112ch19 electrochemistry full size.pdf - ELECTROCHEMISTRY Priority First need to go back and refresh redox coverage from CHM 110 Determine Oxidation

112ch19 electrochemistry full size.pdf - ELECTROCHEMISTRY...

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ELECTROCHEMISTRY First need to go back and refresh redox coverage from CHM 110: Determine Oxidation Number Formal method of book-keeping electrons Definition Rules: Sum oxidation numbers in a specie = charge on specie Oxidation number of element = 0 Oxidation of IA & IIA = +1 or +2 in compounds Oxidation number of hydrogen = +1 in compounds Oxidation number of oxygen = -2 in compounds Priority  Generally, maximum possible oxidation number = Group # Examples: MgH 2 LiNO 3 NH 4 + KO 2 H 2 C 2 O 4 K 2 Cr 2 O 7
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Oxidation-Reduction (Redox) Reactions •involves transfer of electrons between reactants and changes in oxidation #s •every redox reaction involves oxidation and reduction half-reactions L oss of E lectrons is O xidation (an increase in oxidation number) says G ain of E lectrons is R eduction (a decrease in oxidation number) Oxidizing agent - oxidizes other species, it is itself reduced Reducing agent - reduces other species, it is itself oxidized O xidation I s L oss (of electrons) R eduction I s G ain (of electrons) Organic oxidation: adds oxygen or removes hydrogen forms: C-O, C-N, C-X breaks: C-H Organic reduction: adds hydrogen or removes oxygen forms: C-H breaks: C-O, C-N, C-X
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