This is it! The final Regents Chemsitry Lecture!
III. Radioactive Compounds A. Risks in using radioactive compounds 1. Exposure Too much exposure to radiation (accidental or on purpose) can cause Serious illness or death Mutations which can be passed on to future generations 2. Disposal Some radioacitve waste can last for thousands of years. Currently running out of room to store the waste Power plants 3. Accident Accidental release of radiation or radioactive waste can be very damaging to people and the environment. Chernobyl
B. Uses of Radioisotopes Many different uses for radioactive isotopes Specific isotopes can be used for specific purposes 1. Tracers Use to follow chemicals through complex reactions Photosynthesis, Cell Respiration 14C 18O 3H Makes chemicals radioactive, so we can see where they go 14CO2 14C6H12O6
2. Diagnosis Inject isotope into a person to detect an illness If the isotope goes to the wrong place, there may be a problem Use isotopes with low radioactivity, short half lives and quickly eliminated from the body. Used to detect thyroid problems 131I Used to detect brain tumors 99Tc Used to detect intestinal problems Ba
3. Treatment Other forms of radiation can be used to kill cancer cells 60Co Cancer cells are killed easier by radiation than normal cells Radium Expose tumor to radiation, it kills more cancer cells than normal cells 131I is also used to treat thyroid problems, as well as diagnose them.
4. Sterilization Some foods or materials are exposed to radiation to kill bacteria and molds Gamma radiation 5. Measurement Radiation is absorbed as it passes through different materials Can measure thickness of substances very accurately using radiation
6. Determining Age 14C When something is alive, it has a specific amount of 14C in it When it dies, the 14C undergoes half lives and decays Count the number of half lives to determine the age (Carbon dating) 238U Decays to 206Pb Very long half life Measure the ratio of 238U to 206Pb in rocks to determine their age.