Deck 20: Nuclear Chemistry

Question 1

Uranium-235 decays by alpha emission. What isotope is also produced by this transformation?

A) Pa-234
B) Th-237
C) Pu-237
D) Th-231
E) Pu-239

Answer 1

Th-231

Question 2

What is the name for spontaneous emission of particles or electromagnetic radiation by certain nuclei?

A) Protons
B) Isotopes
C) Radioactivity
D) Neutrons
E) Electrons

Answer 2

Radioactivity

Question 3

Beta particles are identical to

A) protons.
B) helium atoms.
C) hydrogen atoms.
D) helium nuclei.
E) electrons.

Answer 3

electrons.

Question 4

What is the missing symbol in this plutonium fission reaction?

A)
B)
C)
D)
E)

Question 5

When atoms of beryllium-9 are bombarded with alpha particles, neutrons are produced. What new isotope is also formed?

A)
B)
C)
D)
E)

Question 6

The only stable isotope of aluminum is aluminum-27. What type of radioactive decay should be expected from ?

A)
B)
C)
D)
E)

Question 7

Which equation correctly represents positron decay of ?

A)
B)
C)
D)
E)

Question 8

Alpha particles are identical to

A) protons.
B) helium atoms.
C) hydrogen atoms.
D) helium nuclei.
E) electrons.

Question 9

In the equation below, what particle or type of radiation needs to be included to balance the equation? ²⁰⁸Pb → ? + ²⁰⁴Hg

A) Gamma particle
B) Alpha particle
C) Proton
D) Beta particle
E) Positron

Question 10

As a result of beta decay, the product nucleus is

A) one atomic number lower than the original element.
B) two atomic numbers higher than the original element.
C) one atomic number higher than the original element.
D) two atomic numbers lower than the original element.
E) four atomic numbers lower than the original element.

Question 11

What other particle is emitted when a neutron is converted to a proton in a nucleus?

A) Gamma particle
B) Alpha particle
C) Positron
D) Beta particle
E) None of the answers is correct.

Question 12

Which is an incorrect representation of the indicated particle or nucleus?

A)
B)
C)
D)
E)

Question 13

In the equation below, what particle or type of radiation needs to be included to balance the equation? ²³⁴Th → ? + beta particle

A) Ac-234
B) Pa-234
C) Ac-235
D) Pa-235
E) Ac-233

Question 14

In the equation below, what particle or type of radiation needs to be included to balance the equation? ²⁰⁸Po → ? + ²⁰⁸At

A) Gamma particle
B) Alpha particle
C) Proton
D) Beta particle
E) Positron

Question 15

A typical radius of an atomic nucleus is about

A) 100 µm.
B) 5000 mm.
C) 100 nm.
D) 5 × 10^-3 pm.
E) 500 pm.

Question 16

Select the nuclide that completes the following nuclear reaction ?

A)
B)
C)
D)
E) None of these choices is correct.

Question 17

What is the name given to the nuclear process that results from the bombardment of nuclei by neutrons, protons, or other nuclei?

A) Nuclear transmutation
B) Protonation
C) Nucleation
D) Nuclear condensation
E) Radioactivity

Question 18

Which equation correctly represents electron capture by the nucleus?

A)
B)
C)
D)
E)

Question 19

In the equation below, what particle or type of radiation needs to be included to balance the equation? ²²⁰Rn → ? + alpha particle

A) Ra-224
B) Rn-224
C) Rn-216
D) At-220
E) Po-216

Question 20

When atoms of aluminum-27 are bombarded with alpha particles, a neutron and an element are produced. Which particular isotope of this element is formed?

A)
B)
C)
D)
E)

Question 21

Charcoal found under a stone at Stonehenge, England, has a carbon-14 activity that is 0.60 that of new wood. How old is the charcoal? (The half-life of carbon-14 is 5730 years.)

A) Less than 5730 yr
B) Between 5730 and 11,460 yr
C) Between 11,460 and 17,190 yr
D) More than 17,190 yr

Question 22

The radiochemist, Will I. Glow, studied thorium-232 and found that 2.82 × 10^-7 moles emitted 8.42 × 10⁶ α particles in one year. What is the decay constant for thorium-232?

