Deck 20: The Nucleus: a Chemists View

Question 1

Which of the following is a product of α decay of ?

A)
B)
C)
D)
E)

Answer 1

Question 2

The nuclide is radioactive. When one of these atoms decays, a series of α- and β⁻-particle emissions occurs, taking the atom through many transformations to end up as an atom of
) How many α particles are emitted in converting
Into
?

A) 8
B) 214
C) 4
D) 6
E) 2

Answer 2

6

Question 3

is an unstable isotope. Which radioactive decay would be expected?

A)
B) α
C) fission
D) β
E)

Answer 3

Question 4

When undergoes β emission, what are the products?

A) + β
B)
C) + β
D) + β
E) + β

Question 5

An unstable isotope of Ta-184 is a beta producer. What is the other product of the reaction?

A) Hf-184
B) W-184
C) W-183
D) Pt-192
E) Ta-185

Question 6

The nuclide Ra-222 is the daughter nuclide resulting from the α decay of what parent nuclide?

A) Th-226
B)
C) Rn-208
D) U-224
E) Hg-297

Question 7

The stable nuclide is formed from
By a long series of α and β decays. Which of the following nuclides could not be involved in this decay series?

A) Po-218
B) Pu-239
C) Tl-210
D) Ra-226
E) Th-234

Question 8

The U-238 nucleus decays to form Pb-206 by α and β decays.
Calculate the number of α decays.

A) 2
B) 4
C) 6
D) 8
E) none of these

Question 9

Which types of processes are likely when the neutron-to-proton ratio in a nucleus is too large?
I.α decay
II.β decay
III.positron production
IV.electron capture

A) IV only
B) III, IV
C) II, III
D) I, II
E) II only

Question 10

Heavy nuclides with too few neutrons to be in the band of stability are most likely to decay by what mode?

A) α-particle production.
B) fission
C) β production
D) positron production
E) none of these

Question 11

The U-238 nucleus decays to form Pb-206 by α and β decays.
Calculate the number of β decays.

A) 4
B) 2
C) 8
D) 6
E) none of these

Question 12

Electron capture transforms into what nuclide?

A)
B)
C)
D)
E)

Question 13

It is desired to determine the concentration of arsenic in a lake sediment sample by means of neutron activation analysis. The nuclide captures a neutron to form
, which in turn undergoes β decay. The daughter nuclide produces the characteristic γ rays used for the analysis. What is the daughter nuclide?

A)
B)
C)
D)
E)

Question 14

A radioactive isotope of vanadium, , decays by producing β particles and gamma rays. The nuclide formed has the atomic number

A)23
B)21
C)22
D)24
E) none of these

Question 15

Which reaction will produce an isotope of the parent nuclide?

A) β + ?
B)
C) β + ?
D)
E)

Question 16

The most likely decay mode (or modes) of the unstable nuclide would be

A) positron production.
B) α-particle production.
C) β emission
D) electron capture.
E) either positron production or electron capture or both.

Question 17

The ratio of the atomic radius to the nuclear radius is approximately

A) 10⁵
B) 10^-5
C) 10^-15
D) 10²
E) 10¹⁵

Question 18

Which of the following processes decreases the atomic number by 2?

A) proton production
B) alpha-particle production
C) gamma-ray production
D) beta production
E) positron-particle production

Question 19

What is the most likely decay for the Mn-57 nucleus?

A) positron emission
B) γ-ray emission
C) β decay
D) α decay
E) proton emission

Question 20

Identify the missing particle in the following equation:

A)
B)
C)
D)
E) none of these

Question 21

What is the number of half-lives needed for a radioactive element to decay to one-fourth of its original activity? (Choose the nearest number.)

A) 1
B) 4
C) 3
D) 5
E) 2

Question 22

Which of the following balanced equations is labeled incorrectly?

A) beta production:
B) bombardment:
C) alpha production:
D) alpha emission:
E) fusion:

Question 23

Radioactive elements decay via first-order kinetics. Consider a certain type of nucleus that has a rate constant of 1.9× 10^-2 h^-1. A sample contains 6.6× 10⁸ radioactive nuclides. Calculate the time required to reduce that number to 2.8× 10⁸.

A) 4.5 h
B) 2.0 × 10¹⁰ h
C) 4.5 × 10¹ h
D) 2.0 × 10¹ h
E) 8.1 × 10^-1 h

Question 24

Breeder reactors are used to convert the nonfissionable nuclide into a fissionable product. Neutron capture of the
Is followed by two successive beta decays. What is the final fissionable product?

