Chemistry 1010 Final
Which of the following options correctly describe the behavior and dangers of iodine-131? Select all that apply.
- 131I can cause thyroid cancer. - 131I emits beta particles.
The symbol Pu94244 represents a isotope of plutonium. Match each part of the symbol with its correct meaning.
- 94 represents the: Atomic Number - 244 represents the: Mass Number - there are 94: Protons in the nucleus - there are 244: Protons + neutrons in the nucleus
Which two elements are commonly used as a source of neutrons in nuclear reactors?
- 9Be - 238Pu
Match each marked component of a nuclear power plant with the correct description.
- A -> control rods - B -> fuel rods - C -> primary coolant - D -> steam generator - E -> reactor vessel
Which of the following options correctly describe a chain reaction? Select all that apply.
- A chain reaction is one that becomes self-sustaining. - In a chain reaction, one of the reaction products is recycled as a reactant.
Which of the following options correctly describe the relationship between the number of half-lives that have passed and the fraction of the original sample remaining? Select all that apply.
- After 4 half-lives there will be 6.25% of the original sample remaining. -After 2 half-lives there is 1/4 of the original sample remaining.
What directives were issued to U.S. nuclear power plants by the NRC, to be implemented by December 2016? Select all that apply.
- All reactors must be supported by sufficient portable safety equipment to be used in the event of a power shut-down. - Venting systems for boiling water reactors must be improved.
Which of the following options correctly describe electrical energy produced by different types of power plants? Select all that apply.
- Both fossil fuel plants and nuclear power plants utilize energy released by a reaction to generate electricity. - Both nuclear power plants and fossil fuel plants make use of a steam turbine to generate electricity. - No type of power plant shows 100% efficiency in converting chemical energy to electrical energy.
Which of the following options correctly describe the components of a nuclear power plant? Select all that apply.
- Cooling towers and/or a sizable body of water near the nuclear reactor are important to remove excess heat from the reactor. - The control rods and fuel rods are contained within a reactor vessel. - The primary coolant transfers the heat generated by the nuclear reactor to a steam generator.
Identify the element produced when Bi83212 undergoes alpha decay, as shown by the incomplete equation below. Select all that apply. Bi83212 → XZA + α24
- Element X is thallium, symbol Tl. - The atomic number Z is equal to 81.
Which of the following options correctly describe the process of nuclear fission? Select all that apply.
- Energy is released during nuclear fission. - During nuclear fission, a large nucleus splits into smaller ones.
Which of the following options correctly identify possible disadvantages of using graphite as the primary coolant in a nuclear reactor, such as those experienced at Chernobyl? Select all that apply.
- Graphite is a form of carbon, which can burn if the temperature is high enough. - Hot graphite can react with water to produce hydrogen gas, which is flammable.
Which of the following statements correctly describe beta emission from a radioactive isotope? Select all that apply.
- In this type of radioactive decay, a neutron is converted to a proton in the nucleus. - The atomic number increases by 1.
Which of the following options correctly describe the Chernobyl nuclear disaster?
- Large quantities of radioactive material were released into the atmosphere and over the surrounding countryside. - A loss of cooling water caused the nuclear plant to explode. - The disaster occurred during an electric power safety test. - A lack of sufficient control rods contributed to the overall disaster.
Which of the following options correctly describe the fuel used in a nuclear power station? Select all that apply.
- Nuclear fuel pellets are packed into fuel rods, which are bundled together. - The nuclear fuel contains UO2 pellets.
Which of the following options correctly describe aspects of the Fukushima-Daiichi nuclear disaster in Japan in 2011? Select all that apply.
- Radioactive materials were accidentally vented from the plant. - This disaster was precipitated by damage due to an earthquake and a tsunami. - Reactor cooling systems failed.
Which of the following options correctly describe the factors that influence the ability of a nucleus to undergo fission? Select all that apply.
- Small nuclei are less likely to undergo fission. - The number of protons and neutrons influence the ability of a nucleus to undergo fission. - Heavy nuclei may undergo fission if bombarded with high-energy neutrons.
Which of the following options correctly describe how nuclear waste is handled at nuclear power stations in the United States? Select all that apply.
- Spent nuclear fuel rods are stored temporarily in deep basins of water. - Most reactor waste in the United States is stored at the site where it was generated.
Which of the following options correctly describe different possible methods of storing high-level radioactive waste? Select all that apply.
- Storage in a sealed geological repository will require the least amount of human intervention. - Storage at the nuclear power plant where the waste is generated.
