Radioactivity And Balancing Nuclear Reactions: Balancing .

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1General Chemistry IIJasperseNuclear Chemistry. Extra Practice ProblemsTRadioactivity and Balancing Nuclear Reactions: BalancingNuclear Reactions and Understanding which Particles areInvolvedThe Stability of Atomic Nuclei: The Belt of Stability,Recognizing Whether An Isotope is likely to be stable or not,and predicting what it will do if it isn’t.Rates of Radioactive Decay. Nuclear Half Lives andRadioactive Decay Mathp1Miscellaneousp9p5Mass Deficit. Binding Energy: e mc2p10p7Answer Keyp11Key Equations Given for Test:E cell E reduction E oxidation G –96.5nE cell ( G in kJ)Ecell E – [0.0592/n]log Qlog K nE /0.0592Mol e– [A time (sec)/96,500]time (sec) mol e 96,500/current (in A)t (t1/2/0.693) ln (Ao/At)ln (Ao/At) 0.693 t /t1/2E mc2 (m in kg, E in J, c 3x108 m/s)Radioactivity and Balancing Nuclear Reactions: Balancing Nuclear Reactions and Understanding whichParticles are InvolvesT1.Which of the following statements is true for a 14C?a.b.c.d.e.2.it has 6 protons and 6 neutronsit has 12 protons and 12 neutronsit has 12 protons and 8 neutronsit has 6 protons and 8 neutronsnone of the aboveWhich of the following statements is true for a 37Cl– anion?a.b.c.d.e.it has 17 protons, 18 electrons, and 20 neutronsit has 17 protons, 16 electrons, and 17 neutronsit has 37 protons, 37 electrons, and 20 neutronsit has 20 protons, 8 electrons, and 11 neutronsnone of the aboveT3.Which of the following statements is true for a 25Mg 2 cation?a.b.c.d.e.it has 12 protons, 14 electrons, and 12 neutronsit has 12 protons, 10 electrons, and 12 neutronsit has 12 protons, 10 electrons, and 13 neutronsit has 24 protons, 12 electrons, and 24 neutronsnone of the aboveProtons Atomic NumberNeutrons Isotope Mass - Atomic NumberElectrons Atomic number (protons)adjusted for charge if ionic (anion charge,extra electrons. Cation charge, fewer e's)

4.T5.6.7.Beta emission is associated witha.conversion of a neutron to a proton.d.b.c.conversion of a proton to a neutron.increase in mass number.e.α-particle (alpha)ß-particle (beta), ase in mass number by 4 and atomicnumber by 2.emission of γ rays.Electron-capture is associated witha.conversion of a neutron to a proton.d.b.c.conversion of a proton to a neutron.increase in mass number.e.decrease in mass number by 4 and atomicnumber by 2.emission of γ rays.Alpha emission is associated witha.conversion of a neutron to a proton.b.c.conversion of a proton to a neutron. increase in massnumber.d. e.decrease in mass number by 4 and atomicnumber by 2.emission of γ rays.d.e.decrease in mass number.emission of γ rays. Positron emission is associated witha.b.c.8.4He20e 10e 1conversion of a neutron to a proton.conversion of a proton to a neutron.increase in mass number.The first step in the disintegration of uranium is238U à 234Th. What particle is emitted in this reaction?T238a.b.c.U à 234Th ?d.e.α particleneutronprotonelectronγ ray9. The isotope Cr–53 is produced by the beta decay of which of the following:a.b.c.d.e.53MnCr52Cr53V54V544He20e 10e 110. What other particle is formed in the fusion of two protons to form deuterium (H-2)?1Ta.b.c.H 1Hà 2H ?protonneutronelectron5811. Which particle is absorbed when Fe à ?a.b.c.α particleneutronproton 5859d.e.positronγ rayd.e.electronγ rayFe?Fe à 59Fe α-particle (alpha)ß-particle (beta), electronpositron0γ01n01H1gammaneutronproton

