Chemistry I Accelerated Study Guideline - Chapter Twenty-Five Nuclear Chemistry

Chemistry I Accelerated Study Guideline - Chapter Twenty-Five Nuclear Chemistry ________________________________________________________ By the end of...
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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

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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 page 3

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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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 page 6

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? page 8

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 page 10

_______________. 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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