In the absence of reprocessing, which of the following options are feasible for the storage of high-level radioactive waste? Select all that apply.
- Storage in geological repositories deep underground - Storage at the nuclear power plant where the waste is generated
Which of the following statements correctly describe the changes that occur when a nucleus emits alpha particles? Select all that apply.
- The atomic number decreases by 2. - The nucleus emits 2 protons and 2 neutrons.
Which of the following options correctly describe the control rods in a nuclear reactor? Select all that apply.
- The control rods contain substances that absorb neutrons. - The control rods are used to control the rate at which heat is generated.
Which of the following statements correctly describe the half-life of a radioactive nuclide? Select all that apply.
- The half-life is the time taken for the level of radioactivity in a sample to drop to half of its initial value. - The half-life for a given radioisotope is the same under all reaction conditions. - The time taken for half the nuclei to decay is the same regardless of the initial number of nuclei present.
Which of the following were (and are) among the consequences of the Chernobyl nuclear disaster? Select all that apply.
- The incident resulted in immediate fatalities. - There has been an increased incidence of various forms of cancer in the area. - People in the area experienced radiation sickness.
Which of the following factors do NOT affect the half-life of a radioisotope? Select all that apply.
- The initial concentration of radioisotope present in the sample - The physical state of the radioactive sample - The atmospheric pressure - The temperature of the sample
Which of the following options correctly describe how neutrons are generated from a neutron source such as poo-bee? Select all that apply.
- The name "poo-bee" indicates that the neutron source contains plutonium and beryllium. - 9Be reacts with alpha particles to produce neutrons. - A heavy radioactive element such as plutonium decays to release He24 particles.
Examine the nuclear equation n01 + U92235 → Ba56141 + Kr3692 + 3n01. Which of the following options correctly describe the neutrons involved in this reaction? Select all that apply.
- The neutron that appears on the left of the equation must be shown because it is required to initiate the reaction. - The neutrons are not canceled in this type of equation.
Which of the following options correctly interpret the symbol Rn224/86? Select all that apply.
- The number 86 is the atomic number of the isotope. - 86 represents the number of protons in the nucleus. -Rn is the symbol of the element.
Which of the following factors do NOT affect the half-life of a radioisotope? Select all that apply.
- The physical state of the radioactive sample - temperature of sample - atmospheric pressure - initial concentration of radioisotope present in sample
Which of the following options correctly describe how to calculate the energy released in a nuclear reaction? Select all that apply.
- The quantity Δm reflects the change in mass that occurs when protons and neutrons are interconverted. - The equation ΔE = Δmc2 is used. - The energy change is directly related to the change in mass during the reaction.
Which of the following options correctly describe how to balance a nuclear equation? Select all that apply.
- The sum of the subscripts on the left of the equation must equal the sum of the subscripts on the right. - The sum of the mass numbers on the left of the equation must equal the sum of the mass numbers on the right.
Which of the following statements correctly describe the three natural types of radioactive emission? Select all that apply.
- The symbol e−10 denotes beta radiation. - The symbol for an alpha particle is He24. - An alpha particle has a charge of +2.
Which of the following options correctly interpret and explain the equation E = mc2? Select all that apply.
- This equation shows that matter can be converted into energy - This equation can be used to explain how a nuclear reaction produces energy. - The symbol c in this equation represents the speed of light.
Which of the following options correctly describe the nuclear incident at Three Mile Island in Pennsylvania in 1979?
- This incident involved a loss of coolant from the reactor. -There were no fatalities during this incident. - There was a partial meltdown at the Three Mile Island reactor.
Match each type of radioactive emission to the correct description.
- alpha particle-> positively charged; consists of 2 protons and 2 neutrons - beta particle -> high-speed electron emitted from the nucleus - gamma ray -> high-energy photon, with no charge or mass
Renewable energy sources include:
- hydroelectric power - geothermal power - solar power
Which of the following factors determine whether or not a nucleus will undergo nuclear fission? Select all that apply.
- the size of the nucleus - The number of protons in the nucleus
Match each letter in the following nuclear equation with the correct value or symbol in each case. U92235 + n01 → A38x + By140 + 2n01
- x -> 94 - y -> 54 - A -> Sr - B -> Xe
Match each type of radiation correctly to the resulting change in atomic number.
- α emission -> atomic number decreases by 2 - β emission -> atom number increases by 1 - γ radiation -> atomic number remains unchanged
Which types of radiation are emitted with no resulting change in the mass number of the isotope? Select all that apply.
