Chemistry

Chemistry: The Central Science | 13th Edition | ISBN: 9780321910417 | Authors: Theodore E. Brown; H. Eugene LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward; Matthew E. Stoltzfus
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Author: Theodore E. Brown; H. Eugene LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward; Matthew E. Stoltzfus
Publisher: Pearson
ISBN: 9780321910417
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Chapter: Problem: 5E

Chemistry: The Central Science 13
The steps below show three of the steps in the radioactive decay chain for \({ }_{90}^{232} T h\) The half-life of each isotope is shown below the symbol of the isotope. (a) Identify the type of radioactive decay for each of the steps (i), (ii), and (iii). (b) Which of the isotopes shown has the high

Chapter: Problem: 1DE

Chemistry: The Central Science 13
This chapter has focused on the properties of elements that exhibit radioactivity. Because radioactivity can have harmful effects on human health, very stringent experimental procedures and precautions are required when undertaking experiments on radioactive materials. As such, we typically do not ha

Chapter: Problem: 1E

Chemistry: The Central Science 13
Indicate whether each of the following nuclides lies within the belt of stability in Figure 21.2: (a) neon-24, (b) chlorine-32, (c) tin-108, (d) polonium-216. For any that do not, describe a nuclear decay process that would alter the neutron-to-proton ratio in the direction of increased stability. [S

Chapter: Problem: 2E

Chemistry: The Central Science 13
Write the balanced nuclear equation for the reaction represented by the diagram shown here. [Section 21.2]

Chapter: Problem: 3E

Chemistry: The Central Science 13
3E Draw a diagram similar to that shown in Exercise 21.2 that illustrates the nuclear reactionBi He + Tl.

Chapter: Problem: 4E

Chemistry: The Central Science 13
In the sketch below, the red spheres represent protons and the gray spheres represent neutrons. (a) What are the identities of the four particles involved in the reaction depicted? (b) Write the transformation represented below using condensed notation. (c) Based on its atomic number and mass number,

Chapter: Problem: 6E

Chemistry: The Central Science 13
The accompanying graph illustrates the decay of \({ }_{42}^{88} \mathrm{Mo}\), which decays via positron emission. (a) What is the half-life of the decay? (b) What is the rate constant for the decay? (c) What fraction of the original sample of \({ }_{42}^{88} \mathrm{Mo}\) remains after 12 min? (d) W

Chapter: Problem: 7E

Chemistry: The Central Science 13
All the stable isotopes of boron, carbon, nitrogen, oxygen, and fluorine are shown in the accompanying chart (in red), along with their radioactive isotopes with \(t_{1 / 2}>1\) min (in blue). (a) Write the chemical symbols, including mass and atomic numbers, for all of the stable isotopes. (b) Which

Chapter: Problem: 8E

Chemistry: The Central Science 13
The diagram shown here illustrates a fission process. (a) What is the unidentified product of the fission? (b) Use Figure 21.2 to predict whether the nuclear products of this fission reaction are stable. [Section 21.7]

Chapter: Problem: 9E

Chemistry: The Central Science 13
9E Radioactivity and Nuclear Equations (Section) Indicate the number of protons and neutrons in the following nuclei: (a) Cr. (b)TI, (c) argon-38.

Chapter: Problem: 10E

Chemistry: The Central Science 13
10E Radioactivity and Nuclear Equations (Section) Indicate the number of protons and neutrons in the following nuclei: (a) I, (b) 138 Ba, (c) neptunium-237.

Chapter: Problem: 11E

Chemistry: The Central Science 13
11E Radioactivity and Nuclear Equations (Section) Give the symbol for (a) a neutron, (b) an alpha particle, (c) gamma radiation.

Chapter: Problem: 12E

Chemistry: The Central Science 13
12E Radioactivity and Nuclear Equations (Section) Give the symbol for (a) a proton, (b) a beta particle, (c) a positron.

Chapter: Problem: 13E

Chemistry: The Central Science 13
13E Radioactivity and Nuclear Equations (Section) Write balanced nuclear equations for the following processes: (a) rubidium-90 undergoes beta emission: (b) selenium-72 undergoes electron capture; (c) krypton-76 undergoes positron emission: (d) radium-226 emits alpha radiation.

Chapter: Problem: 14E

Chemistry: The Central Science 13
14E Radioactivity and Nuclear Equations (Section) Write balanced nuclear equations for the following transformations: (a) bismuth-213 undergoes alpha decay: (b) nitrogen-13 undergoes electron capture: (c) technicium-98 undergoes electron capture; (d) gold-188 decays by positron emission.

Chapter: Problem: 15E

Chemistry: The Central Science 13
15E Radioactivity and Nuclear Equations (Section) Decay of which nucleus will lead to the following products: (a) bismuth-211 by beta decay; (b) chromium-50 by positron emission: (c) tantalum-179 by electron capture; (d) radium-226 by alpha decay?

Chapter: Problem: 16E

Chemistry: The Central Science 13
16E Radioactivity and Nuclear Equations (Section) What particle is produced during the following decay processes: (a) sodium-24 decays to magnesium-24: (b) mercury-188 decays to gold-188: (c) iodine-122 decays to xenon-122; (d) plutonium-242 decays to uranium-238?

Chapter: Problem: 17E

Chemistry: The Central Science 13
17E Radioactivity and Nuclear Equations (Section) The naturally occurring radioactive decay series that begins with U stops with formation of the stable Pb nucleus. The decays proceed through a series of alpha-particle and beta-particle emissions. How many of each type of emission are involved in t

Chapter: Problem: 18E

Chemistry: The Central Science 13
18E Radioactivity and Nuclear Equations (Section) A radioactive decay series that begins with Th ends with formation of the stable nuclide Pb. How many alpha particle emissions and how many beta-particle emissions are invoked in the sequence of radioactive decays?

Chapter: Problem: 19E

Chemistry: The Central Science 13
19E Patterns of Nuclear Stability (Section) Predict the type of radioactive decay process for the following radionuclides: (a) B, (b)Cu. (c) phosphorus-32, (d) chlorine-39.

Chapter: Problem: 20E

Chemistry: The Central Science 13
20E Patterns of Nuclear Stability (Section) Each of the following nuclei undergoes either beta decay or positron emission. Predict the type of emission for each: (a) tritium, H. (b) Sr. (c) iodine-120, (d) silver-102.

Chapter: Problem: 21E

Chemistry: The Central Science 13
21E Patterns of Nuclear Stability (Section) One of the nuclides in each of the following pairs is radioactive. Predict which is radioactive and which is stable: (a) K and K. (b) 209Bi and 208 Bi. (c) nickel-58 and nickel-65.

Chapter: Problem: 22E

Chemistry: The Central Science 13
22E Patterns of Nuclear Stability (Section) One nucHe in each of these pairs is radioactive. Predict which is radioactive and which is stable: (a) 4020Ca and 4520Ca. (b) 12C and 14C, (c) lead-206 and thorium-230. Explain your choice in each case.

Chapter: Problem: 23E

Chemistry: The Central Science 13
23E Patterns of Nuclear Stability (Section) Which of the following nuclides have magic numbers of both protons and neutrons: (a) heium-4. (b) oxygen-18, (c) calcium- 40, (d) zinc-66. (e) lead-208?

