Chemistry I Accelerated
Study Guideline - Chapter Twenty-Five
Nuclear Chemistry
________________________________________________________
By the end of this chapter the skills you should be able to demonstrate
are:
1. Define radioisotope, radioactive decay, and transmutation.
2. Characterize alpha, beta, and gamma radiation by composition and
penetrating strength.
3. Describe the operation of a particle accelerator and nuclear fission
power plant.
4. Show how transuranium elements are synthesized by transmutation.
5. Compare nuclear fission and fusion.
6. Write balanced nuclear equations for alpha and beta decay processes.
7. Apply three tests for relative stability of nuclides.
8. Perform half-life calculations.
8. Describe three methods of detecting radiation and state each methods
limitations.
9. List the biological effects of radiation and the units used to measure
them.
10. Describe the positive and negative uses for radioactive nuclides.
Suggested Problems: p. 822-823 #58, 68, 74, 78
Radiation
Identify each of the three beams of radiation in the figure as alpha, beta, or gamma radiation. Then state the
charge of each beam and give the evidence for your answer. Finally state whether the radiation beam is a
particle or pure energy.
Beam #
Type of
Radiation
Charge
1
2
3
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Evidence Particle or
Energy
Nuclear Chemistry
An alpha particle has a charge of _________ and a mass of ________. When an alpha particle is
emitted the atomic number of the element is ______________ by _________ and its mass number is
______________ by _________.
Write the alpha decay of the following elements:
1. Lead-214
2. Radium-226
3. Thorium-230
Beta particles are _____________ charged and have identical properties to those of a(n)
______________. Beta emission converts a(n) ________________ in the nucleus to a(n)
_______________ and an ____________ which is emitted at high speed. When a beta particle is emitted,
the atomic number of the element is ______________ by _________ and its mass number is
_________________.
Write the beta decay of the following elements:
1. Thorium-234
2. Bismuth-210
3. Neptunium-238
________________ reactions are those in which collisions of nuclei occur. Bombarding particles include
the neutron whose symbol is __________ and alpha particles whose symbol is ___________. Charged
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particles can be accelerated to high speeds for bombardment in ______________ and ______________
fields. When a charged particle has high velocity, it possesses enough energy to bring about a nuclear
reaction despite _____________ with components of the atom.
Balance the following bombardment reactions:
1. Bombardment of cobalt-59 with a neutron produces cobalt-60
2. Bombardment of aluminum-27 with an alpha particle to produce phosphorus-30 and one other particle
3. Bombardment of Plutonium-239 with a neutron produces americium-240 and one other particle
4. Plutonium-239 can be produced along with three other particles by bombarding uranium-238 with an
alpha particle
5. With what particle would you bombard sulfur-32 to produce hydrogen-1 and phosphorus-32? Write the
nuclear equation.
6. With what particle would you bombard bismuth-209 to produce astatine-211 and 2 neutrons?
7. Neutron bombardment of Uranium-235 splits the Uranium into tellurium-137, zirconium-97 and two
other particles.
8. Neutron bombardment of lithium-6 produce an alpha particle and one other particle.
9. Write the nuclear equation.Alpha-particle bombardment of plutonium-239 produces a neutron and
another isotope.
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10. Plutonium-238 can also be produced by a two step process. First uranium-238 is bombarded with
deuterium to produce neptunium-238 and two neutrons. Then the neptunium decays to produce
plutonium-238.
11. Bombardment of curium-246 with carbon-13 to produce nobelium-254 and five other particles
12. Bi-211 is a radioisotope. It decays by alpha emission to yield another radioisotope which emits beta
radiation as it decays to a stable isotope. Write equations for the nuclear reactions and name the decay
products.
13. What isotope remains after three beta particles and five alpha particles are lost from thorium-234
isotope.
Harnessing the Nucleus
1. Define nuclear fission.
2. Define nuclear chain reaction.
3. Would the radioactive decay of a naturally occurring isotope be a good choice for a nuclear power plant?
Explain.
4. Briefly describe the contributions of Fermi and Meitner in the discovery of nuclear fission.
5. How is a runaway nuclear reaction prevented in a nuclear power plant?
6. What are some of the reasons that some people are against nuclear fission power plants.
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2
7. How does E = mc describe a nuclear fission reaction?
For each of the following nuclear accidents, explain what happened.
8. Three Mile Island
9. Chernobyl, Ukraine
Nuclear Power Plants
Many nuclear power plants in operation today are dependent on the controllable fission of uranium-235.
The enormous amount of heat generated from this fission reaction is transferred via a high pressure water
system to a
secondary
circulation
system. Water
within this
low-pressure
system is
boiled to gas.
As it rapidly
expands, its
energy is used
to cause huge
turbine blades
to turn. These
turning blades
cause the shaft
to spin a shaft
that drives an
electric
generator.