- β particles - γ radiation
Match each type of radiation to the correct description.
-electromagnetic radiation -> includes all different types of light - nuclear radiation -> includes alpha and beta particles as well as gamma radiation
How many fatalities resulted from the Three Mile Incident of 1979?
0
The rad is defined as the absorption of ____ J of radiation energy per ____ of tissue.
0.01; kg
The half-life of the isotope Br3574 is approximately 25 minutes. If a 4.0-mg sample is given to a patient, how much of the isotope remains after 125 minutes?
0.12 mg - reason 125/25 = 5 half lives passed. There will be 3.12% of original sample remaining or 3.12/100 x 4.0 = 0.12 mg
Only the neutrons that are produced should be shown in a nuclear fission equation because it is assumed that _____ initiates the nuclear reaction.
1
Place the steps involved in producing electricity from nuclear power in the correct order, starting with the first step at the top of the list.
1. heat is generated by nuclear reactions in a reactor vessel 2. heat is transferred to the primary coolant 3. the primary coolant transfers heat to a steam generator 4. a steam turbine transfers energy to an electrical generator
How many protons and neutrons are found in chlorine-37?
17 protons; 20 neutrons
A person who undergoes a CT scan with and without contrast dye is exposed to 20 mSv of radiation (1000 mSv=1Sv). This is the same as _____ rem. (1 Sv=100 rem)
2
When a nucleus emits an alpha particle, the atomic number decreases by _____ and the mass number decreases by _____.
2; 4
How many neutrons are in the carbon-11 isotope?
5
The half-life of radium-226 is 1.60 x 103 yr. How much time must pass before a 2.50-g sample decays to a point where only 0.156 g of the isotope remains?
6400 years
Which of the following patients had the largest radiation absorbed dose when exposed to the same amount of energy? (1 rad= 0.01 J/kg tissue)
A patient weighing 20 kg
IR, visible, and ultraviolet radiation are all types of ______ radiation, whereas ______ radiation includes alpha and beta particles as well as gamma radiation.
electromagnetic; nuclear
When an atom or molecule is hit by ionizing radiation, ____ can be removed
electrons
Einstein's equation E = mc2 means that matter can be converted into:
energy
True or false: A radioactive sample will be less active at a lower temperature, and radioactive waste can be safely stored by freezing it.
false
True or false: The pathway that uranium-238 takes during radioactive decay is unpredictable.
false
True or false: A nuclear equation is balanced in the same way as any other chemical equation.
false - reason: In a chemical equation the atoms must balance. In a nuclear equation the atoms do not balance, since one nucleus is converted into another. Instead, the protons and neutrons will balance.
The process during which a large nucleus is split into smaller ones is called nuclear _____.
fission
The time taken for half the radioactive nuclei in a sample to decay is called the _____ of the radioisotope.
half-life
Yucca Mountain is a _____.
long-term underground nuclear waste repository
During nuclear fission, the mass of the products is slightly _____ than the mass of the reactants. This mass difference accounts for the energy _____ by the reaction.
lower, released
During beta emission, a(n) _____ is converted into a(n) _____ in the nucleus of the atom. During this process a high-energy _____, also called a β particle, is expelled from the nucleus.
neutron; proton; electron
The control rods in a nuclear reactor contain substances such as boron or cadmium, which are able to absorb _____.
neutrons
The rate at which energy is produced is referred to as _____, which is typically measured in kilo- or mega- _____.
power; watts
The spontaneous emission of nuclear radiation (particles and/or energy) from an unstable nucleus is called ______.
radioactivity
The annual dose of ionizing radiation absorbed can be expressed in either of two units, the sievert and the
rem
A critical mass is _____.
the amount of fissionable fuel required to sustain a chain reaction
True or false: The electrical energy generated by a nuclear power station is no different from the electrical energy produced by a fossil fuel plant.
true
Match the number of half-lives that have passed with the percentage of the original sample remaining. Instructions
- 1 half life: 50% - 2 half lives: 25% - 3 half lives: 12.5% - 5 half lives: 3.13%
Which of the following options correctly describe the risks associated with different types of electrical power plants? Select all that apply.
- Both nuclear power plants and coal-based plants represent a significant danger to mine workers. - Coal-based power plants produce large quantities of greenhouse gases.
Which of the following factors impact the efficiency and practicality of harnessing the Sun's energy for our energy needs? Select all that apply.
- Geographical location - Smog and cloud cover - The sun does not shine at night.
Which of the following options correctly describe the installation of solar panels to power homes and businesses in the United States? Select all that apply.
