Chem 1010 Chapter 5
The strong nuclear force is very sensitive to ________. the weak nuclear force distance electromagnetism mass
b
A shorter half-life means that a radioactive substance is relatively ________. unstable common stable difficult to detect
a
How do fission power plants work? The heat from a nuclear reaction is used to produce steam that drives a turbine. The krypton gas generated in the fission process is used to drive a turbine. The neutrons from a nuclear reaction undergo fusion with water to produce hydrogen gas, which is a combustible fuel. The neutrons from a nuclear reaction undergo fusion with water to produce hydrogen gas, which drives a turbine. The electrons from a nuclear reaction are harnessed to produce an electrical current.
a
Is it at all possible for a hydrogen nucleus to emit an alpha particle? no, because it does not contain enough nucleons no, because it would require the nuclear fission of hydrogen, which is impossible yes, but it does not occur very frequently yes, because alpha particles are the simplest form of radiation
a
The half life of cobalt-60 is approximately 5 years. If you have 10 grams of cobalt-60, how much is left after 15 years? 1.25 grams 5 grams 2.5 grams 10 grams
a
The half-life of carbon-14 is 5,730 years. A sample is found to have one-eighth the original amount of carbon-14 in it. How old is the sample? 17,200 years 5,730 years 4,5800 years 716 years none of the above
a
The isotope Cesium-137, which has a half-life of 30 years, is a product of nuclear power plants. How long will it take for this isotope to decay to about one-sixteenth its original amount? 120 years 960 years 480 years 240 years
a
What is the half life of a substance if it decays from 10 grams to 2.5 grams in 18 days? 9 days 36 days 4.5 days 18 days
a
Which of the following is a major disadvantage of nuclear-fission-based power plants? More than one of the above is a major disadvantage of a nuclear fission based power plant. The power plants are complex and there are many safety requirements to prevent contamination of the environment. The reactors can be used to produce their own fuel. The amount of energy per kilogram of fuel is greater than any other fuel source. The byproducts of the fission process are radioactive and have very long half-lives.
a
Which of the following sources of radiation provides most of our yearly exposure? background radiation living near nuclear power plants televisions (cathode ray tubes) smoke detectors dental and medical X-rays
a
Radioactivity is a tendency for an element or a material to ________. radiate heat emit radiation glow in the dark emit electrons emit light
b
Which of the following statements best describes the role of neutrons in the nucleus? The neutrons stabilize the nucleus by attracting protons and other neutrons. The neutrons stabilize the nucleus by adding mass. The neutrons stabilize the nucleus by balancing charge. The neutrons stabilize the nucleus by forming bonds with other neutrons. The neutrons stabilize the nucleus by attracting protons.
a
Which of the following statements best describes the role of neutrons in the nucleus? The neutrons stabilize the nucleus by attracting protons and other neutrons. The neutrons stabilize the nucleus by adding mass. The neutrons stabilize the nucleus by balancing charge. The neutrons stabilize the nucleus by forming bonds with other neutrons. The neutrons stabilize the nucleus by attracting protons.
a
Which of the following statements best describes why a large nucleus is more likely to undergo radioactive decay? The nuclear forces are not as strong as the repulsive electrical forces between protons. The nuclear force between the nucleons are very strong and squeeze out other nucleons. The nucleon-nucleon attraction is stronger than the proton-proton repulsion. The proton-proton repulsion cannot overcome the nucleon attraction. All nuclei are equally likely to undergo radioactive decay.
a
Which type of radiation is being emitted in the following incomplete nuclear equation? 218/84 Po → 214/82 Pb + ?? alpha none of the above A and B beta gamma
a
Why might the following nuclear reaction not be very good for energy production in a fission reactor? 235/92 U → 135/56 Ba + 99/36 Kr + 1 neutron The material only produces one neutron so the chain reaction will not be very efficient. Interatomic attraction between the products will impede the efficient separation of the atoms from the unstable nuclei. The products are too large. The mass of the byproducts is too high and therefore the energy released will not be high enough. There are too many products produced
a
The half-life of carbon-14 is 5,730 years. A sample is found to have one-eighth the original amount of carbon-14 in it. How old is the sample? 4,5800 years 17,200 years 5,730 years none of the above 716 years
b
A radioactive sample has a half life of 5.0 min. What fraction of the sample is left after 20.0 min? 1/2 1/16 1/4 1/8 There is no way to know without knowing the identity of the isotope.
