CHEM 120 Week 6 Assignment; Energy, Nuclear Chemistry, (20 points)

1. In your own words, describe what is occurring during the process of electron beta decay, explaining what is ejected from the unstable nucleus and focusing subatomic changes. (2 points for clear and accurate description). 2. Write balanced chemical reactions for the following: (1 point each, 4 points total) a. Cobolt-60 undergoes beta decay b. Americium-241 undergoes alpha decay c. Copper-60 undergoes positron emission d. Gallium-66 undergoes electron capture 3. Strontium-89 is an isotope used in the treatment of bone cancer and has a half- life of 50.57 days. If 20 grams of this isotope is injected into a patient, how much will remain after 354 days? (1 point for correct answer with all work shown). 4. An isotope has a half-life of 45 minutes. What % of a sample of this isotope will remain after 1.5 hours, assuming that we start with 100%? (1 point for correct answer with all work shown). 5. Compare and contrast a source of ionizing energy with a source of non-ionizing energy. (1 point) MC/select all questions: 1 point each 6. Which of the following would be an exothermic process? There may be more than one correct answer. • Magma solidifying • Tinder burning • Ice cream melting • Ice melting 7. Which polymer(s) is/are found in the human body? (select all that apply). • Polypropylene • DNA • Protein • Cellulose 8. Which of the following directly illustrates the 1st law of thermodynamics: • Heat flows from a hot stone to the cool ground spontaneously. • The energy from the sun • Ice melts when heated • In a small/insulated chamber, a piece of wood burns burns; however, the total energy within the system is unchanged. 9. Molybdenum-99 decays by beta decay emission, resulting in an electron and: • Technetium-43 • Technetium-99 • Niobium-42 • Niobium-99 10. In the process of electron capture: • an electron and a proton react to form a neutron • an electron and a neutron react to form to a proton • a proton is converted to a neutron and an electron. • a neutron is converted to a proton and an electron. 11. In alpha decay, what change is observed in the atomic number? • decrease of 2 • decrease of 4 • increase of 2 • no change 12. In beta decay, what change is observed in the atomic number? • decrease of 2 • no change • increase of 1 • decrease of 1 13. An isotope with 82 neutrons and 49 protons undergoes positron emission. How many neutrons will be in the new isotope? • 81 • 82 • 83 • 48 14. Which of the following is an exothermic process” • photosynthesis • ethanol evaporating • Water Freezing • octane evaporating 15. You have four potential imaging isotopes, A, B, C, and D. Their half-lives are 50 seconds, 10 mins, 18 hours, and 6 years respectively. Which of these would you choose for medical imaging applications? • A • B • C • D 16. This radioactive decay process causes a decrease in the atomic number. More than one answer may be correct: • Alpha • Beta • Gamma • Positron Emission