Chapter: Problem: 24E

Chemistry: The Central Science 13
Despite the similarities in the chemical reactivity of elements in the lanthanide series, their abundances in Earths crust vary by two orders of magnitude. This graph shows the relative abundance as a function of atomic number. How do you explain the sawtooth variation across the series?

Chapter: Problem: 25E

Chemistry: The Central Science 13
25E Patterns of Nuclear Stability (Section) Using the concept of magic numbers, explain why alpha emission is relatively common, but proton emission is nonexistent.

Chapter: Problem: 26E

Chemistry: The Central Science 13
26E Patterns of Nuclear Stability (Section) Which of the following nuclides would you expect to be radioactive: 58 26Fe. 60 27Co. 92 41 Nb. mercury-202, radium-226? Justify your choices.

Chapter: Problem: 27E

Chemistry: The Central Science 13
Why are nuclear transmutations involving neutrons generally easier to accomplish than those involving protons or alpha particles?

Chapter: Problem: 28E

Chemistry: The Central Science 13
28E Nuclear Transmutations (Section) In 1930 the American physicist Ernest Lawrence designed the first cyclotron in Berkeley, California. In 1937 Lawrence bombarded a molybdenum target with deuterium ions, producing for the first time an element not found in nature. What was this element? Starting

Chapter: Problem: 29E

Chemistry: The Central Science 13
29E Nuclear Transmutations (Section) Complete and balance the following nuclear equations by supplying the missing particle: (a) 25298Cf + 105B^3 10n + ? (b) 21 H + 32 He^42 He + ? (c) 11 H + 115B^3? (d) 12253l-*12254Xe + ? (e) 5926Fe- 0-1e + ?

Chapter: Problem: 30E

Chemistry: The Central Science 13
30E Nuclear Transmutations (Section) Complete and balance the following nuclear equations by supplying the missing particle: (a) 147N + 42 He*? + 11 H, (b) 40 19K + 0 -1e 1 orbital electron2 ->? (c) ? + 42 He-30 14Si + 11 H, (d) 5826Fe + 2 10 n-6027Co + ? (e) 23592U + 10 n-13554Xe + 2 10 n + ?

Chapter: Problem: 31E

Chemistry: The Central Science 13
31E Nuclear Transmutations (Section) Wr ite balanced equations for (a) 23892U1a. n2241 94Pu. (b) 14 7N1a. p217 80. (c) 56 26Fe1a. b-260 29Cu.

Chapter: Problem: 32E

Chemistry: The Central Science 13
32E Nuclear Transmutations (Section) Write balanced equations for each of the following nuclear reactions: (a) 238 921)1 n, g2239 92Ur (b) 16 801p. a213 7N. (c) 18 801nr b-219 9F.

Chapter: Problem: 33E

Chemistry: The Central Science 13
33E Rates of Radioactive Decay (Section) Each statement that follows refers to a comparison between two radioisotopes. A and X. Indicate whether each of the following statements is true or false, and why. (a) If the half-life for A is shorter than the half-life for X. A has a larger decay rate co

Chapter: Problem: 34E

Chemistry: The Central Science 13
34E Rates of Radioactive Decay (Section) It has been suggested that strontium-90 (generated by nuclear testing) deposited in the hot desert will undergo radioactive decay more rapidly because it will be exposed to much higher average temperatures. (a) Is this a reasonable suggestion? (b) Does the p

Chapter: Problem: 35E

Chemistry: The Central Science 13
35E Rates of Radioactive Decay (Section) Some watch dials are coated with a phosphor like ZnS, and a polymer in which some of the 1H atoms have been replaced by 3H atoms, tritium. The phosphor emits light when struck by the beta particle from the tritium decay, causing the dials to glow in the dark

Chapter: Problem: 36E

Chemistry: The Central Science 13
36E Rates of Radioactive Decay (Section) It takes 4 h 39 min for a 2.00-mg sample of radium-230 to decay to 0.25 mg. What is the half-life of radium-230?

Chapter: Problem: 37E

Chemistry: The Central Science 13
37E Rates of Radioactive Decay (Section) Cobalt-60 is a strong gamma emitter that has a half-life of 5.26 yr. The cobalt-60 in a radiotherapy unit must be replaced when its radioactivity falls to 75% of the original sample. If an original sample was purchased in June 2013, when will it be necessa

Chapter: Problem: 38E

Chemistry: The Central Science 13
38E Rates of Radioactive Decay (Section) How much time is required for a 6.25-mg sample of 51 Cr to decay to 0.75 mg if it has a half-life of 27.8 days?

Chapter: Problem: 39E

Chemistry: The Central Science 13
39E [21.39] Rates of Radioactive Decay (Section) Radium-226, which undergoes alpha decay, has a half-life of 1600 yr. (a) How many alpha particles are emitted in 5.0 min by a 10.0-mg sample of 226Ra? (b) What is the activity of the sample in mCi?

Chapter: Problem: 40E

Chemistry: The Central Science 13
40E Rates of Radioactive Decay (Section) Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. (a) How many beta particles are emitted in 600 s by a 3.75-mg sample of 60Co? (b) What is the activity of the sample in Bq?

Chapter: Problem: 41E

Chemistry: The Central Science 13
The cloth shroud from around a mummy is found to have a \({ }^{14} C\) activity of 9.7 disintegrations per minute per gram of carbon as compared with living organisms that undergo 16.3 disintegrations per minute per gram of carbon. From the halflife for \({ }^{14} C\) decay, 5715 yr, calculate the ag

Chapter: Problem: 42E

Chemistry: The Central Science 13
A wooden artifact from a Chinese temple has a \({ }^{14} C\) activity of 38.0 counts per minute as compared with an activity of 58.2 counts per minute for a standard of zero age. From the half-life for \({ }^{14} C\) decay, 5715 yr, determine the age of the artifact. Equation transcription: Te

Chapter: Problem: 43E

Chemistry: The Central Science 13
43E Rates of Radioactive Decay (Section) Potassium-40 decays to argon-40 with a half-life of 1.27 * 109 yr. What is the age of a rock in which the mass ratio of 40Ar to 40K is 4.2?

Chapter: Problem: 44E

Chemistry: The Central Science 13
44E Rates of Radioactive Decay (Section) The half-life for the process 238U-*206Pb is 4.5 * 109 yr. A mineral sample contains 75.0 mg of 238U and 18.0 mg of 206Pb. What is the age of the mineral?

Chapter: Problem: 45E

Chemistry: The Central Science 13
45E Energy Changes in Nuclear Reactions (Section) The thermite reaction. Fe203(s) + 2 Al(s) 2 Fe(s) + AI203(s)r Ahf = -851.5 kJ>mol, is one of the most exothermic reactions known. Because the heat released is sufficient to melt the iron product, the reaction is used to weld metal under the ocean.

Chapter: Problem: 46E

Chemistry: The Central Science 13
46E Energy Changes in Nuclear Reactions (Section) An analytical laboratory balance typically measures mass to the nearest 0.1 mg. What energy change would accompany the loss of 0.1 mg in mass?

