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Nuclear Chemistry Chapter 21B

Nuclear Chemistry Chapter 21B. West Valley High School General Chemistry Mr. Mata. Nuclear Radiation Discoveries. Rontgen discovers x-rays (1895). Henri Becquerel (1896) discovered that uranium salts fogged photo plates.

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Nuclear Chemistry Chapter 21B

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  1. Nuclear Chemistry Chapter 21B West Valley High School General Chemistry Mr. Mata

  2. Nuclear Radiation Discoveries • Rontgen discovers x-rays (1895). • Henri Becquerel (1896) discovered that uranium salts fogged photo plates. • Marie & Pierre Curie isolated uranium atoms from pitchblende and discover elements radium and polonium (1898). • Rutherford isolates alpha & beta (1899). • Villard discovers gamma particles (1900).

  3. Nuclear Radiation Discoveries • Rutherford discovers + nucleus (1911). • Rutherford conducts 1st transmutation (1919) • Rutherford isolates proton (1919). • Chadwick discovers neutron (1932). • Lise Meitner & Otto Hahn discover elements thorium & protactinium (1935). • Fermi achieves first fission reaction(1942). • First electricity from fission reaction (1951).

  4. Chemical vs. Nuclear Reactions • Chemical Reaction Nuclear Reaction • Change in electrons change in nucleus (stable e- config.) (nucleons = P & N) • Temp, Press, Conc Temp, Press, Conc affect reactions. don’t affect reactions. • Energy released radioactive decay (heat & light) (alpha, beta, gamma) • Can be neutralized. Can’t be neutralized.

  5. Nuclear Fission and Fusion • Fission:Splitting nucleus into smaller parts. • Fusion:Two nuclei combine to produce a heavier nucleus .

  6. Fission

  7. Fission Produces a Chain Reaction

  8. Nuclear Fission • Enormous amounts of energy released. • 1 kg of U-235 releases energy = 20,000 tons TNT! • Atomic bombs start uncontrolled chain reactions. • Heavy nucleus is split into smaller nuclei. • Converts mass into energy E = mc2 • 10n + 23592U [23692U] (unstable) • 23692U 9038Sr + 14354Xe + 3 10n

  9. Nuclear Fission Bombs • First used in atomic bombs dropped on Hiroshima & Nagasaki (August 1945). • Both 23994Pu and 23592U were used. • U-235 bomb dropped on Hiroshima. • Pu-239 bomb dropped on Nagasaki. • U.S. only country to ever use nuclear bombs against enemy in war.

  10. Effects of Fission • Atomic bomb: energy released suddenly as heat, pressure, radiation, neutrons. • Nuclear reactor: energy released slowly in the form of heat and radiation. • Neutrons released which cause other materials to become radioactive. • fission products remain “hot” for centuries.

  11. Peaceful Uses of Fission • Nuclear power plants to generate electricity. • Fuel rods (containing U) give off neutrons. • Controlled using control rods (Zr or graphite)toabsorb neutrons. • Causes reaction to occur at steady rate. • Energy of reaction is absorbed by water (steam) which drives turbine to produce electricity.

  12. Nuclear Fusion • Thermonuclear reaction: • Energy released from the sun • Fusion releases more energy than fission. • Fusion products not radioactive. • Takes place at very high temperatures—in excess of 40,000,000C.

  13. Application of Fusion • Fusion reactions are used in hydrogen bombs (“H” bombs”). • More powerful than fission bombs. • H-bomb is triggered by a fission bomb. • Unsuccessful attempts have been made to harness fusion to produce controllable energy.

  14. Processing Nuclear Fuel • Uranium ore -> uranium oxide • Uranium oxide -> uranium flouride (UF6) • UF6 (0.7% enriched U-235) • UF6 (3% enriched U-235) nuclear reactors. • UF6 (80% + U-235) nuclear weapons.

  15. Chapter 21 SUTW Prompt • Describe how nuclear fission differs from nuclear fusion. • Complete a 8 -10 sentence paragraph using the SUTW paragraph format. Hilight using green, yellow, and pink. • Due Date: Tomorrow (start of class).

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