Spontaneity of Redox Reactions, Lecture notes of Biochemistry

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Spontaneity of Redox Reactions « Compare the reaction when zinc metal is placed in copper(II) solution and the reaction when copper metal is placed in a zinc solution **Demo: Comparing two Similar Redox Reactions*** ceeh — ee / : 2 Ca Net won eguahon + PAs + cegy 2 Zn egy * Cu “) Sponteneaey Ond Beal Vs. Nek ioe eguahen * q a Zan cg) = ———— > No ten! r u . A oe au gy Must be @ Shorger OA, Hen Zn Nom) © Znesy must be @ shorser (es een (Cu esy Different atoms and ions have different abilities/strength to reduce or oxidize other atoms or ions o Atoms and ions are listed in tables, ranked according to their ability/tendency to oxidize or reduce other atoms or ions A table of oxidizing and reducing agents is arranged as follows: o Acomplete list is found on pg.7 of data booklet © Tables are usually always written as a list of reduction half-reactions in the forward direction Table of Selected Standard Electrode Potentials* a ' Jectrical Potential £° | +2.87 r ~ Reduction Half-Reaction most (eectivel| a + ghrongest on. PhOsis) + SOQ aqy + + - $1.69 i | MaOy (aq) + SH* aq) + +151 hecor& | Au*taq) + wee ket Cu lag) + SO. aq) + 4H tag) + So*aq) + Sis) + 2H%taqy + 2e AgBris) + ¢ 2H aq) + 2e7 = | Pb**iaq) + 2e wv be Agis) + Piaq) LOO, Nits) S mies weaker . RUN. most reechve / feduc tion Strongese RA Wn Genetoh, OR, + Ne Creed PR, A. oxidatin