Chapter: Problem: 47E

Chemistry: The Central Science 13
47E Energy Changes in Nuclear Reactions (Section) How much energy must be supplied to break a single aluminum- 27 nucleus into separated protons and neutrons if an aluminum-27 atom has a mass of 26.9815386 amu? How much energy is required for 100.0 grams of aluminum-27? (The mass of an electron is

Chapter: Problem: 48E

Chemistry: The Central Science 13
48E Energy Changes in Nuclear Reactions (Section) How much energy must be supplied to break a single 21 Ne nucleus into separated protons and neutrons if the nucleus has a mass of 20.98846 amu? What is the nuclear binding energy for 1 mol of 21 Ne?

Chapter: Problem: 49E

Chemistry: The Central Science 13
The atomic masses of hydrogen-2 (deuterium), helium-4, and lithium-6 are 2.014102 amu, 4.002602 amu, and 6.0151228 amu, respectively. For each isotope, calculate (a) the nuclear mass, (b) the nuclear binding energy, (c) the nuclear binding energy per nucleon. (d) Which of these three isotopes has the

Chapter: Problem: 50E

Chemistry: The Central Science 13
The atomic masses of nitrogen-14, titanium-48, and xenon-129 are 13.999234 amu, 47.935878 amu, and 128.904779 amu, respectively. For each isotope, calculate (a) the nuclear mass, (b) the nuclear binding energy, (c) the nuclear binding energy per nucleon.

Chapter: Problem: 51E

Chemistry: The Central Science 13
51E Energy Changes in Nuclear Reactions (Section) The energy from solar radiation falling on Earth is 1.07 x 1016 kJ>min. (a) How much toss of mass from the Sun occurs in one day from just the energy falling on Earth (b) If the energy released in the reaction 235U + 10n 14156B

Chapter: Problem: 52E

Chemistry: The Central Science 13
52E Energy Changes in Nuclear Reactions (Section) Based on the following atomic mass values:1H. 1.00782 amu: 2H. 2.01410 amu: 3H. 3.01605 amu: 3He. 3.01603 amu: 4He. 4.00260 amuand the mass of the neutron given in the text, calculate the energy released per mole in each of the following nuclear r

Chapter: Problem: 53E

Chemistry: The Central Science 13
53E Energy Changes in Nuclear Reactions (Section) Which of the following nuclei is l<ely to have the largest mass defect per nucleon: (a) 59Co, (b) 11B. (c) 118Sn. (d) 243Cm? Explain your answer.

Chapter: Problem: 54E

Chemistry: The Central Science 13
The isotope \({ }_{28}^{62} N i\) has the largest binding energy per nucleon of any isotope. Calculate this value from the atomic mass of nickel-62 (61.928345 amu) and compare it with the value given for iron-56 in Table 21.7. Equation transcription: Text transcription: { }_{28}^{62} N i

Chapter: Problem: 55E

Chemistry: The Central Science 13
55E Nuclear Power and Radioisotopes (Sections) Iodine-131 is a convenient radbisotope to monitor thyroid activity in humans. It is a beta emitter with a half-life of 8.02 days. The thyroid is the only gland in the body that uses bdine. A person undergoing a test of thyroid activity drinks a solut

Chapter: Problem: 56E

Chemistry: The Central Science 13
56E Nuclear Power and Radioisotopes (Sections) Why rs it important that radioisotopes used as diagnostic tools in nuciear medicine produce gamma radiation when they decay? Why are alpha emitters not used as diagnostic tools?

Chapter: Problem: 57E

Chemistry: The Central Science 13
57E Nuclear Power and Radioisotopes (Sections) (a) Which of the following are required characteristics of an isotope to be used as a fuel in a nuclear power reactor? (i) It must emit gamma radiation., (i) On decay, it must release two or more neutrons.. (I) It must have a half-life les

Chapter: Problem: 58E

Chemistry: The Central Science 13
58E Nuclear Power and Radioisotopes (Sections) (a) Which of the following statements about the uranium used in nuclear reactors is or are true? (i) Natural uranium has too little 235U to be used as a fuel, (i) 2381) cannot be used as a fuel because it forms a supercritical mass too easily.

Chapter: Problem: 59E

Chemistry: The Central Science 13
59E Nuclear Power and Radioisotopes (Sections) What is the function of the control rods in a nuclear reactor? What substances are used to construct control rods? Why are these substances chosen?

Chapter: Problem: 60E

Chemistry: The Central Science 13
60E Nuclear Power and Radioisotopes (Sections) (a) What is the function of the moderator in a nuciear reactor? (b) What substance acts as the moderator in a pressurized water generator? (c) What other substances are used as a moderator in nuciear reactor designs?

Chapter: Problem: 61E

Chemistry: The Central Science 13
61E Nuclear Power and Radioisotopes (Sections) Complete and balance the nuclear equations for the following fission or fusion reactions: (a) 21 H + 21 H32 He + (b) 239 92U + 10 n-133 51Sb + 98 41Nb + -1 On

Chapter: Problem: 62E

Chemistry: The Central Science 13
62E Nuclear Power and Radioisotopes (Sections) Complete and balance the nuclear equations for the following fission reactions: (a) 235 92U + 10 n-160 62Sm + 72 30Zn + -10 n. (b) 239 94 Pu + 10 n144 58 Ce + - + 2 10 n

Chapter: Problem: 63E

Chemistry: The Central Science 13
A portion of the Suns energy comes from the reaction \(4_{1}^{1} H \rightarrow{ }_{2}^{4} H e+2_{1}^{0} e\) which requires a temperature of \(10^{6}\) to \(10^{7}\) K. (a) Use the mass of the helium-4 nucleus given in Table 21.7 to determine how much energy is released when the reaction is run wi

Chapter: Problem: 64E

Chemistry: The Central Science 13
The spent fuel elements from a fission reactor are much more intensely radioactive than the original fuel elements. (a) What does this tell you about the products of the fission process in relationship to the belt of stability, Figure 21.2? (b) Given that only two or three neutrons are released per f

Chapter: Problem: 65E

Chemistry: The Central Science 13
65E Nuclear Power and Radioisotopes (Sections) Which type or types of nuclear reactors have these characteristics? (a) Does not use a secondary coolant, (b) Creates more fissionable material than it consumes, (c) Uses a gas. such as He or C02. as the primary coolant

Chapter: Problem: 66E

Chemistry: The Central Science 13
66E Nuclear Power and Radioisotopes (Sections) Which type or types of nuclear reactors have these characteristics? (a) Can use natural uranium as a fuel, (b) Does not use a moderator, (c) Can be refueled without shutting down

Chapter: Problem: 67E

Chemistry: The Central Science 13
67E Nuclear Power and Radioisotopes (Sections) Hydroxyl radicals can pluck hydrogen atoms from molecules (hydrogen abstraction), and hydroxide ions can pluck protons from molecules (deprotonation'). Write the reaction equations and Lewis dot structures for the hydrogen abstraction and deprotonati

Chapter: Problem: 68E

Chemistry: The Central Science 13
68E Nuclear Power and Radioisotopes (Sections) Which are classified as ionizing radiation: X rays, alpha particles, microwaves from a cell phone, and gamma rays?