b
Complete the following nuclear equation: 210/83 Bi → ?? + 0/-1 e 210/82 Pb 210/84 Po 206/82 Pb 211/84 Th none of the above
b
When 226/88 Ra decays by emitting an alpha particle, what is the atomic number of the resulting nucleus? What is the resulting atomic mass? atomic number = 86; atomic mass = 224 atomic number = 86; atomic mass = 222 atomic number = 87; atomic mass = 224 atomic number = 87; atomic mass = 226
b
Which of the following nuclear equations correctly describes alpha emission? Th → Pa + e none of the above Th → Ac + e Th → e Th → Pa + e
b
Which of the following statements about fission is true? None of the answers are true. The amount of energy released in the fission of large nuclei is very large. The amount of energy released in the fusion of small nuclei is very large. Bombarding a nucleus with neutrons always leads to fission. The fragments of a fusion reaction are always the same size.
b
Which process would release energy from gold, fission or fusion? From carbon? gold: fission; carbon: fission gold: fission; carbon: fusion gold: fusion; carbon: fission gold: fusion; carbon: fusion
b
The combining of two light nuclei of low mass to produce a heavy nucleus is called ______. spontaneous fission nuclear fission nuclear fusion double beta decay
c
What does Einstein's energy equation (E = mc2) say about the energy that is derived from nuclear fission reactions? The energy is proportional to the increase in mass of the nucleus undergoing fission. None of the answers are correct. The energy released is due to the missing mass of the products compared to the mass of the starting materials. The energy equation does not apply towards fission, only fusion. The energy is derived from the light that is emitted when the atom splits.
c
Which of the following emits more radiation? fallout from nuclear tests in the '50s and '60s a television set a coal-fired power plant a computer monitor a nuclear power plant
c
Which of the following nuclear equations correctly describes beta emission? U → He U → Pu + He none of the above U → U + He U → Th + He
c
Which type of radiation is being emitted in the following incomplete nuclear equation? 218/84 Po → 214/82 Pb + ?? none of the above gamma alpha beta A and B
c
Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleons composing it? Why don't the nucleon masses add up to the total nuclear mass? Neither. The mass of the atomic nucleus is exactly the sum of the masses of the nucleons. Greater. The mass of the atomic nucleus also has mass of the "atomic glue" that holds the nucleons together in the nucleus. Greater. We need to add the masses of the surrounding electrons to the masses of the nucleons. Less. The individual nucleons have greater mass when separated from the nucleus. This additional mass is a result of the energy of separation.
d
The alpha particle has twice the electric charge of the beta particle but deflects less than the beta in a magnetic field because it ________. moves much slower moves much faster has much less inertia because it is less massive has much more inertia because it is more massive
d
The combining of two light nuclei of low mass to produce a heavy nucleus is called ______. spontaneous fission double beta decay nuclear fission nuclear fusion
d
Uranium-235 releases an average of 2.5 neutrons per fission, while plutonium-239 releases an average of 2.7 neutrons per fission. Which of these elements might you therefore expect to have the smaller critical mass? The number of neutrons per fission will not effect the size of critical mass. The critical mass of these elements cannot be determined from only the number of neutrons per fission. uranium-235 plutonium-239
d
What does Einstein's energy equation (E = mc2) say about the energy that is derived from nuclear fission reactions? None of the answers are correct. The energy equation does not apply towards fission, only fusion. The energy is derived from the light that is emitted when the atom splits. The energy released is due to the missing mass of the products compared to the mass of the starting materials. The energy is proportional to the increase in mass of the nucleus undergoing fission.
d
Why is the carbon-14 dating not accurate for estimating the age of materials more than 50,000 years old? Actually, carbon-14 dating is accurate back to around 5 million years ago. This form of radioactive dating is only accurate back 1,400 years. Living organisms are too decomposed after 50,000 years. The concentration of carbon-14 in a body after 50,000 years is too low.
d
Why is the carbon-14 dating not accurate for estimating the age of materials more than 50,000 years old? Actually, carbon-14 dating is accurate back to around 5 million years ago. This form of radioactive dating is only accurate back 1,400 years. Living organisms are too decomposed after 50,000 years. The concentration of carbon-14 in a body after 50,000 years is too low.
d
Which of the following elements is the most stable from a nuclear point of view? uranium argon All are equally stable. hydrogen iron
e
Which of the following might be considered a viable application of a radioactive tracer? All would be applications of tracers. None of these would be applications of tracers. placing radioactive sources around a room to trace the location of people as they move through the room embedding a radioactive plug in a valuable necklace so that its location can be determined using a Geiger counter adding a stream of radioisotopes to waste water to examine where pollution goes when it flows into the ocean
e
