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Nuclear Chemistry

Dive into the world of nuclear chemistry with this comprehensive guide detailing chemical vs. nuclear reactions, types of radiation emission, nuclear stability factors, and radioactive decay rates. Explore concepts with FermiLab, CERN, LHC, and SuperCollider.

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Nuclear Chemistry

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  1. Nuclear Chemistry Chapter 4.4 and 25

  2. Particle Accelorators • Lawrence’s cyclotron: http://www.lbl.gov/Science-Articles/Archive/early-years.html • FermiLabhttp://www.fnal.gov/ • CERN http://public.web.cern.ch/public/ • A.k.a. “Large hadron collider” (LHC) • SuperColliderhttp://www.hep.net/ssc/

  3. Chemical vs. Nuclear Reactions Chemical Nuclear • Bonds are broken or formed. • Atoms are unchanged, but rearranged. • Involve valence electrons. • Associated with small energy changes. • Reaction rate influenced by temp, pressure, concentration, catalysts. • Nuclei emit particles and/or rays. • Atoms are converted into atoms of another element. • Involve protons, neutrons, and electrons. • Associated with large energy changes. • Reaction rate not normally affected by temp, pressure, catalysts.

  4. Radioactivity • Radiation – the rays and particles emitted by the radioactive material • Radioactive atoms undergo significant changes in their identity • Atoms of one element change to atoms of another element • Reason? Nuclei are unstable • Gain stability by losing energy

  5. What types of radiation do nuclei emit? • Radioisotopes – isotopes of the same atoms with unstable nuclei • Undergo radioactive decay to become more stable • Most common radiation types: • Alpha • Beta • Gamma

  6. Nuclear Stability • Which atomic nuclei are radioactive? • Neutrons – add attractive force within the nucleus • Stability – related to balance between electrostatic and strong nuclear forces • Neutron/proton ratio • Low atomic numbers ~1:1 ratio • High atomic numbers ~1.5:1 ratio • Figure 25.8 p. 811

  7. Type of decay depends on reason for instability • Too many neutrons to be stable (above band of stability): • Beta decay • Alpha decay • Gamma decay • Too few neutrons to be stable (below band of stability): • Positron emission • Electron capture

  8. Types of Decay Notes on Board….

  9. Radioactive Decay Rates • Radioisotopes have differing decay rates • Half-life – time required for one-half of a radioisotope’s nuclei to decay into its products • Example: • Strontium-90 half-life (t) = 29 years • Today - 10.0 g strontium • 29 years from now – 5.0 g strontium

  10. Radioactive Decay Rates • Equation: amount remaining = initial amount (1/2)n OR amount remaining = initial amount (1/2)t/T t = time elapsed T = duration of one half life *** must have same units of time • Table 25.5 p. 818 • Radioisotopes all have different half-lives

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