Chapter: Problem: 69E

Chemistry: The Central Science 13
69E Nuclear Power and Radioisotopes (Sections) A laboratory rat is exposed to an alpha-radiation source whose acth/ity is 14.3 mCi. a) What is the acth/ity of the radiation in disintegrations per second? In becquerels (b) The rat has a mass of 385 g and is exposed to the radiation for 14.0 s. absor

Chapter: Problem: 70E

Chemistry: The Central Science 13
70E Nuclear Power and Radioisotopes (Sections) A 65-kg person is accidentally exposed for 240 s to a 15-mCi source of beta radiation coming from a sample of SOSr. (a) What is the activity of the radiation source in disintegrations per second? In becquerefe? (b) Each beta particle has an energy of

Chapter: Problem: 71E

Chemistry: The Central Science 13
The table to the right gives the number of protons (p) and neutrons (n) for four isotopes. (a) Write the symbol for each of the isotopes. (b) Which of the isotopes is most likely to be unstable? (c) Which of the isotopes involves a magic number of protons and/or neutrons? (d) Which isotope will yield

Chapter: Problem: 72E

Chemistry: The Central Science 13
72E Radon-222 decays to a stable nucleus by a series of three alpha emissions and two beta emissions. What is the stable nucleus that is formed?

Chapter: Problem: 73AE

Chemistry: The Central Science 13
Equation 21.28 is the nuclear reaction responsible for much of the helium-4 production in our Sun. How much energy is released in this reaction?

Chapter: Problem: 74E

Chemistry: The Central Science 13
74E Chlorine has two stable nuclides. 35CI and 37CI. In contrast. 36CI is a radioacth/e nuclide that decays by beta emission. (a) What is the product of decay of 36CI? (b) Based on the empirical rules about nuclear stability, explain why the nucleus of 36CI is less stable than eit

Chapter: Problem: 75E

Chemistry: The Central Science 13
When two protons fuse in a star, the product is \({ }^{2} H\) plus a positron (Equation 21.26). Why do you think the more obvious product of the reaction, \({ }^{2} \mathrm{He}\), is unstable? Equation transcription: Text transcription: { }^{2} H { }^{2} {He}

Chapter: Problem: 76E

Chemistry: The Central Science 13
76E Nuclear scientists have synthesized approximately 1600 nuclei not known in nature. More might be discovered with heavy-ion bombardment using high-energy particle accelerators. Complete and balance the following reactions, which involve heavy-ion bombardments: (a) 63 Li + 56 28Ni j? (b) 40 20C

Chapter: Problem: 77AE

Chemistry: The Central Science 13
In 2010, a team of scientists from Russia and the U.S. reported creation of the first atom of element 117, which is not yet named and is denoted [117]. The synthesis involved the collision of a target of \({ }_{97}^{249} B k\) with accelerated ions of an isotope which we will denote Q. The product at

Chapter: Problem: 78AE

Chemistry: The Central Science 13
78AE The synthetic radbisotope technetium-99. which decays by beta emission. is the most widely used isotope in nuclear medicine. The following data were collected on a sample of 99Tc: Disintegrations per Minute Time (h) 180 0 130 2.5 104

Chapter: Problem: 79E

Chemistry: The Central Science 13
79E According to current regulations, the maximum permissible dose of strontium-SO in the body of an adult is 1 pCi(1 x 10-6 Ci). Using the relationship rate = kN. calculate the number of atoms of strontium-90 to which this dose corresponds. To what mass of strontium-90 does this correspond? The ha

Chapter: Problem: 80E

Chemistry: The Central Science 13
80E Suppose you had a detection device that could count every decay event from a radioactive sample of plutonium-239 (fl/2 is 24.000 yr). How many counts per second would you obtain from a sample containing 0.385 g of plutonium-239?

Chapter: Problem: 81E

Chemistry: The Central Science 13
Methyl acetate \(\left(\mathrm{CH}_{2} \mathrm{COOCH}_{3}\right)\) is formed by the reaction of acetic acid with methyl alcohol. If the methyl alcohol is labeled with oxygen-18, the oxygen-18 ends up in the methyl acetate: (a) Do the COH bond of the acid and the OH bond of the alcohol break i

Chapter: Problem: 82AE

Chemistry: The Central Science 13
82AE An experiment was designed to determine whether an aquatic plant absorbed iodide ion from water. Iodine-131 (fl/2 = 8.02 days) was added as a tracer, in the form of iodide ion. to a tank containing the plants. The initial activity of a 1.00-p L sample of the water was 214 counts per minute. Af

Chapter: Problem: 83AE

Chemistry: The Central Science 13
83AE Each of the following transmutations produces a radionuclide used in positron emission tomography (PET). (a) In equations (i) and (i), identify the species signified as JX.* (b) In equation (i). one of the species is indicated as "d. What do you think it represents? (i) 14N

Chapter: Problem: 84E

Chemistry: The Central Science 13
84E The nuclear masses of 7Be. 5Be. and 10Be are 7.0147, 9.0100. and 10.0113 amu. respectively. Which of these nuclei has the largest binding energy per nucleon?

Chapter: Problem: 85AE

Chemistry: The Central Science 13
85AE A26.00-g sample of water containing tritium. 31 H. emits 1.50 * 103 beta parte ies per second. Tritium is a weak beta emitter with a half-life of 12.3 yr. What fraction of all the hydrogen in the water sample is tritium?

Chapter: Problem: 86AE

Chemistry: The Central Science 13
88AE The Sun radiates energy into space at the rate of 3.9 * 1026 J/s. (a) Calculate the rate of mass loss from the Sun in kg/s. (b) How does this mass loss arise? (c) It is estimated that the Sun contains 9 * 1056 free protons. How many protons per second are consumed in nucle

Chapter: Problem: 88AE

Chemistry: The Central Science 13
88AE Tests on human subjects in Boston in 1S65 and 1S66. following the era of atomic bomb testing, revealed average quantities of about 2 pCi of plutonium radioactivity in the average person. How many disintegrations per second does this level of activity imply? If each alpha partic le deposits 8 x

Chapter: Problem: 87AE

Chemistry: The Central Science 13
87AE The average energy reteased in the fission of a single uranium- 235 nucleus is about 3 * 10-11 J. If the conversion of this energy to electricity in a nuclear power plant is 40% efficient, what mass of uranium-235 undergoes fission in a year in a plant that produces 1000 megawatts? Recall that

Chapter: Problem: 89IE

Chemistry: The Central Science 13
89IE A 53.8-mg sample of sodium perchlorate contains radioacth/e chlorine-36 (whose atomic mass is 36.0 amu). If 29.6% of the chlorine atoms in the sample are chlorine-36 and the remainder are naturally occurring nonradbactive chlorine atoms, how many disintegrations per second are produced by this

Chapter: Problem: 90IE

Chemistry: The Central Science 13
90IE Cak: ulate the mass of octane. C8H18</). that must be burned in air to evolve the same quantity of energy as produced by the fusion of 1.0 g of hydrogen in the following fusion reaction: 4 11 H42 He + 2 01e Assume that all the products of the combustion of octane are in their gas phases. U

Chapter: Problem: 91IE

Chemistry: The Central Science 13
Naturally found uranium consists of \(99.274 \%^{238} U, 0.720 \%^{235} U\), and \(0.006 \%^{233} U\). As we have seen, \(235 U\) is the isotope that can undergo a nuclear chain reaction. Most of the \(235 U\) used in the first atomic bomb was obtained by gaseous diffusion of uranium hexafluoride, \(

