AP Chemistry
Name___________________________
Chapter 9 Molecular Geometry PRACTICE TEST
Date_________
SECTION I: Multiple Choice (Time: 1.5 minutes allotted per question). Select the best answer for each
question. You need not show any work. Calculators are not permitted on this section of the test.
Practice estimating to find the best answer.
1.
Which of the following molecules contains a central atom with sp2 hybridization?
a)
b)
c)
d)
e)
Ans: b
2.
Chapter/Section: 9.1
Difficulty: Easy
Which of the following does not contain at least one pi bond?
a)
HCN
b)
O3
c)
C2H4
d)
C3H8
e)
All of the above (A-D) contain at least one pi bond.
Ans: d
3.
Algorithm: No
Algorithm: Yes
Chapter/Section: 9.1
Difficulty: Moderate
Which statement about N2 is false?
a)
It is a gas at room temperature.
b)
The oxidation state is +3 on one N and –3 on the other.
c)
It has one sigma and two pi bonds between the two atoms.
d)
It can combine with H2 to form NH3.
e)
It has two pairs of nonbonding electrons.
Ans: b
Algorithm: No
Chapter/Section: 9.1
Tetracyanoethylene has the skeleton shown below:
Difficulty: Easy
From its Lewis structure determine the following:
4.
How many sigma and pi bonds are in the molecule?
a)
4 sigma and 5 pi
b)
6 sigma and 8 pi
c)
9 sigma and 8 pi
d)
9 sigma and 9 pi
e)
5 sigma and 8 pi
Ans: d
5.
Difficulty: Moderate
Algorithm: No
Chapter/Section: 9.1
Difficulty: Moderate
In which of the compounds below is there more than one kind of hybridization (sp, sp2, sp3) for carbon?
I.
CH3CH2CH2CH3
II.
CH3CH = CHCH3
III.
CH2 = CH  CH = CH2
IV.
H CC  H
a)
b)
c)
d)
e)
Ans: b
7.
Chapter/Section: 9.1
How many nonbonded electron pairs are in the molecule?
a)
0
b)
2
c)
4
d)
5
e)
8
Ans: c
6.
Algorithm: No
II and III
II only
III and IV
I, II, and III
III only
Algorithm: No
Chapter/Section: 9.1
Difficulty: Easy
A  (pi) bond is the result of the
a)
overlap of two s orbitals
b)
overlap of an s orbital and a p orbital
c)
overlap of two p orbitals along their axes
d)
sidewise overlap of two parallel p orbitals
e)
sidewise overlap of two s orbitals
Ans: d
Algorithm: No
Chapter/Section: 9.1
Difficulty: Easy
8.
In which pair do both compounds exhibit predominantly ionic bonding?
a)
SCl6 and HF
b)
Na2SO3 and CH4
c)
KI and O3
d)
BaF2 and H2O
e)
LiBr and BaO
Ans: e
9.
Chapter/Section: 8.1
Difficulty: Easy
Keyword 1: Chemistry
Difficulty: Easy
Keyword 1: Chemistry
In which case is the bond polarity incorrect?
+
a)
H–F–
+
b)
K–O–
+
c)
Mg–H–
+
d)
Cl–I–
+
e)
Si–S–
Ans: d
10.
Algorithm: Yes
Algorithm: No
Chapter/Section: 8.2
Which of the following molecules has no dipole moment?
a)
CO2
b)
NH3
c)
H2O
d)
all
e)
none
Ans: a
Algorithm: No
Chapter/Section: 8.3
Difficulty: Easy
11. As the number of bonds between two carbon atoms increases, which one of the following decreases?
a)
number of electrons between the carbon atoms
b)
bond energy
c)
bond length
d)
all of these
e)
none of these
Ans: c
Algorithm: No
Chapter/Section: 8.8
Difficulty: Easy
Draw the Lewis structures of the molecules below and use them to answer the following questions:
12.
I.
BH3
II.
NO2
III.
SF6
IV.
O3
V.