A) 3.35 × 10^-14 yr^-1
B) 4.96 × 10^-11 yr^-1
C) 1.40 × 10¹⁰ yr^-1
D) 2.99 × 10¹³ yr^-1
E) None of the answers is correct.

Question 23

A mass of 6.02 × 10²⁶ amu is equivalent to

A) 1 J.
B) 1 kg.
C) 1 g.
D) 1 mol.
E) 1 mg.

Question 24

Polonium-208 is an alpha emitter with a half-life of 2.90 years. How many milligrams of polonium from an original sample of 2.00 mg will remain after 8.00 years?

A) 0.147 mg
B) 0.296 mg
C) 0.725 mg
D) 6.77 mg
E) 1.90 mg

Question 25

What is the nuclear binding energy per nucleon for ? (1 kg = 6.022 × 10²⁶ amu;
C = 2.99792458 × 10⁸ m/s)
Particle Mass (amu) 24.985839 1.007276 1.008665

A) 0.214 J/nucleon
B) 3.20 × 10^-11 J/nucleon
C) 1.28 × 10^-12 J/nucleon
D) 0.999 J/nucleon
E) 7.35 × 10^-11 J/nucleon

Question 26

Calculate the energy released in joules when one mole of polonium-214 decays according to the following equation. (1 kg = 6.022 × 10²⁶ amu; N_A = 6.022 × 10²³ mol^-1;
C = 2.99792458 × 10⁸ m/s)

A) 8.78 × 10¹⁴ J/mol
B) 7.2 × 10¹⁴ J/mol
C) 8.76 × 10¹¹ J/mol
D) -9.75 × 10^-3 J/mol
E) 1.46 × 10^-9 J/mol

Question 27

Iodine-131, t_1/2 = 8.0 days, is used in the diagnosis and treatment of thyroid gland diseases. If a laboratory sample of iodine-131 initially emits 9.95 × 10¹⁸ β particles per day, how long will it take for the activity to drop to 6.22 × 10¹⁷ β particles per day?

A) 2.0 days
B) 16 days
C) 32 days
D) 128 days
E) None of the answers is correct.

Question 28

What is the nuclear binding energy per nucleon of uranium-234? [1 kg = 6.022 × 10²⁶ amu; N_A = 6.022 × 10²³ mol^-1; c = 2.99792458 × 10⁸ m/s]

A) 2.75 × 10^-10 J/nucleon
B) 3.04 × 10^-10 J/nucleon
C) 1.38 × 10^-12 J/nucleon
D) 1.27 × 10^-12 J/nucleon
E) 1.18 × 10^-12 J/nucleon

Question 29

The nuclear binding energy per nucleon is defined by which of the following?

A)
B) (Nuclear binding energy)² × (# nucleons)
C)
D) (# nucleons)² × (mol of nucleons)
E) None of the answers is correct.

Question 30

An isotope with a high value of N/Z will tend to decay through

A) α decay.
B) β decay.
C) positron decay.
D) electron capture.
E) γ decay.

Question 31

What fraction of radioactive atoms remains in a sample after six half-lives?

A) zero
B) 1/6
C) 1/16
D) 1/32
E) 1/64

Question 32

Cesium-134 is a β emitter with a half-life of 2.0 years. How much of a 2.50-g sample of cesium-134 will remain after 10 years?

A) 0.0024 g
B) 0.078 g
C) 0.25 g
D) 0.50 g
E) 80.0 g

Question 33

What is the energy equivalent of 1 amu? (c = 2.99792458 × 10⁸ m/s)

A) 5.0 × 10^-19 J
B) 5.4 × 10⁴³ J
C) 6.6 × 10⁹ J
D) 1.5 × 10^-10 J

Question 34

What is the name for the difference between the mass of an atom and the sum of the masses of its constituent nucleons?

A) Gamma particle
B) Alpha particle
C) Mass difference
D) Beta particle
E) Mass defect

Question 35

A rock contains 0.37 mg of Pb-206 and 0.95 mg of U-238. Approximately how many U-238 atoms were in the rock when it was formed billions of years ago? (The half life for ²³⁸U → ²⁰⁶Pb is 4.51 × 10⁹ yr.)

