Presentation is loading. Please wait.

Presentation is loading. Please wait.

Nuclear Chemistry Chapter 4: Discovering the Secrets of the Nucleus From a Photographic Mystery to the Atomic Bomb Chapter 5: Harnessing the Secrets of.

Similar presentations


Presentation on theme: "Nuclear Chemistry Chapter 4: Discovering the Secrets of the Nucleus From a Photographic Mystery to the Atomic Bomb Chapter 5: Harnessing the Secrets of."— Presentation transcript:

1 Nuclear Chemistry Chapter 4: Discovering the Secrets of the Nucleus From a Photographic Mystery to the Atomic Bomb Chapter 5: Harnessing the Secrets of the Nucleus Nuclear Energy, Nuclear Medicine, and a Nuclear Calendar

2 Figure 4.1 © 2003 John Wiley and Sons Publishers

3 Antoine Henri Becquierel. © 2003 John Wiley and Sons Publishers Courtesy Culver Pictures, Inc.

4 Radioactive Decay Discovered by Antoine Henri Becquerel in 1896 –He saw that photographic plates developed bright spots when exposed to uranium metals

5 Types of nuclear reactions Radioactive Decay – nucleus decays spontaneously giving off an energetic particle Nuclear Bombardment – shoot a high energy particle at the nucleus of another atom and watch what happens

6

7 Writing Nuclear Equations

8 Figure 4.4: The components of α rays, β rays, and γ rays. © 2003 John Wiley and Sons Publishers

9 Figure 4.2: The penetrating power of radiation. © 2003 John Wiley and Sons Publishers

10 Figure 5.3: Ionizing power and penetrating power: an analogy. © 2003 John Wiley and Sons Publishers

11 Which component of radioactivity would be stopped by this single page? Which two components would be stopped (completely or almost completely) by this entire book? Which component would pass, almost undiminished, through both this single page and this entire book? QUESTION

12 Types of radioactive decay alpha particle emission beta emission positron emission electron capture gamma emission

13 Types of radioactive decay alpha particle emission –loss of a helium nucleus.

14

15 Problem Pu-239 (plutonium 239) loses an alpha particle (He nucleus). Write the nuclear reaction

16 Types of radioactive decay beta emission –A neutron splits into a proton and electron which is spit out as a  particle.

17  particle emission

18 Types of radioactive decay positron emission –A proton kicks out positive charge (a positron,  +) to become a neutron. –The positron collides with an electron annihilating both and generating energy

19 Types of radioactive decay electron capture (EC) –an electron (from inner shell) is sucked into the nucleus to combine with a proton – produces a neutron. gamma emission –emission of energy (photon) from an unstable nucleus.

20 © 2003 John Wiley and Sons Publishers How does an atom’s atomic number change when its nucleus loses a(n): (a) α particle, (b) β particle, (c)  ray? How does that atom’s mass number change with the loss of each of these? QUESTION

21 Pu-239 (plutonium 239) loses an alpha particle (He nucleus). Write the nuclear reaction.

22 Can we predict types of radioactive decay that will occur? Nuclear particles are held together by a strong attractive force Like electrons, protons are arranged in shells Even numbers of protons and neutrons are most stable. An approximately 1-1 neutron to proton ration is generally most stable Atomic number > 83 is never stable.

23 Nuclear Bombardment Reactions Transmutation – changing one element to another by shooting a nuclear particle at its nucleus. All transuranium elements (more than 92 protons) were created synthetically in particle accelerators.

24 Transmutation Reaction

25 Energy of Nuclear Reactions ≠ ≠

26 A flare ejected from the surface of the sun. © 2003 John Wiley and Sons Publishers Courtesy NASA

27 Applications Medicine –Chemotherapy –Power pacemakers –Diagnostic tracers Agriculture –Irradiate food –Pesticide Energy –Fission –Fusion

28 X-ray examination of luggage at a security station. © 2003 John Wiley and Sons Publishers Courtesy Robert Maass/Corbis Images

29 Gamma ray analysis of a fitting for a medical device shows it to be free of flaws. © 2003 John Wiley and Sons Publishers Courtesy Amersham Technology

30 An image of a thyroid gland obtained through the use of radioactive iodine. © 2003 John Wiley and Sons Publishers Courtesy Custom Medical Stock Photo

31 Images of human lungs obtained from a γ-ray scan. © 2003 John Wiley and Sons Publishers Courtesy CNRI/Phototake

32 A cancer patient receiving radiation therapy. © 2003 John Wiley and Sons Publishers Courtesy Kelley Culpepper/Transparencies, Inc.

33 Figure 5.6: The Geiger counter. © 2003 John Wiley and Sons Publishers

34 Nuclear Reactions as an Energy Source Uranium-235, a source of nuclear power.

35 Figure 4.8: A typical fission reaction of U-235. © 2003 John Wiley and Sons Publishers

36 Figure 4.9: Schematic diagram of the cascading effect of a typical chain reaction initiated by a single neutron. © 2003 John Wiley and Sons Publishers

37 The world’s first atomic explosion, July 16, 1945 at Alamogordo, New Mexico. © 2003 John Wiley and Sons Publishers Courtesy Scott Camazine/Photo Researchers

38 The uranium bomb, 3m (10 ft) long and 0.7 m (2.3 ft) in diameter, was called “Little Boy.” © 2003 John Wiley and Sons Publishers Courtesy National Archives, photo no. 77-BT-187

