Posted: June 9th, 2015
Unit 8 Review – Nuclear Chemistry.
1. Vocabulary – define and understand how to use the following terms:
a) Alpha emission
b) Alpha radiation
c) Beta emission
d) Beta radiation
e) Chemical reaction
f) Down quarks
j) Gamma emission
k) Gamma radiation
l) Gamma rays
n) Half-life (include the symbol too)
q) Nuclear reaction
u) Radioisotope thermal generator
v) Strong nuclear force
x) Up quarks
2. Explain the specific particles and charges that make up each of the following:
3. What are some applications of nuclear chemistry?
4. What do the numbers below tell you next to the element symbol for uranium?
5. How can you tell if radioisotopes are naturally occurring or not looking at the following symbols?
6. What type of materials can stop each of the following?
a) Alpha emissions or particles:
b) Beta emissions or particles:
c) Gamma emissions:
7. What is X in this equation?
94239Pu + 201n ? X + -10e
8. What are needed for each of the following to occur?
9. Write an example of each of the following types of reactions. How do you know each reaction from the other?
a) Alpha emission
b) Beta emission
c) Gamma emission
10. What is the “Upper limit of Z” in naturally occurring radioisotopes? What does this mean?
11. What element do you find as a heat source in radioisotope thermal generators?
12. Compare and contrast how energy is produced by a fission nuclear power plant and how it is produced in stars (such as our sun), showing similarities and differences. Write a nuclear equation for each process.
13. The data in the table show the amount of a 500 g sample of sulfur-35 over time.
a) Make a graph of the data, labeling all axes and adding a title.
b) What is the half-life of sulfur-35? Explain your answer.
c) Sulfur-35 decays by beta emission. Write a nuclear equation that shows the decay of sulfur-35 and its products.
14. Describe the subatomic structure of the nucleus of carbon-14, including the structure of each nucleon.
a) Draw a picture.
b) Describe the forces that hold the nucleus together and draw them on your diagram.
c) Write the equation for the carbon-14 isotope decay by beta emission. Explain the process.
15. Describe what happens in a stellar nuclear fusion reaction.
a) How could hydrogen be used in a nuclear fusion reactor?
b) Describe how a fusion nuclear reactor power plant would work.
For the following questions use the Chemistry Problems & Solutions Online book: http://k12.kitaboo.com/eBookWs/ebook/science/science04/Launch.html#
16. Read pages 226-227 (Problem Set 97) to help you answer the following questions from the problem set:
a) Which of the following statements is true?
i. Electrostatic forces hold the nucleus together.
ii. Strong nuclear forces hold quarks together.
iii. Strong nuclear forces are involved in chemical reactions.
iv. Electrostatic forces cause electrons to attract one another.
b) What is the difference between chemical reactions and nuclear reactions?
c) Arrange the following particles in order of size, from smallest to largest: atom, neutron, nucleus, quark.
d) In one kind of nuclear reaction, two nuclei fuse, or join together, to form a larger nucleus. This kind of reaction happens only at very high pressures. Explain why such high pressures are necessary to cause these reactions to occur. (Hint: Remember that the strong nuclear force acts over a much smaller distance than the electrostatic force.)
17. Read pages 228-231 (Problem Set 98) to help you answer the following questions from the problem set:
a) The penetrating power of different kinds of radiation depends on the amount of energy the radiation has. The more energy a given form of radiation has, the greater it’s penetrating power. Arrange the three most common forms of radiation in order from highest energy to lowest energy. Explain your answer.
b) A sample of radium-226 contains 1.0 x 108 atoms of radium-226. How many atoms of radium-226 will remain after three half-lives?
c) A particular radioactive isotope has a half-life of 5.0 s. What fraction of the original amount of isotope will remain in a sample after 20.0 s?
d) Torium-234 has a half-life of 24.1 days. What percentage of the original thorium-234 in a sample will remain after 144.6 days?
e) A scientist allows alpha, beta, and gamma radiation to pass between two electrically charged plates. The beam of alpha radiation curves toward the negatively charge plate. The beam of beta radiation curves towards the positively charged plate. The beam of gamma radiation does not curve. Explain these observations. (Hint: Think about the charges of alpha particles, beta particles, and gamma rays).
18. Read pages 232-233 (Problem Set 99) to help you answer the following questions from the problem set:
a) Complete the transmutation equation shown below. Assume that there is only one unknown product.
b) Define transmutation in your own words.
c) Complete the transmutation equation below. Assume that there is only one unknown product.
d) Complete the transmutation equation shown below. Assume that there is only one unknown reactant.
19. Read pages 234-235 (Problem Set 100) to help you answer the following questions from the problem set:
a) In stars like our sun, hydrogen nuclei (protons) combine to form helium nuclei. Is this a fusion reaction or fission reaction? Explain your answer.
b) In most nuclear power plants, uranium-238 (238U) nuclei break down to form thorium-234 (234Th) nuclei and alpha particles. Is this a fusion reaction or a fission reaction? Explain your answer.
c) Samarium-146 (146Sm) can decay to form neodymium-142 (142Nd). Each atom of 146Sm that decays produces one atom of 142Nd and one alpha particle. If the mass of 1 mol 146Sm is 145.130 g, the mass of 1 mol 142Nd is 141.9077 g, and the mass of 1 mol of alpha particles is 4.0015 g, how much mass is lost during the decay of 1 mol 146Sm to 142Nd?
d) Calculate the amount of energy released during the decay described in Question c). Give your answer in joules. (Hint: Convert mass to kilograms c = 2.997925 x 108 m/s)
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