- Installation on a system that rotates to follow the Sun's path has a higher initial cost than a fixed solar array of the same size. - Solar panels are usually mounted facing due south. - Installation on a system that rotates to follow the Sun's path optimizes the efficiency of the unit.
Which of the following will need to be taken into account in advancing nuclear technologies? Select all that apply.
- Methods for dealing with nuclear waste - More efficient transformation of energy - Developing materials that can operate at higher temperatures
Which of the following options correctly describe semiconductors? Select all that apply.
- Photovoltaic cells are made from semiconductors. - Most semiconductors are made from a crystalline form of silicon.
Which of the following are commonly powered by photovoltaic cells? Select all that apply.
- Safety lighting - Calculators - Communication satellites - Navigational buoys
Which alternative energy source has seen a notable increase in the amount of electricity generated in the last decade? (Select all that apply.)
- Solar/PV - Wind
What challenges are associated with the fabrication of photovoltaic devices? Select all that apply.
- Some radiant energy is lost due to reflection and absorption (to produce heat instead of electric current). - The starting material (SiO2) from which silicon is extracted is inexpensive, but the processes to extract and purify silicon are expensive.
Which of the following options correctly describe spent nuclear fuel? Select all that apply.
- Spent nuclear fuel is classified as high-level radioactive waste. - Spent nuclear fuel contains many different radioactive isotopes.
Which of the following options correctly describe how a simple photovoltaic cell is assembled? Select all that apply.
- The conduction of electricity is made possible by p-n junctions. - Multiple layers of doped n- and p-type semiconductors are placed in close contact. - A specific arrangement of p-n junctions ensures that electrons flow in a specific direction
What challenges are associated with the fabrication of photovoltaic devices? Select all that apply.
- The starting material (SiO2) from which silicon is extracted is inexpensive, but the processes to extract and purify silicon are expensive. - Some radiant energy is lost due to reflection and absorption (to produce heat instead of electric current).
Which units may be used to express power, which is the rate at which energy is produced? Select all that apply.
- Watts - J/s
As a result of the Fukushima-Daiichi nuclear disaster in 2011 _______. (Select all that apply.)
- all nuclear power plants in Japan were shut down - approximately 300,000 people were evacuated temporarily
Which of the following disadvantages are specifically associated with coal-based power plants but not nuclear power plants? Select all that apply.
- ash generation - generation of air pollutants
Select the two types of semiconductors from the following list.
- p-type - n-type
Photovoltaic cells constructed of thin layers of alternating n- and p-type semiconductors are preferable to those with thicker layers because _____. Select all that apply.
- they are more efficient due to lower internal resistance - smaller quantities of silicon are needed for device construction
Which of the following elements may be added to pure silicon to create a p-type semiconductor? Select all that apply.
-Boron -Gallium
In a crystal of silicon, each silicon atom is bonded to ____ other silicon atoms.
4
Which of the following statements correctly defines radioactivity?
An unstable isotope of an element spontaneously emits radiation.
One of the worst nuclear power plant accidents occurred at ______ in 1986.
Chernobyl
T/F:Most of the electricity generated in the U.S. is produced from nuclear power.
False
The world's most recent nuclear disaster occurred at _______ in _______.
Fukushima Daiichi; 2011
One possible disadvantage of using graphite as a primary coolant in a nuclear reactor is that burning graphite can react with water to produce ______ gas, which is explosive.
H2
Which state generates the most geothermal energy and why?
Hawaii; volcanic activity
Which statement is about the use of water to generate power is correct?
Hydroelectric dams have been used for over a century to generate electricity.
Why is pure silicon not a good electric conductor under ordinary circumstances?
In a crystal of Si the 4 outer electrons of the Si atoms are fixed in the Si-Si bonds and cannot move through the crystal.
Why do PV cells offer substantial cost savings for the U.S. Coast Guard's navigational buoys compared to batteries?
Less maintenance is required.
A benefit of using multilayer solar cells is to alternate thin layers of p-type and n-type semiconductors so that electrons have a shorter distance to travel. What is the outcome of this?
Lowered internal resistance; increased efficiency
Which of the following types of storage facilities are currently used for long-term storage of nuclear waste in the United States?
Nuclear waste is enclosed in concrete vaults on-site at the nuclear reactor where it is generated.
Which area would be the best location to place a solar panel?
San Diego, CA
What compound is silicon most frequently extracted from to obtain its elemental form?
SiO2
What is spent nuclear fuel?
