Unit 4 Practice Exam. 1. Given the equation representing a nuclear reaction in which X represents a nuclide:

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1 Unit 4 Practice Exam 1. Given the equation representing a nuclear reaction in which X represents a nuclide: Which nuclide is represented by X? A) B) C) D) 7. Radiation is spontaneously emitted from hydrogen-3 nuclei, but radiation is not spontaneously emitted from hydrogen-1 nuclei or hydrogen-2 nuclei. Which hydrogen nuclei are stable? A) nuclei of H-1 and H-2, only B) nuclei of H-1 and H-3 only C) nuclei of H-2 and H-3 only D) nuclei from H-1, H-2, and H-3 2. The nucleus of a radium-226 atom is unstable, which causes the nucleus to spontaneously A) absorb electrons B) absorb protons C) decay D) oxidize 3. What is the mass number of an alpha particle? A) 1 B) 2 C) 0 D) 4 4. Which nuclear emission has the greatest mass? A) B) C) D) 5. Which balanced equation represents a spontaneous radioactive decay? A) B) C) D) 8. Which radioisotope has an atom that emits a particle with a mass number of 0 and a charge of +1? A) 3 H B) 16 N C) 19 Ne D) 239 Pu 9. Which particle is emitted when an atom of 85 Kr spontaneously decays? A) an alpha particle B) a beta particle C) a neutron D) a proton 10. What is the decay mode of 37 K? A) - B) + C) D) a 11. Which statement best describes gamma radiation? A) It has a mass of 1 and a charge of 1. B) It has a mass of 0 and a charge of 1. C) It has a mass of 0 and a charge of 0. D) It has a mass of 4 and a charge of Positrons and beta particles have A) the same charge and the same mass B) the same charge and different masses C) different charges and the same mass D) different charges and different masses 12. Which of these types of radiation has the greatest penetrating power? A) alpha B) beta C) gamma D) positron 13. Which type of radiation has neither mass nor charge? A) gamma B) neutron C) alpha D) beta

2 14. The diagram below represents radiation passing through an electric field. 20. Which term represents a nuclear reaction? A) combustion B) fermentation C) transmutation D) saponification 21. Given the balanced equation representing a reaction: Which type of emanation is represented by the arrow labeled 2? A) alpha particle B) beta particle C) positron D) gamma radiation 15. Which radioisotope has the fastest rate of decay? A) 14 C B) 37 Ca C) 53 Fe D) 42 K 16. Which phrase describes the decay modes and the half-lives of K-37 and K-42? A) the same decay mode but different half-lives B) the same decay mode and the same half-life C) different decay modes and different half-lives D) different decay modes but the same half-life 17. A radioactive isotope has a half-life of 2.5 years. Which fraction of the original mass remains unchanged after 10. years? A) 1/2 B) 1/4 C) 1/8 D) 1/ After decaying for 48 hours, of the original mass of a radioisotope sample remains unchanged. What is the half-life of this radioisotope? A) 3.0 h B) 9.6 h C) 12 h D) 24 h 19. Which radioisotopes have the same decay mode and have half-lives greater than 1 hour? A) Au-198 and N-16 B) Ca-37 and Fe-53 C) I-131 and P-32 D) Tc-99 and U-233 Which type of reaction is represented by this equation? A) combustion B) decomposition C) saponification D) transmutation 22. Which equation represents natural transmutation? A) B) C) D) 23. Which nuclear equation represents a natural transmutation? A) B) C) D) 24. In which process does a heavy nucleus split into two lighter nuclei? A) titration B) fission C) electrolysis D) neutralization 25. The greatest amount of energy released per gram of reactants occurs during a A) redox reaction B) fission reaction C) substitution reaction D) neutralization reaction

3 26. What is one benefit associated with a nuclear fission reaction? A) The products are not radioactive. B) Stable isotopes are used as reactants. C) There is no chance of biological exposure. D) A large amount of energy is produced. 31. Given the fusion reaction: Which particle is represented by X? A) B) C) D) 27. Which nuclide is listed with its half-life and decay mode? A) K-37, 1.24 h, B) N-16, 7.2 s, - C) Rn-222, 1.6 x 10 3 y, D) U-235, 7.1 x 10 8 y, Given the nuclear reaction: What does X represent in this reaction? A) B) C) D) 28. Given the balanced equation representing a nuclear reaction: 33. Given the correctly balanced nuclear equation: Which phrase identifies and describes this reaction? A) fission, mass converted to energy B) fission, energy converted to mass C) fusion, mass converted to energy D) fusion, energy converted to mass Which particle is represented by the X? A) B) C) D) 34. Given the nuclear reaction: 29. A nuclear reaction in which two light nuclei combine to form a more massive nucleus is called A) addition B) fission C) fusion D) substitution 30. Which change takes place in a nuclear fusion reaction? A) Matter is converted to energy. B) Energy is converted to matter. C) Ionic bonds are converted to covalent bonds. D) Covalent bonds are converted to ionic bonds. What is the identity of particle X? A) alpha particle B) beta particle C) proton D) neutron 35. During a nuclear reaction, mass is converted into A) charge B) energy C) isomers D) volume 36. A nuclear fission reaction and a nuclear fusion reaction are similar because both reactions A) form heavy nuclides from light nuclides B) form light nuclides from heavy nuclides C) release a large amount of energy D) absorb a large amount of energy

