Question 1

The s-process involves a slow succession of neutron absorption and beta decay processes during the normal life of a star.

Accepted Answer

A) True 
 B)False

Question 2

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?

Accepted Answer

A) 0.027 rads 
B) 1.2 rads 
C) 37 rads 
D) 85 rads 
E) None of these choices are correct. 
A) 0.027 rads 
B) 1.2 rads 
C) 37 rads 
D) 85 rads 
E) None of these choices are correct.

Question 3

A 7.85 × 10-5 mol sample of copper-61 emits 1.47 × 1019 positrons in 90.0 minutes. What is the decay constant for copper-61?

Accepted Answer

A) 0.00230 h -1 
B) 0.00346 h -1 
C) 0.207 h -1 
D) 0.311 h -1 
E) None of these choices are correct. 
A) 0.00230 h -1 
B) 0.00346 h -1 
C) 0.207 h -1 
D) 0.311 h -1 
E) None of these choices are correct.

Question 4

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?

Accepted Answer

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

Question 5

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?

Accepted Answer

A) 2.4 × 10 -20 
B) 1.5 × 10 -7 
C) 1.8 × 10 -16 
D) 6.1 × 10 -15 
E) None of these choices are correct. 
A) 2.4 × 10 -20 
B) 1.5 × 10 -7 
C) 1.8 × 10 -16 
D) 6.1 × 10 -15 
E) None of these choices are correct.

Question 6

The isotope   has a half-life of 21 hours. If a sample initially contains exactly 10000 atoms of   , approximately how many of these atoms will remain after one week?

Accepted Answer

A) 1250 
B) 78 
C) 39 
D) 0 
E) None of these choices are correct. 
A) 1250 
B) 78 
C) 39 
D) 0 
E) None of these choices are correct.

Question 7

The radioisotope   will decay through

Accepted Answer

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

Question 8

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

Accepted Answer

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

Question 9

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10-2 g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 1020. What is the atomic weight of the unknown element?

Accepted Answer

A) 32 amu 
B) 16 amu 
C) 8 amu 
D) 4 amu 
E) None of these choices are correct. 
A) 32 amu 
B) 16 amu 
C) 8 amu 
D) 4 amu 
E) None of these choices are correct.

Question 10

In living organisms, C-14 atoms disintegrate at a rate of 15.3 atoms per minute per gram of carbon. A charcoal sample from an archaeological site has a C-14 disintegration rate of 9.16 atoms per minute per gram of carbon. Estimate the age of this sample. The half-life of C-14 is 5730 years.

Accepted Answer

A) 3170 years 
B) 3430 years 
C) 4020 years 
D) 4790 years 
E) 6750 years 
A) 3170 years 
B) 3430 years 
C) 4020 years 
D) 4790 years 
E) 6750 years

Question 11

The radioisotope   will decay through

Accepted Answer

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

Question 12

Iodine-131, t1/2 = 8.0 days, is used in 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?

Accepted Answer

A) 2.0 days 
B) 16 days 
C) 32 days 
D) 128 days 
E) None of these choices are correct. 
A) 2.0 days 
B) 16 days 
C) 32 days 
D) 128 days 
E) None of these choices are correct.

Question 13

So-called "magic numbers" of particles are thought to convey extra stability to certain nuclei. These magic numbers refer to which of the following particles?

Accepted Answer

A) Protons only 
B) Electrons only 
C) Positrons only 
D) Neutrons only 
E) Protons and Neutrons 
A) Protons only 
B) Electrons only 
C) Positrons only 
D) Neutrons only 
E) Protons and Neutrons

Question 14

Which of the following cannot be an example of nuclear fusion?

Accepted Answer

A) A nuclear reaction in which two reactants have greater binding energy than their fused product. 
B) A nuclear reaction in which a carbon nucleus is produced. 
C) The primary energy-producing reaction in the Sun. 
D) The primary energy-producing reaction in a hydrogen bomb. 
E) A reaction in which the reactants are less stable than the products. 
A) A nuclear reaction in which two reactants have greater binding energy than their fused product. 
B) A nuclear reaction in which a carbon nucleus is produced. 
C) The primary energy-producing reaction in the Sun. 
D) The primary energy-producing reaction in a hydrogen bomb. 
E) A reaction in which the reactants are less stable than the products.

Question 15

The isotope   has a half-life of 7.5 seconds. If a sample contains 144 atoms of   approximately how many such atoms were there present 30 seconds earlier?

