Chemistry, 6e (McMurry/Fay)
Chapter 22 Nuclear Chemistry
22.1 Multiple-Choice Questions
1) Mass defect is the mass lost when
A) an atom is formed from individual protons, neutrons, and electrons.
B) a nucleus is formed from individual protons and neutrons.
C) electrons are removed from an atom.
D) electrons are added to an atom.
2) The sum of the masses of the protons and neutrons in a given nucleus minus the mass of that nucleus
is always
A) negative.
B) positive.
C) temperature dependent.
D) zero.
3) The binding energy is defined as
A) the amount of energy absorbed when electrons are added to an ion.
B) the amount of energy absorbed when protons and neutrons form a nucleus.
C) the amount of energy released when electrons are removed from the atom.
D) the amount of energy required to break apart a nucleus into individual protons and neutrons.
4) A binding energy curve is a plot of binding energy per nucleon versus atomic number. In what region
of the binding energy curve are the most stable elements found?
A) in the lower left region (low atomic mass)
B) in the central top region (moderate atomic mass)
C) in the lower right region (heavy atomic mass)
D) binding energy is not dependent on atomic mass
5) Which of the following isotopes is the most stable?
A) 6He, 4.89 MeV/nucleon
B) 20Ne, 8.03 MeV/nucleon
C) 28Si, 8.44 MeV/nucleon
D) 232Th, 7.62 MeV/nucleon
6) Which of the following isotopes is the least stable?
A) 7Be, 5.37 MeV/nucleon
B) 23Na, 8.11 MeV/nucleon
C) 94Zr, 8.67 MeV/nucleon
D) 240Pu, 7.26 MeV/nucleon
7) The total binding energies for 3He, 4He, and 6He are 7.72 MeV, 28.29 MeV, and 29.26 MeV
respectively. Arrange the 3 isotopes in increasing order of binding energy per nucleon.
A) 3He < 4He < 6He
B) 6He < 4He < 3He
C) 4He < 3He < 6He
D) 3He < 6He < 4He
8) Calculate the mass defect for the formation of phosphorus-31. The mass of a phosphorus-31 nucleus
is 30.973765 amu. The masses of a proton and a neutron are 1.00728 and 1.00866 amu, respectively.
A) 0.13015 amu
B) 0.15404 amu
C) 0.27261 amu
D) 0.27399 amu
9) If the mass of one neutron is 1.00866 amu, the mass of one proton is 1.00728 amu, and the mass of
14C nucleus is 13.99995 amu, calculate the binding energy for the 14C nucleus.
A) 9.92 × 109 kJ/mol
B) 1.02 × 1010 kJ/mol
C) 5.54 × 1011 kJ/mol
D) 5.95 × 1011 kJ/mol
10) If the mass of one neutron is 1.00866 amu, the mass of one proton is 1.00728 amu, and the mass of
12C nucleus is 11.99671 amu, calculate the binding energy for the 12C nucleus.
A) 8.90 × 109 kJ/mol
B) 8.90 × 1012 kJ/mol
C) 1.10 × 1015 kJ/mol
D) 1.10 × 1018 kJ/mol
11) How much energy is released for alpha decay of 236U? The masses of 4He, 232Th, and 236U are
4.002604, 232.038124, and 236.045637 amu, respectively.
A) 1.473 × 108 kJ/mol
B) 4.418 × 108 kJ/mol
C) 4.909 × 108 kJ/mol
D) 7.209 × 108 kJ/mol
12) What is the mass change in grams for the reaction 2 NO2(g) → N2O4(g)? The enthalpy for the
reaction is -57.2 kJ.
A) -6.36 × 10-13 g
B) -6.36 × 10-10 g
C) -1.91 × 10-7 g
D) -1.91 × 10-4 g
13) Which does not apply to a nuclear fusion reaction?
A) Atoms of one element cannot be converted to atoms of another element.
B) Energy is conserved.
C) Matter is conserved.
D) None of these apply to a nuclear fusion reaction.
14) Which of the following is not an advantage of fusion reactions over fission reactions for power
generation?
A) cheap and plentiful fuel
B) ease of reaction initiation
C) Fusion products are non-polluting.
D) Fusion products are nonradioactive.
