Chemistry 113 Practice Exam 4 Spring 2016 Directions on actual Exam: The exam consists of 2 sections (Chemical Bonding and Geometry and IMFs. Each multiple choice question is worth 4.33 points. You are allowed to use a scientific (nonprogrammable) calculator, periodic table, and VSEPR Theory Table. Useful information: ΔH°rxn = Σn×D(bonds broken) - Σn×D(bonds formed) where Σn represents the sum of the moles of a particular type of bond D represents bond energy per mole of bond Chemical Bonding and Geometry 1. The Lewis dot symbol for the calcium ion is A) 2+ B) Ca C) 2+ D) Ca2+ E) Ca 2. The electron dot structure for AsCl3 molecule shows A) a total of 84 electron dots B) three single bonds and 10 lone pairs C) two single bonds, one double bond, and 9 lone pairs D) one single bond, two double bonds, and 8 lone pairs E) three single bonds and one lone pair 3. The correct Lewis structure for CO2 is: C O O A) O O B) O O C) O O D) O 4. Which of the following Lewis structures is incorrect? A) B) C) D) E) 5. How many covalent bonds will be formed by bromine in BrO3– for the dot structure that expands the octet to minimize formal charge and places negative formal charges on only the most electronegative atom(s). The Pauling electronegativity values are: Br = 2.8; O = 3.5 A) 3 B) 4 C) 5 D) 6 E) 7 6. Estimate the enthalpy change for the reaction 2CO + O2  2CO2 given the following bond energies. BE(CO) = 1074 kJ/mol BE(O=O) = 499 kJ/mol BE(C=O) = 802 kJ/mol A) +2380 kJ/mol B) +744 kJ/mol C) +1949 kJ/mol D) –561 kJ/mol E) –744 kJ/mol 7. Give the number of lone pairs around the central atom and the molecular shape of the ion ClO3–. A) 0 lone pairs, trigonal B) 1 lone pair, bent C) 1 lone pair, trigonal pyramidal D) 2 lone pairs, T-shaped E) 2 lone pairs, trigonal 8. Which of the following substances is/are bent? (i) H2S (ii). CO2 (iii) ClNO (iv) NH2– (v) O3 A) only (iii) B) only (i) and (v) C) only (i), (iii), and (v) D) all are bent except for (iv) E) all are bent except for (ii) 9. Which of the following molecules is polar? A) CH4 B) SF6 C) F2 D) CH3F E) CO2 10. Indicate the type of hybrid orbitals used by the central atom in TeF4. A) Sp B) sp2 C) sp3 D) sp3d E) sp3d2 11. The hybridization of the O atom in CO2 will be A) S B) Sp C) sp2 D) sp3 E) sp3d 12. The number of pi bonds in the molecule below is A) 1 B) 2 C) 3 D) 5 E) 9 IMF’s 13. Order the forces (dipole-dipole, London dispersion, ionic, and hydrogen-bonding) from weakest to strongest . a) dipole-dipole, London dispersion, ionic, and hydrogen-bonding b) London dispersion, dipole-dipole, hydrogen-bonding, and ionic c) hydrogen-bonding, dipole-dipole, London dispersion, and ionic d) dipole-dipole, ionic, London dispersion, and hydrogen-bonding e) London dispersion, ionic, dipole-dipole, and hydrogen-bonding 14. Which of the following would you expect to have the highest boiling point? a) F2 b) Cl2 c) ...

1. Chemistry 113 Practice Exam 4 Spring 2016
Directions on actual Exam: The exam consists of 2 sections
(Chemical Bonding and Geometry and IMFs. Each multiple
choice question is worth 4.33 points. You are allowed to use a
scientific (nonprogrammable) calculator, periodic table, and
VSEPR Theory Table.
Useful information:
ΔH°rxn = Σn×D(bonds broken) - Σn×D(bonds formed)
where Σn represents the sum of the moles of a particular type of
bond
D represents bond energy per mole of bond
Chemical Bonding and Geometry
1.
The Lewis dot symbol for the calcium ion is
A)
2+
B)
C)
2+
D)
Ca2+
E)
Ca

2. 2.
The electron dot structure for AsCl3 molecule shows
A)
a total of 84 electron dots
B)
three single bonds and 10 lone pairs
C)
two single bonds, one double bond, and 9 lone pairs
D)
one single bond, two double bonds, and 8 lone pairs
E)
three single bonds and one lone pair
3.
The correct Lewis structure for CO2 is: C
O
O
A)
O
O
B)
O
O

