Chapter 3 2 A sample containing only carbon, hydrogen, phosphorus

Test Bank General Chemistry, 10th edition 21

79. A sample containing only carbon, hydrogen, phosphorus, and oxygen is subjected to

elemental analysis. After complete combustion, a 0.4946-g sample of the compound yields

0.7092 g of CO2, 0.4355 g of H2O, and 0.3812 g of P4O10. What is the empirical formula of

the compound?

A)

CH3PO

B)

C2H3PO

C)

C2H6P2O4

D)

C3H9PO

E)

CH2P4O13

80. A sample containing only carbon, hydrogen, and silicon is subjected to elemental analysis.

After complete combustion, a 0.1099-g sample of the compound yields 0.2193 g of CO2,

0.1346 g of H2O, and 0.07485 g of SiO2. What is the empirical formula of the compound?

A)

CH3Si

B)

C2H4Si

C)

C4H12Si

D)

C6H12Si2

E)

CH2Si

81. Of the following, the only empirical formula is

A)

C4H10.

B)

C4H6.

C)

C5H14.

D)

H2O2.

E)

O2.

82. Which of the following is the empirical formula for the molecule below?

A)

CHO

B)

CH3COOH

C)

C2H4O2

D)

CH2O

E)

none of the above.

83. Analysis of a compound showed that it contained 76.0 % fluorine atoms and 24.0 % carbon

atoms by mass. What is its empirical formula?

A)

CF2

B)

C2F3

C)

CF3

D)

C2F5

E)

CF

84. A sample of an oxide of antimony (Sb) contained 39.5 g of antimony combined with 13.0 g

of oxygen. What is the simplest formula for the oxide?

A)

SbO2

B)

SbO

C)

Sb2O3

D)

Sb2O

E)

Sb2O5

85. Chlorine was passed over 1.30 g of heated titanium, and 4.20 g of a chloride-containing

compound of Ti was obtained. What is the empirical formula of the chloride-containing

compound?

A)

TiCl2

B)

TiCl4

C)

TiCl

D)

TiCl3

E)

Ti2Cl3

86. A 2.39-g sample of an oxide of chromium contains 1.48 g of chromium. Calculate the

simplest formula for the compound.

A)

CrO5

B)

Cr2O

C)

CrO2

D)

CrO

E)

Cr2O3

87. A compound is composed of only C and H. It contains 92.26 % C. What is its empirical

formula?

A)

C2H5

B)

C2H3

C)

C3H4

D)

CH

E)

CH2

88. A compound composed of only C and F contains 17.39 % C by mass. What is its empirical

formula?

A)

CF3

B)

CF

C)

C2F

D)

CF4

E)

CF2

89. A hydrocarbon, subjected to elemental analysis, was found to contain 85.63 % carbon and

14.37 % hydrogen by mass. What is the empirical formula of the hydrocarbon?

A)

CH4

B)

C2H4

C)

C6H

D)

C10H

E)

CH2

Test Bank General Chemistry, 10th edition 24

90. A particular compound contains, by mass, 41.4 % carbon, 3.47 % hydrogen, and 55.1 %

oxygen. A 0.050-mol sample of this compound weighs 5.80 g. The molecular formula of

this compound is

A)

C3H3O3.

B)

C3H3O.

C)

CHO.

D)

C4H4O4.

E)

C5H5O5.

91. What is the empirical formula of an oxide of nitrogen that contains 25.93 % nitrogen by

mass?

A)

NO2

B)

N2O

C)

N2O3

D)

NO

E)

N2O5

92. The analysis of an organic compound showed that it contained 1.386 mol of C, 0.0660 mol

of H, 0.924 mol of O, and 0.462 mol of N. How many nitrogen atoms are there in the

empirical formula for this compound?

A)

9

B)

7

C)

2

D)

4

E)

3

93. A sample containing 0.700 mol of a compound is composed of 4.21  1023 atoms of sodium,

24.79 g of chlorine atoms, and 33.57 g of oxygen atoms. The formula of the compound is

A)

NaClO3.

B)

NaClO5.

C)

NaClO.

D)

NaClO4.

E)

NaClO2.

Test Bank General Chemistry, 10th edition 25

94. The analysis of an organic compound showed that it contained 0.0700 mol of C, 0.175 mol

of H, and 0.0350 mol of N. Its molecular mass is 86 amu. How many atoms of carbon are

there in the empirical formula for the compound, and how many are in the molecular

formula?

A)

empirical = 2, molecular = 3

B)

empirical = 2, molecular = 6

C)

empirical = 2, molecular = 4

D)

empirical = 5, molecular = 10

E)

empirical = 3, molecular = 3

95. A given hydrocarbon is burned in the presence of oxygen gas and is converted completely to

water and carbon dioxide. The mole ratio of H2O to CO2 is 1.33:1.00. The hydrocarbon

could be

A)

C2H2.

B)

C2H6.

C)

CH4.

D)

C3H4.

E)

C3H8.

96. A given hydrocarbon is burned in the presence of oxygen gas and is converted completely to

carbon dioxide and water. Equal numbers of moles of CO2 and H2O are produced. The

hydrocarbon could be

A)

C3H4.

B)

C5H10.

C)

C2H3.

D)

CH3.

E)

C3H5.

97. An organic compound that has the empirical formula CHO has a molecular mass of 145

amu. Its molecular formula is

A)

C9H9O9.

B)

C4H4O4.

C)

C3H3O3.

D)

C5H5O5.

