Download MULTIPLE CHOICE. Choose the one alternative that best

Chemistry 1C-Dr. Larson
Chapter 21 Review Questions
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) By what process does thorium-230 decay to radium-226
__________ ?
A) alpha emission
B) beta emission
C) electron capture
D) gamma emission
E) positron emission
2) This reaction is an example of __________.
210 Po → 206 Pb + __________
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A) gamma emission
B) electron capture
C) positron emission
D) beta emission
E) alpha decay
3) This reaction is an example of __________.
41 Ca → 41 K + __________
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A) beta decay
B) positron decay
C) gamma emission
D) electron capture
E) alpha decay
4) Radium undergoes alpha decay. The product of this reaction also undergoes alpha decay. What is the
product of this second decay reaction __________ ?
A) Hg
B) Po
C) U
D) Th
E) Rn
5) 41Ca decays by electron capture. The product of this reaction undergoes alpha decay. What is the product
of this second decay reaction __________ ?
A) Sc
B) Ar
6) What is the mass number of a neutron
A) 2
B) 4
C) Cl
D) Ca
E) Ti
D) 0
E) 3
__________ ?
C) 1
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7) Nuclei above the belt of stability can lower their neutron-to-proton ratio by_____
A) electron capture.
B) positron emission.
C) gamma emission.
D) beta emission.
E) Any of the above processes will lower the neutron-to-proton ratio.
8) What is the largest number of protons that can exist in a nucleus and still be stable __________ ?
A) 92
B) 50
C) 84
D) 83
E) 206
9) Bombardment of uranium-235 with a neutron generates tellurium-135, 3 neutrons, and __________.
A) zirconium-99.
B) krypton-101.
C) strontium-99.
D) zirconium-98.
E) krypton-103.
10) The reaction shown below is responsible for creating 14C in the atmosphere. What is the bombarding
particle __________ ?
14 N + __________ → 14 C + 1 H
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A) electron
B) neutron
C) positron
D) alpha particle
E) proton
11) What order process is radioactive decay __________ ?
A) zeroth
B) first
C) second
D) third
E) fourth
12) 131I has a half-life of 8.04 days. Assuming you start with a 1.53 mg sample of 131I, how many mg will
remain after 13.0 days __________ ?
A) 0.835
B) 0.422
C) 0.268
D) 0.499
E) 0.440
13) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the mass defect (in amu)
of a 60 Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.) __________.?
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A) 0.4827
B) 27.7830
C) 0.5405
2
D) 0.0662
E) 0.5489
14) What happens to the mass number and the atomic number of an element when it undergoes beta decay?
A) The mass number does not change and the atomic number increases by 1.
B) The mass number increases by 2 and the atomic number increases by 1.
C) The mass number decreases by 4 and the atomic number decreases by 2.
D) Neither the mass number nor the atomic number change.
E) The mass number does not change and the atomic number decreases by 2.
15) Which one of the following is a correct representation of a beta particle?
A) 1 β
0
B) 0 e
-1
C) 2 β
4
D) 0 e
1
E) 4 e
2
16) Of the following processes, which one changes the atomic number?
A) alpha emission
B) electron capture
C) positron emission
D) beta emission
E) All of these processes change the atomic numbers.
17) Which type of radioactive decay results in no change in mass number and atomic number for the starting
nucleus?
A) alpha
B) positron emission
C) beta
D) gamma
E) electron capture
18) Alpha decay produces a new nucleus whose __________ than those respectively of the original nucleus.
A) atomic number is 2 less and mass number is 4 less
B) atomic number is 2 less and mass number is 2 less
C) atomic number is 2 more and mass number is 4 more
D) atomic number is 1 less and mass number is 2 less
E) atomic number is 2 more and mass number is 2 less
19) What is the missing product from this reaction?
32 P → 32 S + __________
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A) 4 He
2
B) 0 γ
0
C) 0 e
1
D) 0 e
-1
E) 0 p
1
D) 1
E) 2
20) What is the atomic number of a neutron __________ ?
A) 3
B) 0
C) 4
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21) What happens to the mass number and the atomic number of an element when it emits gamma radiation?
A) The mass number decreases by four and the atomic number decreases by two.
B) The mass number remains unchanged while the atomic number increases by one.