15) Relative to the amount of energy released in a typical chemical reaction, the amount of energy
released in a typical fission reaction is about
A) the same.
B) 10 times greater.
C) 108 times greater
D) 1010 times greater
16) Breaking a chemical bond requires approximately 102 kJ/mol of energy. What is closest to the order
of magnitude of the energy required to split a nucleus in to its individual protons and neutrons?
A) 103 kJ/mol
B) 104 kJ/mol
C) 108 kJ/mol
D) 1010 kJ/mol
17) Which reaction is expected to release the greatest amount of energy?
A) 2 H → H2
B)
1H
1
+
2H
1
→
3He
2
C)
1n
0
+
235U
92
→
137Te
52
+
97Zr
40
+ 2 1n
D)
1n
0
+
235U
92
→
142Ba
56
+
91Kr
36
+ 3
1n
0
18) Elements with ________ atomic mass are best possible candidates for a fusion reaction.
A) very low
B) moderate
C) moderate to heavy
D) very heavy
19) Elements with ________ atomic mass are best possible candidates for a fission reaction.
A) very low
B) moderate
C) moderate to heavy
D) very heavy
20) Four heavy elements (A, B, C, and D) will fission when bombarded by neutrons. In addition to
fissioning into two smaller elements, A also gives off a beta particle, B gives off gamma rays, C gives
off neutrons, and D gives off alpha particles. Which element would make a possible fuel for a nuclear
reactor?
A) element A
B) element B
C) element C
D) element D
21) What does the term “critical mass” mean? It is the
A) amount of fissionable material which will self-sustain a nuclear chain reaction.
B) difference between mass of individual protons and neutrons and the mass of the nucleus.
C) energy which holds the nucleus together.
D) mass of fuel in a nuclear reactor core.
22) What mass percent of 235U (the fissionable isotope) is used in the fuel in nuclear power plants?
A) 3%
B) 14%
C) 27%
D) 83%
23) In fusion reactions to make superheavy elements, energy is required to bring the two nuclei together
and to form additional mass. How much energy must be converted into mass for the alpha bombardment
of 253Es to form 257Md? (The isotopic masses are 253Es = 253.08294 amu, 4He = 4.00260 amu,
257Md = 257.09558 amu.)
A) 3.01 × 106 kJ/mol
B) 9.04 × 108 kJ/mol
C) 3.59 × 1011 kJ/mol
D) 7.21 × 1011 kJ/mol
24) Nitrogen-14 (14.003074 amu) is synthesized in the sun by fusion of 13C (13.003355 amu) and 1H
(1.007825 amu). How much energy is released in this nuclear reaction?
A) 2.432 × 106 kJ/mol
B) 7.295 × 108 kJ/mol
C) 9.141 × 1010 kJ/mol
D) 1.807 × 1011 kJ/mol
25) Oxygen-16 (15.994915 amu) is synthesized in the sun by fusion of 12C (12.000000 amu) and 4He
(4.00260 amu). How much energy is released in this nuclear reaction?
A) 2.48 × 103 kJ/mol
B) 2.30 × 106 kJ/mol
C) 6.92 × 108 kJ/mol
D) 7.20 × 1011 kJ/mol
26) The masses of 4He, 6Li, and 10B are 4.0015, 6.0135, and 10.0102 amu respectively. The fission of a
boron-10 nucleus into He-4 and Li-6 would
A) absorb energy.
B) evolve energy.
C) result in no energy change.
D) Need more information
27) Which of the following reactions correctly shows the transmutation of an element by neutron
absorption followed by beta emission?
A)
203Tl
81
+
1n
0
→
1e
0
−
+
202Pb
92
B)
165Tl
67
+
0e
1−
→
0n
1
+
164Dy
66
C)
127I
53
+
1n
0
→
0e
1−
+
128Xe
54
D)
140Ce
58
+
0e
1−
→
1n
0
+
141La
57
28) The nuclear transmutation reaction that leads to the synthesis of plutonium-241 is shown below.
What is the identity of the α-particle bombardment target in this reaction?
? +
4He
2
→
241Pu
94
+
1n
0
A)
237U
92
B)
238U
92
C)
245Cm
96
D)
246Cm
96
29) What is the missing product of the nuclear reaction?