Steam that has
lost energy is
cooled in the
condenser and recirculated within the low pressure system.
Using the above information and this diagram answer the following questions:
_____ 1. The fuel rods contain which of the following?
a. uranium ore b. enriched U-235
c. enriched U-232
d. deuterium and tritium
_____ 2. The primary purpose of the control rods is to _______________.
a. supply low-voltage neutrons
b. initiate the fission reaction
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c. filter the high pressure water
d. absorb excess neutrons
_____ 3. The high pressure water system is usually encased in concrete shielding. This shielding _______.
a. acts as a thermal insulator
b. prevents ionization by background radiation
c. protects personnel from exposure to radiation
d. protects against earth’s movement
_____ 4. Although the temperature within the high pressure system may reach 300°C, water remains in the
liquid state because of ________________________.
a. the properties of radioactive water
b. limited space for expansion
c. efficiency of the condenser
d. concrete shielding
_____ 5. The function of the generator is to convert ________________________.
a. kinetic energy of steam into electrical energy
b. electrical energy to kinetic energy
c. steam to liquid water
d. liquid water to steam
Nuclear Fusion
1. Define nuclear fusion.
2. What is a tokamak?
3. Write the equation for a nuclear fusion reaction.
4. Why do scientist believe nuclear fusion is superior to fission?
5. What makes nuclear fusion so hard to achieve?
6. Why are nuclear fusion reactions called thermonuclear reactions?
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Half-Life Problems
1. The half-life of cesium-137 is 30.2 years. If the initial mass of a sample of cesium-137 is 1.000 kg, how
many grams will remain after 151 years?
2. A sample that contained 24 grams of C-14 when alive now as a fossil contains 1.5 grams. How old is the
fossil?
3. A 64 gram sample of germanium-66 is left undisturbed for 12.5 hours. At the end of that period, only 2.0
grams remain. What is the half-lie of germanium-66?
4. With a half-life of 28.8 years, how long will it take for 1.00 g of strontium-90 to decay to 125 mg?
5. Cobalt-60 has a half-life of 5.3 years. If a pellet that has been in storage for 26.5 years contains 14.5
grams of Cobalt-60, how much Cobalt-60 was present when the pellet was put in storage?
6. A 1.000 kg block of phosphorous-32, which has a half-life of 14.3 days, is stored for 100.1 days. How
much phosphorous-32 remains at the end of this period.
7. A sample of air is collected from a basement to test for the presence of radon-222, which has a half-life
of 3.8 days. However, delays prevent the sample from being tested until 7.6 days later. Measurements
indicate the presence of 6.5 µg of radon-222. How much radon-222 was present in the sample when it
was initially collected?
8. The half-life of sodium-25 is 1.0 minutes. If you start with 1.00 kg. How many grams will remain after
3.75 minutes?
9. A 0.500 kg sample of iodine-131, which has a half-life of 8.0 days, is prepared. After 42 days, how much
iodine is present?
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10. What is the half-life of polonium-214 if, after 825 seconds a 1.0 grams sample decays to 31.25 mg?
11. What is the length of the half-life in minutes of an isotope if after 1.00 hours 20% of the starting
material remains?
12. A sample origionally contained 50 µCi (microcuries) of P-32. Today it contains only 15 µCi. If the
half-life of P-32 is 14.3 days. How old is the sample?
13. How old is human fossil if only 1/15 of the C-14 remains?
14. The radioisotope cesium-137 has a half-life or 30 years. A sample of Cs-137 contains 544 grams in
1985. In what year will there be only 27 grams left.
Biological Effect of Radiation
Curie
dosimeter (film badge)
Geiger counter
genetic damage
REM
somatic damage
1. The unit of measurement most commonly used to measure radiation exposure in humans is the
__________.
2. Damage to an organism that has received radiation directly is called ____________________.
3. A ____________________ is an instrument that measures the total amount of radiation to which a
person has been exposed.
4. A ____________________ is an instrument that detects and counts ionizing particles.
5. ____________________ may result in the birth of deformed offspring.
6. One ____________________ is equal to the number of nuclear disintergrations per second from one
gram of radium.
7. Describe how a dosimeter (film badge) works.
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8. Why does ionizing radiation damage living tissue?