C) The mass number and atomic numbers remain unchanged.
D) The mass number remains unchanged while the atomic number decreases by one.
E) The mass number increases by four and the atomic number increases by two.
22) At approximately what number of protons, or neutrons, does the 1:1 ratio of protons to neutrons start to
produce unstable nuclei?
A) 10
B) 50
C) 80
D) 30
E) 20
23) Which one of the following can be done to shorten the half-life of the radioactive decay of uranium-238?
A) oxidize it to the +2 oxidation state
B) heat it
C) convert it to UF 6
D) freeze it
E) none of the above
24) The beta decay of cesium-137 has a half-life of 30 years. How many years must pass to reduce a 25 mg
sample of cesium 137 to 8.7 mg?
A) 3.2
B) 50
C) 46
D) 32
25) The carbon-14 dating method can be used to determine the age of a
A) papyrus scroll.
B) clay pot.
C) rock.
D) stone axe head.
E) flint arrowhead.
26) The basis for the carbon-14 dating method is that
A) the amount of carbon-14 in all objects is the same.
B) carbon-14 is very unstable and is readily lost from the atmosphere.
C) living tissue will not absorb carbon-14 but will absorb carbon-12.
D) the ratio of carbon-14 to carbon-12 in the atmosphere is a constant.
E) All of the above are correct.
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E) 52
27) The half-life of a radionuclide
A) gets shorter with passing time.
B) gets longer with increased temperature.
C) is constant.
D) gets shorter with increased temperature.
E) gets longer with passing time.
Consider the following data for a particular radionuclide:
Time (min)
0
3
6
9
12
Nt (g)
1.23
1.15
1.08
1.01
0.940
28) What is the rate constant (in min -1) for the decay of this radionuclide?
A) 0.0242
B) 44.64
C) 0.0224
D) 0.0324
E) 30.9
D) 0.0224
E) 44.64
29) What is the half-life (in min) of this radionuclide?
A) 0.0242
B) 30.9
C) 0.0324
30) Cesium-137 undergoes beta decay and has a half-life of 30 years. How many beta particles are emitted by a
14.0-g sample of cesium-137 in three minutes?
A) 6.2 × 1022
B) 8.4 × 1015
C) 8.1 × 1015
D) 1.3 × 10-8
E) 6.1 × 1013
31) Which one of the following is true?
A) Some spontaneous nuclear reactions are exothermic.
B) All spontaneous nuclear reactions are endothermic.
C) All spontaneous nuclear reactions are exothermic.
D) There is no relationship between exothermicity and spontaneity in nuclear reactions.
E) Some spontaneous nuclear reactions are endothermic.
32) When two atoms of 2H are fused to form one atom of 4He, the total energy evolved is 3.83 × 10-12 J. What
is the total change in mass (in kg) for this reaction? (C = 3.00 × 108 m/s)
A) 4.26 × 10-26
B) 1.28 × 10-17
C) 4.26 × 10-29
D) 3.45 × 108
E) 1.15
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33) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the binding energy (in J)
of a 60 Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.)
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A) 4.940 × 10-13
B) 8.206 × 10-11
C) 2.735 × 10-16
D) 9.117 × 10-28
E) 2.735 × 10-19
34) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the binding energy per
nucleon (in J) of a 60 Co nucleus? (The mass of a cobalt-60 nucleus is 59.9338 amu.)
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A) 9.432 × 10-13
B) 2.487 × 10-12
C) 7.009 × 10-14
D) 3.039 × 10-12
E) 1.368 × 10-12
35) What type of reaction is known as a thermonuclear reaction?
A) transmutation
B) neutron emission
C) fission
D) fusion
E) beta emission
36) The main scientific difficulty in achieving a controlled fusion process is the
A) enormous repulsion between nuclei being fused.
B) very large number of gamma rays emitted.
C) very large number of x-rays emitted.
D) very large number of positrons emitted.
E) enormous repulsion between the electrons of atoms being fused.
37) Which one of the following forms of radiation can penetrate the deepest into body tissue?
A) gamma
B) proton
C) beta
D) positron
E) alpha
38) Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope uranium-235. The half-life of
strontium-90 is 28.8 yr. What percentage of a strontium-90 sample remains after 75.0 yr?
