The document discusses oxidation-reduction (redox) reactions, including definitions and examples. It covers topics like rusting, fire, combustion, fuels, ignition sources, and both everyday and hazardous chemical reactions involving oxidation. Color changes and the role of elements like oxygen, chlorine, and metals are also examined in the context of redox processes.

2. Oxidation-Reduction page 145 top left, Lab Manual, 6 th Ed.

3. Oxidation-Reduction p.145 top left

4. Loss of Electrons is Oxidation (LEO), Gain of Electrons is Reduction (GER) page 145 middle down

5. Baseball analogy

6. Loss or gain of an electron makes a difference. Left has Copper(II) chloride (aqua-blue color), right has Copper(I) chloride (green solid).

7. Vanadium was named for the beauty of the colors in V’s several oxidation states. Chromium is named for the bright colors of its compounds (Greek chroma = color)

8. Colors of manganese compounds MnO (black, left), Mn 3 O 4 (gray, top), Mn 2 O 3 (green, bottom), MnO 2 (red-brown)

9. Ethanol Breathalyzer

10. Oxidizing Agent & Reducing Agent p.145 bottom left

11. Zinc in Copper sulfate solution p.145 bottom right

12. Activity series page 149

13. p.146 top, 6 th Ed.

14. Life, Nitrogenase, & Antiseptics page 146, 6 th Ed.

15. SCUBA Diving shows the gases of animal life as divers must bring tanks of oxygen and carbon dioxide bubbles are released.

16. Nodules on root hairs of legume plants (peas & beans) formed by nitrogenase bacteria Nitrogenase catalyzes the reaction of dinitrogen from the air to produce ammonia. (at room temp. and pressure!)

17. Haber Process: Making Ammonia from Nitrogen and Hydrogen

18. Decomposition of Compounds with air (or without) page 147 top, 6 th Ed.

19. Antiseptics (Disinfectants) page 146 bottom (#4), 6 th Ed.

20. Water treatment and purification page 147, #6, 6th Ed.

21. In 1992, Greenpeace and the Sierra Club called for a ban on all chlorine.

22. Uses of chlorine in 2002 in 1993

23. Chlorine is used for Swimming pool disinfection Sodium hypochlorite (NaOCl) reacts with water to slowly release elemental Cl 2 Chlorine (Cl 2 ) slowly evaporates from the pool, so more must be added periodically. Mixing too much or incorrect use can cause fatal accidents.

24. Bleach reacts with acids or with bases to produce poisonous gases.

25. Bleach effect on colors Bleach reacts with carbon-carbon double bonds in the colored pigment and decolorizes (bleaches) it. Green felt in water and in Hydrogen peroxide

26. Bleach effect on chemical structure

27. Stain removers, cleansers, & bleaches page 148 top left, 6 th Ed.

28. Rust stains in sink, toilet bowl, and bath due to soluble iron ions in the water

29. Cleansers often have strong bases & oxidizers and are frequently corrosive and caustic. Some jobs require acid cleansers, too.

30. Hydrogen peroxide 3% disinfects cuts 6% bleaches hair 30% bleaches skin to white on contact (very corrosive) 98% hydrogen peroxide is used as oxidizer for rocket fuel.

31. Antioxidants

32. Atmospheres of Planets in our Solar System

33. Air pollutants are usually oxidized molecules

34. A reaction like that of B&W film photography: Silver chloride white powder with a paper clip on top is exposed to a bright light, which darkens the AgCl as free Ag is formed

35. B&W Film Photography

36. Photography has many redox reactions (Color photography shown here)

37. Three invisible gases are involved in a fire: oxygen in, carbon dioxide out, and water vapor out. Plants are rich in potassium, and so are the ashes (potash is the source & etymology for potassium).

38. Combustion triangle (here in Spanish) Three requirements for combustion: Fuel (gaseous fuel) Oxygen (or other oxidizer) Ignition (heat, spark, or match)

39. To extinguish a fire, one must remove one (or more) of the three requirements Remove the fuel (spread it out, cover it). Remove the oxygen (cover the fire with a solid lid, smother it with carbon dioxide or water). Remove the heat (soak it with water, spread it out) Remove free radicals (radicals are needed for flames) [4th requirement would use a flame tetrahedron]

40. Fire extinguisher Sign for extinguisher location:

41. Fire suppression using Halons at an airport

42. Match for Ignition

43. Phosphorus, Matches

44. Candle Wax melts Liquid wax moves up in wick by capillary action. Gaseous wax burns when it reaches ignition temperature.

45. Oxygen

46. Steel wool in air & O2 Steel wool glows red-hot with a small flame in air. That glowing steel wool bursts into a larger flame in pure oxygen. (in German: reiner Sauerstoff)

47. Fuels burn faster and hotter in 100% oxygen than in air (20% O2) Blowtorch flame

48. Can melt through metals with an acetylene (& 100% oxygen) torch

49. Apollo 1 accident while training on launching pad 100% oxygen was used within the capsule. A fire started with seat materials that would not burn in 20% oxygen. Astronauts White, Grissom, and Chaffee died.

50. Liquid oxygen Fuels burn faster in pure (100%) oxygen than in air (20% O2) Fuels burn even faster in liquid oxygen. See video of charcoal lighting at Purdue and video of diamond burning in liquid O2

51. Space Shuttle Challenger accident, Jan. 28, 1986

52. Chlorine, Bromine, & Iodine

53. Halogens in water & dense organic solvent Chlorine water reduces bromide to bromine & iodide to iodine

54. Candle burns in chlorine gas Candle continues burning until chlorine is used up. The products are mostly solids (in comparison to the gases of a candle in air), so the smoke is much thicker.

55. Hydrogen burns in bromine vapor

56. Spontaneous combustion was starting in this stack of fiber boards. When smoke was detected, the stack was cut open to show the burned area. The stack insulates, holding in any heat generated by oxidation or pyrolysis. Rags used in linseed oil frequently combust spontaneously (i.e., without ignition).

57. Spontaneous Human Combustion cannot occur. Charles Dickens’ Bleak House (1853) describes a spontaneous human combustion, which Dickens believed could occur.

58. Hypergolic fuels need no ignition Rocket fuels have no need for spark plugs or other ignition source. These fuels and their oxidizers are so potent that they react on mixing and start their own flame (these are called hypergolic). A liquid fuel rocket is shown at left.

59. Ignition

60. Explosives: Gunpowder

61. Gunpowder Ingredients: Charcoal, Sulfur & Nitre (Potassium Nitrate)

62. Fireworks

63. Firecracker Usually made of black powder (gunpowder). Charcoal, sulfur, and potassium nitrate or potassium chlorate.

64. Hazard diamond placards

65. Texas City Explosion, April 16, 1947 Ammonium nitrate fertilizer on ship Grand Camp

66. Oklahoma City bombing, April 19, 1995 Timothy Mc Veigh, trained by U.S. Army in explosives use and preparation. Used Ammonium nitrate fertilizer and fuel oil, ignited by fuse and detonators.

67. September 11, 2001 BLEVE 9/11/2001

68. Thermite reaction: Rust and Dust (Al) used to weld rails and in incendiary bombs

69. Thermite reaction Incendiary materials: Mg, thermite, white P in incendiary bombs of WWII Dresden, Hamburg, etc.