Chem 102 1st Edition Lecture 22Outline of Last Lecture I. Nuclear ChemistryII. Radioactive Decay ReactionsIII. Nuclide StabilityIV. Nuclear TransmutationV. Radioactive DecayOutline of Current LectureI. Detecting RadioactivityII. Energy in Nuclear ReactionsIII. Fusion/FissionIV. Radiation EffectsCurrent LectureI. Detecting Radioactivity-Photographic film- records extent of exposure to radiation. Darker film is more exposed. -Geiger Counter- Measure ionization of matter caused by radiation. Ions and electrons conduct and electrical current. -Scintillator- Counts flashes of light when radiation strikes a substance whose electronsreturn to a lower energy state (Phosphor)-Radiotracers- Radioisotope used to trace the path of an element. II. Energy in Nuclear Reactions- Lots of energy is stored in the nucleus. Einsteins equation: E=mc2 As a system loses mass it loses energy. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-All spontaneous nuclear reactions are exothermic, negative. -Mass defect- mass of a nucleus is always < mass of component nucleons. -Nuclear binding energy- Energy required to break a nucleus into individual nucleons. III. Fusion/ Fission-Fusion- light elements combine into heavier ones. AKA thermodynamic reactions, occur in the sun. -Fission- Splitting of heavy nuclei into smaller nuclei, exothermic. Chain reactions is where one reaction initiates the next. -Critical mass- amount of fissionable material required to sustain reaction. Subcritical isbelow, supercritical is excess. Hiroshima bomb was a supercritical explosion. IV. Radiation Effects-Ionizing- causes molecule to ionize, harmful to biological systems-Non-ionizing- Not as harmful, doesn’t cause ionizing.-Alpha particles- penetrations stops at the skin, only dangerous if ingested. -Bete particles- penetrates 1 cm into tissue.-X-rays- Penetrate
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