The radioactive material remaining in the fuel rods that have been used in a nuclear reactor
Which compound of uranium is typically used in nuclear fuel?
UO2
Which of the following methods of producing power is perhaps the most environmentally friendly?
Use of photovoltaic cells
Which of the following substances is most frequently used as the secondary coolant in a nuclear power plant?
Water
Which of the following does NOT describe the capture of wind energy (both in the past and present) as a potential source of power?
Wind farms can be placed at any location in the world to efficiently produce energy.
Thin-film solar cells are made from _____ silicon or nonsilicon materials such as _____.
amorphous; CdTe
Hundreds of PV cells are interconnected to form solar
arrays or panels
Solar thermal energy can be harnessed by a process called _____ solar power (CSP), in which solar collectors gather a large area of sunlight into a small area. This light is converted to heat, which is used to generate electrical power.
concentrating
The process of intentionally adding small amounts of other elements to pure silicon is called
doping
The energy harnessed by drilling into underground reservoirs containing hot water or steam is called ____ energy.
geothermal
The energy harnessed by drilling into underground reservoirs containing hot water or steam is called _____ energy.
geothermal
Leukemia is a ____ effect of radiation exposure.
long term
The Sun's rays hit earth every hour with enough energy to _____.
meet the world's energy demand for an entire year.
Noncrystalline silicon absorbs photons _____ efficiently than crystalline silicon, allowing the construction of _____ semiconductor layers and a cheaper photovoltaic cell.
more; thinner
Boron and gallium doped silicon semiconductors may function as _____ semiconductors.
p-type
Hundreds of PV cells are interconnected to form solar
panels
A(n) _____ cell converts light energy directly into electrical energy.
photovoltaic, or solar, or PV
When a water wheel or hydroelectric dam harnesses the energy of water, the ______ energy of the water at the top of a waterfall, before the precipice, is converted to ______ energy in the wheel or turbine blades.
potential; kinetic
Stable isotopes differ from radioactive isotopes in their neutron-to- ____ ratio.
proton
A(n) _____ is a material that has a limited capacity to conduct an electric current.
semiconductor
Which equation is used to calculate the energy released in a nuclear reaction?
ΔE = Δmc2
Why is ionizing radiation used to treat some cancers?
Ionizing radiation damages the DNA in cancer cells, which are then unable to multiply and spread.
What is the specific danger associated with the radioactive isotope iodine-131?
It causes thyroid cancer.
How does the process of nuclear fission produce energy?
Mass of the reactants is converted into energy, which is released.
Which of the following is the correct balanced nuclear equation for the beta decay of magnesium-27?
Mg1227 → AI1327 + e−10
Which of the following is the largest source of ionizing radiation in the United States?
Radon
The largest source of background ionizing radiation in the United States is _____, which is formed in the decay series of uranium.
Rn
An aqueous solution of _____ acid is often used as the primary coolant in nuclear reactors. This solution absorbs heat and also acts as a(n) _____ by slowing down neutrons.
boric; moderator
A reaction that is self-sustaining because one of the reaction products becomes a reactant is called a(n) ____ reaction.
chain
In the U.S. the primary energy source used to generate electricity is:
combustion of fossil fuels
Renewable energy sources are:
continually and rapidly replenished from natural sources
The amount of fissionable nuclear fuel required to sustain a nuclear chain reaction is called a _____ mass.
critical
Radioactive isotopes tend to achieve stability by a sequence of steps called a radioactive _____ series.
decay
Which of the following options correctly explain how a nuclear power plant is used to generate electricity?
The heat generated by the nuclear reaction is used to generate steam, which drives a turbine to produce electrical energy.
What is the function of the primary coolant in a nuclear reactor?
The primary coolant absorbs the heat generated in the nuclear reactor and transfers it to the steam generator.
Which of the following determines the stability of a particular isotope?
The ratio of neutrons to protons in the nucleus
What is the role of the secondary coolant in a nuclear power plant?
The secondary coolant is converted to steam, which runs the steam turbine to generate electricity.
Leukemia is predicted to be higher in children as a result of the Fukushima-Daiichi disaster. What explains this?
They had higher radiation absorbed doses because they had smaller body masses than adults.
Which of the following is a long-term health effect of the Chernobyl disaster?
Thyroid cancer
Which option correctly identifies the isotope A produced in the nuclear fission process n01 +U92235 → I53138 + Ayx + n03?
Y3995
Which of the following sites was designated in 1997 as a long-term storage facility for high-level radioactive waste in the United States?
Yucca Mountain