Ch.20 - Nuclear Chemistry
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- Calculate the mass defect (in g/mol) and the binding energy (in MeV/nucleon) for the following nuclei. Which of the two is more stable? (a) 7Li (atomic mass = 7.016004) (b) 39K (atomic mass = 38.963706)
Problem 79
Problem 80a
Calculate the binding energy (in MeV/nucleon) for the following nuclei. (a)58Ni (atomic mass = 57.93535)
Problem 80b
Calculate the binding energy (in MeV/nucleon) for the following nuclei. (b) 84Kr (atomic mass = 83.91151)
- What is the energy change ∆E (in kJ/mol) when an a particle is emitted from 174Ir? The atomic mass of 174Ir is 173.96666 the atomic mass of 170Re is 169.95804, and the atomic mass of a 4He atom is 4.00260.
Problem 82
- Thorium-232 decays by a 10-step series of nuclear reactions, ultimately yielding lead-208, along with 6 α particles and 4 β particles. How much energy (in kJ/mol) is released during the overall process? The relevant masses are 232Th = 232.038 054, 208Pb = 207.976 627, electron = 0.000 548 6, and 4He = 4.002 603.
Problem 86
Problem 87a
The radioactive isotope 100Tc decays to form the stable iso-tope 100Mo. (a) There are two possible pathways for this decay. Write balanced equations for both.
Problem 87b
The radioactive isotope 100Tc decays to form the stable iso-tope 100Mo. (b) Only one of the pathways is observed. Calculate the energy released by both pathways, and explain why only one is observed. Relevant masses are: 100Tc = 99.907 657, 100Mo = 99.907 48, electron = 0.000 548 6.
- Identify the false statement about nuclear fission. (a) Nuclear fission is induced by bombarding a U-235 sample with beta particles. (b) Nuclear fission is the splitting of a heavy element into lighter elements. (c) Mass is converted to energy in nuclear fission. (d) Nuclear fission releases huge amounts of energy compared to chemical reactions. (e) Nuclear fission can cause a chain reaction because additional neutrons are produced with each fission of a nucleus.
Problem 88
- Control rods in a nuclear reactor are often made of boron because it absorbs neutrons. Write the nuclear equation in which boron-10 absorbs a neutron to produce lithium-7 and an alpha particle.
Problem 90
- What is the difference between uranium fuel rods in a nuclear power plant and uranium fuel for an atomic weapon?
Problem 91
- Can fuel rods in a power plant be used to make an atomic weapon without further treatment? Explain.
Problem 92
- What are the benefits of using fusion over fission as a source of nuclear energy? Why have fusion reactors not been developed yet?
Problem 93
- How much energy is released (in kJ) in the fusion reaction of 2H to yield 1 mol of 3He? The atomic mass of 2H is 2.0141, and the atomic mass of 3He is 3.0160.
Problem 94
- How much energy (in kJ/mol) is produced in the following fission reaction of plutonium-239?
Problem 95
- How much energy (in kJ/mol) is released in the fusion reaction with 2H and 3He?
Problem 96
- How much energy (in kJ/mol) is released in the fusion reaction of 1H and 2H atoms?
Problem 97
Problem 98a
Give the products of the following nuclear reactions. (a)
Problem 98b
Give the products of the following nuclear reactions. (b)
Problem 99a
Balance the following equations for the nuclear fission of 235U. (a)
Problem 99b
Balance the following equations for the nuclear fission of 235U. (b)
- Element
Problem 100
was prepared in 1982 by bombardment of atoms with atoms. Identify the other product that must have formed, and write a balanced nuclear equation assuming no other products were formed. - Molybdenum-99 is formed by neutron bombardment of a naturally occurring isotope of Mo. If one neutron is absorbed and no by-products are formed, what is the starting isotope?
Problem 101
- One of the new superheavy elements added to the periodic table in 2016 was synthesized when a beam of 48Ca ions was directed at a target of 249Cf. (a) Write a balanced nuclear equation for the formation of this element.
Problem 104
(b) What isotope is formed after the nuclide formed in the nuclear transmutation reaction in part (a) emits four alpha particles? - One of the new superheavy elements added to the periodic table in 2016 was synthesized when a beam of 48Ca ions was directed at a target of 243Am. (a) Write a balanced nuclear equation for the formation of this element.
Problem 105
(b) What isotope is formed after the nuclide formed in the nuclear transmutation reaction in part (a) emits one alpha particle? (c) How many alpha particles were emitted to reach the isotope 268Db, the final decay product? - Fraud in science is rare but does happen occasionally. In 1999, the creation of three superheavy elements (one new) was claimed when 208Pb was bombarded with 86Kr. The claim was subsequently found to be fraudulent and was with-drawn. Identify the isotopes X, Y, and Z that were claimed.
Problem 106
- The most abundant isotope of uranium, 238U, does not undergo fission. In a breeder reactor, however, a 238U atom captures a neutron and emits two b particles to make a fis-sionable isotope of plutonium, which can then be used as fuel in a nuclear reactor. Write a balanced nuclear equation.
Problem 107
- A gastrointestinal tract X-ray exposes a patient to 5000 microSv of radiation. For X-rays, (1 Sv = 1 Gy), how many joules are absorbed by a 60-kg person?
Problem 108
- A 255-gram laboratory rat is exposed to 23.2 rads. How many grays did the rat receive? How many joules were absorbed by the rat?
Problem 109
- The maximum level of radon in drinking water is 4.0 pCi (4.0 x 10^-12Ci) per milliliter. (a) How many disintegrations occur per minute in 1 mL of water at the maximum radon level? (b) If the radioactive isotope is 222Rn(t1/2 = 3.8 days), how many 222Rn atoms are present in 1 mL of the water?
Problem 110
- Determine the activity of 10.0 mg of ²²⁶Ra in units of Bq and Ci. The half-life of ²²⁶Ra is 1600 years.
Problem 111