209Bi
83
+
1p
1
→ ? +
210Po
85
A) α
B) β+
C) β–
D) n
30) When
162Dy
66
is formed by bombardment of
158Gd
64
, what particle(s) was (were) used for the
bombardment?
A) one α
B) two β–
C) 4 neutrons
D) 2 protons
31) A shorthand way of writing transmutation equations is to show the bombarding particle and the
subsequent emitted particle in parentheses. Which of the following equations shows the balanced
nuclear reaction for
6Li
3
(n, α)?
A)
6Li
3
+
1n
0
→
4He
2
+
3H
1
B)
6Li
3
+
4He
2
→
1n
0
+
9B
5
C)
6Li
3
+
1n
0
→
4He
2
+
2He
2
D)
6Li
3
+
4He
2
→
1n
0
+
10Be
4
32) A shorthand way of writing transmutation equations is to show the bombarding particle and the
subsequent emitted particle in parentheses. Which particle is produced by
7Li
3
(p, α)?
A)
4H
1
B)
3He
2
C)
10Be
4
D)
4He
2
33) The first transuranium element was synthesized by bombarding
238U
92
with neutrons. After
capturing one neutron, the resulting nuclide was unstable and decayed by beta emission. What was the
product of these two nuclear reactions?
A)
239Np
93
B)
239Pa
91
C)
235Th
90
D)
239U
92
34) Radiation is detected by its ________ properties.
A) gravitational
B) ionizing
C) kinetic
D) thermal
35) Which one of the following instruments would be the least suitable for detecting particles given off
in radioactive decay?
A) electron microsope
B) Geiger counter
C) photographic film
D) scintillation counter
36) Which one of the following is most penetrating?
A) alpha particles
B) beta particles
C) gamma rays
D) positrons
37) Which ionizing radiation has the greatest energy?
A) α
B) β
C) γ
D) χ
38) A becquerel is:
A) the amount of sample that undergoes 1 disintegration per second.
B) the amount of sample that undergoes 3.7 × 1010 disintegrations per second.
C) the amount of tissue damage done by radiation.
D) equal to 0.01 J of energy absorbed per kilogram of tissue.
39) A sievert is:
A) the amount of sample that undergoes 1 disintegration per second.
B) the amount of sample that undergoes 3.7 × 1010 disintegrations per second.
C) the amount of tissue damage done by radiation.
D) equal to 0.01 J of energy absorbed per kilogram of tissue.
40) A curie is:
A) the amount of sample that undergoes 1 disintegration per second.
B) the amount of sample that undergoes 3.7 × 1010 disintegrations per second.
C) the amount of tissue damage done by radiation.
D) equal to 0.01 J of energy absorbed per kilogram of tissue.
41) What is the abbreviation used for the curie, a unit used in the measurement of nuclear disintegrations
per unit time?
A) Cu
B) Cr
C) Ci
D) Ce
42) A rad is:
A) the amount of sample that undergoes 1 disintegration per second.
B) the amount of sample that undergoes 3.7 × 1010 disintegrations per second.
C) the amount of tissue damage done by radiation.
D) equal to 0.01 J of energy absorbed per kilogram of tissue.
43) Which unit of radiation describes the amount of radiation emitted by a radioactive substance?
A) becquerel
B) gray
C) rad
D) rem
44) Which unit of radiation describes the amount of energy absorbed by a kilogram of tissue exposed to
a radiation source?
A) becquerel
B) curie
C) rad
D) rem
45) Which unit of radiation is frequently used in medicine to describe the amount of tissue damage
caused by a radioactive substance?
A) becquerel
B) curie
C) rad
D) rem
46) The effects of ionizing radiation depend on
A) length of exposure to radiation.
B) location of source (internal or external).
C) type and energy of radiation.
D) All of these
47) Ionizing radiation having the lowest energy is exhibited by
A) α particles.
B) β particles.
C) γ rays.
D) X-rays
48) Which type of radiation is not used for medical applications?
A) alpha emission
B) beta emission
C) gamma radiation
D) positron emission
49) Which of the following isotopes is not used for medical purposes?
