Important topics to review or the final:
- Enthalpy and energy calculations: calorimetry, heats of reaction etc
- Molecular shape aspects: m, l and n aspects of elements and atoms
- Types of bonds and their characteristics
- Periodic table trends and group characteristics
3
Part I: Multiple Choice: (3 pts each).
1.
Calculate the density of SO3 gas at 350C and 715 torr in g/L
a) 0.0285
b) 1.43
c) 2.15
d) 2.98
2.
What is the chemical formula of a gas if it has a pressure of 1.40 atm and a density of 1.82 g/L at 27 0C?
a) CO2
b) CO
c) CH4
d) O2
3.
Calculate the amount of heat released to the environment when 245 g of steam at 1400C is cooled -150C.
4.
Pi bonds are formed through the overlap of what type of orbitals?
a) s
b) p
c) sp
d) sp2
5.
What intermolecular force is most important in explaining why glucose, C6H6O6 is soluble in water?
a) Hydrogen bonding
b) Ion-dipole
c) London dispersion forces
d) Dipole-dipole
6.
What intermolecular force is most responsible for molecular iodine, I2, being a solid at room temperature?
a) Hydrogen bonding
b) Ion-dipole
c) London dispersion forces
d) Dipole-dipole
7.
What gives ionic liquids their low melting point?
a) Low molecular weight
b) No ionic bonding
c) High lattice energy
d) Large ions and shape mismatch between them
8.
Which atom can accommodate an octet of electrons, but doesn’t necessarily have to accommodate an octet?
a) N
9.
b) C
a) Sr; N
11.
c) I; N
d) I; As
a) Mg2+, Na+, F – , O2–, N3–
b) N3–, Mg2+, O2–, Na+, F –
c) N3–, O2–, Mg2+, F – , Na+
d) N3–, O2–, F – , Na+, Mg2+
Which element has the most negative electron affinity?
b) C
c) F
d) Ne
Which alkaline earth metal reacts the most vigorously with water at room temperature?
a) Be
13.
b) Sr, As
(II) N, P, As
Arrange the ions N3–, O2–, Mg2+, Na+, F – in order of increasing ionic radius starting with the smallest
first.
a) B
12.
d) B
Which atom in each group (I and II) has the smallest atomic radius?
(I) Sr, In, I
10.
c) H
b) Ca
c) Ba
d) Sr
Metals tend to react with the halogens to form metal halides. What is the reactivity order for the
halogens?
a) F2 > Cl2 > Br2 > I2
b) Cl2 > F2 > Br2 > I2
c) Br2 > I2 > Cl2 > F2
d) I2 > Br2 > Cl2 > F2
14.
A reactive element with a relatively high electronegativity would be expected to have a relatively
a) small negative electron affinity and a relatively low ionization energy.
b) small negative electron affinity and a relatively high ionization energy.
c) large negative electron affinity and a relatively low ionization energy.
d) large negative electron affinity and a relatively high ionization energy.
15.
Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0. Which
statement best describes the bonding in A3B?
a) The AB bond is largely covalent with a - on A.
b) The AB bond is largely covalent with a on A.
c) The compound is largely ionic with A as the cation.
d) The compound is largely ionic with A as the anion.
16.
5
–
NO2 is expected to have
a) bonds flickering back and forth between single bonds and double bonds.
b) one single and one double bond.
c) two double bonds.
d) two identical bonds intermediate between a single and a double bond.
17.
In the Lewis structure for SCl2O, the formal charges are:
a) 0, 0, 0
b) +1, 0, –2
c) +1, 0, –1
on S,
on the Cl atoms, and
d) +4, –1, –2
18.
Based on VSEPR theory, which should have the smallest XAX bond angle?
19.
The molecular geometry of phosphorus trichloride PCl3 is
20.
a) trigonal planar
b) trigonal pyramidal
d) bent
e) T–shape
21.
c) tetrahedral
b) 109.5˚
c) 120˚
d) 180o
b) N–F
c) F–F
d) Cl–F
Which one of the following compounds produces a basic solution when dissolved in water?
a) SO2
23.
.
Which covalent bond is the most polar?
a) C–F
22.
e) –1, 0, +1
What is the approximate Cl–P–Cl bond angle in phosphorus trichloride PCl3?
a) 90˚
b) Na2O
c) CO2
d) OF2
For an electron in a given atom, the larger n, the
a) larger the average distance from the nucleus and the higher the orbital energy.
b) larger the average distance from the nucleus and the lower the orbital energy.
c) smaller the average distance from the nucleus and the higher the orbital energy.
d) smaller the average distance from the nucleus and the lower the orbital energy.
on O.
24.
The bond angles marked a, b, and c in the molecule below are approximately
respectively.
a) 109.5˚, 109.5˚, 109.5˚
b) 120˚, 109.5˚, 120˚
c) 109.5˚, 109.5˚, 90˚
d) 90˚, 90˚, 90˚
,
, and
,
e) 109.5˚, 109.5˚, 120˚
Part-II: For full credit, show all your work legibly, include units, and report your answer to the correct number
of significant figures. No work shown = 0 points.
25.
Complete and balance the following reaction equations. For full credit, include the phase (s, l, g, or aq)
for all reactants and products.
H2O (l) 
A. (4 pts)
Na (s) +
B. (4 pts)
CO2 (aq) +
C. (4 pts)
CaO (s) + H2O (l) 



Na2CO3 (aq) + H2O (l)


26.
