Chapter 33
When thorium decays by emitting a beta particle, what is the atomic number of the resulting nucleus?
91
What is meant by the idea of a critical mass?
A critical mass of uranium is large enough so that neutrons ejected from one fissioning nucleus will hit another nucleus before exiting the mass.
Compared with the sum of isolated-nucleon masses, their collective mass in a composite nucleus is
Compared with the sum of isolated-nucleon masses, their collective mass in a composite nucleus is
What components are the safeguards to prevent a reactor from generating energy out of control?
Control rods
Do today's nuclear power plants use fission, fusion, or both?
Do today's nuclear power plants use fission, fusion, or both?
What kind of nuclear power is responsible for sunshine? Give an example.
Fusion: proton + deuteron produces helium-3
What were the two methods used to separate U-235 from U-238 in the Manhattan Project during World War II?
Gaseous diffusion and magnetic separation
From most abundant to least abundant, arrange the isotopes hydrogen, deuterium, and tritium.
Hydrogen (most abundant), deuterium, tritium (least abundant)
What becomes of the "lost" mass per nucleon in fission and fusion reactions?
It becomes kinetic energy.
What is the effect of placing small amounts of fissionable isotopes with large amounts of U-238?
Neutrons from the fission transmute U-238 to Pu-239, a fissionable fuel.
What occurs when a nitrogen nucleus captures an extra neutron?
None of the above.
What isotope is produced when U-239 emits a beta particle?
Np-239
What are the four main components of a fission reactor?
Nuclear fuel, control rods, a moderator, heat-extracting fluid
Why doesn't a chain reaction normally occur in uranium mines?
Only a small fraction of natural uranium is the fissionable U-235, so most of the released neutrons do not trigger another fission.
What isotope is produced when Np-239 emits a beta particle?
Pu-239
When a pair of hydrogen nuclei are fused to create helium, how does the mass of the resulting helium nucleus compare with the sum of the nuclear masses before fusion?
The mass of the helium nucleus is less than the sum of the masses of the hydrogen nuclei.
Which ions of like charge and equal speed are least deflected in a mass spectrometer?
The more massive ions
Which is more prevalent in the food we eat: carbon-12 or carbon-14?
There is about one carbon-14 atom for every 100 billion carbon-12 atoms.
In what way is a nuclear reactor similar to a conventional fossil-fuel plant?
They both boil water to make steam
What element reacts in a breeder reactor to breed nuclear fuel?
U-238
Why is lead found in all deposits of uranium ore?
Uranium undergoes radioactive decay, transmuting into lead.
Is work required to pull a nucleon out of an atomic nucleus? Does the nucleon, once outside, have more energy than it did when it was inside the nucleus? In what form is this energy?
Yes, work is required; more energy; more mass per nucleon
Carbon-14 is produced in the atmosphere principally by
cosmic-ray bombardment
The nucleus having the most tightly bound nucleons is
iron
What change in atomic number occurs when a nucleus emits an alpha particle? A beta particle? A gamma ray?
-2, +1, 0