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- How much energy must be supplied to break a single ²¹Ne 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 ²¹Ne?
Problem 48
Problem 49c
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
(c) the nuclear binding energy per nucleon.
Problem 50a
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.
- The energy from solar radiation falling on Earth is 1.07 * 10^16 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 235U + 10n → 14156Ba + 9236Kr + 310n (235U nuclear mass, 234.9935 amu; 141Ba nuclear mass, 140.8833 amu; 92Kr nuclear mass, 91.9021 amu) is taken as typical of that occurring in a nuclear reactor, what mass of uranium-235 is required to equal 0.10% of the solar energy that falls on Earth in 1.0 day?
Problem 51
Problem 52
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 amu—and 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 controlled fusion process:
(a) 21H + 31H → 42He + 10n
(b) 21H + 21H → 32He + 10n
(c) 21H + 32He → 42He + 11H
- 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 iodide is radioactive. (a) Why is NaI a good choice for the source of iodine? (b) If a Geiger counter is placed near the person’s thyroid (which is near the neck) right after the sodium iodide solution is taken, what will the data look like as a function of time?
Problem 55
Problem 55c
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 iodide is radioactive. (c) A normal thyroid will take up about 12% of the ingested iodide in a few hours. How long will it take for the radioactive iodide taken up and held by the thyroid to decay to 0.01% of the original amount?
- (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 of less than one hour. (iv) It must undergo fission upon the absorption of a neutron. (b) What is the most common fissionable isotope in a commercial nuclear power reactor?
Problem 57
- 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. (ii) 238U 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 that it is more than 50% 235U in composition. (iv) The neutron-induced fission of 235U releases more neutrons per nucleus than the fission of 238U.
Problem 58
- What is the function of the control rods in a nuclear reactor? What substances are used to construct the control rods? Why are these substances chosen?
Problem 59
Problem 60c
(c) What other substances are used as a moderator in nuclear reactor designs?
Problem 62
Complete and balance the nuclear equations for the following fission reactions:
(a) 23592U + 10n → 16062Sm + 7230Zn + _ 10n
(b) 23994Pu + 10n → 14458Ce + _ + 2 10n
- A portion of the Sun’s energy comes from the reaction 4 11H → 42He + 2 0-1e, which requires a temperature of 106 to 107 K. Use the mass of the helium-4 nucleus given in Table 21.7 to determine how much energy is released per mol of hydrogen atoms.
Problem 63
Problem 64b
The spent fuel elements from a fission reactor are much more intensely radioactive than the original fuel elements. (b) Given that only two or three neutrons are released per fission event and knowing that the nucleus undergoing fission has a neutron-to-proton ratio characteristic of a heavy nucleus, what sorts of decay would you expect to be dominant among the fission products?
- 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.
Problem 65
- 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
Problem 66
- 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 R¬COOH with hydroxyl radical and hydroxide ion, respectively. Why is the hydroxyl radical more toxic to living systems than the hydroxide ion?
Problem 67
Problem 68
Which are classified as ionizing radiation: X rays, alpha particles, microwaves from a cell phone, and gamma rays?
- A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. If the RBE of the radiation is 9.5, calculate the effective absorbed dose in mrem and Sv.
Problem 69
Problem 69a
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?
Problem 69b
A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (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 having an energy of 9.12 * 10-13 J. Calculate the absorbed dose in millirads and grays.
Problem 71a
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.
Problem 72
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?
Problem 74b
Chlorine has two stable nuclides, 35Cl and 37Cl. In contrast, 36Cl is a radioactive nuclide that decays by beta emission. (b) Based on the empirical rules about nuclear stability, explain why the nucleus of 36Cl is less stable than either 35Cl or 37Cl.
- When two protons fuse in a star, the product is ²H plus a positron. Write the nuclear equation for this process.
Problem 75
Problem 76
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) 63Li + 5628Ni → ?
(b) 4020Ca + 24896Cm → 14762Sm + ?
(c) 8838Sr + 8436Kr → 11646Pd + ?
(d) 4020Ca + 23892U → 7030Zn + 4 10n + 2 ?
Problem 77a,c
In 2010, a team of scientists from Russia and the United States reported creation of the first atom of element 117, which is named tennessine, and whose symbol is Ts. The synthesis involved the collision of a target of 24997Bk with accelerated ions of an isotope which we will denote Q. The product atom, which we will call Z, immediately releases neutrons and forms 294117Ts: 24997Bk + Q → Z → 294117Ts + 3 10n (a) What are the identities of isotopes Q and Z? (c) Collision of ions of isotope Q with a target was also used to produce the first atoms of livermorium, Lv. The initial product of this collision was 296116Lv. What was the target isotope with which Q collided in this experiment?
- Each of the following transmutations produces a radionuclide used in positron emission tomography (PET). (b) In equation (iii), one of the species is indicated as “d.” What do you think it represents? (i) 14N1p, a2X (ii) 18O1p, X218F (iii) 14N1d, n215O
Problem 81
Problem 81a
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.'
(i) 14N(p,α)X
(ii) 18O(p,X)18F
(iii) 14N(d,n)15O
Problem 82
The nuclear masses of 7Be, 9Be, and 10Be are 7.0147, 9.0100, and 10.0113 amu, respectively. Which of these nuclei has the largest binding energy per nucleon?