A)
B)
C)
D)
E)

Question 25

The Cs-131 nuclide has a half-life of 30 years. After 120 years, about 3 g remain. The original mass of the Cs-131 sample is closest to

A) 30 g
B) 70 g
C) 60 g
D) 50 g
E) 40 g

Question 26

It is desired to determine the blood volume of a live mouse. To do this, 0.10 mL of a saline suspension of red blood cells labeled with is injected into the tail vein. Before injection the gamma rays were counted for this 0.10-mL solution, and the count rate was found to be 1.0 × 10⁴ cpm. After a sufficient time for the blood to be thoroughly mixed, 0.10 mL of blood is removed and counted. The sample is found to have a count rate of 476 cpm. What is the approximate blood volume of the mouse?

A) 0.48 mL
B) 4.7 mL
C) 21 mL
D) 4.8 mL
E) 2.1 mL

Question 27

The rate constant for the decay of a radioactive element is 4.72 × 10^-3/day. What is the half-life of this element?

A) 2.36 × 10^-3 days
B) 2.12 × 10² days
C) 1.47 × 10² days
D) 1.06 × 10² days
E) 2.19 × 10² days

Question 28

The half-life of ⁹⁰Sr is 28 years. How long will it take for a given sample of ⁹⁰Sr to be 85% decomposed?

A) 3.3 × 10¹ years
B) 2.9 years
C) 3.3 × 10² years
D) 6.6 years
E) 7.7 × 10¹ years

Question 29

When the U-235 nucleus is struck with a neutron, the Ce-144 and Sr-90 nuclei are produced, along with some neutrons and beta particles.
How many neutrons are emitted?

A) 5
B) 6
C) 2
D) 3
E) 4

Question 30

When the U-235 nucleus is struck with a neutron, the Ce-144 and Sr-90 nuclei are produced, along with some neutrons and beta particles.
How many beta particles are emitted?

A) 5
B) 6
C) 3
D) 2
E) 4

Question 31

When the Pd-106 nucleus is struck with an alpha particle, a proton is produced along with a new element. What is this new element?

A) Cd-109
B) Ag-108
C) Ag-109
D) Cd-112
E) none of these

Question 32

What nuclide is necessary to balance the following fission reaction? __________

A)
B)
C)
D)
E)

Question 33

Radioactive elements decay via first-order kinetics. Consider a certain type of nucleus that has a rate constant of 2.4 × 10^-2 h^-1. A sample contains 6.5 × 10⁸ radioactive nuclides. Calculate the time required for 59% of the nuclides to decompose.

A) 1.0 × 10¹ h
B) 2.2 × 10^-1 h
C) 1.6× 10¹ h
D) 2.2 × 10¹ h
E) 3.7 × 10¹ h

Question 34

Radioactive tracers are useful in studying very low concentrations of chemical species. A chemist has a sample of HgI₂ in which part of the iodine is the radioactive nuclide of mass 131, so that the count rate is 5.0 × 10¹¹ counts per minute per mole of I. The solid mercuric iodide is placed in water and allowed to come to equilibrium. Then 100 mL of the solution is withdrawn, and its radioactivity is measured and found to give 22 counts per minute. What is the molar concentration of iodide ion in the solution?

A) 1.1 × 10^-11
B) 1.1 × 10^-9
C) 1.1 × 10^-10
D) 4.4 × 10^-10
E) 4.4 × 10^-11

Question 35

When the U-235 nucleus is struck with a neutron, the Zn-72 and Sm-160 nuclei are produced, along with some neutrons. How many neutrons are emitted?

A) 2
B) 3
C) 4
D) 5
E) 6

Question 36

The number of a certain radioactive nuclide present in a sample decays from2.0 × 10² to 6.0 × 10¹ in 23 minutes. What is the half-life of this radioactive species?

A) 1.6 × 10¹ minutes
B) 5.2 × 10^-2 minutes
C) 1.3 × 10¹ minutes
D) 5.3 × 10¹ minutes
E) 3.0 minutes

Question 37

A 0.20-mL sample of a solution containing that produces 3.7 × 10³ cps is injected into the bloodstream of an animal. After circulatory equilibrium has been established, a 0.20-mL sample of blood is found to have an activity of 20 cps. Calculate the blood volume of the animal.

A) 18 mL
B) 180 mL
C) 11 mL
D) 37 mL
E) none of these

Question 38

A radioactive element has a half-life of 17 min. How many minutes will it take for the number of atoms present to decay to 1/8th of the initial value?

A) 450 min
B) 51 min
C) 2.1 min
D) 136 min
E) 250 min

Question 39

What is the most likely decay for the Fe-53 nucleus?

A) γ-ray emission
B) α decay
C) β decay
D) positron emission
E) two of these

Question 40

The rate constant for the beta decay of a particular radioactive element is 2.34 × 10^-2/day. What is the half-life of this nuclide?

