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Topic: Nuclear Chemistry. Aim: How do you distinguish natural and artificial transmutations? Do Now: Complete the decay equation. 239 Pu _____ + _____ (Hint: Use Tables N & O, the Per. Table, & your notes from Monday) HW: Text p. 879 #1-3, 5, 7, 8 p. 886 #14. Transmutations.
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Topic: Nuclear Chemistry Aim: How do you distinguish natural and artificial transmutations? Do Now: Complete the decay equation. 239Pu _____ + _____ (Hint: Use Tables N & O, the Per. Table, & your notes from Monday) HW: Text p. 879 #1-3, 5, 7, 8 p. 886 #14
Transmutations • Natural: types we already studied (wrote equations for these) – nucleus spontaneously decays to form a new element • Table N radioisotopes all decay naturally (spontaneously) • Give off alpha beta, or positron particles • Artificial: transforming 1 element into another by bombarding the nucleus with high-energy particles • Particle accelerators speed up the particles enough to cause an artificial transmutation • How man-made elements are produced
Artificial Transmutations • Nitrogen nucleus bombards Californium nucleus • 4 neutrons given off – forms element Dubnium • New element (Dubnium) is synthetic
Artificial Transmutations • Tell me what’s happening in this reaction • Use words like “bombard”, “emit”, etc.
How to ID Natural vs. Artificial Transmutations • Artificial transmutations MUST HAVE 2 REACTANTS, whereas natural transmutations have ONLY 1 REACTANTB/C THE ELEMENT DECAYS SPONTANEOUSLY • Review book p. 221 #16-23
Practical Applications – Artificial Transmutation Nuclear Energy Mass is converted into energy Energy yield is approx. 1 billion times the energy released when the same amt of a fossil fuel is burned!
Nuclear Fission Fission: nucleus of one atom splits into 2 or more pieces Hint: Fission has an “i”, so does “splits” Basic process: Nucleus is bombarded with a high-speed neutron Nucleus splits & gives off energy Lighter nuclei formed are more stable than the parent nucleus, but are often radioactive themselves. FISSION simple animation
Fission Chain Reaction Example: Uranium Neutrons given off as products can bombard other uranium nuclei, causing them to split as well – etc. In a controlled setting, this is a nuclear reactor that can be used for energy http://phet.colorado.edu/en/simulation/nuclear-fission (java) In an uncontrolled setting, this is atomic bomb – Manhattan Project
Nuclear Fusion Fusion: 2 light nuclei unite to form a heavier nucleus Hint: fusion has a “u”, so does unite Hydrogen bomb - 1951 Fusion Reactor Proton-Proton chain in stars
Fission & Fusion High energy requirements High temperature is necessary – why? High pressure is necessary – why?
Sample Questions Review book p. 223 #24-33