312. The isotope Ti–48 is produced by the beta decay of which of the following:a.b.c.d.e.T53MnCr52Cr53V54V4He20e 10e 154α-particle (alpha)ß-particle (beta), electronpositron0γ01n01H1gammaneutronproton13. Plutonium-238 is an α emitter and a compact heat source. Coupled with a PbTe thermoelectric device, it was onceused as a very reliable electrical energy source for cardiac pacemakers. What is the product of the radioactive decay ofplutonium-238?238a.b.c.Pu à α particle ?thorium-230uranium-234curium-242d.e. californium-246plutonium-234 14. Nitrogen-13 decays by positron emission to produce 13a.b.c.TN à positron 13.15. In the initial sequence of thorium-232 decay, an alpha particle is emitted followed by a beta particle. What is theproduct of these two decay steps?232a.b.c.d.e.16.175 β particle ?4He20e 10e 1radium-228actinium-228thorium-228francium-228The correct answer differs from these possibilities.Pt spontaneously decays into 171Os. What is another product of this decay?175Ta.b.c.Th à α particle171Pt à Os ?d.e.α particleβ particle 1e particle γ rayHe atomα-particle (alpha)ß-particle (beta), electronpositron0γ01n01H1gammaneutronproton

417. Which isotope is produced when 216Po decays by emitting an alpha particle followed by 2 beta particles?T216a.b.c.Po à α particle 2β particles210PoPo214Pod.e.212 ?2182204He20e 10e 1α-particle (alpha)ß-particle (beta), . Cobalt-56 decays by emitting a positron. What is the product?56a.b.c.Co à positron ?cobalt-55cobalt-56nickel-56d.e. iron-56iron-55 19. Radon-220 (220Rn) decays to polonium-216. What particle is emitted?a.b.c.T betapositronneutrond.e.alphagamma20. Cobalt-60 decays to nickel-60. What particle is ha21. Uranium-238 decays to lead-206 through a series of nuclear reactions. Only α particles and β particles are emitted.How many α particles are emitted?40a.b.c.246d.e.810He20e 10e 1α-particle (alpha)ß-particle (beta), electronpositron22. If a nitrogen-14 nuclide captures an alpha particle, a proton is produced along withTa.b.c.neutrons.boron-10.oxygen-17.d.e. fluorine-18.carbon-17.γ01n01H1gammaneutronproton

5The Stability of Atomic Nuclei: The Belt of Stability, Recognizing Whether An Isotope is likely to bestable or not, and predicting what it will do if it isn’t.T23. What repulsive forces must be overcome for any element other than hydrogen to exist?a.b.c.d.e.The repulsion between neutrons and other neutrons.The repulsion between protons and other protons.The repulsion between protons and neutrons.The repulsion between positrons and electrons.The repulsion between neutrons and electrons.24. All elements with Z 83 area.b.Stable and unreactiveRadioactive.c.d.Likely to decay by β emission.Likely to have neutron/proton rations ofless than or equal to 1:1.25. Light elements with Z 20 generally have a neutron/proton ratios about equal toa.b.c.0.5.0.8.1.0.d.e.1.3.1.5.See Periodic Table for Help26. The heaviest stable elements will generally have a neutron/proton ratio about equal toa.b.T0.5.0.8.c.d.1.0.1.5.See Periodic Table for Help27. Which one of the following statements is not correct?a.b.c.d.Carbon-10 is unstable because it has too few neutrons.See Periodic Table for HelpAll nuclides with Z 83 decay into nuclides with smaller Z values.Generally, the number of neutrons in a nuclide is equal to or less than the atomic number.As the atomic number increases, the ratio of neutrons to protons in a nuclide increases.28. Which one of the following statements is not correct?a.b.c.d.e.Oxygen-15 is unstable because it has too few neutrons.Nucleons are held together in a nuclide by the electromagnetic force.All nuclides with Z 83 decay into more stable nuclides with smaller Z values.As the atomic number increases, the ratio of neutrons to protons in a nuclide increases.Generally the number of neutrons in a nuclide equals the number of protons, or nearly so, whenthe atomic number is small, i.e., Z 18.29. Which of the following statements is false?Ta. U–238 is unstable, as expected based on the “rule of 83”b. N–16 is unstable and radioactive because its neutron/proton ratio is too highc. Nuclear reactions often produce large amounts of energy because small amounts of mass are convertedinto energy (see Einstein’s famous equation, e mc2)d. All radioactive isotopes decay completely and disappear within a short time (1 year or less)9030. Predict the decay pathway for Sr. (Strontium-88 is the most abundant stable isotope for Sr.) (Strontium-90 is aparticularly hazardous radioactive isotope because, as an alkali earth metal, it will substitute for calcium in bones andteeth.)a.b.c.d.e.α emissionβ emissionpositron emissionNormalThis Nucliden/pγ emissionX-ray emission1. Periodic table: find "actual" n/p ratio2. Is the nuclide n/p ratio too high?*Convert n p by beta emission3. Is the nuclide n/p ratio too small? Convert p nby either electron capture or positron emission4. Does Z exceed 83? Reduce fast by alpha emission.