A) 38.4
B) 2.60
C) 16.5
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D) 7.40
E) 68.1
39) A rock contains 0.313 mg of lead-206 for each milligram of uranium-238. The half-life of for the decay of
uranium-238 to lead-206 is 4.5 × 109 yr. The rock was formed __________ yr ago.
A) 1.41 × 10 9
B) 1.08 × 10 9
C) 2.00 × 10 9
D) 1.56 × 10 9
E) 1.39 × 10 9
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
40) What happens in the nucleus of an atom that undergoes positron emission?
41) High speed electrons emitted by an unstable nucleus are __________.
42) The only element with no neutrons is __________.
43) Stable nuclei with low atomic numbers, up to 20, have a neutron to proton ratio of approximately
__________.
44) What is the source of the tremendous energies produced by nuclear reactions?
45) The amount of fissionable material necessary to maintain a chain reactions is called the __________ .
46) What was the purpose of the Manhattan project?
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
47) Gamma radiation only changes the atomic number but not the mass number of a nucleus.
48) The neutron/proton ratio of stable nuclei increases with increasing atomic number .
49) The energy produced by the sun is the result of nuclear fusion.
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
50) Electrons do not exist in the nucleus, yet beta emission is ejection of electrons from the nucleus. How does
this happen?
51) When an isotope undergoes electron capture, what happens to the captured electron?
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Answer Key
Testname: CHAPTER 21 QUIZ
1) A
Page Ref: Sec. 21.1
2) E
Page Ref: Sec. 21.1
3) B
Page Ref: Sec. 21.1
4) B
Page Ref: Sec. 21.1
5) C
Page Ref: Sec. 21.1
6) C
Page Ref: Sec. 21.1
7) D
Page Ref: Sec. 21.2
8) D
Page Ref: Sec. 21.2
9) D
Page Ref: Sec. 21.3
10) B
Page Ref: Sec. 21.3
11) B
Page Ref: Sec. 21.4
12) D
Page Ref: Sec. 21.4
13) E
Page Ref: Sec. 21.6
14) A
Page Ref: Sec. 21.1
15) B
Page Ref: Sec. 21.1
16) E
Page Ref: Sec. 21.1
17) D
Page Ref: Sec. 21.1
18) A
Page Ref: Sec. 21.1
19) D
Page Ref: Sec. 21.1
20) B
Page Ref: Sec. 21.1
21) C
Page Ref: Sec. 21.1
22) E
Page Ref: Sec. 21.2
23) E
Page Ref: Sec. 21.4
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Answer Key
Testname: CHAPTER 21 QUIZ
24) C
Page Ref: Sec. 21.4
25) A
Page Ref: Sec. 21.4
26) D
Page Ref: Sec. 21.4
27) C
Page Ref: Sec. 21.4
28) C
Page Ref: Sec. 21.4
29) B
Page Ref: Sec. 21.4
30) C
Page Ref: Sec. 21.4
31) C
Page Ref: Sec. 21.6
32) C
Page Ref: Sec. 21.6
33) B
Page Ref: Sec. 21.6
34) E
Page Ref: Sec. 21.6
35) D
Page Ref: Sec. 21.8
36) A
Page Ref: Sec. 21.8
37) A
Page Ref: Sec. 21.9
38) C
Page Ref: Sec. 21.4
39) C
Page Ref: Sec. 21.4
40) A proton is converted to a neutron and a positron.
Page Ref: Sec. 21.1
41) beta particles
Page Ref: Sec 21.1
42) hydrogen; H
Page Ref: Sec 21.1
43) 1
Page Ref: Sec. 21.2
44) conversion of matter to energy, mass loss
Page Ref: Sec. 21.6
45) critical mass
Page Ref: Sec 21.7
46) to build a bomb based on nuclear fission
Page Ref: Sec. 21.7
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Answer Key
Testname: CHAPTER 21 QUIZ
47) FALSE
Page Ref: Sec 21.1
48) TRUE
Page Ref: Sec 21.2
49) TRUE
Page Ref: Sec 21.8
50) A neutron breaks apart to produce a proton and an electron in the nucleus. The proton remains in the nucleus and
the electron is ejected.
Page Ref: Sec. 21.1
51) It combines with a proton in the nucleus to form a neutron.
Page Ref: Sec. 21.1
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