Intro stoichiometry
Name:
1.
2.
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
C.
CaC3 O6
NaNH
B.
Na2 NH
C.
NaNH2
CH
B.
CH2
C.
CH3
P 2 O5
B.
N2 O4
C.
C 3 H6
CaCO3
B.
CaC2 O4
C.
CaC3 O6
page 1
3.
D. Na(NH)2
4.
D. CH4
5.
D. C6 H12 O6
A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What
is the empirical formula of this compound?
A.
2.
D. CaCO2
Which represents both an empirical and a molecular formula?
A.
6.
CaC2 O4
A compound is 92.3% carbon and 7.7% hydrogen. The empirical formula of this
compound is
A.
5.
B.
A compound contains 0.5 mole of sodium, 0.5 mole of nitrogen, and 1.0 mole of
hydrogen. The empirical formula of the compound is
A.
4.
CaCO3
1.
CHO, C6 H12 O6
A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What
is the empirical formula of this compound?
A.
3.
Date:
D. CaCO2
6.
Intro stoichiometry
7.
The molecular mass of a compound of carbon and hydrogen is 42. Its empirical
formula is
A.
8.
CH2
C.
CH3
D. CH4
CH
B.
CH2
C.
CH3
SO
B.
SO2
C.
SO3
8.
D. CH4
A compound contains 57% sulfur and 43% oxygen by mass. What is the empirical
formula of this compound?
A.
10.
B.
A compound consists of 85.7% carbon and 14.3% hydrogen by mass. Its empirical
formula is
A.
9.
CH
7.
9.
D. S2 O3
The empirical formula of a compound is CH2 . Which molecular formula is
correctly paired with a structural formula for this compound?
A.
C2 H4
B.
C.
C2 H4
D. C3 H8
E.
C3 H8
C 2 H4
page 2
10.
Intro stoichiometry
11.
Given two formulas representing the same compound:
Formula A
CH3
11.
Formula B
C 2 H6
Which statement describes these formulas?
A.
Formulas A and B are both empirical.
B.
Formulas A and B are both molecular.
C.
Formula A is empirical, and formula B is molecular.
D. Formula A is molecular, and formula B is empirical.
12.
The percent by mass of oxygen in CO is approximately
A.
13.
57%
C.
43%
D. 17%
5.9%
B.
17.6%
C.
21.4%
13.
D. 82.4%
14.
The percent by mass of nitrogen in Mg(CN)2 is equal to
A.
15.
B.
What is the percent by mass of hydrogen in NH3 (formula mass = 17:0)?
A.
14.
73%
12.
14
76
100
B.
14
50
100
C.
28
76
100
D.
28
50
100
The percent by mass of carbon in CO2 (g) is equal to
A.
44
12
100
B.
12
44
100
C.
28
12
100
page 3
15.
D.
12
28
100
Intro stoichiometry
16.
The percent by mass of aluminum in Al2 O3 is approximately
A.
17.
47.1
D. 52.9
8.0
B.
16
C.
17.
32
D. 64
1.7%
B.
5.0%
C.
6.7%
20
B.
33
C.
50
192 g
B.
112 g
C.
3.69%
B.
16.8%
C.
19.
D. 67
64.0 g
20.
D. 48.0 g
A hydrated salt is a solid that includes water molecules within its crystal structure.
A student heated a 9.10-gram sample of a hydrated salt to a constant mass of
5.41 grams. What percent by mass of water did the salt contain?
A.
18.
D. 7.1%
What is the total mass of oxygen in 1.00 mole of Al2 (CrO4 )3 ?
A.
21.
C.
A 1.20-gram sample of hydrated salt is heated to a constant mass of 0.80 gram.
What was the percent by mass of water contained in the original sample?
A.
20.
35.4
What is the percent by mass of hydrogen in CH3 COOH (formula mass = 60)?
A.
19.
B.
The percent by mass of nitrogen in N2 O is
A.
18.
18.9
16.
40.5%
page 4
D. 59.5%
21.
Intro stoichiometry
22.
What is the percent by mass of oxygen in propanal, CH3 CH2 CHO?
A.
23.
25.
B.
27.6%
C.
38.1%
D. 62.1%
The percent composition by mass of magnesium in MgBr2 (gram-formula mass =
184 grams/mole) is equal to
A.
24.
10.0%
22.
24
184
100
B.
160:
184
100
C.
184
24
100
D.
184
160:
23.
100
Which equation represents a substitution reaction?
24.
A.
C2 H4 + H2 ! C2 H6
B.
CH4 + 2O2 ! CO2 + 2H2 O
C.
C3 H8 + Cl2 ! C3 H7 Cl + HCl
D. C4 H8 + Br2 ! C4 H8 Br2
Given the reaction:
25.
2X + Cr2 O3 ! X2 O3 + 2Cr
The metal represented by X in the equation could be
A.
26.
Pb
B.
Sn
C.
Ni
D. Al
In the balanced equation:
26.
+
H3 PO4 (aq) + NH3 (aq) (
+ X(aq) + NH4 (aq),
the particle represented by X(aq) is
A.
