Week 7 1. Radioactive isotopes find practical use in all of the following applications except Biomedical tracers Smoke detectors Household cleaning agents Cancer treatment 2. The dream of ancient alchemists was to transform lead into gold. Today, it is theoretically possible to make the dream come true. Which one of the following would allow lead to be transformed into gold? Chemical reaction Physical change Combustion Nuclear fission

3. What type of nuclear reaction results in a single nucleus undergoing a decrease in atomic number, no change in mass number, and the release of high light energy? Alpha decay C. Gamma radiation Beta decay D. Nuclear fusion 4.According to the graph, what is the approximate half-life of throium-234? 10 days C. 25 days 50 days D. 100 days

5. A radioactive substance has a half-life of 40 years 5. A radioactive substance has a half-life of 40 years. What fraction of the sample will remain at the end of 160 years? ½ C. 1/8 ¼ D. 1/16 6. Nuclear Reactions produce a tremendous amounts of energy. Where does the energy originate? The conversion of mass into energy The valence electrons during chemical bonding The conversion of thermal energy into nuclear energy The extreme temperatures produced during nuclear reactions

8. Describe the reaction illustrated by: 7. Which subatomic particle is used as a projectile to start a fission reaction? Proton Neutron Electron Alpha particle 8. Describe the reaction illustrated by: 1H + 2H  3He Fission Alpha decay Gamma decay Fusion

9. A group of identical atoms would be classified as A solution. A compound. An element. A mixture 10. Carbon dioxide, CO2, is an example of a(n) Solution Compound Element Mixture