A) 1.32 atoms
B) 5.8 × 10^-6 atoms
C) 2.4 × 10¹⁸ atoms
D) 3.3 × 10¹⁸ atoms
E) 3.5 × 10²¹ atoms

Question 36

The ¹⁴C activity of some ancient Peruvian corn was found to be 10 disintegrations per minute per gram of carbon. If present-day plant life shows 15 dpm/g, how old is the Peruvian corn? (The half-life of ¹⁴C is 5730 yr.)

A) 1460 yr
B) 1910 yr
C) 3350 yr
D) 3820 yr
E) 9080 yr

Question 37

Cobalt-60 is a beta emitter with a half-life of 5.3 years. Approximately what fraction of cobalt-60 atoms will remain in a particular sample after 26.5 years?

A) 1/5
B) 1/16
C) 1/26
D) 1/32
E) 1/64

Question 38

Determine how much energy is released when thorium-230 decays according to the following equation. (1 kg = 6.022 × 10²⁶ amu; N_A = 6.022 × 10²³ mol^-1;
C = 2.99792458 × 10⁸ m/s)

A) 3.98 × 10⁹ kJ/mol
B) 4.61 × 10⁸ kJ/mol
C) 7.20 × 10¹¹ kJ/mol
D) 4.90 × 10⁹ kJ/mol
E) 7.15 × 10¹¹ kJ/mol

Question 39

1 joule equals ________.

A) 1 kg • m
B) 1 g • m² • s²
C) 1 kg • m²/s
D) 1 g • m²/s
E) 1 kg • m²/s²

Question 40

What is the nuclear binding energy per nucleon of potassium-40? (1 kg = 6.022 × 10²⁶ amu; N_A = 6.022 × 10²³ mol^-1;
C = 2.99792458 × 10⁸ m/s)

A) 1.33 × 10^-12 J/nucleon
B) 5.33 × 10^-11 J/nucleon
C) 5.64 × 10^-11 J/nucleon
D) 1.41 × 10^-12 J/nucleon
E) 2.97 × 10^-12 J/nucleon

Question 41

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 × 10⁹ yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

A) 8.1 × 10^-10 yr.
B) 2.4 × 10⁹ yr.
C) 2.8 × 10⁹ yr.
D) 4.6 × 10⁹ yr.
E) 6.8 × 10⁹ yr.

Question 42

In the following reaction, identify X.

A)
B)
C)
D)
E)

Question 43

The half-life of ¹⁴C is 5730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

A) 3.0 × 10^-2
B) 0.20
C) 3.5
D) 0.33
E) 0.29

Question 44

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial ¹⁴C atoms is still there? (t_1/2 = 5730 yr)

A) 0
B) 1 × 10^-10
C) 5.7 × 10^-5
D) 1.0 × 10^-3
E) 5.7 × 10^-1

Question 45

Which isotope, when bombarded with nitrogen-15, yields four neutrons and the artificial isotope dubnium-260?

A) Californium-245
B) Thorium-257
C) Nobelium-245
D) Californium-249
E) Dubnium-249

Question 46

Identify the missing species in the following nuclear transmutation.

A)
B)
C)
D)
E)

Question 47

Identify the missing species in the following nuclear transmutation. U-238 + ? → 1 neutron + Fm-249

A)
B)
C)
D)
E)

Question 48

A pure sample of tritium, ³H, was prepared and sealed in a container for a number of years. Tritium undergoes β decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of ³H and 6.35 mol of ³He present?

A) 2.34 yr
B) 3.38 yr
C) 9.77 yr
D) 14.1 yr
E) 25.6 yr

Question 49

A patient's thyroid gland is to be exposed to an average of 5.5 µCi for 16 days as an ingested sample of iodine-131 decays. If the energy of the β radiation is 9.7 × 10^-14 J and the mass of the thyroid is 32.0 g, what is the dose received by the patient? (1 rad = 1 × 10^-5 J/g; 1 Ci = 3.7 × 10¹⁰ disintegrations/s)

A) 0.027 rads
B) 85 rads
C) 37 rads
D) 23 rads
E) None of the answers is correct.

Question 50

In the following reaction, identify X.

A) 7β
B) 3α
C) 4n
D)
E) 15p

Question 51

A sample of a radioisotope shows an activity of 999 disintegrations per minute due to beta decay. If after 1.10 years the activity is 952 disintegrations per minute, what is the half-life of this radioisotope?

