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Nuclear Reactions. Fusion and Fission. Nuclear. NU – CLE – AR yes NU – CU – LAR no. Review of Subatomic Particles . Proton p, positive charge Nucleon Atomic number, Z Neutron n, no charge Nucleon Neutron number, N Electron e - Found in electron cloud, outside nucleus
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Nuclear Reactions Fusion and Fission
Nuclear • NU – CLE – AR yes • NU – CU – LAR no
Review of Subatomic Particles • Proton • p, positive charge • Nucleon • Atomic number, Z • Neutron • n, no charge • Nucleon • Neutron number, N • Electron • e- • Found in electron cloud, outside nucleus • Same number as protons in a neutral atom
Mass Number and Isotopes • Elements are defined by their atomic number, Z • The mass number, A, is the total number of nucleons A = Z + N • Elements can have different numbers of neutrons, therefore different mass numbers. These different species are called isotopes. • Some isotopes are more stable than others.
http://en.wikibooks.org/wiki/Basic_Physics_of_Nuclear_Medicine/Print_version 4/12/09
Fusion vs. Fission • Fusion • The combination of small nuclei into larger nuclei • Fission • The splitting of large nuclei into smaller nuclei • Both release large amounts of energy http://www.atomicarchive.com/Fusion/Fusion1.shtml 4/12/09 http://www.atomicarchive.com/Fusion/Fusion1.shtml
Mass Equivalence • Where does the energy released from fusion and fission come from? • Missing mass becomes energy • Not a violation of conservation of mass • E=mc2 http://web.mit.edu/jinseok/www/notes/notes_20031217/notes_20031217.shtml 4/12/09
Supernovas http://www.lpl.arizona.edu/undergrad/classes/spring2009/Pierazzo_214-1/Lectures/L7-Sun.pdf 4/12/09
Calculating Binding Energy • Ebinding = Eunbound – Ebound mc2 = munboundc2 – mboundc2 • m is the mass defect • 931.50 MeV/u • Hydrogen Fusion to Deuterium p + n 2H + Energy 1.007 825 u + 1.008 665 u 2.014 102 u + E 0.002388 u is missing! (0.002388u)c2 = 2.224 MeV
Calculating Binding Energy • Ebinding = Eunbound – Ebound mc2 = munboundc2 – mboundc2 • m is the mass defect • 931.50 MeV/u • Uranium decays to Thorium + Alpha particle 238U 234Th + 4He 238.050 783 u 234.043 601 u + 4.001 506 u + E 0.005676 u is missing! (0.005676 u)c2 = 5.29 MeV
MeV= Mega electron volt = ?? • MeV is another unit of energy • 1.60219 x 10-19 J = 1 eV ∴ 1.60219 x 10-13 J = 1 MeV • Energy released from nuclear reactions is roughly one million time greater than that released from chemical reactions. • CH4 + 2O2 = CO2 + 2H2O + energy 1 mole CH4 550 kJ (about one banana) Producing 1 mole of Helium in the Sun 6.6 x 108 kJ (1,200,000 bananas)