A) 3H
B) 14C
C) 32P
D) 60Co
50) A few sheets of ordinary paper can form an effective shield against what type of radiation?
A) alpha particles
B) cosmic rays
C) gamma rays
D) neutrons
51) A small block of wood or heavy clothing can form an effective shield against what type of radiation?
A) beta particles
B) cosmic rays
C) gamma rays
D) neutrons
52) What type of shielding can be used to protect against gamma rays?
A) cloth
B) lead
C) wood
D) No shielding is effective against gamma rays.
53) Which is more dangerous in terms of short-lived exposure to radiation? One mole of
A) 89Sr, β–, t1/2 = 50.5 days.
B) 90Sr, β–, t1/2 = 28.5 years.
C) 91Sr, β–, t1/2 = 9.5 hours.
D) 94Sr, β–, t1/2 = 74 seconds.
54) Which type of radiation source would pose the greatest health risk when used internally for a
medical procedure?
A) an alpha emitter, t1/2 = 6 hours
B) a beta emitter, t1/2 = 6 hours
C) a beta emitter, t1/2 = 15 days
D) a gamma emitter, t1/2 = 6 hours
55) Most of the radiation to which people are exposed comes from
A) atmospheric testing of nuclear weapons.
B) emissions from nuclear power plants.
C) medical procedures.
D) natural sources.
56) Radiation is dangerous to organisms because
A) all radionuclides are poisonous.
B) it causes electrolysis of water in the cells.
C) it causes nuclear reactions in the cells.
D) it ionizes molecules in the cells.
57) Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-
gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per
minute. If the half-life for carbon-14 is 5715 years, how old is a wood sample that gives a rate for
carbon-14 decay of 3.9 counts per minute?
A) 4.6 × 103 yr
B) 6.6 × 103 yr
C) 1.0 × 104 yr
D) 2.9 × 104 yr
58) An archeological artifact was subjected to radiocarbon dating. The artifact showed a carbon-14
decay rate of 13.8 disintegrations/min per gram of carbon. Carbon-14 has a half-life of 5715 years, and
currently living organisms decay at the rate of 15.3 disintegrations/min per gram of carbon. What is the
approximate age of the artifact?
A) 257 years old
B) 371 years old
C) 591 years old
D) 851 years old
59) The ratio of 238U to 206Pb is used to date old mineral samples. Each 1.000 g of 238U that decays
eventually produces 0.866 g of 206Pb. If the half-life of 238U is 4.468 × 109 years, what is the age of a
mineral that has a 238U/206Pb mass ratio of 2.00?
A) 2.94 × 109 years
B) 3.60 × 109 years
C) 3.87 × 109 years
D) 4.47 × 109 years
60) If a log contains 60.0% of the 14C present in a living tree, how long has the log been dead? The
half-life of 14C is 5730 years.
A) 2290 years
B) 3430 years
C) 4220 years
D) 7560 years
61) The practical limit for 14C dating occurs when its activity falls to 0.20% of its original value due to
interference in detectors by natural background radiation. If the half-life is 5715 years, what is the
maximum age of a sample that can be dated by 14C without interference?
A) 1.3 × 104 years
B) 2.9 × 104 years
C) 5.1 × 104 years
D) 2.9 × 106 years
62) If the age of the Earth is 4.5 billion years and the half-life of 40K is 1.26 billion years, what percent
of the Earth’s original amount of 40K remains today?
A) 4.2%
B) 8.4%
C) 12%
D) 16%
63) Radium occurs only in uranium ores, typically with an observed Ra/U ratio of 1mg/3kg. Uranium
ores normally contain only about 200 ppm of U. How many kilograms of uranium ore must be processed
to obtain 1 mg of radium?
A) 1700 kg ore
B) 15,000 kg ore
C) 6.0 × 108 kg ore
D) None of these
22.2 Algorithmic Questions
1) Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-
gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per
minute. If the half-life for carbon-14 is 5715 years, how old is a wood sample that gives a rate for
carbon-14 decay of 11.9 counts per minute?
