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Chapter 9: Nuclear Chemistry

Chapter 9: Nuclear Chemistry. Radioactivity Nuclear Equations Radiation Detection Half-Life Medical Applications Fission & Fusion. -. -. -. +. +. +. Isotopes of Hydrogen. Isotopes = Atoms of the same element but having different masses. 1 1. 2 1. 3 1. H. H. H. Protium

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Chapter 9: Nuclear Chemistry

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  1. Chapter 9: Nuclear Chemistry • Radioactivity • Nuclear Equations • Radiation Detection • Half-Life • Medical Applications • Fission & Fusion

  2. - - - + + + Isotopes of Hydrogen • Isotopes = Atoms of the same element but having different masses. 1 1 2 1 3 1 H H H Protium 99.99% Tritium Trace % Deuterium 0.01% Average Atomic weight of Hydrogen = 1.00794amu

  3. 12 13 14 C C C 6 6 6 - - - - - - + + + - + + + + + + + + + - - + + + + + + - - - - - - - Isotopes of Carbon - - 98.89% 1.11% Trace % Average Atomic weight of C= 12.011amu

  4. 14 3 1 C H 6 - - + + + + + - + + - - Radioactive Isotopes - - Hydrogen-3 Carbon-14 Nucleus is unstable So falls apart (decays) Giving radioactive particles

  5. 123 53 131 53 I I 60 27 Co 99m Tc 43 Radioactive Isotopes in Medicine Diagnose thyroid function Treat hyperthyroid (destroys cells) Destroy tumors (g radiation) Diagnose bone, tissue (most common)

  6. 210 84 210 84 206 206 Pb Pb Po Po 82 82 + + + + + + + + 4 2 4 2 He He Alpha Decay a Particle +

  7. 14 6 14 - N C 7 + + + + + + + + 1 1 1 0 0 -1 0 -1 + e n H e + + + + Beta Decay b Particle + - + neutron proton electron

  8. 14 6 14 6 14 14 - N N C C 7 7 + + + + + + + + 0 -1 0 -1 + e e + + + + Beta Decay b Particle + - +

  9. 99m 43 99m 43 99 43 99 Tc Tc Tc Tc 43 + + + + + + + + + + + + Gamma Decay g decay g +

  10. - Ionizing Radiation Radiation knocks off an electron An ion A radical Ions & radicals cause damaging chain reactions

  11. - Geiger Counter Radiation knocks off an electron An ion Gas in instrument tube Ions detected by Counter

  12. - + + Radiation: Penetration through Air a 4 cm b 6-300 cm 400 m g

  13. - + + Tissue Penetration Depth a 0.05 mm 0.06-5 mm b >50 cm g

  14. - + + Radiation: Shielding Heavy Cloth a Pb, thick concrete Paper Cloth b g

  15. 4 2 4 2 He He Nuclear Equations a: Radon gas in Buildings 226 88 222 Rn + Ra 86 Gas 218 Po + 84 Cancer

  16. 60 27 Co 0 -1 0 -1 e e 131 53 I Nuclear Equations b: Cancer Treatment 60 Ni + 28 b: Thyroid check & treatment 131 Xe + 54

  17. Radiation Detection Activity # of disintegrations by of 1g Ra Curie (Ci): 1 Ci = 3.7 x 1010disintegrations sec Becquerel (Bq) 1 Bq = 1 disintegration sec

  18. Radiation Detection Absorbed Dose

  19. Tissue Penetration Depth - a 0.05 mm 0.06-5 mm b + + >50 cm g Radiation Detection: Biological Effect Radiation Absorbed Dose (Rad) (D): 1 rad = 1 x 10-2J kg tissue 1 rad = 2.4 x 10-3 cal kg tissue

  20. - + + Tissue Penetration Depth a 0.05 mm 0.06-5 mm b >50 cm g Radiation Absorbed Dose (Rad) (D): 1 Gray = 1 J kg tissue 100 rad = 1 Gray

  21. Radiation Detection Biological Damage

  22. Radiation Equivalent for Man (rem) RBE 20 1 1 a b g 1 Rem = 1 Rad x RBE relative biological effectiveness

  23. Annual Radiation Exposure in USA Total = 170 mrem / yr Cosmic = 40 mrem Air, H2O, Food = 30 mrem X-rays: Chest = 50 mrem Dental = 20 Smoking = 35 mrem TV = 2 mrem Radon = 200 mrem Wood,concrete,bricks = 50 mrem Ground = 15 mrem

  24. Biological Effects of Radiation Dose in rem (at one time) 0-25genetic damage possible but usually undetected 25-100 decrease # of white blood cells (temporary) 100-200 mild radiation sickness (vomit, diarrhea, strong decrease # white blood cells) >300 (diarrhea, hair loss, infection) 500 LD50 for humans

  25. Biological Effects of Radiation Dose in rem 300 LD50 for dogs 800 LD50 for rats 50,000 LD50 for Bacterium 100,000 LD50 for Insects 500 LD50 for humans

  26. Therapeutic Doses of Radiation Dose in rem 4,500 Lymphoma 5,000 – 6,000 Skin cancer 6,000 Lung cancer 6,000 – 7000 Brain Tumor

  27. FDA approved killing of bacteria with: 0.3 – 1 kGy ionizing radiation from Co-60 or Cs-137 (gamma producers)

  28. 131 53 I Half-Life t1/2 = Time for 1/2 sample to decay t1/2 = 8 days 8 days 5 g 10 g 20 g

  29. Half-Life I-131 8 days Co-60 5.3 yrs Tc-99m 6 hrs

  30. Positron Emission Tomography (PET) 0 +1 e 11 6 + C + + + 0 + + + + + 11 + B 0 1 1 1 0 5 H n + + 0 +1 e b+ Positron + proton neutron positron

  31. Positron Emission Tomography (PET) 0 -1 0 +1 e e 11 6 - + C + + + 0 + + + + + 11 + B 0 5 + + 11 5 0 +1 e B electron 2g rays b+ Positron Detectable g rays  image Shows blood flow 11 6 C + positron

  32. Positron Emission Tomography (PET) 0 -1 0 +1 e e 11 6 - + C + + + 0 + + + + + 11 + B 0 5 + + 0 +1 0 -1 e e 2g electron 2g rays b+ Positron Detectable g rays  image Shows blood flow + positron electron gamma

  33. 91 36 Kr 235 92 236 92 1 0 U U n 142 56 Ba Fission Splitting atoms for Energy Energy + unstable • Uses: • Atomic Bomb • Nuclear Power

  34. Fission Need critical mass of U-235 to sustain chain rxn to produce enough E for an explosion

  35. Fission U-235 • Nuclear Power plants: • Controlled fission • avoids critical mass

  36. 2 1 4 2 3 1 1 0 + He H n H + + + Fusion Combining atoms for Energy Deuterium Energy 100,000,000OC + + Tritium > E than from fission But impractical since heat too high • Uses: • Sun • Hydrogen Bomb

  37. Fusion Making radioactive particles Add 2 stable nuclei  unstable nucleus

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