631. Np-237 is most likely to decay byTa.b.c.gamma emission.beta emission.positron emission.NormalThis Nuclided.e.n/palpha emission.electron capture.1. Periodic table: find "actual" n/p ratio2. Is the nuclide n/p ratio too high?*Convert n p by beta emission3. Is the nuclide n/p ratio too small? Convert p nby either electron capture or positron emission4. Does Z exceed 83? Reduce fast by alpha emission.32. What decay pathway is likely for cobalt-60? (Cobalt-59 is a stable isotope for Co.) (Cobalt-60, on the other hand, isused as a radioactive source approved by the FDA for irradiation of food. This process kills microbes and insects andcan delay ripening.)a.b.c.α emissionβ emissionpositron emissionγ emissionX-ray emissionc.d.alpha emission.Either positron emission orelectron capture.33. Nitrogen-12 is most likely to decay bya.b.gamma emission.beta emission.Normald.e.This NuclideNormalThis Nucliden/pn/p34. What type of emission is likely for Re-188? (Rhenium-185 is a stable isotope.) Rhenium-188 is a radioisotope fortreatment of cancer.Ta.b.c.d.e.αβpositronNormalThis Nucliden/pγ rayX-ray35. Fact: 63Zn is unstable and radioactive. Is its n/p ratio too high or too low? Which process could lead tostability? (Make sure that both parts of the answer are correct.)a.b.c.d.Its n/p ratio is too low. It could attain stability by either electron capture or positron emission.Its n/p ratio is too low. It could attain stability by beta emission.Normal This Nuclide n/pIts n/p ratio is too high. It could attain stability by electron capture.Its n/p ratio is too high. It could attain stability by beta emission.36. Fact: 34P is unstable and radioactive. Is its n/p ratio too high or too low? In that case, which process couldlead to stability? (Make sure that both parts of the answer are correct.)a.b.c.d.e.Its n/p ratio is too low. It could attain stability by electron capture.Its n/p ratio is too low. It could attain stability by beta emission.Its n/p ratio is too high. It could attain stability by electron capture.Its n/p ratio is too high. It could attain stability by beta emission.Its n/p ratio is too high. It could attain stability by positron emission.NormalThis Nucliden/pT37. Which of the following nuclides are most likely to be unstable because they have too many neutrons?1. Periodic table: find "actual" n/p ratio2. Is the nuclide n/p ratio too high?*Convert n p by beta emission3. Is the nuclide n/p ratio too small? Convert p nby either electron capture or positron emission4. Does Z exceed 83? Reduce fast by alpha emission.I. carbon-14II. sodium-24III. silicon-26IV. aluminum-27V. phosphorous-31a.b.c.only II and IIII and IIId.e.III, IV, and Vall of these