Chapter: Problem: 92IE

Chemistry: The Central Science 13
92IE A sample of an alpha emitter having an activity of 0.18 Ci is stored in a 25.0-mL sealed container at 22 SC for 245 days. (a) How many alpha particles are formed during this time? (b) Assuming that each alpha particle is converted to a heium atom, what is the partial pressure of heium gas in

Chapter: Problem: 93IE

Chemistry: The Central Science 13
93IE Charcoal samples from Stonehenge in England were burned in 02. and the resultant C02 gas bubbled into a solution of Ca(0H)2 (Bmewater), resulting in the precipitation of CaC03. The CaC03 was removed by filtration and dried. A 788-mg sample of the CaC03 had a radioacth/ity of 1.5 x 10-2 Bq due

Chapter: Problem: 94IE

Chemistry: The Central Science 13
94IE A 25.0-mL sample of 0.050 M barium nitrate solution was mixed with 25.0 mL of 0.050 M sodium sulfate solution labeled with radioactive sulfur-35. The activity of the initial sodium sulfate solution was 1.22 x 106 Bq/mL. After the resultant precipitate was removed by filtration, the remaining f

Chapter: Problem: 21.1

Chemistry: The Central Science 13
Indicate whether each of the following nuclides lies within the belt of stability in Figure 21.2: (a) neon- 24, (b) chlorine-32, (c) tin-108, (d) polonium-216. For any that do not, describe a nuclear decay process that would alter the neutron-to-proton ratio in the direction of increased stability. [

Chapter: Problem: 21.2

Chemistry: The Central Science 13
Write the balanced nuclear equation for the reaction represented by the diagram shown here. [Section 21.2] 45 46 47 48 61 62 63 64 Number of protons

Chapter: Problem: 21.3

Chemistry: The Central Science 13
Draw a diagram similar to that shown in Exercise 21.2 that illustrates the nuclear reaction 211 83Bi 4 2He + 207 81Tl. [Section 21.2]

Chapter: Problem: 21.4

Chemistry: The Central Science 13
In the sketch below, the red spheres represent protons and the gray spheres represent neutrons. (a) What are the identities of the four particles involved in the reaction depicted? (b) Write the transformation represented below using condensed notation. (c) Based on its atomic number and mass number,

Chapter: Problem: 21.5

Chemistry: The Central Science 13
The steps below show three of the steps in the radioactive decay chain for 232 90Th. The half-life of each isotope is shown below the symbol of the isotope. (a) Identify the type of radioactive decay for each of the steps (i), (ii), and (iii). (b) Which of the isotopes shown has the highest activity?

Chapter: Problem: 21.6

Chemistry: The Central Science 13
The accompanying graph illustrates the decay of 88 42Mo, which decays via positron emission. (a) What is the half-life of the decay? (b) What is the rate constant for the decay? (c) What fraction of the original sample of 88 42Mo remains after 12 min? (d) What is the product of the decay process? [Se

Chapter: Problem: 21.7

Chemistry: The Central Science 13
All the stable isotopes of boron, carbon, nitrogen, oxygen, and fluorine are shown in the accompanying chart (in red), along with their radioactive isotopes with t1>2 7 1 min (in blue). (a) Write the chemical symbols, including mass and atomic numbers, for all of the stable isotopes. (b) Which radioa

Chapter: Problem: 21.8

Chemistry: The Central Science 13
The diagram shown here illustrates a fission process. (a) What is the unidentified product of the fission? (b) Use Figure 21.2 to predict whether the nuclear products of this fission reaction are stable. [Section 21.7] 0n1 0n1 0n1 94Pu 239 40Zr 95 ?

Chapter: Problem: 21.9

Chemistry: The Central Science 13
Indicate the number of protons and neutrons in the following nuclei: (a) 56 24Cr, (b) 193 Tl, (c) argon- 38.

Chapter: Problem: 21.10

Chemistry: The Central Science 13
Indicate the number of protons and neutrons in the following nuclei: (a) 129 53I, (b) 138 Ba, (c) neptunium-237.

Chapter: Problem: 21.11

Chemistry: The Central Science 13
Give the symbol for (a) a neutron, (b) an alpha particle, (c) gamma radiation.

Chapter: Problem: 21.12

Chemistry: The Central Science 13
Give the symbol for (a) a proton, (b) a beta particle, (c) a positron.

Chapter: Problem: 21.13

Chemistry: The Central Science 13
Write balanced nuclear equations for the following processes: (a) rubidium-90 undergoes beta emission; (b) selenium-72 undergoes electron capture; (c) krypton-76 undergoes positron emission; (d) radium-226 emits alpha radiation.

Chapter: Problem: 21.14

Chemistry: The Central Science 13
Write balanced nuclear equations for the following transformations: (a) bismuth-213 undergoes alpha decay; (b) nitrogen-13 undergoes electron capture; (c) technicium-98 undergoes electron capture; (d) gold-188 decays by positron emission.

Chapter: Problem: 21.15

Chemistry: The Central Science 13
Decay of which nucleus will lead to the following products: (a) bismuth-211 by beta decay; (b) chromium-50 by positron emission; (c) tantalum-179 by electron capture; (d) radium-226 by alpha decay?

Chapter: Problem: 21.16

Chemistry: The Central Science 13
What particle is produced during the following decay processes: (a) sodium-24 decays to magnesium- 24; (b) mercury-188 decays to gold-188; (c) iodine-122 decays to xenon-122; (d) plutonium-242 decays to uranium-238?

Chapter: Problem: 21.17

Chemistry: The Central Science 13
The naturally occurring radioactive decay series that begins with 235 92U stops with formation of the stable 207 82Pb nucleus. The decays proceed through a series of alpha-particle and beta-particle emissions. How many of each type of emission are involved in this series?

Chapter: Problem: 21.18

Chemistry: The Central Science 13
A radioactive decay series that begins with 232 90Th ends with formation of the stable nuclide 208 82Pb. How many alphaparticle emissions and how many beta-particle emissions are involved in the sequence of radioactive decays?

Chapter: Problem: 21.19

Chemistry: The Central Science 13
Predict the type of radioactive decay process for the following radionuclides: (a) 8 5B, (b) 68 29Cu, (c) phosphorus-32, (d) chlorine-39.

Chapter: Problem: 21.20

Chemistry: The Central Science 13
Each of the following nuclei undergoes either beta decay or positron emission. Predict the type of emission for each: (a) tritium, 3 1H, (b) 89 38Sr, (c) iodine-120, (d) silver-102.

Chapter: Problem: 21.21

Chemistry: The Central Science 13
One of the nuclides in each of the following pairs is radioactive. Predict which is radioactive and which is stable: (a) 39 19K and 40 19K, (b) 209 Bi and 208 Bi, (c) nickel-58 and nickel-65.

Chapter: Problem: 21.22

Chemistry: The Central Science 13
One nuclide in each of these pairs is radioactive. Predict which is radioactive and which is stable: (a) 40 20Ca and 45 20Ca, (b) 12 C and 14 C, (c) lead-206 and thorium-230. Explain your choice in each case.

Chapter: Problem: 21.23

Chemistry: The Central Science 13
Which of the following nuclides have magic numbers of both protons and neutrons: (a) helium-4, (b) oxygen-18, (c) calcium-40, (d) zinc-66, (e) lead-208?