H2 PO4 (aq)
B.
HPO4 2 (aq)
C.
PO4 3 (aq)
page 5
D. H3 PO4 (aq)
Intro stoichiometry
27.
Given the reaction:
27.
C2 H2 + 2H2 ! C2 H6
This reaction represents
A.
28.
29.
substitution
B.
addition
C.
esteri cation
D. saponi cation
Which equation represents a double replacement reaction?
A.
2 Na + 2 H2 O ! 2 NaOH + H2
B.
C.
LiOH + HCl ! LiCl + H2 O
D. CH4 + 2 O2 ! CO2 + 2 H2 O
28.
CaCO3 ! CaO + CO2
Given the reaction:
29.
Mg(s) + 2AgNO3 (aq) ! Mg(NO3 )2 (aq) + 2Ag(s)
Which type of reaction is represented?
30.
A.
single replacement
B.
double replacement
C.
synthesis
D. decomposition
Base your answer(s) to the following question(s) on the balanced chemical equation
below.
2H2 O ! 2H2 + O2
What type of reaction does this equation represent?
page 6
30.
Intro stoichiometry
31.
Base your answer(s) to the following question(s) on the information below.
31.
Given the reaction between 1-butene and chlorine gas:
C4 H8 + Cl2 ! C4 H8 Cl2
Which type of chemical reaction is represented by this equation?
32.
Given the balanced equation:
32.
AgNO3 (aq) + NaCl(aq) ! NaNO3 (aq) + AgCl(s)
This reaction is classi ed as
33.
A.
synthesis
B.
decomposition
C.
single replacement
D. double replacement
Given the balanced equation:
33.
2KClO3 ! 2KCl + 3O2
Which type of reaction is represented by this equation?
34.
A.
synthesis
B.
decomposition
C.
single replacement
D. double replacement
Given the incomplete equation for the combustion of ethane:
34.
2C2 H6 + 7O2 ! 4CO2 + 6
What is the formula of the missing product?
A.
CH3 OH
B.
HCOOH
C.
H2 O
page 7
D. H2 O2
Intro stoichiometry
35.
Which list includes three types of chemical reactions?
A.
condensation, double replacement, and sublimation
B.
condensation, solidi cation, and synthesis
C.
decomposition, double replacement, and synthesis
35.
D. decomposition, solidi cation, and sublimation
36.
Given the balanced equation representing a reaction:
H2 SO4 (aq) + 2KOH(aq) ! K2 SO4 (aq) + 2H2 O(`)
Which type of reaction is represented by this equation?
A.
decomposition
B.
neutralization
C.
single replacement
D. synthesis
page 8
36.
Intro stoichiometry
37.
Base your answer(s) to the following question(s) on the information below.
In a laboratory, 0.100 mole of colorless hydrogen iodide gas at room
temperature is placed in a 1.00-liter ask. The ask is sealed and warmed,
causing the HI(g) to start decomposing to H2 (g) and I2 (g). Then the
temperature of the contents of the ask is kept constant.
During this reaction, the contents of the ask change to a pale
purple-colored mixture of HI(g), H2 (g), and I2 (g). When the color of the
mixture in the ask stops changing, the concentration of I2 (g) is determined
to be 0.013 mole per liter. The relationship between concentration and time
for the reactant and products is shown in the graph below.
Write a balanced equation to represent the decomposition reaction occurring in the
ask.
page 9
37.
Intro stoichiometry
38.
Given the balanced particle-diagram equation:
38.
Which statement describes the type of change and the chemical properties of the
product and reactants?
A.
The equation represents a physical change, with the product and reactants
having di erent chemical properties.
B.
The equation represents a physical change, with the product and reactants
having identical chemical properties.
C.
The equation represents a chemical change, with the product and reactants
having di erent chemical properties.
D. The equation represents a chemical change, with the product and reactants
having identical chemical properties.
39.
Which balanced equation represents a single-replacement reaction?
A.
Mg + 2AgNO3 ! Mg(NO3 )2 + 2Ag
B.
2Mg + O2 ! 2MgO
C.
MgCO3 ! MgO + CO2
39.
D. MgCl2 + 2AgNO3 ! 2AgCl + Mg(NO3 )2
40.
What is the mass in grams of 1.00 mole of O2 gas?
A.
11.2
B.
16.0
C.
22.4
page 10
40.
D. 32.0
Intro stoichiometry
41.
The gram molecular mass of Ca3 (PO4 )2 is
A.
42.
B.
279 g
C.
310 g
D. 342 g
What is the gram molecular mass of calcium nitrate, Ca(NO3 )2 ?
A.
43.
246 g
41.
164 g
B.
150 g
C.
102 g
D. 70.0 g
What is the gram molecular mass of 1 mole of C3 H5 (OH)3 ?
A.
48 g
B.
58 g
C.
74 g
43.
D. 92 g
44. Which substance has the greatest molecular mass?
A.
45.
NO
C.
CF4
D. I2
29 g
B.
34 g
C.
45.