PCl5
Which of the molecules obeys the octet rule?
a)
I
b)
II
c)
III
d)
IV
e)
V
Ans: d
Algorithm: No
Chapter/Section: 8.10
Difficulty: Easy
Keyword 1: Chemistry
Keyword 2: general chemistry
Keyword 3: bonding
Keyword 4: covalent bonding
Keyword 5: octet rule
13. How many of the molecules have no dipole moment?
a)
1
b)
2
c)
3
d)
4
e)
They are all polar.
Ans: c
Algorithm: No
Chapter/Section: 8.13
Difficulty: Moderate
Keyword 1: Chemistry
Keyword 2: general chemistry
Keyword 3: bonding
Keyword 4: molecular geometry
Keyword 5: dipole moment
14.
Which of these molecules show resonance?
a)
I, II
b)
II, IV
c)
II, V
d)
III, IV
e)
III, V
Ans: b
15.
Chapter/Section: 8.12
Difficulty: Moderate
This molecule contains a carbon atom with trigonal planar geometry.
a)
CH3CHO
b)
CO2
c)
CH3Cl
d)
C2H6
e)
none of these
Ans: a
16.
Algorithm: No
Algorithm: No
Chapter/Section: 8.13
Difficulty: Moderate
As indicated by Lewis structures, which of the following species could probably not exist as a stable
molecule?
a)
NH3
b)
N2H2
c)
N2H4
d)
N2H6
e)
N2O4
Ans: d
Algorithm: No
Chapter/Section: 8.11
Difficulty: Moderate
17.
The Lewis structure for H3BO3 is
a)
H
O
B
O
H
O
H
O
H
O
H
O
H
O
H
b)
H
O
B
O
H
c)
H
O
B
O
H
d)
H
O
B
O
H
e)
H
O
B
O
H
Ans: d
18.
Difficulty: Moderate
Algorithm: No
Chapter/Section: 8.12
Difficulty: Easy
Which has the greater N–O bond length, NO2– or NO3–?
a)
NO2–
b)
NO3–
c)
The bond lengths are the same.
d)
More information is needed.
e)
None of these (A-D).
Ans: b
20.
Chapter/Section: 8.11
In the cyanide ion (CN–), the nitrogen has a formal charge of
a)
-2
b)
-1
c)
0
d)
2
e)
More information is needed.
Ans: c
19.
Algorithm: No
Algorithm: No
Chapter/Section: 8.12
Difficulty: Moderate
Choose the statement that best describes the PbCl4 molecule in the gas phase.
a)
The bond angles are all about 109°.
b)
The molecule is polar.
c)
The molecule has a dipole moment.
d)
The bonds are nonpolar.
e)
More than one of the above.
Ans: a
Algorithm: No
Chapter/Section: 8.13
Difficulty: Moderate
21.
Which of the following types of molecules always has a dipole moment?
a)
Linear molecules with two identical bonds.
b)
Tetrahedral molecules (four identical bonds equally spaced).
c)
Trigonal pyramid molecules (three identical bonds).
d)
Trigonal planar molecules (three identical bonds equally spaced).
e)
None has a dipole moment.
Ans: c
22.
Algorithm: No
Chapter/Section: 8.13
Difficulty: Easy
Of the following, which molecule has the largest bond angle?
a)
O3
b)
OF2
c)
HCN
d)
H2O
e)
More than one of the above have equally large bond angles.
Ans: c
Algorithm: No
Chapter/Section: 8.13
Difficulty: Moderate
Keyword 1: Chemistry
SECTION II: Free Response
“Directions: Questions 1–3 are long free-response questions that require about 20 minutes each to
answer and are worth 10 points each. Questions 4–7 are short free-response questions that require
about 7 minutes each to answer and are worth 4 points each. Write your response in the space provided
following each question. Examples and equations may be included in your responses where appropriate.
For calculations, clearly show the method used and the steps involved in arriving at your answers. You
must show your work to receive credit for your answer. Pay attention to significant figures.”
1. Answer d & e, below.