7Rates of Radioactive Decay. Nuclear Half Lives and Radioactive Decay Matht (t1/2/0.693) ln (Ao/At)Tln (Ao/At) 0.693 t /t1/238. A half-life isa.b.c.d.constantly changing.half of the lifetime of an unstable nucleus.the time for one-half of an unstable nuclei to decay.independent of the rate constant for decay.39. The half-life of a radioactive isotope is 1.0 minute. In an experiment, the number of decay events was monitored in 1minute intervals over a 5-minute period. Suppose 50 decay events were observed in the first minute. In the secondminute, events were observed, and in the 5th minute, events were observed.a.b.c.50, 5025, 325, 25d.e.Min (Half/lives) Events01234550, 10025, 13Percentage40. Uranium-238 decays to form thorium-234 with a half-life of 4.5 109 years. How many years will it take for 75% ofthe uranium-238 to decay?Ta.b.c.9.0 1010 years4.5 109 years4.5 1010 yearsd.e.(Half/lives) Percentage9.0 109 years3.8 109 years01234ln (Ao/At) 0.693 (t /t1/2)41. Tritium, (3H) is used in glowing “EXIT” signs located where there is no electricity for light bulbs. If the half-life oftritium is 12.26 years, what percentage of the original quantity of the isotope is left in the sign after 18.5 years? (Youshould be able to both calculate exactly, but also be able to choose from among these options without a calculator.)a.b.c.0.632%63.2%35.1%ln (Ao/At) 0.693 (t /t1/2)d.e.1.51%25.0%(Half/lives) Percentage012345T42. Iodine-131 has a half-life of 8.1 days and is used as a tracer for the thyroid gland. If a patient drinks a sodium iodide(NaI) solution containing iodine-131 on a Tuesday, how many days will it take for the concentration of iodine-131 todrop to 5.0% of its initial concentration?t (t1/2/0.693) ln (Ao/At)a. 19 daysd. 35 daysb. 0.81 daye. 4.3 daysc. 8.1 days

8t (t1/2/0.693) ln (Ao/At)Tln (Ao/At) 0.693 t /t1/243. Phosphorus-32 is a radioactive isotope used as a tracer in the liver. How much phosphorus-32 was originally used ifthere is only 3.50 mg left in a sample after 288 h? (The half-life of phosphorus-32 is 14.3 days.)a.b.c.1.96 mg6.26 mg4.17 mgd.e.7.00 mg17.9 mgln (Ao/At) 0.693 (t /t1/2)44. Carbon-14 measurements on the linen wrappings from the Book of Isaiah on the Dead Sea Scrolls indicated that thescrolls contained about 79.5% of the carbon-14 found in living tissue. Approximately how old are these scrolls? Thehalf-life of carbon-14 is 5730 years.t (t1/2/0.693) ln (Ao/At)a. 570 yearsd. 1900 yearsb.c.T820 years1300 yearse.4600 years45. The half-life of 18F is 109.7 minutes. If radiolabeled Prozac were administered to a patient for a PET scan at 8:00 A.M.on Monday, at what time would its activity reach 10% of the original activity?a. 9:49 A.M., Mondayd. 2:04 P.M., Mondayt (t1/2/0.693) ln (Ao/At)b. 9:07 P.M., Fridaye. 6:07 P.M., Mondayc. 10:42 A.M., Tuesday46. The activity of a sample of gas obtained from a basement containing radon-222 was found to be 8 pCi/L. This isotopehas a half-life of 3.8 days. If no additional radon-222 entered the basement, how long would it take for the activity todecline to 1 pCi/L?a. about 4 daysd. a bit less than 10 days t (t1/2/0.693) ln (Ao/At)b.c.a bit more than 10 daysabout 1 daye.about 20 daysT47. A 10.00 g sample of wood from an archaeological site produced 3072 β particles in a 10-hour measurement owing tothe presence of carbon-14, while a 10.00 g sample of new wood produced 9216 β particles in the same period of time.The half-life of carbon-14 is 5730 years. How old is the wood from the archaeological site?a.b.c.d.e.5730 years2865 years4040 years9080 yearsThe correct answer differs by more than100 years from the values given in A–D.t (t1/2/0.693) ln (Ao/At)

