Indietro
- What is the balanced nuclear equation for the alpha decay of plutonium-238? (a)
Problema 1
(b) (c) (d) - Fluorine-18 undergoes positron emission with a half-life of 1.10 x 10^2 minutes. If a patient is given a 250 mg dose for a PET scan, how long will it take for the amount of fluorine-18 to drop to 75 mg? (a) 56 minutes (b) 96 minutes (c) 132 minutes (d) 191 minutes
Problema 4
- A sample of 201Tl, a radioisotope used to determine the function of the heart, decays initially at a rate of 25,700 disintegrations/min, but the decay rate falls to 15,990 disintegrations/min after 50.0 hours. What is the half-life of 201Tl, in hours? (a) 73.0 hours (b) 105 hours (c) 1.56 x 10^-2 hours (d) 3.84 x 10^2 hours
Problema 5
- In a cave in Oregon, archaeologists found bones, plant remains, and fossilized feces. DNA remaining in the feces indi-cates their human origin but not their age. To date the remains, the decay rate was measured and found to be 2.71 disinte-grations/min per gram of carbon. Currently living organisms have a decay rate of 15.3 disintegrations/min per gram of carbon, and the half-life of 14C is 5715 years. How old are the remains? (a) 1460 years (b) 9900 years (c) 14300 years (d) 18600 years
Problema 6
- Calculate the binding energy a uranium-235 nucleus in units of MeV/nucleon. The mass of an 235U atom is 235.043 929, the mass of a proton is 1.007 28, the mass of a neutron is 1.008 67, and the mass of an electron is 5.486 x 10^-4. (1 MeV = 1.60 x 10^-13 J) (a) 2.84 MeV/nucleon (b) 1.70 x 10^3 MeV/nucleon (c) 11.3 MeV/nucleon (d) 7.62 MeV/nucleon
Problema 7
- Identify the true statement about nuclear power plants and nuclear weapons. (a) Nuclear power plants and nuclear weapons both use uranium enriched to about 90% U-235. (b) Nuclear power plants emit large amounts of CO2 just like coal burning power plants. (c) The United States produces less than 1% of its electrical power from nuclear energy. (d) A nuclear weapon explodes when two pieces of fission-able uranium-235 are pushed together to reach a critical mass.
Problema 8
- How much energy in kJ/mol is released by the fission of uranium-235 to form barium-140 and krypton-93? The atomic masses are
Problema 9
(a) 6.59 x 10^9 kJ/mol (b) 1.66 x 10^10 kJ/mol (c) 1.98 x 10^11 kJ/mol (d) 1.66 x 10^16 kJ/mol - A sample 99mTc used for a whole body bone scan has an activity of 600 MBq. If the half-life is 6.01 hours, what mass of 99mTc was injected? (a) 3.1 ng (b) 8.4 microgram (c) 67 microgram (d) 2.7 mg
Problema 11
Problema 20.36d
Write balanced nuclear equations for the following processes.
(d) Positron emission of 165Ta
Problema 20.31d
Complete and balance the following nuclear equations.
(d) <ISOTOPE CHEM REACTION>
- Isotope A decays to isotope E through the following series of steps, in which the products of the individual decay events are themselves radioactive and undergo further decay until a stable nucleus is ultimately reached. Two kinds of processes are represented, one by the shorter arrows pointing right and the other by the longer arrows pointing left. (b) Identify and write the symbol
Problema 25
for each isotope in the series: 
- Positron emission and electron capture both give a product nucleus whose atomic number is 1 less than the starting nucleus. Explain.
Problema 26
- What is the difference between an a particle and a helium atom?
Problema 27
- Why does beta emission raise the atomic number of the product while positron emission lowers. the atomic number?
Problema 28
- Why does gamma emission not change the atomic number of the product?
Problema 29
Problema 30a
Complete and balance the following nuclear equations. (a)
Problema 30b
Complete and balance the following nuclear equations. (b)
Problema 30d
Complete and balance the following nuclear equations. (d)
Problema 31a
Complete and balance the following nuclear equations. (a)
Problema 31b
Complete and balance the following nuclear equations. (b)
- What particle is produced by the decay of thorium-214 to radium-210?
Problema 32
- What particle is produced by the decay of uranium-239 to neptunium-239?
Problema 33
Problema 34a
What particle is produced in each of the following decay reactions? (a)
Problema 34b
What particle is produced in each of the following decay reactions? (b)
Problema 34c
What particle is produced in each of the following decay reactions? (c)
Problema 35a
What particle is produced in each of the following decay reactions? (a)
Problema 35b
What particle is produced in each of the following decay reactions? (b)
Problema 35c
What particle is produced in each of the following decay reactions? (c)
Problema 36a
Write balanced nuclear equations for the following processes. (a) Alpha emission of 162Re
Problema 36b
Write balanced nuclear equations for the following processes. (b) Electron capture of 138Sm