A) 4.38 × 10^-2 yr
B) 11.4 yr
C) 0.25 yr
D) 15.8 yr
E) 9.1 yr

Question 52

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5730 yr)

A) 6800 yr
B) 2500 yr
C) 4700 yr
D) 10,000 yr
E) 7200 yr

Question 53

Rubidium-87 decays by beta decay with a half-life of 4.9 × 10¹⁰ yr. How many ⁸⁷Rb atoms are in a moon rock sample that has a rubidium decay rate of 3500 disintegrations per hour?

A) 9.0 × 10¹⁶ atoms
B) 4.3 × 10^-4 atoms
C) 2.2 × 10¹⁸ atoms
D) 2.5 × 10¹⁴ atoms
E) 1.7 × 10¹⁴ atoms

Question 54

An 85-kg person exposed to barium-141 receives 2.5 × 10⁵ β particles, each with an energy of 5.2 × 10^-13 J. How many rads does the person receive? (1 rad = 1 × 10^-5 J/g)

A) 2.4 × 10^-20 rads
B) 1.5 × 10^-7 rads
C) 1.8 × 10^-16 rads
D) 6.1 × 10^-15 rads
E) None of the answers is correct.

Question 55

Identify the missing species in the following nuclear transmutation.

A)
B)
C)
D)
E) None of the answers is correct.

Question 56

Identify the missing species in the following nuclear transmutation.

A)
B)
C)
D)
E)

Question 57

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were preserved for the next 3900 years, what ¹⁴C decay rate should be expected from the wood used to make the chair? (t_1/2 = 5730 yr)

A) 26 dpm
B) 12 dpm
C) 11 dpm
D) 10 dpm
E) 8 dpm

Question 58

How many ¹⁴C atoms are in a charcoal sample that has a decay rate of 3500 disintegrations per min? (For ¹⁴C, t_1/2 = 5730 yr.)

A) 2.9 × 10⁷ atoms
B) 8.0 × 10^-7 atoms
C) 1.4 × 10¹⁴ atoms
D) 1.5 × 10¹³ atoms
E) 6.02 × 10²⁰ atoms

Question 59

Estimate the age of a bottled wine that has a tritium, ³H, content 60% that of freshly bottled wine. Tritium decays by beta decay and has a half-life of 12.3 yr.

A) 0.029 yr
B) 7.4 yr
C) 9.1 yr
D) 16 yr
E) 35 yr

Question 60

Which isotope, when bombarded with bismuth-209, would yield two neutrons and an isotope with atomic number 121 and mass number 299?

A) Pb-211
B) Po-209
C) Sr-92
D) Rn-38
E) Sr-38

Question 61

The energy released by the sun is the result of

A) natural radioactivity.
B) nuclear fusion.
C) combustion of hydrogen.
D) photosynthesis.
E) nuclear fission.

Question 62

What role does cadmium metal (Cd) play in a nuclear reactor?

A) Slows down the fission neutrons (moderator)
B) Transfers heat from the reactor to the heat exchanger (primary coolant)
C) Controls chain reaction (control rods)
D) Transfers heat from the condenser to the environment (cooling tower)
E) Undergoes fission (fuel rods)

Question 63

In passing through matter, alpha particles lose energy chiefly by causing

A) fermentation.
B) neutralization.
C) ionization.
D) condensation.
E) carbonation.

Question 64

Exposure to 10 nCi for 10 minutes is more hazardous for a child than for an adult because

A) the child's cells are dividing more rapidly than the adult's and are, therefore, more susceptible to the radiation.
B) the child's smaller body size makes the effective dose larger for the child than for the adult.
C) the child's immune system is not developed well enough to resist damage.
D) the child's skin is not as thick as an adult's and cannot block as much radiation.
E) None of these reasons is correct.

Question 65

What is the nuclear process called where small nuclei are combined into larger ones?

A) Photonuclear reactions
B) Nuclear fission
C) Thermal conductivity
D) Nuclear combination
E) Nuclear fusion

Question 66

A particle accelerator uses which of the following to increase the kinetic energy of charged species so that a reaction will occur?

