(Paper) PMT Sample Papers And Practice Questions (Nuclear Chemistry)

Paper : PMT Sample Papers And Practice Questions (Nuclear Chemistry)

  1. Which one of the following types of particles is the MOST highly penetrating to biological tissues?
    1. alpha particles
    2. beta particles
    3. positrons
    4. neutrons
    5. electrons 

  2. In lecture, you observed a radioactive plate that contained uranium oxide as a pigment (i.e., "Fiestaware"). What color was the plate?
    1. yellow
    2. purple
    3. white
    4. orange
    5. green 

  3. An ancient wood sculpture was determined to be 2380 years old. Calculate the percentage of the carbon-14 originally present in the wood that remains today. For carbon-14: t1/2 = 5730 years. 

  4. Americium-241 is the radioactive isotope that is used in smoke detectors. Americium-241 undergoes alpha decay with a half-life of 458 years. What is the product nuclide that is produced when americium-241 radioactively decays?
    1. neptunium-237
    2. curium-241
    3. plutonium-241
    4. americium-240
    5. plutonium-240 

  5. Positron emission tomography (PET) scans are used medicinally to diagnose certain biological disorders. The most common radioactive isotope used in this procedure is fluorine-18, which is a positron emitter. In a PET scan, which one of the following species is actually measured in order to create a three-dimensional image of the afflicted organ?
    1. alpha particles
    2. beta particles
    3. gamma rays
    4. positrons
    5. neutrons 

  6. In lecture, you observed a desiccator that was used for many years to store radioactive radium compounds. What color was the desiccator?
    1. yellow
    2. orange
    3. purple
    4. green
    5. black 

  7. The radioactive nuclide, iodine-131, is used medicinally as a radiotracer for the diagnosis and treatment of illnesses associated with the thyroid gland. If the rate constant for decay of iodine-131 is 9.9 x 10-7 s-1, calculate the half-life (in s) of iodine-131. 

  8. Calculate the binding energy per nucleon in millions of electron volts (MeV) for nitrogen-15. The atomic mass of nitrogen-15 is 15.00011 amu. 

  9. What is the final, stable nuclide, X, if radon-222 decays by the emission of four alpha particles and four beta particles?
    1. tungsten-206
    2. tungsten-214
    3. platinum-202
    4. platinum-210
    5. lead-206 

  10. An archeologist unearths a bone sample and wants to know the age of the bone. Her chemist friend determines that 41.7% of the initial amount of carbon-14 in the bone sample has decayed. If the half-life of carbon-14 is 5730 years, the age of the bone is:
    1. 4460 years
    2. 5730 years
    3. 7230 years
    4. 10200 years
    5. 11460 years 

  11. Which of the following characteristics is/are important considerations for radiotracers that will be used for diagnosing illness in the body?
    1. The radiotracer should have a short half-life.
    2. The radiotracer should localize in a certain part of the body.
    3. The radiotracer should produce radiation that can be detected externally.
    4. (a) and (b).
    5. (a), (b) and (c). 

  12. When a nuclide is assembled from its constituent protons, neutrons, and electrons, there is about a 1% decrease in mass. When a chemical compound is similarly made from its constituent elements there is no discernible change in mass. The best reason for this difference is that:
    1. chemical reactions are intrinsically different from nuclear reactions.
    2. the formation of a nuclide from its constituents is always exothermic whereas the formation of a compound from the elements can be either exothermic or endothermic.
    3. Einstein's equation, E = mc2, applies to nuclei but not to molecules.
    4. chemical reactions release far less energy than nuclear reactions and so the mass change is too small to observe.
    5. mass is conserved in chemical reactions but is not conserved in nuclear reactions. 