A) 4.27 × 10¹ days
B) 3.38 × 10^-1 days
C) 2.14 × 10¹ days
D) 8.55 × 10² days
E) 2.96 × 10¹ days

Question 41

Calculate ΔE in kilojoules per mole for the reaction Atomic masses:
,
,
)

A) 0
B) +2.4 × 10⁶ kJ/mol
C) +4.6 × 10⁸ kJ/mol
D) -4.6 × 10⁸ kJ/mol
E) -2.4 × 10⁶ kJ/mol

Question 42

Which statement is true about the following reaction?

A) No energy change is associated with the reaction.
B) Energy is released in the reaction.
C) Energy is absorbed in the reaction.
D) Not enough information is given for us to determine the energy change.

Question 43

If more than one neutron from each fission event causes another fission event, the fission situation is described as

A) supercritical.
B) critical.
C) moderated.
D) subcritical.
E) none of these

Question 44

Which of the following statements is true of the fission of uranium-235?

A) The nuclides produced are individually heavier than the uranium nuclide.
B) The ultimate nuclides produced are more stable than the uranium nuclide.
C) The electron is captured by the nucleus, which becomes unstable.
D) The products include neutrons.
E) two of these

Question 45

The questions below refer to the following:Iron-56, , has a binding energy per nucleon of 8.79 MeV. (1 MeV = 1.60 × 10^-13 J)
Determine the amount of energy needed to "decompose" 1 mol of iron-56 nuclei.

A) 4.74 × 10¹³ J
B) 3.47 × 10¹¹ J
C) 8.90 × 10¹¹ J
D) 1.13 × 10¹⁴ J
E) 7.75 × 10¹³ J

Question 46

If a tree dies and the trunk remains undisturbed for 13,750 years, what percentage of the original ¹⁴C is still present? (The half-life of ¹⁴C is 5730 years.)

A) 2.20%
B) 19.0%
C) 45.0%
D) 5.20%

Question 47

Calculate the change in energy, in kilojoules per mole, for the transmutation of radium from the given molar masses:

A) -4.7 × 10⁸ kJ/mol
B) -4.7 × 10¹⁴ kJ/mol
C) +1.6 × 10⁸ kJ/mol
D) -1.6 kJ/mol
E) -5.2 kJ/mol

Question 48

Fresh rainwater or surface water contains enough tritium to show 5.5 decompositions per minute per 100. g of water. Tritium has a half-life of 12.3 years. You are asked to check a vintage wine claimed to have been produced in 1946. How many decompositions per minute should you expect to observe in 100. g of that wine?

A) 1.7
B) 0.035
C) 0.17
D) 181
E) 0.35

Question 49

The smallest amount of radioactive material that will support a self-sustained reaction is called the

A) moderator.
B) critical mass.
C) molar mass.
D) supercritical mass.
E) subcritical mass.

Question 50

Consider the following process: Which statement describes ΔE for the process?

A) 1.15 × 10¹¹ J/mol is released.
B) 1.15 × 10¹⁴ J/mol is released.
C) 1.15 × 10¹⁸ J/mol is absorbed.
D) 1.15 × 10¹¹ J/mol is absorbed.
E) none of these

Question 51

The half-life of ⁹⁰Sr is 28.1 years. How long will it take a 17.7-g sample of ⁹⁰Sr to decompose to 0.18 g?

A) 1.1 × 10¹ years
B) 8.1 × 10¹ years
C) 1.9× 10² years
D) 2.9 × 10^-1 years
E) 2.8 × 10³ years

Question 52

The questions below refer to the following:Iron-56, , has a binding energy per nucleon of 8.79 MeV. (1 MeV = 1.60 × 10^-13 J)
Determine the difference in mass between 1 mol of iron-56 nuclei and the component nucleons of which it is made.

A) 5.27 × 10^-4 kg
B) 2.43 × 10^-5 kg
C) 6.65 × 10^-5 kg
D) 7.21 × 10^-4 kg
E) 9.41 × 10^-6 kg

Question 53

One of the hopes for solving the world's energy problem is to make use of the fusion reaction How much energy is released when 1 mol of deuterium is fused with 1 mol of tritium according to the above reaction? The masses of the atoms and the neutrons are as follows:
The speed of light is 2.9979 × 10⁸ m/s.

A) 1.69 × 10¹² J
B) 5.63 × 10⁸ J
C) 8.44 × 10¹¹ J
D) 7.84 × 10⁴⁴ J
E) 56.3 J

Question 54

Use the following data to determine the expected ¹⁴C activity in the Shroud of Turin. The atmospheric activity of ¹⁴C is 15 cpm/gC (counts per minute per gram of carbon). Assume that the cloth was made in the year A.D. 24. The half-life of ¹⁴C is 5730 years.