A) Electromagnetic fields
B) Fission reaction
C) Gravitational field
D) Fusion reaction
E) Combustion reaction

Question 67

It is believed that two carbon-12 nuclei can react in the core of a supergiant star to form sodium-23 and hydrogen-1. Calculate the energy released from this reaction for each mole of hydrogen formed. (1 kg = 6.022 × 10²⁶ amu; N_A = 6.022 × 10²³ mol^-1;
C = 2.99792458 × 10⁸ m/s)

A) 2.16 × 10¹⁴ kJ
B) 2.16 × 10¹¹ kJ
C) 2.16 × 10⁸ kJ
D) 2.16 × 10⁵ kJ
E) None of the answers is correct.

Question 68

Which type of nuclear process requires an extremely high temperature (millions of degrees)?

A) Beta decay
B) Fission reaction
C) Fusion reaction
D) Alpha decay
E) Positron emission

Question 69

Which of the following materials is put into a nuclear reactor to slow the chain reaction?

A) Heavy water
B) Moderators
C) Control rods
D) Reflectors
E) Chlorine

Question 70

What causes the radiation damage to matter when gamma rays damages it?

A) Another isotope
B) Oxidation
C) Reduction
D) Free radicals and ions
E) Corrosion

Question 71

The dose unit of ionizing radiation is called the rad. The rad is defined in terms of

A) the half-life of a radioisotope.
B) the energy deposited per gram of an object.
C) the biological damage produced.
D) the accumulation of fission products.
E) the number of ions per centimeter.

Question 72

Which statement is false?

A) Fission occurs among the heaviest isotopes, whereas fusion occurs more readily for light isotopes.
B) The mass defect (Δm) for a fission reaction is negative, whereas Δm for fusion is positive.
C) In order for fusion reactions to occur, temperatures must be in the millions of degrees.
D) The fission of Pu-239 atoms produces isotopes of many different elements.
E) Neutron-induced fission processes can occur at room temperature, rather than at millions of degrees.

Question 73

A 30.0-kg child receives 2.65 × 10⁷ β particles, each with an energy of 4.60 × 10^-13 J. If the RBE = 0.78, how many millirem did the child receive?

A) 3.2 × 10^-7 millirem
B) 5.2 × 10^-7 millirem
C) 5.2 × 10^-4 millirem
D) 3.2 × 10^-2 millirem
E) None of these choices is correct.

Question 74

What element is the stable end-product of the uranium radioactive decay series?

A) Th
B) Pu
C) Ra
D) Au
E) Pb

Question 75

Sodium-21 will emit positrons, each having an energy of 4.0 × 10^-13 J. What is this energy in MeV? (1 MeV = 1.602 × 10^-13 J)

A) 4.0 × 10^-7 MeV
B) 2.5 MeV
C) 40 MeV
D) 2.5 × 10⁶ MeV
E) 2.5 × 10^-6 MeV

Question 76

Which type of radiation is the least dangerous to humans?

A) Positrons
B) Neutrons
C) Alpha
D) Beta
E) Gamma

Question 77

Calcium-39 undergoes positron decay. Each positron carries 5.49 MeV of energy. How much energy will be emitted when 0.00250 mol of calcium-39 decays? (1 MeV = 1.602 × 10^-13 J)

A) 13.2 kJ
B) 1.32 × 10⁴ kJ
C) 1.32 × 10⁶ kJ
D) 1.32 × 10⁹ kJ
E) None of these choices is correct.

Question 78

A 55-kg person exposed to thorium-234 receives 7.5 × 10⁴ β particles, each with an energy of 1.6 × 10^-14 J. How many rads does the person receive?

A) 2.1 × 10^-19 rads
B) 1.2 × 10^-17 rads
C) 2.2 × 10^-9 rads
D) 1.2 × 10^-9 rads
E) None of these choices is correct.

Question 79

Which of the following is an advantage of nuclear power plants over coal-burning plants? Nuclear power plants

A) form numerous radioactive fission products.
B) do not pollute the air with SO₂, soot, and fly-ash.
C) produce more thermal pollution than coal plants.
D) use more fuel.

Question 80

Which type of radiation is the most dangerous to humans?

A) Protons
B) Neutrons
C) Alpha
D) Beta
E) Gamma