Week 13 Nuclear Chemistry PDF

Nuclear Chemistry  Nuclides Nuclide = a particular type of nucleus, characterized by a specific atomic number and nucleon number Nucleon number or mass number = the number of nucleons (protons and Nuclide Symbolism and Isotopes  Nuclear Stability Electrostatic force = the for...

Nuclear Chemistry  Nuclides Nuclide = a particular type of nucleus, characterized by a specific atomic number and nucleon number Nucleon number or mass number = the number of nucleons (protons and Nuclide Symbolism and Isotopes  Nuclear Stability Electrostatic force = the force that causes opposite electrical charges to attract each other. Strong force = the force between nucleons (protons and neutrons). Neutrons increase the attraction from the strong force without increasing electrostatic repulsion Band of Stability Alpha Emission Beta (-) Emission Beta +(Positron) Emission Electron Capture Gamma Emission  Nuclear Reactions Nuclear reactions involve changes in the nucleus, whereas chemical reactions involve the loss, gain, and sharing of electrons. Different isotopes of the same element may undergo very different nuclear reactions, even though an element’s isotopes all share the same chemical  Nuclear Reactions (cont.) Unlike chemical reactions, the rates of nuclear reactions are unaffected by temperature, pressure, and the presence of other atoms to which the radioactive atom may be bonded. Nuclear reactions, in general, give off much more energy Nuclear Equations General Nuclear Equations  Half-life = the time it takes for one-half of a sample to disappear.  An Example about half life of radioactive atoms Half life of the radioactive decay below is 20 minutes. How many moles of X and Y will be present 1 hour later when 1 mole of X decays X ===> Y + energy Time X Y 0 min 1 mole 0 (begining) 20 minutes 0.5 mole 0.5 mole 40 minutes 0.25 mole 0.75 mole Radioactive Decay Series  Radiation Effect on Body Radioactive emissions ionize atoms and molecules. This also leads to free radicals (particles with unpaired electrons). H2O → H2O+ + e− H2O+ + H2O → + H23O ++ e− → H + OH− OH These reactive particles react with important substances in the body, leading to immediate damage and delayed problems, such as  Uses for Radioactive Nuclides Cancer radiation treatment Computer imaging techniques Radiocarbon dating Smoke detectors Food irradiation Radioactive tracers Application of Nuclear Chemistry Which Oxygen Belongs to Which Molecule? We can follow the accumulation site of a drug in the different organs of the body by using isotopes FDG PET Gamma irradiation (Gamma sterilization) of the industrial products (medical apparatus, foods, etc) https://youtube.com/watch?v=pe6AKh_tLys  Nuclear Energy Binding energy = the amount of energy released when a nucleus is formed. Binding energy per nucleon generally increases from small atoms to atoms with a mass number around 56. Thus fusing small atoms to form medium-sized atoms (nuclear fusion) releases energy. Binding energy per nucleon generally decreases from atoms with a mass number around 56 to larger atoms. Thus splitting large atoms to form medium- sized Binding Energy per Nucleon Nuclear Fission Chain Reaction Nuclear Reactor Nuclear Fusion Powers the Sun