A) 12 cpm/gC
B) 5.1 cpm/gC
C) 28 cpm/gC
D) 7.3 cpm/gC
E) 11 cpm/gC

Question 55

The half-life for electron capture for is 1.3 billion years. What will be the
Ratio in a rock that is 4.5 billion years old?

A) 0.10
B) 0.091
C)10
D)11
E) 0.36

Question 56

The Br-82 nucleus has a half-life of about 1.0 × 10³ minutes. If you needed at least 2.0 g of Br-82 and had ordered 29 g of NaBr (assuming all of the Br in the NaBr was Br-82), how many days could you wait for delivery?

A) 2.9days
B) 1.1 days
C) 2.7 days
D) 2.4 days
E) 3.5 days

Question 57

Radioactive elements decay via first-order kinetics. Consider a certain type of nucleus that has a rate constant of 1.0 × 10^-3 h^-1. A sample contains 5.0 × 10⁹ radioactive nuclides. Calculate the number of nuclides remaining after 39 days have passed.

A) 64
B) 7.8 × 10^-11
C) 2.0 × 10⁹
D) 5.0 × 10⁹
E) 2.5 × 10⁹

Question 58

Which of the following is not a factor in determining the biological effects of radiation exposure?

A) the energy of the radiation
B) the age of the organism when the exposure occurs
C) the penetrating ability of the radiation
D) the ionizing ability of the radiation
E) the chemical properties of the radiation source

Question 59

A sample of wood from an Egyptian mummy case gives a ¹⁴C count of 9.4 cpm/gC (counts per minute per gram of carbon). How old is the wood? (The initial decay rate of ¹⁴C is 15.3 cpm/gC, and its half-life is 5730 years.)

A) 3.5 × 10³ years
B) 4.0 × 10³ years
C) 5.1 × 10³ years
D) 1.7 × 10³ years
E) 2.8 × 10³ years

Question 60

The half-life for electron capture for is 1.30 × 10⁹ years. What percent of the original
Remains after 3.90 ×10⁹ years?

A) 12.5%
B) 75.0%
C) 25.0%
D) 33.3%
E) 50.0%

Question 61

Explain how a particle accelerator works.

Question 62

Discuss and explain the operation of a scintillation counter.

Question 63

Distinguish between a cyclotron and a linear accelerator.

Question 64

Distinguish alpha-particle production and beta-particle production, and provide an example of each.

Question 65

Radiocarbon dating is based on which decay process?

A)
B)
C)
D) All of the above
E) None of the above

Question 66

Which of the following instruments is/are used to detect and measure radioactivity levels?
1) Geiger counter
2) Richter scale
3) Seismic scale
4) Scintillation counter

A) ​1 only
B) ​3 only
C) ​1 and 4
D) ​2 and 3
E) ​1, 2, 3, and 4

Question 67

Discuss and explain the operation of a nuclear reactor.

Question 68

In the presence of a magnetic field in cyclotron, an ion is introduced at the center and is accelerated in an expanding _____ path by use of alternating electric fields.

A) ​sinusoidal
B) ​spiral
C) ​linear
D) ​Hamilton
E) ​Euler

Question 69

Which of the following statements is/are true of nuclear fission?
1) For the nuclear fission process to be self-sustaining, at least one neutron from each fission event must go on to split another nucleus.2. If more than one neutron from each nuclear fission event causes another fission event, the process dies out and the reaction is said to be subcritical.3. A fission bomb operates by suddenly combining two subcritical masses of fissionable material to form a supercritical mass.

A) ​1 only
B) ​2 only
C) ​3 only
D) ​2 and 3
E) ​1 and 3

Question 70

Which of the following statements is/are true of damage by radiation?
1) Somatic damage is damage to an organism itself, resulting in sickness or death.2. Genetic damage is damage to the genetic machinery, which produces malfunctions in the offspring of the organism.3. The official SI unit for radiation dose is the Gray, which is 10⁻² Joule of energy deposited per kg of tissue.

A) ​3 only
B) ​2 only
C) ​1 only
D) ​1 and 2
E) ​1 and 3

Question 71

Which of the following is not a charged species?

A) particle
B) particle
C) particle
D) all of the above
E) none of the above

Question 72

What is the purpose of a moderator surrounding the uranium cylinders in a reactor core?​

A) ​To slow down the neutrons
B) ​To accelerate the neutrons
C) ​To produce α particles
D) ​To produce β particles
E) ​To absorb β particles

Question 73

What is the result of a collision between an electron and a positron?

A) γ rays
B) x-rays
C) antimatter
D) a quark
E) all of the above are possible