57 g
D. 74 g
What is the gram formula mass of Ca3 (PO4 )2 ?
A.
47.
B.
44.
What is the gram formula mass of Ca(OH)2 ?
A.
46.
H2 O2
196 g
B.
214 g
C.
46.
245 g
D. 310. g
One mole of O2 has approximately the same mass as one mole of
A.
CH4
B.
S
C.
42.
LiH
page 11
D. Cl2
47.
Intro stoichiometry
48.
The gram-formula mass of (NH4 )2 CO3 is
A.
49.
46.0 g
B.
64.0 g
48.
C.
78.0 g
D. 96.0 g
The gram formula mass of NH4 Cl is
A.
22.4 g/mole
B.
28.0 g/mole
49.
C.
53.5 g/mole
D. 95.5 g/mole
50.
Show a correct numerical setup for calculating the formula mass of glucose,
C6 H12 O6 .
50.
51.
What is the percent composition by mass of sulfur in the compound MgSO4
(gram-formula mass = 120. grams per mole)?
51.
A.
52.
B.
27%
C.
46%
D. 53%
What is the total number of moles of hydrogen in 1 mole of (NH4 )2 HPO4 ?
A.
53.
20.%
5
B.
7
C.
8
D. 9
What is the percent by mass of oxygen in magnesium oxide, MgO ?
A.
20%
B.
40%
C.
52.
50%
page 12
D. 60%
53.
Intro stoichiometry
54.
Given the unbalanced equation:
54.
Al2 (SO4 )3 + Ca(OH)2 ! Al(OH)3 + CaSO4
What is the coe cient in front of the CaSO4 when the equation is completely
balanced with the smallest whole-number coe cients?
A.
55.
1
B.
2
C.
3
D. 4
Given the unbalanced equation
55.
Cr0 + Sn2+ ! Cr3+ + Sn0
What is the coe cient in front of the Cr3+ when the equation is balanced using
smallest whole-number coe cients?
A.
56.
B.
2
C.
3
D. 6
When the equation H2 O2 ! H2 O + O2 is completely balanced, the sum of all the
coe cients will be
A.
57.
1
5
B.
8
C.
3
D. 4
Given the unbalanced equation:
+
What is the coe cient in front of the Cl
balanced using whole numbers?
A.
1
B.
57.
Cl ! 2Mn2 + 8H2 O +
2MnO4 + 16H+ +
2
56.
Cl2
when the equation is completely
C.
5
D. 10
page 13
Intro stoichiometry
58.
Given the reaction:
Fe3+ +
58.
Sn2+ !
Fe2+ +
Sn4+
When the reaction is completely balanced using smallest whole numbers the
coe cient of Fe3+ will be
A.
59.
B.
2
C.
3
D. 4
When the equation NH3 + O2 ! N2 + H2 0 is completely balanced using the
smallest whole numbers, the coe cient of the O2 will be
A.
60.
1
1
B.
2
C.
3
D. 4
Given the unbalanced equation:
60.
Ca0 + Al3+ ! Ca2+ + Al0
When the equation is completely balanced with the smallest whole-number
coe cients, what is the coe cient of Ca0 ?
A.
1
B.
2
59.
C.
3
D. 4
page 14
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Intro stoichiometry
02/04/2013
1.
Answer:
D
21.
Answer:
C
2.
Answer:
A
22.
Answer:
B
3.
Answer:
C
23.
Answer:
A
4.
Answer:
A
24.
Answer:
C
5.
Answer:
A
25.
Answer:
D
6.
Answer:
A
7.
Answer:
26.
Answer:
A
B
8.
Answer:
27.
Answer:
B
B
9.
Answer:
28.
Answer:
C
D
10.
Answer:
29.
Answer:
A
C
11.
Answer:
30.
Answer:
C
12.
Answer:
B
13.
Answer:
B
14.
Answer:
32.
Answer:
D
C
15.
Answer:
33.
Answer:
B
B
16.
Answer:
34.
Answer:
C
D
17.
Answer:
35.
Answer:
C
D
18.
Answer:
36.
Answer:
B
C
19.
Answer:
B
37.
Answer:
20.
Answer:
A
31.
Answer:
decomposition, analysis, redox,
endothermic, electrolysis
Acceptable answers include addition,
chlorination, halogenation, redox, and
synthesis.
Acceptable answers but not limited to:
2HI(g) ! H2 (g) + I2 (g) 2HI ! I2 + H2
Teacher's Key
38.
Answer:
C
39.
Answer:
A
40.
Answer:
D
41.
Answer:
C
42.
Answer:
A
43.
Answer:
D
44.
Answer:
D
45.
Answer:
D
46.
Answer:
D
47.
Answer:
B
48.
Answer:
D
49.
Answer:
C
50.
Answer:
6(12:0) + 12(1:0) + 6(16:0)
51.
Answer:
B
52.
Answer:
D
53.
Answer:
B
54.
Answer:
C
55.
Answer:
B
56.
Answer:
A
57.
Answer:
D
58.
Answer:
B
59.
Answer:
C
60.
Answer:
C
Page 2