3. C)
O
O
D)
O
4.
Which of the following Lewis structures is incorrect?
A)
B)
C)
D)
E)
5.
How many covalent bonds will be formed by bromine in BrO3–
for the dot structure that expands the octet to minimize formal
charge and places negative formal charges on only the most
electronegative atom(s). The Pauling electronegativity values
are:
Br = 2.8; O = 3.5
A)
3
B)

4. 4
C)
5
D)
6
E)
7
6.
2CO2 given the following bond energies.
BE(O=O) = 499 kJ/mol
BE(C=O) = 802 kJ/mol
A)
+2380 kJ/mol
B)
+744 kJ/mol
C)
+1949 kJ/mol
D)
–561 kJ/mol
E)
–744 kJ/mol
7.
Give the number of lone pairs around the central atom and the
molecular shape of the ion ClO3–.
A)
0 lone pairs, trigonal
B)
1 lone pair, bent
C)

5. 1 lone pair, trigonal pyramidal
D)
2 lone pairs, T-shaped
E)
2 lone pairs, trigonal
8.
Which of the following substances is/are bent?
(i) H2S (ii). CO2 (iii) ClNO (iv) NH2– (v) O3
A)
only (iii)
B)
only (i) and (v)
C)
only (i), (iii), and (v)
D)
all are bent except for (iv)
E)
all are bent except for (ii)
9.
Which of the following molecules is polar?
A)
CH4
B)
SF6
C)
F2
D)
CH3F
E)
CO2

6. 10.
Indicate the type of hybrid orbitals used by the central atom in
TeF4.
A)
Sp
B)
sp2
C)
sp3
D)
sp3d
E)
sp3d2
11.
The hybridization of the O atom in CO2 will be
A)
S
B)
Sp
C)
sp2
D)
sp3
E)
sp3d
12.
The number of pi bonds in the molecule below is
A)
1
B)
2

7. C)
3
D)
5
E)
9
IMF’s
13. Order the forces (dipole-dipole, London dispersion, ionic,
and hydrogen-bonding) from weakest to strongest .
a) dipole-dipole, London dispersion, ionic, and hydrogen-
bonding
b) London dispersion, dipole-dipole, hydrogen-bonding, and
ionic
c) hydrogen-bonding, dipole-dipole, London dispersion, and
ionic
d) dipole-dipole, ionic, London dispersion, and hydrogen-
bonding
e) London dispersion, ionic, dipole-dipole, and hydrogen-
bonding
14. Which of the following would you expect to have the
highest boiling point?
a) F2
b) Cl2
c) Br2
d) I2
e) All of the above have the same boiling point.
15. The molecules in a sample of SO2 are attracted to each
other by a combination of
a) London forces and H-bonding
b) H-bonding and ionic bonding
c) covalent bonding and dipole-dipole interactions
d) London forces and dipole-dipole interactions
e) none of these

8. 16. When a water molecule forms a hydrogen bond with
another water molecule, which atoms are involved in the
interaction?
a) a hydrogen from one molecule and a hydrogen from the
other molecule
b) a hydrogen from one molecule and an oxygen from the
other molecule
c) an oxygen from one molecule and an oxygen from the
other molecule
d) an oxygen and a hydrogen from the same molecule
e) two hydrogens from one molecule and one hydrogen from
the other molecule
Chemical Bonding and Geometry
17. Which formula is matched with the correct number of
valence electrons in the free (not bonded) central atom, bonds,
and lone pairs in the molecule for the underlined atom?
a. SeH2; 6 valence electrons, 2 bonds, and 1 lone pair
b. SiCl4; 4 valence electrons, 4 bonds, and 0 lone pairs
c. FCl; 1 valence electron, 1 bond, and 0 lone pairs
d. SCl2; 6 valence electrons, 2 bonds, and 0 lone pairs
e. PH3; 4 valence electrons, 3 bonds, and 1 lone pair
18. The electron-dot structure for the species NH4O+ contains
a. 1 double bond and 4 single bonds
b. 5 single bonds and 3 lone pairs.
c. 5 single bonds and 2 lone pairs.
d. 5 single bonds and 1 lone pair.
e. 5 single bonds and zero lone pairs.
19. What is the hybridization of the carbon atom in CO2?
a. sp2
b. sp3

9. c. sp3d
d. sp3d2
e. sp
20. Which of the following molecules requires two resonance
hybrid Lewis structures to account for the bonding?
a. SO2
b. CO2
c. O2
d. CH4
e. C2H4
21. Which of the following is the best electron-dot description
for sulfur dioxide, SO2?
22. Which of the following compounds (or ions) contains an
atom that does NOT follow the octet rule?
a. BrF3
b. CBr4
c. NO+
d. BF4-
e. NCl3
23. What is atom X in the Lewis structure of the following
anion?
a. Xe
b. Cl
c. S
d. N
e. C
24. Which of the following statements is correct?
a. Covalent bonds usually involve two nonmetals and ionic
bonds usually involve two metals.
b. Covalent bonds usually involve two metals and ionic bonds
usually involve a metal and a nonmetal.