A) 5.3 × 102 yr
B) 7.6 × 102 yr
C) 1.1 × 103 yr
D) 9.4 × 103 yr
22.3 Short Answer Questions
1) The loss in mass that occurs when protons and neutrons combine to form a nucleus is called the
________ of the nucleus, and the corresponding energy released during the formation of that nucleus is
the ________ that holds the nucleus together.
2) The mass of a helium-4 nucleus is ________ (greater than, less than, the same as) the sum of the
masses of two protons plus two neutrons.
3) Helium-3, an electron, a neutron, and a proton have masses of 3.016029 amu, 5.486 × 10-4 amu,
1.00866 amu, and 1.00728 amu, respectively. The mass defect for the formation of helium-3 is
________ amu or ________ g/mol.
4) The mass defect for the formation of lithium-6 is 0.0343 g/mol. The binding energy for lithium-6
nuclei is ________ kJ/mol.
5) The binding energy for lithium-7 nuclei is 3.79 × 1012 J/mol. The binding energy per nucleon for
lithium-7 nuclei is ________ MeV/nucleon.
6) The mass defect for the chemical reaction shown below is ________ g.
2 F → F2 E = -159 kJ/mol
7) The mass change for the reaction shown below is ________ amu. The atomic masses are 3He
(3.0160), 4He (4.0026), 1H (1.0078).
2
3He
2
→
4He
2
+ 2
1H
1
8) The reaction below releases ________ kJ/mol. The atomic masses are 3He (3.0160), 1H (1.0078),
4He (4.0026), 0e (0.0005486).
3He
2
+
1H
1
→
4He
2
+
0e
1
9) Energy is ________ (released, required) in the transmutation reaction shown below. The atomic
masses are 40Ar (39.9624), 1H (1.0078), 40K (39.9640), 1n (1.0087).
40Ar
18
+
1H
1
→
40Kr
19
+
1n
0
10) The two reactions shown below are classified as (1) nuclear ________ and (2) nuclear ________.
(1)
1n
0
+
235U
92
→
142Ba
56
+
91Kr
36
+ 3
1n
0
(2)
1H
1
+
2H
1
→
3He
2
11) What is needed to balance the nuclear fission reaction below?
1n
0
+
235U
92
→
137Te
52
+ ? + 2
1n
0
12) What is needed to balance the nuclear fusion reaction below?
2
1H
1
→
2H
1
+ ?
13) In the transmutation reaction that results in the formation of berkelium-243, shown below, the
nucleus that is bombarded by alpha particles is ________.
? +
4He
2
→
243Bk
97
+ 2
1n
0
241Am
95
14) What is needed to balance the nuclear transmutation reaction below?
241Am
95
→
237Np
93
+ ?
15) Units used for measuring radiation include the becquerel, the curie, the gray, and the sievert, which
have the abbreviations ________, ________, ________, and ________, respectively.
16) Among the types of radiation, α, β, γ, and X, the one that requires the least amount of protective
clothing is ________ radiation.
17) Radiocarbon dating involves the unbalanced equation shown below. Needed to balance this equation
is ________. This is an example of ________ decay.
14C
6
→
14N
7
+ ?
18) Carbon-14 has a half-life of 5715 years. Currently living organisms decay at a rate of 15.3
disintegrations/ min per gram of carbon. If an archeological artifact has a carbon-14 decay rate of 12.0
disintegrations/ min per gram of carbon, the approximate age of the artifact is ________ years old.
19) Human bones found on the west coast of the United States were thought to be remains of a
prospector who lived in the 19th century. The bones were subjected to carbon-14 dating. Carbon-14 has
a half-life of 5715 years. Living organisms decay at a rate of 15.3 disintegrations per minute per gram of
carbon. The bones had a carbon-14 decay rate of 5.13 disintegrations per minute per gram of carbon. To
one significant figure the age of the bones is ________ years old, so the person ________ (did, did not)
live in the 19th century.
20) An average person receives 40 mrem of radiation from medical procedures annually. If a dose as
low as 25 rem can lead to a decrease in white blood cell count, what is the maximum number of medical
procedures that involve radiation allowable before white blood cell count decrease occurs?
21) 201Tl is used in myocardial perfusion imaging. It undergoes beta decay with a half-life of 73 hours
generating 80 keV X-rays. A typical dose is 2.5 mCi which is equal to ________ Bq.