9Miscellaneous48. Nuclear fission produces energy becauseTa.b.c.d.e.neutrons are produced.the total mass of the products is less than that of the reactants.the total mass of the products is more than that of the reactants.it is a very powerful chemical reaction.photons are produced.49. Which of the following statements is true?a.b.Isotopes have the same number of neutrons but have different numbers of protonsIn order to overcome the repulsion between protons, a strong nuclear force is required to hold a stable nucleustogetherIn order to overcome the repulsion between neutrons, a strong nuclear force is required to hold the nucleustogetherThe higher the number of protons in the nucleus the more stable it will be.none of the abovec.d.e.50. Nuclear fusion produces energy becausea.b.c.d.e.Tneutrons are produced.the total mass of the products is less than that of the reactants.the total mass of the products is more than that of the reactants.it is a very powerful chemical reaction.photons are produced.51. Which type of radiation does the most tissue damage, but only when the emitter is internally ingested?a.b.c.αβγd.e.neutronβ 52. Which type of radiation has the greatest penetration ability?a.b.c.αβd.e.neutronβ γ53. Uranium-235 is the fuel in nuclear power plants. When a nucleus of uranium-235 captures a neutron, the nucleus splitsinto two lighter nuclei and initiates a chain reaction. The chain reaction is driven by the emission ofa.b.c.protons.neutrons.positrons.d.e.β particles.α particles.54. The purpose of control rods in a fission reactor is toTa.b.c.d.e.cool down the reactor fuel.prevent oxygen from reaching the fuel.absorb neutrons generated in the fission process.absorb the electrons emitted in the fission process.enhance the neutron capture process.55. Electricity is produced from nuclear reactions bya.b.c.d.e.capturing the electrons that are emitted.accelerating electrons with rapidly moving protons from the nuclear reaction.a process still not understood by scientists.using the energy to make steam to turn turbines.using the energy to accelerate electrons in wires.

10Mass Deficit. Binding Energy: e mc2 Key equation: E mc2 (m in kg, E in J, c 3x108 m/s)56. Nuclear fusion produces energy becauseTa.b.c.d.e.neutrons are produced.the total mass of the products is less than that of the reactants.the total mass of the products is more than that of the reactants.it is a very powerful chemical reaction.photons are produced.57. What quantity of energy would be produced as one atom of plutonium-238 undergoes alpha decay? The nuclide massof 238Pu is 238.0495 amu (3.953 10–22g), and the nuclide mass of uranium-234 is 234.0409 amu (3.886 10–22 g).Alpha particle mass is 6.64465 10–24 g. The speed of light is 2.998 108 m/s.Initial: 3.953 x 10-22- Final: (3.886 x 10-22 6.64465 x 10-24 5.535 x 10-26 g 5.535 x 10-29 kga.b.c.T6.0 10–7 J5.0 x 10–12 J7.0 10–10 Jd.e.2.6 10–8 J1.1 10–12 J58. What quantity of energy would be produced as 1.00 g of plutonium-238 undergoes alpha decay? The nuclide mass of238Pu is 238.0495 amu (3.953 10–22g), and the nuclide mass of uranium-234 is 234.0409 amu (3.886 10–22g). Alphaparticle mass is 6.64465 10–24 g. The speed of light is 2.998 108 m/s.a. 4.4 1010 Jd. 1.3 x 1010 J8b. 3.5 10 Je. 2.7 109 J–13c. 6.2 10 J59. Calculate the nuclear binding energy per nucleon for the beryllium-8 isotope. Here are some helpful data:8Be isotopic massproton massneutron masselectron massspeed of lightTa.b.c.1.2035 10–6 J/nucleon1.08479 10–9 J/nucleon1.1317 10–12 J/nucleon8.0053 amu1.00727646 amu1.00866492 amu5.48579911 10–4 amu2.99792458 108 m/sd.e.1.32931 10–23 g1.67262158 10–24 g1.67492716 10–24 g9.10938188 10–28 g8.7266 10–12 J/nucleon1.08479 10–15 J/nucleon

11General Chemistry IIJasperseNuclear Chemistry. Extra Practice .55.56.57.58.59.DBDBADBCBDCDBDDBDBBBACBCDBBDC

c. Nuclear reactions often produce large amounts of energy because small amounts of mass are converted into energy (see Einstein’s famous equation, e mc2) d. All radioactive isotopes decay completely and disappear within a short time (1 year or less) 30. Predict the decay pathway for 90Sr. (Strontium-88 is the most abundant stable isotope for .

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