  13. The mass of chlorine-37 is 36.96590 amu. The binding energy per nucleon of chlorine-37 is:
    1. -1.41 x 10-12 J/nucleon
    2. 1.29 x 10-12 J/nucleon
    3. 1.37 x 10-12 J/nucleon
    4. 5.08 x 10-11 J/nucleon
    5. 5.08 x 10-8 J/nucleon 

  14. The only stable nuclide with A = 35 is chlorine-35. Which of the following equations correctly describe the process by which phosphorus-35 decays to chlorine-35?
    1. phosphorus-35 -> chlorine-35 + beta particle
    2. phosphorus-35 -> sulfur-35 + beta particle
      sulfur-35 -> chlorine-35 + beta particle
    3. phosphorus-35 -> silicon-35 + beta particle
      silicon-35 -> chlorine-35 + beta particle
    4. phosphorus-35 -> chlorine-35 + positron
    5. phosphorus-35 + e- -> sulfur-35
      sulfur-35 + e- -> chlorine-35 

  15. A freshly prepared sample of yttrium-90 undergoes 7.6 x 105 disintegrations per minute (dpm) at a certain time. Exactly 14 days later, the same sample undergoes 1.6 x 104 dpm. The half-life of yttrium-90 is:
    1. 0.20 day
    2. 2.5 day
    3. 2.7 day
    4. 3.8 day
    5. 14 day 

  16. What is the product nuclide of the decay of thorium-232? Thorium-232 has a half-life of 1.4 x 1010 years and radioactively decays by alpha emission.
    1. radon-230
    2. radium-228
    3. actinium-232
    4. proactinium-232
    5. uranium-235 

  17. Calculate the binding energy per nucleon of boron-11 if the atomic mass of boron-11 is 11.00931 amu.
    1. 3.54 MeV
    2. 5.67 MeV
    3. 6.94 MeV
    4. 7.82 MeV
    5. 8.23 MeV 

  18. An archeologist unearths a bone sample and wants to know the age of the bone. Her chemist friend determines that 35.6% of the initial amount of carbon-14 is present in the bone sample. If the half-life of carbon-14 is 5730 years, the age of the bone is:
    1. 3640 years
    2. 5730 years
    3. 8540 years
    4. 10200 years
    5. 11460 years 

  19. Consider the following types of medical procedures that are used for diagnosing various illnesses:
    1. PET (Positron Emission Tomography) scans
    2. CAT (Computerized Axial Tomography) scans
    3. MRI (Magnetic Resonance Imaging) scans
    4. Tc bone scans
    5. Tl cardiac scans 

Which of these diagnostic procedures involves radioactive decay of an unstable nuclide as the primary means for creating an image of the area of the body being studied?

    1. 1, 2 and 3
    2. 2 and 3
    3. 3, 4 and 5
    4. 1, 4 and 5
    5. 2, 4 and 5 
  1. Four types of radiation arranged in order from lowest to highest health hazard is:
    1. gamma rays < alpha particles < beta particles < neutrons
    2. alpha particles < gamma rays < neutrons < beta particles
    3. beta particles < alpha particles < gamma rays < neutrons
    4. neutrons < alpha particles < gamma rays < beta particles
    5. gamma rays < beta particles < neutrons < alpha particles 

  2. Write a chemical equation for each of the following radioactive decay processes:
    1. phosphorus-32 decays by beta-particle emission.
    2. lithium-8 decays by beta-particle emission followed by alpha-particle emission.
    3. potassium-40 decays by electron capture.
    4. nitrogen-13 decays by positron emission.
    5. thorium-232 decays by alpha-particle emission. 

  3. Calculate the binding energy per nucleon in millions of electron volts for magnesium-27. The atomic mass of magnesium-27 is 26.9843 amu. 

  4. Consider the following information:
    1. The layer of dead skin on our bodies is sufficient to protect us from most alpha-particle radiation.
    2. Plutonium is an alpha-particle producer.
    3. The chemistry of Pu4+ is similar to that of Fe3+.
    4. Pu4+ + 4 e- --> Pu, Eo = -1.28 V 

Using this information, explain why plutonium is one of the most toxic substances known.

  1. Suppose that an archeologist has unearthed a human bone. She asks her chemist friend to determine the percentage of carbon-14 present in the bone. The chemist determines that the bone sample contains 67.3% of the carbon-14 present in living tissue. If the half-life of carbon-14 is 5730 years, calculate the age (in years) of the bone. 

