nuclear chem quiz 2 cards

• Fission


  Nuclear reaction where a heavy nucleus splits into two or more lighter nuclei
• Artificial Transmutation


  Transmutation that happens from high energy particles bombarding a nucleus
• Artificial vs Natural Transmutation

  • Artificial
  • Natural
• When these reactions occur, small amounts of mass can be converted into large amounts of energy
• This energy can be harvested in fission and fusion reactors for everyday energy use
• Fission reaction


  1. Neutron is shot at a radioactive source

  2. Splits producing energy
• If the number of neutrons released isn't controlled, a chain reaction will occur
• Fission reaction is the type of reaction used in nuclear bombs
• Chain reaction


  Series of reactions where each reaction is initiated by the energy produced in the previous one
• Fission reactor


  1. Reaction's energy used to steam

  2. Turns a turbine system, creating electrical energy from nuclear energy

  3. Fuel rods contain fissionable radioactive source

  4. Control rods can regulate the neutrons absorbed, controlling the chain reaction
• Fusion


  • Involves combining (fusing) of nuclei to produce heavier ones
  • All atoms combine to form helium in a star
• Advantages of fusion


  • Produces more energy
  • Less danger (no reaction)
  • Less waste
  • Materials more readily available
• Disadvantages of fusion


  • Too expensive
• In both fusion and fission reactions, small amounts of matter are converted into large amounts of energy
• Atomic masses of nuclides used in fusion are smaller compared to atomic masses of nuclides used in fission
• Half-life


  The time it takes for 1/2 of the atoms of a radioisotope to decay
• Calculating Half-Life


  1. After one half life 50% /½ of the radioactive element is still present

  2. Continues forever -> Number will never be zero!
• Half-lives are on Table N
• Half-lives


  • Shorter half life -> Less stable isotope
  • Longer half life -> More stable isotope
• Half-life problems: Amount Remaining

  1. Find the # of half lives that have taken place using Table N

  2. Cut original mass in half by # of half lives

  3. Total time elapsed = # of half lives x Half life time from Table N
• Half-life problems: Fraction Remaining


  Same set up but you half fractions instead of mass
• Half-life problems: # of half lives


  Find # of half lives by halving the original mass until you get to the final mass
• Half-life problems: Finding Half-Life

  1. Find # of half lives by halving the original mass until you get to the final mass

  2. Divide total time elapsed by # of half life periods you calculated in step 1
• Half-life problems: Finding Original Mass

  1. Find # of half lives by halving the original mass until you get to the final mass

  2. Divide total time elapsed by # of half life periods you calculated in step 1

  3. Work backwards & double the mass 4 times
• Only half the mass, never half the time
• Uses of radioactive isotopes

  • Dating materials (Carbon-14, Uranium)
  • Smoke detectors (Am-241)
  • Medical applications (I-131, Co-60, Tc-99)
• Radioactive isotopes used in medical applications must have short half-life and be quickly eliminated from the body
• Dangers & risks of radioactivity

  • Damage to tissue
  • Gene mutation
  • Pollution from radioactive waste
  • Accidents from nuclear reactors
• Nuclear fission produces radioactive waste that must be stored
• Nuclear waste is currently placed in large lead boxes underground around the country, with Yucca Mountain in Nevada as a large long-term storage facility
• Carbon-14: used to date organic remains (age of organisms)
• Uranium: used to date rocks
• I-131 (thyroid): used to treat hyperthyroidism
• Co-60: used to treat cancer
• Tc-99: used to detect brain tumors