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Chapter 21: Nuclear Chemistry Chemistry 1062: Principles of Chemistry II Andy Aspaas, Instructor.

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Presentation on theme: "Chapter 21: Nuclear Chemistry Chemistry 1062: Principles of Chemistry II Andy Aspaas, Instructor."— Presentation transcript:

1 Chapter 21: Nuclear Chemistry Chemistry 1062: Principles of Chemistry II Andy Aspaas, Instructor

2 Nuclear chemistry Chemical reactions where the nuclei change Independent of chemical surroundings (i.e. it doesn’t matter what compounds the nuclei are part of) Radioactive decay: unstable nuclei spontaneously disintegrate and give off radiation Nuclear bombardment reactions: one nucleus is physically struck by another nucleus to cause a nuclear reaction

3 Nuclear equations Nuclei only! Nuclide symbols used to show: –Mass number, A –Atomic number, Z For particles with no protons, the atomic number represents the charge –Ex. electron: Total mass numbers and atomic numbers must be equal on both sides of reaction

4 Radioactivity Alpha emission: ejection of a helium-4 nucleus –Occurs in nuclei where Z > 83 (transuranium) –Ex. Beta emission: ejection of a high-speed electron –Occurs when N/Z is too large (N = # neutrons) –Ex.

5 Radioactivity Positron emission: ejection of a positron –Positron: positively charged particle with same mass as an electron –Occurs when N/Z is too small –Ex. Electron capture: adding an electron to the nucleus –Competes with positron emission when N/Z is too small –Ex.

6 Radiation Gamma emission: emission of a gamma photon from an excited state nucleus –Metastable nucleus: excited nucleus a lifetime of at least one nanosecond –Ex. Spontaneous fission: when a nucleus Z > 89 spontaneously breaks apart into other nuclei –Ex.

7 Predict the decay Predict the form of radioactive decay the following nuclei will have, and if possible, write a nuclear equation

8 Nuclear bombardment reactions Nuclei such as uranium-235 can be caused to split into several other nuclei if bombarded by a neutron –Fission produces more neutrons, which can go on to cause other uranium nuclei to split The result is a chain reaction which releases the energy of neutron bombs and nuclear fission reactors

9 Nuclear fission reactor Pressurized light water reactor Most common design in US Prairie Island, MN

10 Prairie Island Nuclear Generating Plant, Red Wing, MN


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