Accepted Answer

A) 576 
B) 1152 
C) 2304 
D) 4320 
E) 4.30 × 10 8 
A) 576 
B) 1152 
C) 2304 
D) 4320 
E) 4.30 × 10 8

Question 16

A scintillation counter

Accepted Answer

A) measures the signal coming from an ionized gas. 
B) measures light emissions from excited atoms. 
C) depends on an avalanche of electrons generated as a particle moves through a tube of argon gas. 
D) detects high energy radiation better than low energy radiation. 
E) detects an electric current in a gas. 
A) measures the signal coming from an ionized gas. 
B) measures light emissions from excited atoms. 
C) depends on an avalanche of electrons generated as a particle moves through a tube of argon gas. 
D) detects high energy radiation better than low energy radiation. 
E) detects an electric current in a gas.

Question 17

The isotope   is unstable. This is predictable because

Accepted Answer

A) N/ Z ≠ 1. 
B) N/ Z is relatively low and Z < 20. 
C) N/ Z is relatively large and Z < 20. 
D) Z is small. 
E) N is large. 
A) N/ Z ≠ 1. 
B) N/ Z is relatively low and Z < 20. 
C) N/ Z is relatively large and Z < 20. 
D) Z is small. 
E) N is large.

Question 18

Radioactive decay follows zero-order kinetics.

Accepted Answer

A) True 
 B)False

Question 19

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?

Accepted Answer

A) 3.35 × 10 -14 yr -1 
B) 4.96 × 10 -11 yr -1 
C) 1.40 × 10 10 yr -1 
D) 2.99 × 10 13 yr -1 
E) None of these choices are correct. 
A) 3.35 × 10 -14 yr -1 
B) 4.96 × 10 -11 yr -1 
C) 1.40 × 10 10 yr -1 
D) 2.99 × 10 13 yr -1 
E) None of these choices are correct.

Question 20

Which of the following series of radioactive decays would convert Pa-234 to Ra-226?

Accepted Answer

A) Beta, Alpha, Beta 
B) Alpha, Alpha 
C) Beta, Alpha, Alpha, Beta 
D) Beta, Alpha, Alpha 
E) Alpha, Beta, Gamma 
A) Beta, Alpha, Beta 
B) Alpha, Alpha 
C) Beta, Alpha, Alpha, Beta 
D) Beta, Alpha, Alpha 
E) Alpha, Beta, Gamma

Exam 24: Nuclear Reactions and Their Applications

The s-process involves a slow succession of neutron absorption and beta decay processes during the normal life of a star.

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?

A 7.85 × 10-5 mol sample of copper-61 emits 1.47 × 1019 positrons in 90.0 minutes. What is the decay constant for copper-61?

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?

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?

The isotope has a half-life of 21 hours. If a sample initially contains exactly 10000 atoms of , approximately how many of these atoms will remain after one week?

The radioisotope will decay through

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

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10-2 g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 1020. What is the atomic weight of the unknown element?

In living organisms, C-14 atoms disintegrate at a rate of 15.3 atoms per minute per gram of carbon. A charcoal sample from an archaeological site has a C-14 disintegration rate of 9.16 atoms per minute per gram of carbon. Estimate the age of this sample. The half-life of C-14 is 5730 years.

The radioisotope will decay through

Iodine-131, t1/2 = 8.0 days, is used in 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?

So-called "magic numbers" of particles are thought to convey extra stability to certain nuclei. These magic numbers refer to which of the following particles?

Which of the following cannot be an example of nuclear fusion?

The isotope has a half-life of 7.5 seconds. If a sample contains 144 atoms of approximately how many such atoms were there present 30 seconds earlier?

A scintillation counter

The isotope is unstable. This is predictable because

Radioactive decay follows zero-order kinetics.

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?

Which of the following series of radioactive decays would convert Pa-234 to Ra-226?

Keys to the Study of Chemistry: Definitions, Units, and Problem Solving

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and Reaction Direction

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

Transition Elements and Their Coordination Compounds

Filters

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?

A 7.85 × 10^-⁵ mol sample of copper-61 emits 1.47 × 10¹⁹ positrons in 90.0 minutes. What is the decay constant for copper-61?

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?

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?

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10^-²g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 10²⁰. What is the atomic weight of the unknown element?

Iodine-131, t_1/2 = 8.0 days, is used in 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?

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