4 37. In a nuclear fusion reaction, the mass of the products is A) less than the mass of the reactants because some of the mass has been converted to energy B) less than the mass of the reactants because some of the energy has been converted to mass C) more than the mass of the reactants because some of the mass has been converted to energy D) more than the mass of the reactants because some of the energy has been converted to mass 38. The decay of which radioisotope can be used to estimate the age of the fossilized remains of an insect? A) Rn-222 B) I-131 C) Co-60 D) C Which radioisotope is used to treat thyroid disorders? A) Co-60 B) I-131 C) C-14 D) U A serious risk factor associated with the operation of a nuclear power plant is the production of A) acid rain B) helium gas C) greenhouse gases, such as CO2 D) radioisotopes with long half-lives 41. Refering to Table N, which substance is a radioactive waste product that is safest to release into the atmosphere after it has decayed to a safe radiation level? A) radon-222 B) radium-226 C) cesium-137 D) cobalt-60

5 42. Base your answer to the following question on the information below and on your knowledge of chemistry. Nuclear fission reactions can produce different radioisotopes. One of these radioisotopes is Te-137, which has a half-life of 2.5 seconds. The diagram below represents one of the many nuclear fission reactions. Complete the nuclear equation below for the beta decay of Zr-97, by writing an isotopic notation for the missing product. 43. Base your answer to the following question on the information below In living organisms, the ratio of the naturally occurring isotopes of carbon, C-12 to C-13 to C-14, is fairly consistent. When an organism such as a woolly mammoth died, it stopped taking in carbon, and the amount of C-14 present in the mammoth began to decrease. For example, one fossil of a woolly mammoth is found to have 1/32 of the amount of C-14 found in a living organism. Determine the total time that has elapsed since this woolly mammoth died.

6 44. Base your answer to the following question on the information below. A U-238 atom decays to a Pb-206 atom through a series of steps. Each point on the graph below represents a nuclide and each arrow represents a nuclear decay mode. Explain why the U-238 disintegration series ends with the nuclide Pb-206.

7 45. Base your answer to the following question on the information below and on your knowledge of chemistry. Nuclear Waste Storage Plan for Yucca Mountain In 1978, the U.S. Department of Energy began a study of Yucca Mountain which is located 90 miles from Las Vegas, Nevada. The study was to determine if Yucca Mountain would be suitable for a long-term burial site for high-level radioactive waste. A three-dimensional (3-D) computer scale model of the site was used to simulate the Yucca Mountain area. The computer model study for Yucca Mountain included such variables as: the possibility of earthquakes, predicted water flow through the mountain, increased rainfall due to climate changes, radioactive leakage from the waste containers, and increased temperatures from the buried waste within the containers. The containers that will be used to store the radioactive waste are designed to last 10,000 years. Within the 10,000-year time period, cesium and strontium, the most powerful radioactive emitters, would have decayed. Other isotopes found in the waste would decay more slowly, but are not powerful radioactive emitters. In 1998, scientists discovered that the compressed volcanic ash making up Yucca Mountain was full of cracks. Because of the arid climate, scientists assumed that rainwater would move through the cracks at a slow rate. However, when radioactive chlorine-36 was found in rock samples at levels halfway through the mountain, it was clear that rainwater had moved quickly down through Yucca Mountain. It was only 50 years earlier when this chlorine-36 isotope had contaminated rainwater during atmospheric testing of the atom bomb. Some opponents of the Yucca Mountain plan believe that the uncertainties related to the many variables of the computer model result in limited reliability of its predictions. However, advocates of the plan believe it is safer to replace the numerous existing radioactive burial sites around the United States with the one site at Yucca Mountain. Other opponents of the plan believe that transporting the radioactive waste to Yucca Mountain from the existing 131 burial sites creates too much danger to the United States. In 2002, after years of political debate, a final legislative vote approved the development of Yucca Mountain to replace the existing 131 burial sites. Why is water flow a crucial factor in deciding whether Yucca Mountain is a suitable burial site?

8 Answer Key (R) Unit 4 Practice Test 1. B 2. C 3. D 4. A 5. D 6. C 7. A 8. C 9. B 10. B 11. C 12. C 13. A 14. D 15. B 16. C 17. D 18. C 19. C 20. C 21. D 22. B 23. D 24. B 25. B 26. D 27. B 28. C 29. C 30. A 31. D 32. B 33. B 34. A 35. B 36. C 37. A 38. D 39. B 40. D 41. A y 44. The nucleus of Pb-206 is stable. Pb-206 is not radioactive. If Pb-206 were not stable, it would spontaneously decay. 45. Examples: because water may transport the radioactive materials; cause containers to corrode