Nuclear Chemistry Chapter 21B West Valley High School General Chemistry Mr. Mata
Tsutomu Yamaguchi Survived both Hiroshima & Nagasaki atomic bombs.
Standard 11a Students know the differences between nuclear fission and nuclear fusion reactions.
Essential Question What are the uses of nuclear fission and nuclear fusion reactions?
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).
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).
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.
Nuclear Fission and Fusion Fission: Splitting nucleus into smaller parts. Fusion: Two nuclei combine to produce a heavier nucleus . 9
Fission
Fission Produces a Chain Reaction
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
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.
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.
Peaceful Uses of Fission Nuclear power plants to generate electricity. Fuel rods (containing U) give off neutrons. Controlled using control rods (Zr or graphite) to absorb neutrons. Causes reaction to occur at steady rate. Energy of reaction is absorbed by water (steam) which drives turbine to produce electricity.
Nuclear Fission Reactor
Nuclear Reactor Core the fuel rods in core contain enriched (3%) U-235. control rods can slip between the fuel rods to absorb neutrons. Regulates rate of water being heated in core.
Atomic Bomb Assembly
Hydrogen Bomb Assembly
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.
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 40,000,000C.
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.
Nuclear Fusion Reaction
Chapter 21B 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: Monday, October 24, 2016 (start of class).