Chem 112 Homework
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Nuclear: Complete the following homework problems (both the textbook and the multiple choice
problems) by Sunday, Sept. 14 .
Quiz 2 in Angel is due at 11:55 PM on Monday night, Sept. 15, 2014. You will have 2 attempts.
Textbook Homework Problems: Chemistry Atoms First, First Edition, by Burdge and Overby: Chapter 20,
20.5, 20.25, 20.27, 20.31, 20.35, 20.81, 20.101, 20.17, 20.19, 20.87, 20.59
----------------------------------------------------------------------------------------------------------------------------------Multiple Choice Homework Problems
1. Which combination of number of protons,
number of neutrons and isotope symbol is correct?
Number
of protons
Number
of
neutrons
A.
54
88
142
54
B.
144
54
144
54
3.
230
90
Th→24 He+ yx M
Symbol
A.
B.
C.
D.
E.
Mn
Xe
C.
17
46
63
46
D.
47
156
109
47
Ag
E.
98
151
249
98
Cf
€
Pd
A.
B.
C.
D.
E.
x = 226, y = 90
x = 230, y = 88
x = 226, y = 88
x = 228, y = 86
x = 234, y = 92
4.
Which of the following isotopes is most
likely to be a positron emitter?
25
A.
B.
C.
D.
E.
105
2.
45 Rh has a neutron to proton ratio slightly
higher than needed to place it on the belt of
stability. The type of radioactive decay it is likely
to undergo is:
In the following nuclear reaction, what are
the values of x and y?
5.
α emission
β emission
electron capture
positron emission
none of the above
6.
€
Si
Mg
32
Si
25
Mg
28
Si
27
Which of the following types of nuclear
decay results in an increase in the nuclear
charge?
A.
alpha emission
B.
positron emission
C.
beta emission
D.
electron capture
E.
gamma emission
When
235
92
U is bombarded with one
neutron, fission occurs and the products are
94
three neutrons, 36 K and
€
A
139
56
Ba
B
€
141
56
Ba
1.00 C
139
58
Ce
0.80 D
139
54
Xe
E
142
53
I
1.20 Mass of Mo €
9. The nuclear decay of 88Mo is shown in the
graph below. What is the rate constant for the
decay?
0.60 0.40 0.20 0.00 €
0 €
7.
55
25
5 10 15 20 Time (minutes) Mn can be prepared by electron capture
from which isotope?
€
€
€
€
A
55
24
B
55
26
C
56
25
D
56
23
E
56
26
A
B.
C.
D.
E.
Cr
Fe
Mn
10.
V
Fe
€
8.
The half-life of
239
Pu is 24,000 years What
wastes generated today (~year 2000) will
be present in the year 3000?
A
B.
C.
D.
E.
0.95
0.92
1.03
0.97
0.90
The 14C/12C ratio in a wooden artifact is 1/8
the 14C/12C ratio in today’s atmosphere.
How old is the artifact? (t1/2 for 14C =
5,700 years)
A.
B.
C.
D.
E.
€fraction of the 239Pu present in nuclear
11.
0.04 min−1
0.50 min−1
1.03 min−1
0.09 min−1
0.10 min−1
45,600 years
17,100 years
700 years
1,900 years
11,400 years
A wooden artifact from China has a 14C
activity of 24 counts/min. as compared to
an activity of 31.7 count/min. for modern
(contemporary) wood. What is the age of
the artifact? (The half-life for 14C is 5700
years.)
A.
B.
C.
D.
E.
1700 years
2300 years
4600 years
3750 years
4340 years
12.
A rock contains 0.313mg of 206Pb for each
milligram of 238U. The half-life for the
decay of 238U to 206Pb is 4.5 × 109 yr. How
long ago was the rock formed?
A.
B.
C.
D.
E.
13.
−2.3 × 109 years
2.8 × 109 years
1.8 × 109 years
1.2 × 109 years
4.3 × 109 years
60
A
B
C
D
E
235
A. Pure 92 U is used as the fuel in the
reactor.
B. If allowed to overheat, the reactor can
explode like a nuclear bomb.
C. Water is never used as a coolant for the
€
reactor core.
D. Heat is initially supplied to the reactor
core to start the chain reaction.
E. The control rods present in the reactor
absorb excess neutrons.
Cl is a β-emitter with a half-life of 3.00 ×
105 yr. The β-activity of a sample of NaCl
is 1.20 disintegrations per second. How
many atoms of 36Cl are in the sample,
assuming that 36Cl is the only source of βdecay?
3.25 × 1021
9.81 × 1017
6.02 × 1023
1.64 × 1013
Insufficient information to answer.
15. How much energy must he supplied to break
a single 6Li nucleus into separated protons
and neutrons? (Masses: 6Li = 6.01347 amu;
1
H = 1.00728 amu; 1n, = 1.00867 amu)
A.
B.
C.
3.09 × 1012 J
1.54 × 10−3 J
5.14 × 10−9 J
9.117 × 10−28 J
8.206 × 10−11 J
4.940 × 10−13 J
2.735 × 10−19 J
2.735 × 10−16 J
17. Which one of the following statements
concerning the nuclear reactor is correct?
36
A.
B.
C.
D.
E.
5.14 × 10−12 J
3.09 × 1015 J
16. What is the binding energy of 27 Co ? The
mass of 60Co nucleus is 59.9338amu.
Potassium-40 decays to argon-40 with a
half-life of 1.27 x 109 years. What is the
age of a rock in which the mass ratio of
argon-40 to potassium-40 is 3.6?
A.
B.
C.
D.
E.
14.
1.08 × 109 years
1.39 × 109 years
1.41 × 109 years
1.56 × 109 years
2.00 × 109 years
D.
E
18.
Carbon-11 is used in medical imaging. The
half-life of this radioisotope is 20.4 min.
What percentage of a sample remains after
60.0 min?
A.
B.
C.
D.
E.
71.2 %
5.28 %
13.0 %
34.0 %
2.94 %
Quiz 2
Nuclear
1.
E
2.
B
3.
C
4.
A
5.
C
6.
A
7.
B
8.
D
9.
E
10.
B
11.
B
12.
E
13.
B
14.
D
15.
D
16.
B
17.
E
18.
C