Chapter: Problem: 21.24

Chemistry: The Central Science 13
Despite the similarities in the chemical reactivity of elements in the lanthanide series, their abundances in Earths crust vary by two orders of magnitude. This graph shows the relative abundance as a function of atomic number. How do you explain the sawtooth variation across the series?

Chapter: Problem: 21.25

Chemistry: The Central Science 13
Using the concept of magic numbers, explain why alpha emission is relatively common, but proton emission is nonexistent.

Chapter: Problem: 21.26

Chemistry: The Central Science 13
Which of the following nuclides would you expect to be radioactive: 58 26Fe, 60 27Co, 92 41Nb, mercury-202, radium-226? Justify your choices.

Chapter: Problem: 21.27

Chemistry: The Central Science 13
Why are nuclear transmutations involving neutrons generally easier to accomplish than those involving protons or alpha particles?

Chapter: Problem: 21.28

Chemistry: The Central Science 13
In 1930 the American physicist Ernest Lawrence designed the first cyclotron in Berkeley, California. In 1937 Lawrence bombarded a molybdenum target with deuterium ions, producing for the first time an element not found in nature. What was this element? Starting with molybdenum-96 as your reactant, wr

Chapter: Problem: 21.29

Chemistry: The Central Science 13
Complete and balance the following nuclear equations by supplying the missing particle: (a) 252 98Cf + 10 5B 3 1 0n + ? (b) 2 1H + 3 2He 4 2He + ? (c) 1 1H + 11 5B 3? (d) 122 53I 122 54Xe + ? (e) 59 26Fe 0 -1e + ?

Chapter: Problem: 21.30

Chemistry: The Central Science 13
Complete and balance the following nuclear equations by supplying the missing particle: (a) 14 7N + 4 2He ? + 1 1H (b) 40 19K + 0 -1e 1orbital electron2 ? (c) ? + 4 2He 30 14Si + 1 1H (d) 58 26Fe + 2 1 0n 60 27Co + ? (e) 235 92U + 1 0n 135 54Xe + 2 1 0n + ?

Chapter: Problem: 21.31

Chemistry: The Central Science 13
Write balanced equations for (a) 238 92U1a, n2241 94Pu, (b) 14 7N1a, p217 8O, (c) 56 26Fe1a, b- 260 29Cu.

Chapter: Problem: 21.32

Chemistry: The Central Science 13
Write balanced equations for each of the following nuclear reactions: (a) 238 92U1n, g2239 92U, (b) 16 8O1p, a213 7N, (c) 18 8O1n, b- 219 9F.

Chapter: Problem: 21.33

Chemistry: The Central Science 13
Each statement that follows refers to a comparison between two radioisotopes, A and X. Indicate whether each of the following statements is true or false, and why. (a) If the half-life for A is shorter than the half-life for X, A has a larger decay rate constant. (b) If X is not radioactive, its half

Chapter: Problem: 21.34

Chemistry: The Central Science 13
It has been suggested that strontium-90 (generated by nuclear testing) deposited in the hot desert will undergo radioactive decay more rapidly because it will be exposed to much higher average temperatures. (a) Is this a reasonable suggestion? (b) Does the process of radioactive decay have an activat

Chapter: Problem: 21.35

Chemistry: The Central Science 13
Some watch dials are coated with a phosphor, like ZnS, and a polymer in which some of the 1 H atoms have been replaced by 3 H atoms, tritium. The phosphor emits light when struck by the beta particle from the tritium decay, causing the dials to glow in the dark. The half-life of tritium is 12.3 yr. I

Chapter: Problem: 21.36

Chemistry: The Central Science 13
It takes 4 h 39 min for a 2.00-mg sample of radium-230 to decay to 0.25 mg. What is the half-life of radium-230?

Chapter: Problem: 21.37

Chemistry: The Central Science 13
Cobalt-60 is a strong gamma emitter that has a half-life of 5.26 yr. The cobalt-60 in a radiotherapy unit must be replaced when its radioactivity falls to 75% of the original sample. If an original sample was purchased in June 2013, when will it be necessary to replace the cobalt-60?

Chapter: Problem: 21.38

Chemistry: The Central Science 13
How much time is required for a 6.25-mg sample of 51 Cr to decay to 0.75 mg if it has a half-life of 27.8 days?

Chapter: Problem: 21.39

Chemistry: The Central Science 13
Radium-226, which undergoes alpha decay, has a half-life of 1600 yr. (a) How many alpha particles are emitted in 5.0 min by a 10.0-mg sample of 226 Ra? (b) What is the activity of the sample in mCi?

Chapter: Problem: 21.40

Chemistry: The Central Science 13
Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. (a) How many beta particles are emitted in 600 s by a 3.75-mg sample of 60 Co? (b) What is the activity of the sample in Bq?

Chapter: Problem: 21.41

Chemistry: The Central Science 13
The cloth shroud from around a mummy is found to have a 14 C activity of 9.7 disintegrations per minute per gram of carbon as compared with living organisms that undergo 16.3 disintegrations per minute per gram of carbon. From the halflife for 14 C decay, 5715 yr, calculate the age of the shroud.

Chapter: Problem: 21.42

Chemistry: The Central Science 13
A wooden artifact from a Chinese temple has a 14 C activity of 38.0 counts per minute as compared with an activity of 58.2 counts per minute for a standard of zero age. From the halflife for 14 C decay, 5715 yr, determine the age of the artifact.

Chapter: Problem: 21.43

Chemistry: The Central Science 13
Potassium-40 decays to argon-40 with a half-life of 1.27 * 109 yr. What is the age of a rock in which the mass ratio of 40 Ar to 40 K is 4.2?

Chapter: Problem: 21.44

Chemistry: The Central Science 13
The half-life for the process 238 U 206 Pb is 4.5 * 109 yr. A mineral sample contains 75.0 mg of 238 U and 18.0 mg of 206 Pb. What is the age of the mineral?

Chapter: Problem: 21.45

Chemistry: The Central Science 13
The thermite reaction, Fe2O31s2 + 2 Al1s2 2 Fe1s2 + Al2O31s2, H = -851.5 kJ>mol, is one of the most exothermic reactions known. Because the heat released is sufficient to melt the iron product, the reaction is used to weld metal under the ocean. How much heat is released per mole of Fe2O3 produced? H

Chapter: Problem: 21.46

Chemistry: The Central Science 13
An analytical laboratory balance typically measures mass to the nearest 0.1 mg. What energy change would accompany the loss of 0.1 mg in mass?

Chapter: Problem: 21.47

Chemistry: The Central Science 13
How much energy must be supplied to break a single aluminum-27 nucleus into separated protons and neutrons if an aluminum-27 atom has a mass of 26.9815386 amu? How much energy is required for 100.0 grams of aluminum-27? (The mass of an electron is given on the inside back cover.)

Chapter: Problem: 21.48

Chemistry: The Central Science 13
How much energy must be supplied to break a single 21 Ne nucleus into separated protons and neutrons if the nucleus has a mass of 20.98846 amu? What is the nuclear binding energy for 1 mol of 21 Ne?