9. Give two examples of somatic radiation damage.
10. What causes the audible “click“ or “beep” made by a Geiger counter?
11. Name two radiotracer isotopes and what they are used for.
12. How can radiation be useful in treating cancer?
13. What types of side effects result from radiation therapy? Explain why these side effect occur.
14. Why is radiation an effective treatment for preserving fruits and vegetables?
Review Activity - Nuclear Chemistry
alpha particle
Curie
gamma ray
nuclear reaction
radioactivity
transmutaion
Becquerel
beta particle
Einstein
energy
induced radioactivity moderator
nucleus
particle accelerator
radioisotope
Roentgen
transuranium element X-ray
control rod
fission
neutron
radioactive decay
Rutherford
critical mass
fusion
nuclear fuel
radioactive series
themonuclear device
Our understanding of atomic structure is advanced by studies of changes in the central region, or
_____________ of the atom. In 1895, a kind of invisible electromagnetic wave, called a(n) ____________,
that could darken photographic film, was discovered by _________________. Then ___________
discovered that uranium gives off radiation that can do the same thing. The process involved in this case
turned out to be a nuclear change that resulted in ________________, or a change of one element into
another. This nuclear process, which releases particles and energy is called ___________ or __________.
The radioactive elements polonium and radium were later isolated from uranium ore by
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_______________. Radiation from these and other elements was studied by ____________, who found
that there were three possible types of radiation. A helium nucleus released during radioactive decay is
called a(n) _________ ___________. A released electron is called a(n) _______ ____________. A wave of
shortwavelength electromagnetic radiation that is released is called a(n) _________ ______.
An atom whose center is unstable is called a(n) ____________. Any change in an atom’s center is
called a(n) __________ _______. A new atom formed from such a change may also be unstable. A chain of
elements formed as a result of successive change is called a(n) ____________ ________. If the release of
particles and energy as the result of such changes does not happen naturally, but is made to happen in the
laboratory, it is called ____________ ______________. Particles can be accelerated to high speeds to
create artificial or induced radioactivity in a device called a(n) __________ ____________. ____________
demonstrated that mass can be converted into ____________ during such changes.
The splitting of an atom’s center into roughly equal fragments is called ____________. The minimal
amount of material that will support this change in a self-sustaining way is called the __________
_______. A device in which a chain reaction is carried out at a controlled rate is called a(n)
_____________ _______. A substance, such as graphite, that surrounds the fuel and absorbs excess
_____________ is called a(n) ________________ or a ________________ ________. The process
where centers of atoms are combined to produce a heavier element is called _________________.
Challenge Problems – Nuclear Chemistry
20
10
1. How long will it take for 6.00 x 10 atoms of Zn-71 to decay to leave only 6.00 x 10 atoms?
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2. The radioisotope cesium–137 has a half-life of 30 years. A sample decays at the rate of 544 decays per
minutes in 2005 (decays per minute are proportional to the amount of radioactive material). In what
year will the decay rate be 27 decay per minute?
3. The fusion of two deuterium atoms are used to heat a cylindrical swimming pool that measures 5.00 x
–6
–9
10 Mm in diameter by 2.00 x 10 Gm in depth. Given that the mass of one mole of deuterium is
2.01410 g and the mass of one mole of helium is 4.00260 g, calculate the number of moles of deuterium
required to heat the swimming pool from 12.00°C to 25.00°C.
Note: 1 kg x m2/s2 = 1 joule
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Nuclear Crossword Puzzle
ACROSS
DOWN
2. Radioactive isotopic form
6. Particle that helps hold the nucleus together
(Hint: Type of quark)
7. Kind of energy associated with gamma emission
10. Naturally occurring level of radiation
17. Is composed of two “down” quarks and one
“up” quark
18. Particle composed of 2 neutrons and two
protons
19. Atom that has a net charge
20. Process in which nucleus is split into smaller
nuclei
21. Radiation that can produce charged particles
from atoms or molecules it strikes
22. Trackable isotope
23. Mineral mixture, such as one that contains
unprocessed uranium
24. A natural site of fusion
26. Is released during beta decay
31. Is used to slow down neutrons in fission
reactors
32. Radiation made up of high-energy rays
33. Describes a process, such as decay triggered by
nuclear bombardment, that does not occur
without outside influence
1. Element produced by nuclear fusion of hydrogen
3. Is composed of protons, neutrons and electrons
4. Release of particle or ray
5. Synchrotron in Geneva, Switzerland
6. Abbreviation for gram
8. Change of one kind of atom to another
9. Early particle accelerator.
10. Kind of radiation involving ejection of an electron
11. Elementary particle that makes up protons and
neutrons and that has a fractional charge
12. Number such as 1, 3, 5
13. Emanations produced during nuclear changes
14. Change, such as decay of U-238 to Pb-206, that
occurs without outside influence
15. Can be transformed into energy
16. Combining of nuclei
20. U-235 in a fission reactor
25. High-energy fourth state of matter
27. Energy needed to prevent nucleus from splitting
28. Particular kind or characteristic of quark
29. Protium, deuterium, and tritium
30. Force that accounts for why objects fall towards
earth
34. Initial nuclide in a decay process
35. Nuclear disintergration
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