39 Figure 4.11: The operation of fission bombs. © 2003 John Wiley and Sons Publishers

40 Remains of a building after the explosion of the uranium bomb at Hiroshima, August 6, © 2003 John Wiley and Sons Publishers Courtesy Shigeo Hayashi

41 © 2003 John Wiley and Sons Publishers How was a critical mass achieved in the detonation of the U-235 bomb? In the detonation of the Pu-239 bomb? QUESTION

42

43 Figure 5.1: Schematic diagram of a nuclear power plant. © 2003 John Wiley and Sons Publishers

44 Enrico Fermi built the first atomic pile and produced the first controlled chain reaction on December 2, © 2003 John Wiley and Sons Publishers Courtesy University of Chicago/AIP Neils Bohr Library

45 Cooling towers of a nuclear power plant. © 2003 John Wiley and Sons Publishers Courtesy David Bartruff/Corbis Images

46 The nuclear power plant at Chernobyl, after the accident of April 16, © 2003 John Wiley and Sons Publishers Courtesy Sipa Press

47 Figure 4.10: Enrichment by gaseous diffusion. © 2003 John Wiley and Sons Publishers Nuclear Power Plants require fuel with ~3% fissionable material, nuclear bombs require ~90% fissionable material. Very difficult to concentrate fissionable material.

48 Challenges of Nuclear Power Disposal of waste products

49 Construction of a tunnel that will be used for burial of radioactive wastes deep within Yucca Mountain, Nevada. © 2003 John Wiley and Sons Publishers Courtesy Yucca Mountain Project

50 Disposal of radioactive wastes by burial in a shallow pit. © 2003 John Wiley and Sons Publishers Courtesy Matthew Neal McVay/Stone/Getty Images

51 © 2003 John Wiley and Sons Publishers When an atom of uranium –235 is bombarded with neutrons, one of the many fission reactions it can undergo produces barium and an additional element (as well as energy and additional neutrons) but no α particles or β particles. With this in mind, and with reference to the periodic table, name the additional element produced in this particular mode of fission. QUESTION

52 © 2003 John Wiley and Sons Publishers Using the Law of Conservation of Mass and the Law of Conservation of Energy, show why nuclear fission might not be viewed as a chemical reaction. QUESTION

53 Rate of Nuclear Reactions

54 If a radioactive isotope has a ½ life of 20 minutes, what percent of the sample will remain after 1 hour? If 75% of a sample decays after 6 hours, what is its half life? If a radioisotope has a half-life of 2 weeks, how long will it take for 99% of the sample to decay?

55 Applications – Carbon Dating nitrogen in the atmosphere is bombarded by neutrons to form 14 C This carbon is integrated into CO 2 which then enters the food chain

56 Applications – Carbon Dating

57 © 2003 John Wiley and Sons Publishers Which of the following can be dated by radiocarbon techniques: (a) a rock; (b) a leather slipper; (c) a wooden boat; (d) a mummified body; (e) a silver spoon. Describe your reasoning. QUESTION

58

59 © 2003 John Wiley and Sons Publishers What is the most serious form of damage that could occur if a natural disaster such as a hurricane, a tornado, or an earthquake struck a nuclear power plant? Explain. QUESTION

60 © 2003 John Wiley and Sons Publishers Describe one advantage of a breeder reactor over a conventional nuclear reactor. Describe one disadvantage. QUESTION

61 © 2003 John Wiley and Sons Publishers What is the ultimate fate of every radioactive atom now in existence? QUESTION

62 © 2003 John Wiley and Sons Publishers Name and describe two types of biological damage caused by ionizing radiation. QUESTION

63 Genetic damage caused by radiation. © 2003 John Wiley and Sons Publishers Courtesy Novosti/Science Photo Library/Photo Researchers

64 © 2003 John Wiley and Sons Publishers Into what element is an atom of nitrogen-13 transformed when it emits a positron? QUESTION

65 © 2003 John Wiley and Sons Publishers Which one or more of the detection devices described in this Section would you use if you wished to determine immediately whether the residue left by a spilled chemical is radioactive? Which would you use if you wanted to determine the total, cumulative amount of radiation you might be exposed to in the course of an entire month? QUESTION

66 Marie Sklodowska Curie with her daughter, Irene. © 2003 John Wiley and Sons Publishers Courtesy The Center for the History of Chemistry

67 Ernest Rutherford discovered α rays and β rays. © 2003 John Wiley and Sons Publishers Courtesy C.E. Wynn-Williams

68 James Chadwick received the Nobel Prize in physics in 1935 for his discovery of the neutron. © 2003 John Wiley and Sons Publishers Courtesy Bettmann/Corbis Images

69 Lise Meitner interpreted Otto Hahn’s experimental observations as confirmation that he had split a uranium nucleus. © 2003 John Wiley and Sons Publishers Courtesy Bibliothek Und Archiv zur Geschichte der Max-Planck-Gesellschaft, Berlin

70 J. Robert Oppenheimer and Leslie Groves at the remains of the tower used in the test of the first atomic bomb. © 2003 John Wiley and Sons Publishers Courtesy Bettmann/Corbis Images

71 Albert Einstein, he discovered the equation that relates mass and energy. © 2003 John Wiley and Sons Publishers Courtesy AP/Wide World Photos


Download ppt "Nuclear Chemistry Chapter 4: Discovering the Secrets of the Nucleus From a Photographic Mystery to the Atomic Bomb Chapter 5: Harnessing the Secrets of."

Similar presentations


Ads by Google