Nuclear Chemistry
What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes?
0.70 g
What is the total number of grams of a 32-gram sample of 32P remaining after 71.5 days of decay?
1.0 g
Approximately what fraction of an original Co-60 sample remains after 21 years?
1/16
If 80 milligrams of a radioactive element decays to 10 milligrams in 30 minutes, what is the element's half-life in minutes?
10 min
If of an original sample of krypton-74 remains unchanged after 34.5 minutes, what is the half-life of krypton-74?
11.5 min
After decaying for 48 hours, of the original mass of a radioisotope sample remains unchanged. What is the half-life of this radioisotope?
12h
A sample of which radioisotope emits particles having the greatest mass?
220Fr
What is the number of hours required for potassium-42 to undergo 3 half-life periods?
37.2 hours
Which radioisotope has the fastest rate of decay?
37Ca
What is the number of half-life periods required for a sample of a radioactive material to decay to one-sixteenth its original mass?
4
What is one benefit associated with a nuclear fission reaction?
A large amount of energy is produced
The decay of which radioisotope can be used to estimate the age of the fossilized remains of an insect?
C-14
Which nuclides are used to date the remains of a once-living organism?
C-14 and C-12
In which type of nuclear reaction do nuclei combine to form a nucleus with a greater mass?
Fusion
In which type of nuclear reaction do two light nuclei combine to produce a heavier nucleus?
Fusion
Which list of nuclear emissions is arranged in order from the greatest penetrating power to the least penetrating power?
Gamma Ray, Beta Particle, Alpha Particle
Which radioisotope is used to treat thyroid disorders?
I-131
Nuclear Reactions
Nuclei of unstable isotopes; gain stability by undergoing changes by emitting radiation
Chemical Reactions
Occur when atoms attain stability by gaining/losing/sharing electrons; nucleus never changes when this happens
Which statement explains why fusion reactions are difficult to initiate?
Positive nuclei repel each other
The age of certain minerals can be determined if they contain the nuclide
U-238
Spent Fuel Rods
Uranium Rods that are "used up"; there are no longer "fissionable," and are still radioactive; stored in concrete and steel (to absorb radiation)
When I-131 undergoes radioactive decay, which element is formed?
Xe-131
Which particle is emitted when an atom of 85Kr spontaneously decays?
a beta particle
Which particle has the greatest chance of overcoming the electrostatic forces surrounding the nucleus of an atom?
a neutron
Bombarding a nucleus with high energy particles that change it from one element into another is called
artificial transmutation
When a radioactive nucleus emits a beta particle, the atom's
atomic number is increased by 1
Which particle has the least mass?
beta particle
Which isotopic ratio needs to be determined when the age of ancient wooden objects is investigated?
carbon-14 to carbon-12
Which radioactive isotope is used in treating cancer?
cobalt-60
The fission process in a reactor can be regulated by adjusting the number of neutrons available. This is done by the use of
control rods
Nuclear Power Plants
controlled fission reaction; fuel rods are placed into pools of H2O; fission reactions start -- water gets heated; water is heated -- turns to steam -- drives a turbine --> produces electricity
The ratio of the mass of U-238 to the mass of Pb-206 can be used to
date geological formations
Which procedure is based on the half-life of a radioisotope?
dating to determine age
The nucleus of a radium-226 atom is unstable, which causes the nucleus to spontaneously
decay
When an alpha particle is emitted by an atom, the atomic number of the atom will
decrease by 2
An Alpha decay results in the formation of a new element with the atomic number
decreased by 2
A radioisotope is called a tracer when it is used to
determine the way in which a chemical reaction occurs
An uncontrolled chain reaction takes place during the
explosion of an atomic bomb
Which risk is associated with using nuclear fission to produce energy in a power plant?
exposure of workers to radiation
Which reaction releases the greatest amount of energy per mole of reactant?
fission
Which type of reaction produces energy and intensely radioactive waste products?
fission of uranium
Which nuclear emission has no charge and no mass?
gamma ray
Iodine-131 is used for diagnosing thyroid disorders because it is absorbed by the thyroid gland and
has a very short half-life
Which radioisotope is used in medicine to treat thyroid disorders?
iodine-131
Radiation used in the processing of food is intended to
kill microorganisms that are found in the food
The energy released by a nuclear fusion reaction is produced when
mass is converted to energy
Cobalt-60 and iodine-131 are radioactive isotopes that are used in
medical procedures
Nuclear vs Chemical Energy (Pros)
no burning of fossil fuels; Uranium is cheap and plentiful
Artificial transmutation is brought about by using accelerated particles to bombard an atom's
nucleus
One benefit of nuclear fission reactions is
production of energy
Which phrase describes a risk associated with producing energy in a nuclear power plant?
production of wastes needing long-term storage
The course of a chemical reaction can be traced by using a
radioisotope
A serious risk factor associated with the operation of a nuclear power plant is the production of
radioisotopes with long half-lives
As a sample of the radioactive isotope 131 I decays, its half-life
remains the same
As temperature increases, pressure remaining constant, the half life of a radioactive element
remains the same
High energy is a requirement for fusion reactions to occur because the nuclei involved
repel each other because they have like charges
Which two substances are most commonly used for shielding in a nuclear reactor?
steel and high-density concrete
Fission
the bombardment of a large nucleus with high energy particles; the splitting of heavy molecules into nuclei
Nuclear vs Chemical Energy (Cons)
thermal pollution; storage of radioactive spent fuel rods; possible explosion; terrorist activity; workers exposed to radiation
Atoms of I-131 spontaneously decay when the
unstable nuclei emit beta particles
Samples if elements that are radioactive must contain atoms
with unstable nuclei