lighters. When butane is completely
combusted in oxygen, what is the coecient
for the water produced in the properly balanced
equation that represents the reaction?
A.
10
B.
8
C.
6
D. 4
D. A + BC ! AC + B
20.
17.
Which of the following chemical reactions is a
decomposition reaction?
A.
BaCO3 ! BaO + CO2
B.
2Ca + O2 ! 2CaO
C.
3Br2 + 2FeI3 .2FeBr3 + 3I2
21.
D. MgCl2 + H2 SO4 .MgSO4 + 2HCl
18.
The figure below represents a reaction.
22.
What type of reaction is shown?
A.
synthesis
B.
decomposition
C.
single displacement
23.
D. double displacement
Which pair of formulas represents the empirical
formula and the molecular formula of a compound?
A.
CH2 O, C4 H6 O4
B.
C.
CH4 , C5 H12
D. CH2 , C3 H6
A compound contains 40% calcium, 12% carbon,
and 48% oxygen by mass. What is the empirical
formula of this compound?
A.
CaCO3
B.
C.
CaC3 O6
D. CaCO2
CaC2 O4
Which formulas could represent the empirical
formula and the molecular formula of a given
compound?
A.
CH2 O, C4 H6 O4
B.
C.
CH4 , C5 H12
D. CH2 , C3 H6
CHO, C6 H12 O6
A compound has an empirical formula of CH2 and
a molecular mass of 56. Its molecular formula is
A.
page 4
CHO, C6 H12 O6
C2 H4
B.
C3 H6
C.
C 4 H8
D. C5 H10
Stoichiometry
24.
What is the molecular formula of a compound
with an empirical formula of CH and a molecular
mass of 78?
A.
C6 H6
B.
C4 H10
C.
C2 H2
28.
The accompanying table shows the data collected
during the heating of a 10.0-gram sample of a
hydrated salt.
D. CH
Heating Time
(min)
Mass of Salt
(g)
4.0
9.2
0.0
10.0
8.0
8.6
12.0
8.0
20.0
8.0
30.0
25.
The percent by mass of nitrogen in Mg(CN)2 is
equal to
A.
14
 100
76
B.
14
 100
50
C.
28
 100
76
D.
28
 100
50
What is the percent of water in the original
sample?
A.
29.
26.
What is the empirical formula of a compound
whose composition by mass is 40% sulfur and
60% oxygen?
A.
SO2
B.
SO3
C.
S 2 O3
A compound consists of 46.7% nitrogen and
53.3% oxygen by mass. What is its empirical
formula?
A.
NO
B.
NO2
C.
N2 O
10%
B.
20%
C.
60%
D. 80%
A sample of a substance containing only
magnesium and chlorine was tested in the
laboratory and was found to be composed of
74.5% chlorine by mass. If the total mass of the
sample was 190.2 grams, what was the mass of
the magnesium?
A.
D. S2 O7
30.
27.
8.0
24.3 g
B.
48.5 g
C.
70.9 g
D. 142 g
Given the reaction:
Ca + 2H2 O ! Ca(OH)2 + H2 .
How many moles of H2 O are needed to exactly
react with 2.0 moles of Ca?
D. N2 O3
A.
page 5
1.0
B.
2.0
C.
0.50
D. 4.0
Stoichiometry
31.
Given the equation:
33.
Given the reaction:
Zn + 2HCl ! ZnCl2 + H2
32.
Mg + 2HCl ! MgCl2 + H2
How many moles of HCl would be required to
produce a total of 2 moles of H2 ?
What is the total number of grams of Mg
consumed when 0.50 mole of H2 is produced?
A.
A.
0.5
B.
2
C.
3
D. 4
34.
Given the equation:
6.0 g
B.
B.
2
C.
8
3.0 g
D. 24 g
2H2 + O2 ! 2H2 O
How many moles of carbon dioxide are produced
for each mole of butane consumed?
1
C.
Given the balanced equation representing a
reaction:
2C4 H10 + 13O2 ! 8CO2 + 10H2 O
A.
12 g
What is the total mass of water formed when
8 grams of hydrogen reacts completely with
64 grams of oxygen?
D. 4
A.
page 6
18 g
B.
36 g
C.
56 g
D. 72 g
Stoichiometry
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Stoichiometry
03/20/2014
1.
Answer:
B
21.
Answer:
A
2.
Answer:
A
22.
Answer:
D
3.
Answer:
C
23.
Answer:
C
4.
Answer:
B
24.
Answer:
A
5.
Answer:
C
25.
Answer:
C
6.
Answer:
A
26.
Answer:
B
7.
Answer:
C
27.
Answer:
A
8.
Answer:
C
28.
Answer:
B
9.
Answer:
D
29.
Answer:
B
10.
Answer:
A
30.
Answer:
D
11.
Answer:
B
31.
Answer:
D
12.
Answer:
C
32.
Answer:
D
13.
Answer:
C
33.
Answer:
B
14.
Answer:
B
34.
Answer:
D
15.
Answer:
C
16.
Answer:
C
17.
Answer:
A
18.
Answer:
A
19.
Answer:
A
20.
Answer:
D