Ch.20 - Nuclear Chemistry
Back
- 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 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
- 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
- Nitrogen-16 is formed in the cooling water flowing through a hot reactor core in a nuclear power plant. It is formed when oxygen captures a neutron and then emits a b par-ticle. Determine the activity of 50.0 mg of 16N in units of Bq and Ci.
Problem 112
- The maximum allowable radiation dose for recovery workers at the Fukushima nuclear plant in Japan was set to 100 mSv. A gastrointestinal (GI) tract X-ray is 5 mSv. The radiation exposure of a Fukushima worker is equivalent to how many GI tract X-rays?
Problem 113
- A small sample of wood from an archaeological site in Clo-vis, New Mexico, was burned in O2 and the CO2 produced was bubbled through a solution of Ba(OH)2 to produce a precipitation of BaCO3. When the BaCO3 was collected by filtration, a 1.000 g sample was found to have a radioactivity of 4.0 x 10^-5 Bq. The half-life of 14C is 5715 y, and living organisms have a radioactivity due to 14C if 15.3 disintegrations/min per gram of carbon. If the analysis was carried out in 1960, what is the date of the Clovis site?
Problem 118
- Polonium-210, a naturally occurring radioisotope, is an alpha emitter, with t1/2=138 d. Assume that a sample fo 210Po with a mass of 0.700 mg was placed ina 250.0-mL flask, which was evacuated, sealed, and allowed to sit undisturbed. What would the pressure be inside the flask (in mmHg) at 20 degrees Celsius after 365 days if all the alpha particles emitted has become helium atoms?
Problem 119
- Imagine that you have a 0.007 50 M aqueous MgCl2 solu-tion, prepared so that it contains a small amount of radio-active 28Mg. The half-life of 28Mg is 20.91 h, and the initial activity of the MgCl2 solution is 0.112 mCi>mL. Assume that 20.00 mL of this MgCl2 solution is added to 15.00 mL of 0.012 50 M aqueous Na2CO3 solution and that the resultant precipitate is then removed by filtration to yield a clear filtrate. After a long break to go for a run, you find that the activity of the filtrate measured 2.40 h after begin-ning the experiment is 0.029 mCi>mL. What are the molar concentrations of Mg2+ and CO32- in the filtrate, and what is the solubility product constant of MgCO3?
Problem 120