10. c. Covalent bonds usually involve a metal and a nonmetal and
ionic bonds usually involve two nonmetals.
d. Covalent bonds usually involve two nonmetals and ionic
bonds usually involve a metal and a nonmetal.
e. Covalent bonds usually involve two metals and ionic bonds
involve two nonmetals.
25. The molecular structure of the IO3- ion is best described as:
a. bent or angular.
b. trigonal planar.
c. trigonal pyramidal.
d. trigonal bipyramidal.
e. T-shaped.
26. The electron domain geometry of the AsF6- ion is
octahedral. The hybrid orbitals used by the As atom for
bonding are:
a. sp2
b. sp3d
c. sp
d. sp3d2
e. sp3
27. The F-B-F bond angle in BF3 is ____________.
a. 60°
b. 90°
c. 109.5°
d. 120°
e. 180°
28. The geometry associated with sp hybridization is:
a. linear
b. octahedral
c. trigonal biplanar
d. trigonal planar
e. tetrahedral

11. 29. Which series of elements is arranged in order of increasing
electronegativity?
a. C, Si, P, As, Se
b. O, P, Al, Mg, K
c. Na, Li, B, N, F
d. K, Mg, Be, O, N
e. Li, Be, B, C, Ca
IMF’s
Use the following to answer questions 30-32:
Consider the representations below to answer the next three
questions.
(I)
(II)
(III)
30. How many of the following statements are correct
concerning drawing I?
I.
Each molecule induces a dipole onto the next molecule in close
proximity.
II.
The phenomenon shown is relatively weak and short-lived.
III.
All nonpolar molecules contains this type of interaction.
IV.
The forces that exist in this example are London dispersion
forces.
a) 0
b) 1
c) 2
d) 3

12. e) 4
31. Which drawing best represents the interactions in a sample
of HF?
a) I
b) II
c) III
d) I, II
e) all of the above
32. Which of the following statements are incorrect concerning
drawing III?
a) Electrostatic interactions exist between the molecules.
b) The molecules find the best compromise between attraction
and repulsion.
c) These molecules exhibit ionic bonding.
d) CHCl3 exhibits this type of interaction.
e) Two of the above statements are incorrect.
33. Which of the following is the correct order of boiling
points for KNO3, CH3OH, C2H6, Ne?
a) Ne < CH3OH < C2H6 < KNO3
b) KNO3 < CH3OH < C2H6 < Ne
c) Ne < C2H6 < KNO3 < CH3OH
d) Ne < C2H6 < CH3OH < KNO3
e) C2H6 < Ne < CH3OH < KNO3
34. What is the strongest intermolecular force (IMF) found in a
sample of thousands of C2H6 molecules?
a. London b. dipole dipole c. nonpolar d. H
bond force e. polar
35. What is the strongest intermolecular force (IMF) found in a
sample of thousands of HBr molecules?
a.London b. dipole dipole c. nonpolar d. H
bond force e. polar
36. What is the strongest intermolecular force (IMF) found in a

13. sample of thousands of He atoms?
a. London b. dipole dipole c. nonpolar d. H
bond force e. polar
37. What holds the N atom to the H atom in a molecule of
ammonia, NH3?
a.Ionic bond b. polar bond c. H bond d.
nonpolar bond e. dipole dipole
38. What holds the molecules together in a sample of ammonia,
NH3?
a. Dipole dipole forces b. polar bonds c. H bond
forces d. London forces
39. What holds the O atoms to each other in a molecule of
oxygen gas?
a. Ionic bond b. polar bond c. H bond d.
nonpolar bond e. dipole dipole
40. As intermolecular forces increase, which of the following
decreases?
a. Surface tension b. Boiling Point c. Vapor Pressure
d. Melting Point e. Viscosity
41.Which is true when comparing samples of C6H6(l) (has C-H
bonds) to C2H5OH(l) (has an O-H bond)?
a The vapor pressure of C2H5OH is higher.
b. The boiling point of C6H6 is higher.
c. The surface tension of C2H5OH is lower.
d. The melting point of C2H5OH is lower.
e. The viscosity of C6H6 is lower.
Ca
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Ca
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