Chapter: Problem: 21.49

Chemistry: The Central Science 13
The atomic masses of hydrogen-2 (deuterium), helium-4, and lithium-6 are 2.014102 amu, 4.002602 amu, and 6.0151228 amu, respectively. For each isotope, calculate (a) the nuclear mass, (b) the nuclear binding energy, (c) the nuclear binding energy per nucleon. (d) Which of these three isotopes has the

Chapter: Problem: 21.50

Chemistry: The Central Science 13
The atomic masses of nitrogen-14, titanium-48, and xenon-129 are 13.999234 amu, 47.935878 amu, and 128.904779 amu, respectively. For each isotope, calculate (a) the nuclear mass, (b) the nuclear binding energy, (c) the nuclear binding energy per nucleon

Chapter: Problem: 21.51

Chemistry: The Central Science 13
The energy from solar radiation falling on Earth is 1.07 * 1016 kJ>min. (a) How much loss of mass from the Sun occurs in one day from just the energy falling on Earth? (b) If the energy released in the reaction 235 U + 1 0n 141 56Ba + 92 36Kr + 31 0n (235 U nuclear mass, 234.9935 amu; 141 Ba nuclear

Chapter: Problem: 21.52

Chemistry: The Central Science 13
Based on the following atomic mass values:1 H, 1.00782 amu; 2 H, 2.01410 amu; 3 H, 3.01605 amu; 3 He, 3.01603 amu; 4 He, 4.00260 amuand the mass of the neutron given in the text, calculate the energy released per mole in each of the following nuclear reactions, all of which are possibilities for a co

Chapter: Problem: 21.53

Chemistry: The Central Science 13
Which of the following nuclei is likely to have the largest mass defect per nucleon: (a) 59 Co, (b) 11 B, (c) 118 Sn, (d) 243 Cm? Explain your answer

Chapter: Problem: 21.54

Chemistry: The Central Science 13
The isotope 62 28Ni has the largest binding energy per nucleon of any isotope. Calculate this value from the atomic mass of nickel-62 (61.928345 amu) and compare it with the value given for iron-56 in Table 21.7.

Chapter: Problem: 21.55

Chemistry: The Central Science 13
Iodine-131 is a convenient radioisotope to monitor thyroid activity in humans. It is a beta emitter with a half-life of 8.02 days. The thyroid is the only gland in the body that uses iodine. A person undergoing a test of thyroid activity drinks a solution of NaI, in which only a small fraction of the

Chapter: Problem: 21.56

Chemistry: The Central Science 13
Why is it important that radioisotopes used as diagnostic tools in nuclear medicine produce gamma radiation when they decay? Why are alpha emitters not used as diagnostic tools?

Chapter: Problem: 21.57

Chemistry: The Central Science 13
(a) Which of the following are required characteristics of an isotope to be used as a fuel in a nuclear power reactor? (i) It must emit gamma radiation. (ii) On decay, it must release two or more neutrons. (iii) It must have a half-life less than one hour. (iv) It must undergo fission upon the absorp

Chapter: Problem: 21.58

Chemistry: The Central Science 13
(a) Which of the following statements about the uranium used in nuclear reactors is or are true? (i) Natural uranium has too little 235 U to be used as a fuel. (ii) 238 U cannot be used as a fuel because it forms a supercritical mass too easily. (iii) To be used as fuel, uranium must be enriched so t

Chapter: Problem: 21.59

Chemistry: The Central Science 13
What is the function of the control rods in a nuclear reactor? What substances are used to construct control rods? Why are these substances chosen?

Chapter: Problem: 21.60

Chemistry: The Central Science 13
(a) What is the function of the moderator in a nuclear reactor? (b) What substance acts as the moderator in a pressurized water generator? (c) What other substances are used as a moderator in nuclear reactor designs?

Chapter: Problem: 21.61

Chemistry: The Central Science 13
Complete and balance the nuclear equations for the following fission or fusion reactions: (a) 2 1H + 2 1H 3 2He + : (b) 239 92U + 1 0n 133 51Sb + 98 41Nb + : 1 0n

Chapter: Problem: 21.62

Chemistry: The Central Science 13
Complete and balance the nuclear equations for the following fission reactions: (a) 235 92U + 1 0n 160 62Sm + 72 30Zn + : 1 0n (b) 239 94 Pu + 1 0n 144 58 Ce + : + 2 1 0n

Chapter: Problem: 21.63

Chemistry: The Central Science 13
A portion of the Suns energy comes from the reaction 4 1 1H 4 2He + 2 0 1e which requires a temperature of 106 to 107 K. (a) Use the mass of the helium-4 nucleus given in Table 21.7 to determine how much energy is released when the reaction is run with mol of hydrogen atoms. (b) Why is such a high te

Chapter: Problem: 21.64

Chemistry: The Central Science 13
The spent fuel elements from a fission reactor are much more intensely radioactive than the original fuel elements. (a) What does this tell you about the products of the fission process in relationship to the belt of stability, Figure 21.2? (b) Given that only two or three neutrons are released per f

Chapter: Problem: 21.65

Chemistry: The Central Science 13
Which type or types of nuclear reactors have these characteristics? (a) Does not use a secondary coolant (b) Creates more fissionable material than it consumes (c) Uses a gas, such as He or CO2, as the primary coolant

Chapter: Problem: 21.66

Chemistry: The Central Science 13
Which type or types of nuclear reactors have these characteristics? (a) Can use natural uranium as a fuel (b) Does not use a moderator (c) Can be refueled without shutting down

Chapter: Problem: 21.67

Chemistry: The Central Science 13
Hydroxyl radicals can pluck hydrogen atoms from molecules (hydrogen abstraction), and hydroxide ions can pluck protons from molecules (deprotonation). Write the reaction equations and Lewis dot structures for the hydrogen abstraction and deprotonation reactions for the generic carboxylic acid RCOOH w

Chapter: Problem: 21.68

Chemistry: The Central Science 13
Which are classified as ionizing radiation: X rays, alpha particles, microwaves from a cell phone, and gamma rays?

Chapter: Problem: 21.69

Chemistry: The Central Science 13
A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (a) What is the activity of the radiation in disintegrations per second? In becquerels? (b) The rat has a mass of 385 g and is exposed to the radiation for 14.0 s, absorbing 35% of the emitted alpha particles, each h

Chapter: Problem: 21.70

Chemistry: The Central Science 13
A 65-kg person is accidentally exposed for 240 s to a 15-mCi source of beta radiation coming from a sample of 90 Sr. (a) What is the activity of the radiation source in disintegrations per second? In becquerels? (b) Each beta particle has an energy of 8.75 * 10-14 J. and 7.5% of the radiation is abso

Chapter: Problem: 21.71

Chemistry: The Central Science 13
1 The table to the right gives the number of protons (p) and neutrons (n) for four isotopes. (a) Write the symbol for each of the isotopes. (b) Which of the isotopes is most likely to be unstable? (c) Which of the isotopes involves a magic number of protons and/or neutrons? (d) Which isotope will yie

Chapter: Problem: 21.72

Chemistry: The Central Science 13
Radon-222 decays to a stable nucleus by a series of three alpha emissions and two beta emissions. What is the stable nucleus that is formed?

Chapter: Problem: 21.73

Chemistry: The Central Science 13
Equation 21.28 is the nuclear reaction responsible for much of the helium-4 production in our Sun. How much energy is released in this reaction?