  2. Carbon-14 undergoes radioactive decay because it has a neutron-to-proton (n/p) ratio that is too large. The GREATEST reduction in the neutron-to-proton ratio of the product nuclide can be achieved by the emission of a(n):
    1. alpha particle.
    2. beta particle.
    3. positron.
    4. neutron.
    5. gamma ray. 

  1. Thallium-201 is used in medicine to create images of the heart. A thallium-201 nucleus contains:
    1. 0 neutrons.
    2. 81 neutrons.
    3. 120 neutrons.
    4. 201 neutrons.
    5. None of these. 

  2. Uranium-235 undergoes radioactive decay in a series of steps to produce the stable nuclide, lead-207. If the radioactive decay of uranium-235 involves the emissions (in order): alpha, beta, alpha, beta, alpha, alpha, alpha, alpha, beta, alpha, beta, which of the following nuclides are NOT produced in the decay series?
    1. radon-219
    2. thallium-207
    3. radium-223
    4. proactinium-233
    5. polonium-215 

  3. Scientists have recently shown that a sample of cocaine can be traced to its country of origin by measuring the ratio of carbon-13 to nitrogen-15 (both naturally occurring, stable nuclides) in the cocaine sample. Carbon-14 and nitrogen-16, however, do not occur naturally and both of these nuclides undergo radioactive decay by the same process. Which of the following is the most likely type of radioactive decay for carbon-14 and nitrogen-16?
    1. alpha decay
    2. beta decay
    3. positron decay
    4. spontaneous fission
    5. electron capture 

  4. Uranium-235 is one of the most common fuels used in nuclear power plants. However, uranium-238 cannot be used as a fuel in a nuclear power plant. Which of the following statements best explains why uranium-238 cannot be used as a fuel?
    1. There is not enough uranium-238 in naturally occurring uranium to use it as a fuel.
    2. It is not possible to construct fuel rods which contain uranium-238.
    3. Uranium-238 does not undergo radioactive decay.
    4. Uranium-238 is not a naturally occurring isotope of uranium.
    5. Uranium-238 does not undergo fission easily enough to be used as a fuel. 

  5. Fluorine-18 is one of the radioactive nuclides utilized in Positron Emission Tomography (PET) scans. Fluorine-18 can be synthesized by bombarding oxygen-18 nuclei with hydrogen-1 nuclei,

oxygen-18 + hydrogen-1 --> fluorine-18 + X

What is the identity of the other product, X, in this reaction?

    1. alpha particle
    2. beta particle
    3. positron
    4. neutron
    5. gamma ray

 

Answers

  1. D
  2. D
  3. 75
  4. A
  5. C
  6. C
  7. 7 x 105
  8. 7.7
  9. E
  10. A
  11. E
  12. D
  13. C
  14. B
  15. B
  16. B
  17. C
  18. C
  19. D
  20. A
  21.  
    1. phosphorus-32 -> beta particle + sulfur-32 
    2.  
      1. lithium-8 -> beta particle + beryllium-8
      2. beryllium-8 -> alpha particle + alpha particle 
    3. potassium-40 + electron -> argon-40 
    4. nitrogen-13 -> positron + carbon-13 
    5. thorium-232 -> alpha particle + radium-228
  22. 8.29
  23. The first two facts indicate that Pu is not a significant threat outside of the body. However, if Pu gets inside of the body (ingested or inhaled), the electrochemical data indicate that it can be easily oxidized to Pu4+:

Pu -> Pu4+ + 4e-, Eo = 1.28 V

The large positive potential indicates that oxidation of Pu is quite favorable. Now, because the chemistry of Pu4+ is similar to Fe3+, Pu4+ will tend to concentrate in tissues where Fe3+ is found. For example, Pu4+ could concentrate in bone marrow where red blood cells are produced (recall, hemoglobin has a central Fe3+ ion). Once concentrated there, the alpha particles produced from its decay can do significant damage to the tissue.

  1. 3270
  2. B
  3. C
  4. D
  5. B
  6. E
  7. D

 

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