Practice Exam 4

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Practice Exam 4
Name___________________________________
MULTIPLE CHOICE: 3 points each (30 points total)
1) Give the complete electronic configuration for Br -.
A) 1s22s22p63s23p64s24p6
1) _______
B) 1s22s22p63s23p64s23d104p5
C) 1s22s22p63s23p64s24d104p6
D) 1s22s2p63s2p64s23d104p6
E) 1s22s22p63s23p64s23d104p6
2) Choose the best Lewis structure for SF4.
A)
B)
C)
D)
E)
2) _______
3) Choose the best Lewis structure for NO3⁻.
3) _______
A)
B)
C)
D)
E)
4) Which of the following resonance structures for OCN⁻ will contribute most to the correct
structure of OCN⁻?
A) O C N, with one lone pair on O, two lone pairs on C, and one lone pair on N
B) O C-N, with one lone pair on O and three lone pairs on N
C) O C N, with two lone pairs on O and two lone pairs on N
D) O C N, with three lone pairs on O and one lone pair on N
E) They all contribute equally to the correct structure of OCN⁻.
4) _______
5) Which compound has the longest carbon-carbon bond length?
A) CH3CH3
B) HCCH
5) _______
C) CH2CH2
D) All bond lengths are the same.
6) Give the molecular geometry and number of electron groups for SF4.
A)
B)
C)
D)
E)
square planar, 6 electron groups
square pyramidal, 6 electron groups
T-shaped, 5 electron groups
octahedral, 6 electron groups
seesaw, 5 electron groups
7) Give the molecular geometry and number of electron groups for BrF 3.
A)
B)
C)
D)
E)
6) _______
square planar, 6 electron groups
square pyramidal, 6 electron groups
T-shaped, 5 electron groups
octahedral, 6 electron groups
seesaw, 5 electron groups
7) _______
8) Give the molecular geometry and number of electron groups for BrF 5.
A)
B)
C)
D)
E)
8) _______
square planar, 6 electron groups
square pyramidal, 6 electron groups
T-shaped, 5 electron groups
octahedral, 6 electron groups
seesaw, 5 electron groups
9) Place the following in order of decreasing X-A-X bond angle, where A represents the central
atom and X represents the outer atoms in each molecule.
N2O
9) _______
NO2⁻
NCl3
A) N2O > NO2⁻ > NCl3
B) NCl3 > NO2⁻ > N2O
C) N2O > NCl3 > NO2⁻
D) NO2⁻ > N2O > NCl3
E) NCl3 > N2O > NO2⁻
10) Place the following in order of increasing dipole moment.
A)
B)
C)
D)
E)
I
I
II
I
II
I.
BCl3
<
<
<
<
<
II
III
III
II
I
II.
<
<
<
=
<
BIF2
III.
10) ______
BClF2
III
II
I
III
III
11) Give the hybridization for the O in OF2.
A) sp
B) sp3
11) ______
C) sp2
D) sp3d
E) sp3d2
12) Place the following compounds in order of decreasing strength of intermolecular forces.
I.
A)
B)
C)
D)
E)
CH3CH2CH2CH2CH2CH3
I
III
I
II
III
> II
> I
> III
> III
> II
>
>
>
>
>
II.
(CH3)3CCH3
III.
(CH3)3CCH2CH3
III
II
II
I
I
13) Place the following substances in order of increasing vapor pressure at a given temperature.
SF6
SiH4
SF4
A) SF6 < SiH4 < SF4
B) SF6 < SF4 < SiH4
C) SiH4 < SF4 < SF6
D) SiH4 < SF6 < SF4
E) SF4 < SF6
12) ______
< SiH4
13) ______
FREE RESPONSE: Make sure to show ALL your work for full credit. 10 points each
14) How many of the following molecules have sp2 hybridization on the central atom?
HCN
SO2
OCl2
XeCl2
15) How much energy is required to heat 87.1 g acetone (molar mass = 58.08 g/mol) from a solid at -154.0°C to a
liquid at -42.0°C? The following physical data may be useful.
ΔHfus = 7.27 kJ/mol
Cliq = 2.16 J/g°C
Cgas = 1.29 J/g°C
Csol = 1.65 J/g°C
Tmelting = -95.0°C
16) Determine the solubility of N2 in water exposed to air at 25°C if the atmospheric pressure is 1.2 atm. Assume
that the mole fraction of nitrogen is 0.78 in air and the Henry's law constant for nitrogen in water at this
temperature is 6.1 × 10-4 M/atm.
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
E
E
B
D
A
E
C
B
A
B
B
C
E
1
29.4 kJ
5.7 × 10-4 M
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