CH 302 1st Edition Lecture 16 Outline of Last LectureI. Chernobyl IncidentII. Difference between nuclear and chemical changesIII. Fission ReactionsIV. Fusion ReactionsOutline of Current LectureI. Types of Nuclear ChangesII. Chemical vs Nuclear ChangesIII. Binding EnergyIV. Isotopic StabilityV. Ionizing RadiationCurrent LectureTypes of Nuclear Changes:- Fission Reactionso Nucleus splits into smaller masseso Big tiny + tinyo Nuclide larger and much more heavyo Releases energy- Fusion Reactionso Nucleus combines into a larger mass o Tiny + tiny big o Light to heavy, they fuse together o Releases energy- Decay Reactionso Big big + tinyo Happens spontaneouslyo Natural occurrenceo Usually left off of balanced equation since it has no mass and no charge (just electromagnetic radiation)- Transmutationo NOT spontaneouso Bombarded with alpha particleso Need particle acceleratoro Used in medicine and cancer researchChemical Change vs. Nuclear Change:- Nuclear changes conserve mass numbers- Atomic numbers are conserved on the right and left hand side of the reactionBinding Energy:- This is where energy comes from- Analogous to the breaking and forming of bonds in change of enthalpy- E = mc^2- Difference in masses = mIsotopic Stability:- Fusion: Bigger charges in energyo High energyo Wants to go down in energyo Exothermico Much better way to produce energy- Decay Fissiono Exothermico Wants to go to the lowest energy state (which is the element iron)Ionizing Radiation:- Alpha radiation: positive and massiveo Harmful inside the bodyo Bare helium nucleus will rip electrons off moleculeso Ionization of biomolecules are very unhealthyo Generally not harmful as they are absorbed by the outer layer of dead skin- Beta radiation: negative and low mass- Gamma radiation: uncharged and no mass- Radiation comes from unstable radioisotopeso Naturally found in the environmento Made by humans for medical, energy, defense purposes- Isotopic Stability depends on neutron to proton
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