### Exam 7-9 Practice

```Chemistry 107
Exam 7-9
Good Luck!
1. Determine the wavelength (in nm) of an
X-ray with a frequency of 4.2 x 1018 Hz.
a)
b)
c)
d)
e)
7.1 x 10–11
7.1 x 10–2
1.3 x 1027
1.4 x 1010
7.1 x 10–18
2. A major league pitcher throws a 148.8 g
baseball at a speed of 92.5 mph (41.4 m/s). What
is the de Broglie wavelength of the baseball in
meters?
a)
b)
c)
d)
e)
4.81 x 10–38
4.81 x 10– 41
1.08 x 10– 34
1.08 x 10– 37
1.08 x 10– 40
3. An electron in a hydrogen atom in the n =
6 energy level emits 109.4 kJ/ mol of energy
in a transition to a lower energy level. To
what energy level does the electron fall?
a)
b)
c)
d)
e)
1
2
3
4
5
4. Which of the following transitions for an electron
in a hydrogen atom would release the largest
quantum of energy?
a)
b)
c)
d)
n=3→n=1
n=4→n=3
n=1→n=4
n=2→n=1
5. Which of the following is NOT an
allowed set of quantum numbers?
a)
b)
c)
d)
e)
n=4
n=1
n=5
n=2
n=3
l=3
l=0
l=4
l=1
l=3
ml = 3
ml = 0
ml = – 2
ml = 0
ml = – 2
6. What is the frequency (Hz) of a infrared
light that emits 24.5 kJ/ mol of energy?
a)
b)
c)
d)
e)
3.70x1034
6.14x1013
4.92x1019
8.17x10–8
2.70x10–35
7. Ultraviolet light emits a total of 2.5x10–17 J
of light at a wavelength of 9.8x10–7 m. How
many photons does this correspond to?
a)
b)
c)
d)
e)
1
10
25
100
125
8. Determine the wavelength (nm) of light absorbed
when an electron in a hydrogen atom transitions
from the n = 3 to the n = 5 energy level.
a)
b)
c)
d)
e)
434 nm
656 nm
684 nm
780 nm
1280 nm
9. The de Broglie wavelength of a 455 kg car is
found to be 5.43x10–38 nm. Calculate the speed
(m/ s) of the car.
a) 26.8 m/ s
b) 37.3 m/ s
c) 2.68x10–8 m/ s
d) 3.73x107 m/ s
e) 3.00x108 m/ s
10. Which orbital is described by the following set
of quantum numbers?
n=3
l=1
ml = –1
a)
b)
c)
d)
e)
1s
2s
3s
3p
3d
11. What is the ground state electron configuration
for Mo?
a) Mo: [Kr]5s24d4
b) Mo: [Kr]5s04d6
c) Mo: [Ar]4s23d4
d) Mo: [Ar]4s13d5
e) Mo: [Kr]5s14d5
12. Which of the following correctly
illustrates the valence electron configuration
of sulfur?
a)
3s
3p
3s
3p
2s
2p
3s
3p
b)
c)
d)
13. Which element’s 4+ ion would have the following
electron configuration?
[Kr]4d10
a) Ge
b) Te
c) Sn
d) Se
e) Sb
14. Consider the following isoelectronic series:
Cl–
Ar
K+
Ca2+
Which particle is the largest?
a) Cl–
b) Ar
c) K+
d) Ca2+
e) All particles are the
same size.
15. Consider the following successive ionization
energies (kJ/mol):
IE1
IE2
IE3
IE4
IE5
IE6
IE7
1012
1900
2910
4960
6270
22,200
26,345
Which element in period three would most likely show
this trend in ionization energies?
a) Mg
b) Al
c) Si
d) P
e)S
16. What is the ground state electron configuration
for V?
a) V: [Kr]4s33d2
b) V: [Kr]4s24d3
c) V: [Ar]4s23d3
d) V: [Ar]3d3
e) V: [Kr]4s24d3
17. Which element is the largest?
a) Rb
b) Sr
c) Cs
d) Ba
e) Cl
18. Which of the following is diamagnetic?
a) Sn
b) Sn2+ c) Sn4+ d) Sn2+ and Sn4+ e) All are
paramagnetic
19. Which element is the most non-metallic?
a) K
b) Ca
c) Mg
d) O
e) F
20. How many valence electrons does an atom of Sulfur
possess?
a. 2
b. 3
c. 4
d. 5
e. 6
21. Which element has the greatest effective nuclear
charge?
a. O
b. F
c. S
d. Cl
e. P
22. Which of the following sets gives the
correct formal charges for the elements in
the Lewis structure below?
a.
b.
c.
d.
e.
S: –2
S: +6
S: –2
S: +1
S: 0
S
C
C: –4
C: +4
C: +4
C: 0
C: 0
N: –3
N: +5
N: –3
N: –1
N: –1
N
23. Rank the following in order of increasing
bond polarity:
H─F
a)
b)
c)
d)
e)
H─Br
F─F
H─F < H─Br < F─F < Na─Cl
F─F < H─F < H─Br < Na─Cl
H─Br < H─F < F─F < Na─Cl
F─F < H─Br < H─F < Na─Cl
Na─Cl < H─F < H─Br < F─F
Na─Cl
24. Determine the formal charge of chlorine
in the most stable Lewis structure for ClO2–.
a.
b.
c.
d.
e.
–2
–1
0
+1
+2
25. Which of the following
compounds has ionic bonding?
a.
b.
c.
d.
e.
H2O
C6H12O6
NO2
Al
CaCO3
26. Use average bond energies to determine
ΔHrxn for the burning of H2.
H2(g) + ½ O2(g) → H2O(g)
a.
b.
c.
d.
e.
6 kJ
470 kJ
–243 kJ
–350 kJ
–421 kJ
Bond
Bond Energy
(kJ/mol)
H─H
436
O═O
498
O─O
142
O─H
464
27. Estimate the enthalpy change for the
combustion of methanol, using bond energies.
H
H
C
H
+ 2 O
O
H
a.
b.
c.
d.
e.
-3454 kJ
2652 kJ
-1426 kJ
126 kJ
-802 kJ
O
C
O
+
2 H
O
H
28. Draw the Lewis structure for
NO3– . How many equivalent
resonance structures can be
drawn?
a.
b.
c.
d.
e.
1
2
3
4
5
29. Draw the best Lewis structure for
Ca(OH)2. How many lone pairs of electrons
are on Ca?
a.
b.
c.
d.
e.
0
1
2
3
4
•
•
•
•
•
•
•
•
•
•
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•
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1. B
2. C
3. C
4. A
5. E
6. B
7. E
8. E
9. A
10. D
11. E
12. A
13. B
14. A
15. D
•
•
•
•
•
•
•
•
•
•
•
•
•
•
16. C
17. C
18. D
19. E
20. E
21. B
22. E
23. D
24. C
25. E
26. C
27. E
28. C
29. A
```