E)

C12H12O12.

98. A certain compound has a molar mass of 210 g/mol. Which is a possible empirical formula

for this compound?

A)

CH2O

B)

CHO

C)

C2H2O2

D)

C2HO

E)

C2H2O

99. The empirical formula for a group of compounds is CHCl. Lindane, a powerful insecticide,

is a member of this group. The molar mass of lindane is 290.8. How many atoms of carbon

does a molecule of lindane contain?

A)

3

B)

2

C)

4

D)

6

E)

8

100. The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the

molecular formula of styrene?

A)

C6H6

B)

C2H4

C)

C8H8

D)

C10H12

E)

none of these

Test Bank General Chemistry, 10th edition 27

101. The empirical formula of styrene is CH. An experimental determination of the molar mass

of styrene by a student yields the value of 104 g/mol. What is the molecular formula of

styrene?

A)

C5H10

B)

CH

C)

C8H8

D)

C3H8

E)

C6H9

102. An organic compound has a molecular mass of 279.2 amu and contains 85.96% carbon by

mass. How many carbon atoms are in each molecule of this compound?

A)

16

B)

21

C)

25

D)

29

E)

20

103. An unknown organic compound contains 41.4 % carbon, 3.47 % hydrogen, and 55.1 %

oxygen by mass. A 0.040-mol sample of this compound weighs 3.48 g. What is the

molecular formula of the organic compound?

A)

C3H3O

B)

C2H2O2

C)

C3H3O3

D)

C7H7O7

E)

CHO

104. A compound is composed of only C and I. It contains 5.935 % C by mass and has a molar

mass of 809.44 g/mol. What is its molecular formula?

A)

CI

B)

C4I6

C)

C3I4

D)

C2I2

E)

C2I3

105. An organic compound has a molar mass of 171.1 g/mol and contains 11.10 % hydrogen

atoms by mass. How many hydrogen atoms are in each molecule of this compound?

A)

19

B)

6

C)

21

D)

28

E)

11

106. A compound has a molar mass of 171.6 g/mol and contains 55.94 % oxygen atoms by mass.

How many oxygen atoms are in each molecule of this compound?

A)

6

B)

4

C)

10

D)

2

E)

8

107. A compound contains 43.84 % carbon atoms, 3.65 % hydrogen atoms, and 8.68 % fluorine

atoms by mass. Each molecule of this compound contains one fluorine atom. What is the

total number of carbon, hydrogen, and fluorine atoms in one molecule of this compound?

A)

17

B)

12

C)

9

D)

7

E)

14

108. A molecular compound contains 92.3 % carbon and 7.7 % hydrogen by mass. If 0.432 mol

of the compound weighs 22.46 g, what is its molecular formula?

A)

C8H8

B)

C6H10

C)

C4H8

D)

C4H4

E)

CH

109. Analysis of a compound containing only C and Br revealed that it contains 33.33 % C atoms

by number and has a molar mass of 515.46 g/mol. What is the molecular formula of this

compound?

A)

CBr2

B)

C2Br6

C)

C2Br4

D)

CBr3

E)

C3Br6

110. Complete combustion of a 0.30-mol sample of a hydrocarbon, CxHy, gives 1.20 mol of CO2

and 1.50 mol of H2O. The molecular formula of the original hydrocarbon is

A)

C3H8.

B)

C4H10.

C)

C8H20.

D)

C3H5.

E)

C5H7.

Test Bank General Chemistry, 10th edition 30

I. II. III. IV.

A)

I only

B)

III only

C)

II only

D)

Both I and IV

E)

IV only

112. The balanced chemical equation for the combustion of methane is:

CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)

Which of the following statements concerning this chemical equation is/are correct?

1.

One gram of methane gas reacts with two grams of dioxygen gas, producing

one gram of carbon dioxide gas and two grams of gaseous water.

2.

One mole of methane gas reacts with two moles of dioxygen gas, producing

one mole of carbon dioxide gas and two moles of gaseous water.

3.

One molecule of methane gas reacts with two molecules of dioxygen gas,

producing one molecule of carbon dioxide gas and two molecules of gaseous

water.

A)

1 only

B)

2 only

C)

2 and 3

D)

1 and 3

E)

1,2 and 3

113. Balance the following expression:

__ CH3CH2COOH + __ O2 → __ CO2 + __ H2O

How many moles of O2 are required for the complete combustion of 8 mol of propanoic

acid?

A)

5 mol

B)

30 mol

Test Bank General Chemistry, 10th edition 31

C)

28 mol

D)

37 mol

E)

2 mol

114. The products of the combustion of acetone with oxygen are shown in the following

equation:

__ CH3COCH3 + __ O2 → __ CO2 + __ H2O

When properly balanced, the equation indicates that ____ mol of CO2 are produced for each

mole of CH3COCH3.

A)

3

B)

5

C)

4.5

D)

8

E)

1

115. Ammonia, NH3, and oxygen can be reacted together in the presence of a catalyst to form

only nitrogen monoxide and water. The number of moles of oxygen consumed for every

5.00 moles of NO produced is .

A)

6.25

B)

25.0

C)

18.8

D)

3.13

E)

12.5

KEY: molar interpretation MSC: general chemistry

116. 2KHCO3(s) → K2CO3(s) + CO2(g) + H2O(l)

How many moles of potassium carbonate will be produced if 454 g of potassium hydrogen

carbonate are heated?

A)

2.27 mol

B)

3.29 mol

C)

11.4 mol

D)

227 mol