Chapter: Problem: 21.74

Chemistry: The Central Science 13
Chlorine has two stable nuclides, 35 Cl and 37 Cl. In contrast, 36 Cl is a radioactive nuclide that decays by beta emission. (a) What is the product of decay of 36 Cl? (b) Based on the empirical rules about nuclear stability, explain why the nucleus of 36 Cl is less stable than either 35 Cl or 37 Cl.

Chapter: Problem: 21.75

Chemistry: The Central Science 13
When two protons fuse in a star, the product is 2 H plus a positron (Equation 21.26). Why do you think the more obvious product of the reaction, 2 He, is unstable?

Chapter: Problem: 21.76

Chemistry: The Central Science 13
Nuclear scientists have synthesized approximately 1600 nuclei not known in nature. More might be discovered with heavy-ion bombardment using high-energy particle accelerators. Complete and balance the following reactions, which involve heavy-ion bombardments: (a) 6 3Li + 56 28Ni ? (b) 40 20Ca + 248 9

Chapter: Problem: 21.77

Chemistry: The Central Science 13
In 2010, a team of scientists from Russia and the U.S. reported creation of the first atom of element 117, which is not yet named and is denoted [117]. The synthesis involved the collision of a target of 249 97Bk with accelerated ions of an isotope which we will denote Q. The product atom, which we w

Chapter: Problem: 21.78

Chemistry: The Central Science 13
The synthetic radioisotope technetium-99, which decays by beta emission, is the most widely used isotope in nuclear medicine. The following data were collected on a sample of 99 Tc: Disintegrations per Minute Time (h) 180 0 130 2.5 104 5.0 77 7.5 59 10.0 46 12.5 24 17.5 Using these data, make an appr

Chapter: Problem: 21.79

Chemistry: The Central Science 13
According to current regulations, the maximum permissible dose of strontium-90 in the body of an adult is 1 mCi11 * 10-6 Ci2. Using the relationship rate = kN, calculate the number of atoms of strontium-90 to which this dose corresponds. To what mass of strontium-90 does this correspond? The half-lif

Chapter: Problem: 21.80

Chemistry: The Central Science 13
Suppose you had a detection device that could count every decay event from a radioactive sample of plutonium-239 (t1>2 is 24,000 yr). How many counts per second would you obtain from a sample containing 0.385 g of plutonium-239?

Chapter: Problem: 21.81

Chemistry: The Central Science 13
Methyl acetate 1CH3COOCH32 is formed by the reaction of acetic acid with methyl alcohol. If the methyl alcohol is labeled with oxygen-18, the oxygen-18 ends up in the methyl acetate: CH3COH H18 + OCH3 O CH3C18OCH3 + H2O O (a) Do the COH bond of the acid and the OH bond of the alcohol break in the rea

Chapter: Problem: 21.82

Chemistry: The Central Science 13
An experiment was designed to determine whether an aquatic plant absorbed iodide ion from water. Iodine-131 (t1>2 = 8.02 days) was added as a tracer, in the form of iodide ion, to a tank containing the plants. The initial activity of a 1.00@mL sample of the water was 214 counts per minute. After 30 d

Chapter: Problem: 21.83

Chemistry: The Central Science 13
Each of the following transmutations produces a radionuclide used in positron emission tomography (PET). (a) In equations (i) and (ii), identify the species signified as X. (b) In equation (iii), one of the sp

Chapter: Problem: 21.84

Chemistry: The Central Science 13
The nuclear masses of 7 Be, 9 Be, and 10 Be are 7.0147, 9.0100, and 10.0113 amu, respectively. Which of these nuclei has the largest binding energy per nucleon?

Chapter: Problem: 21.85

Chemistry: The Central Science 13
A 26.00-g sample of water containing tritium, 3 1H, emits 1.50 * 103 beta particles per second. Tritium is a weak beta emitter with a half-life of 12.3 yr. What fraction of all the hydrogen in the water sample is tritium?

Chapter: Problem: 21.86

Chemistry: The Central Science 13
The Sun radiates energy into space at the rate of 3.9 * 1026 J/s. (a) Calculate the rate of mass loss from the Sun in kg/s. (b) How does this mass loss arise? (c) It is estimated that the Sun contains 9 * 1056 free protons. How many protons per second are consumed in nuclear reactions in the Sun?

Chapter: Problem: 21.87

Chemistry: The Central Science 13
The average energy released in the fission of a single uranium-235 nucleus is about 3 * 10-11 J. If the conversion of this energy to electricity in a nuclear power plant is 40% efficient, what mass of uranium-235 undergoes fission in a year in a plant that produces 1000 megawatts? Recall that a watt

Chapter: Problem: 21.88

Chemistry: The Central Science 13
Tests on human subjects in Boston in 1965 and 1966, following the era of atomic bomb testing, revealed average quantities of about 2 pCi of plutonium radioactivity in the average person. How many disintegrations per second does this level of activity imply? If each alpha particle deposits 8 * 10-13 J

Chapter: Problem: 21.89

Chemistry: The Central Science 13
A 53.8-mg sample of sodium perchlorate contains radioactive chlorine-36 (whose atomic mass is 36.0 amu). If 29.6% of the chlorine atoms in the sample are chlorine-36 and the remainder are naturally occurring nonradioactive chlorine atoms, how many disintegrations per second are produced by this sampl

Chapter: Problem: 21.90

Chemistry: The Central Science 13
Calculate the mass of octane, C8H181l2, that must be burned in air to evolve the same quantity of energy as produced by the fusion of 1.0 g of hydrogen in the following fusion reaction: 4 1 1H 4 2He + 2 0 1e Assume that all the products of the combustion of octane are in their gas phases. Use data fr

Chapter: Problem: 21.91

Chemistry: The Central Science 13
Naturally found uranium consists of 99.274%238 U, 0.720% 235 U, and 0.006% 233 U. As we have seen, 235 U is the isotope that can undergo a nuclear chain reaction. Most of the 235 U used in the first atomic bomb was obtained by gaseous diffusion of uranium hexafluoride, UF61g2. (a) What is the mass of

Chapter: Problem: 21.92

Chemistry: The Central Science 13
A sample of an alpha emitter having an activity of 0.18 Ci is stored in a 25.0-mL sealed container at 22 C for 245 days. (a) How many alpha particles are formed during this time? (b) Assuming that each alpha particle is converted to a helium atom, what is the partial pressure of helium gas in the con

Chapter: Problem: 21.93

Chemistry: The Central Science 13
Charcoal samples from Stonehenge in England were burned in O2, and the resultant CO2 gas bubbled into a solution of Ca1OH22 (limewater), resulting in the precipitation of CaCO3. The CaCO3 was removed by filtration and dried. A 788-mg sample of the CaCO3 had a radioactivity of 1.5 * 10-2 Bq due to car

Chapter: Problem: 21.94

Chemistry: The Central Science 13
A 25.0-mL sample of 0.050 M barium nitrate solution was mixed with 25.0 mL of 0.050 M sodium sulfate solution labeled with radioactive sulfur-35. The activity of the initial sodium sulfate solution was 1.22 * 106 Bq>mL. After the resultant precipitate was removed by filtration, the remaining filtrate

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