A. (6 pts) Use average bond enthalpies to estimate the enthalpy for the following gas phase reaction.
Note that O=O is O2.
B. (2 pts) This reaction
heat and is
.
i. produces; exothermic
ii. absorbs; endothermic
iii. absorbs; exothermic
iv. produces; endothermic
Total Page 5
7
27.
A. (2 pts) Draw the Lewis structure for PCl3F2. Include lone pairs.
B. (2 pts) The more electronegative are the atoms bonded to the central atom, the less are the
repulsions between the electron pairs in the bonds. On the basis of this statement, draw the most
probable structure of the molecule PCl3F2. If you did not arrive at a Lewis structure in part A, use this:
Cl
F
F
S
F
Cl
F
C. (2 pts) What is the name of the shape or geometry of the molecule?
D. (3 pts) indicate the bond angles in the molecule.
Bond
F – A – Cl
“A” refers to the central atom.
angle
Cl – A – Cl
F–A–F
E. (1 pts) Is this molecule polar or nonpolar?
If the molecule is polar, indicate on the drawing in part B the direction of the dipole moment using the
notation:
.
Total Page 6
28.
label
A. (6 pts) The inflation of an “air bag” when a car experiences a collision occurs by the explosive
decomposition of sodium azide, NaN3, which yields nitrogen gas that inflates the bag. The following
Lewis structures can be drawn for the azide ion, N3–. Identify each as valid or invalid. For the invalid
structures clearly explain why the structure is invalid.
valid or
invalid?
Lewis structure
Explanation of why the structure is invalid.
a
N
N
N
b
N
N
N
c
N
N
N
d
N
N
N
-
-
-
B. (2 pts) Which one of the structures is best?
a
b
c
d
C. (2 pts) Clearly and completely, but briefly explain your answer in B.
29.
A. (4 pts) Draw all resonance structures for the nitrate ion NO3–.
B. (1 pt) One of two resonance structures for nitrogen dioxide NO2 is shown.
Nitrogen–oxygen bonds in NO2 are
than are those in the nitrate ion.
i) shorter & stronger
ii) longer & weaker
iv) longer & stronger
v) none of the above.
Total Page 7
O
iii) shorter & weaker
N
O
9
Pe riodic Table of t he Element s
1A
1
1
H
1.01
2A
2
3
Li
6.94
4
Be
9 .0 1
11
Na
23.0
12
Mg
24.3
3B
3
4B
4
5B
5
6B
6
19
K
3 9 .1
20
Ca
40.1
21
Sc
45 .0
22
Ti
47 .9
23
V
5 0 .9
24
Cr
52.0
25
Mn
54.9
26
Fe
5 5 .8
37
Rb
85.5
38
Sr
8 7 .6
39
Y
88.9
40
Zr
91.2
41
Nb
9 2 .9
42
Mo
95 .9
43
Tc
(9 8 )
55
Cs
13 3
56
Ba
137
57
La
139
72
Hf
17 8
73
Ta
181
74
W
18 4
75
Re
18 6
88
Ra
22 6
89
Ac
227
87
Fr
( 2 23 )
8B
7B
7
8A
18
2
He
4.00
3A
13
4A
14
5A
15
6A
16
7A
17
5
B
10 .8
6
C
12 .0
7
N
14.0
8
O
1 6 .0
9
F
19.0
10
Ne
2 0 .2
10
1B
11
2B
12
13
Al
27 .0
14
Si
2 8 .1
15
P
31.0
16
S
3 2 .1
17
Cl
3 5 .5
18
Ar
39.9
27
Co
58.9
28
Ni
58 .7
29
Cu
63.5
30
Zn
65.4
31
Ga
69 .7
32
Ge
72 .6
33
As
74.9
34
Se
79.0
35
Br
7 9 .9
36
Kr
83.8
44
Ru
10 1
45
Rh
10 3
46
Pd
10 6
47
Ag
10 8
48
Cd
112
49
In
11 5
50
Sn
119
51
Sb
12 2
52
Te
12 8
53
I
127
54
Xe
13 1
76
Os
190
77
Ir
19 2
78
Pt
19 5
79
Au
19 7
80
Hg
201
81
Tl
204
82
Pb
207
83
Bi
20 9
84
Po
( 2 09 )
64
Gd
15 7
65
Tb
15 9
66
Dy
162
67
Ho
165
68
Er
167
69
Tm
16 9
8
9
85
86
At
Rn
( 21 0 ) ( 2 2 2 )
104
105
10 6
107
10 8
10 9
11 0
Rf
Db
Sg
Bh
Hs
Mt
Ds
( 2 61 ) (2 6 2 ) ( 26 3 ) ( 2 62 ) ( 2 6 5 ) ( 26 6 ) (2 8 1 )
Lant hanides
58
Ce
14 0
59
Pr
14 1
60
Nd
144
61
Pm
( 145)
62
Sm
15 0
63
Eu
152
Ac t inides
90
Th
23 2
91
Pa
23 1
92
U
238
93
94
95
96
97
98
99
10 0
101
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
( 2 3 7 ) ( 24 4 ) ( 2 43 ) ( 2 4 7 ) ( 247 ) ( 2 51 ) (2 5 2 ) ( 25 7 ) ( 2 58 )
70
Yb
173
71
Lu
17 5
10 2
103
No
Lr
( 25 9 ) ( 2 60 )