IMG_0001_NEW_0030_001

IMG_0001_NEW_0030_001 - : the potential difference:...

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Lz+ TODAY'S LECTURE: "Electrochemistry" . Electrical Work . Cell Potential and Free Energy Dependence of Cell Potential on Concentration (Nernst Equation) Equilibrium Constants for Redox Reactions . Concentration Cells Free Energy and Gell EfficiencY . For a real cell: 10".,u"t ( Pr"* W*tu.t : -nFEuy (acrual) < W-r* : -nFEut -_---t@ . Resistance (frictional heating as electrons flow through wires) + potential work lost as heat o fid Law of thermodynamics: A,S*u"o" > 0 Cel eftLrrcy - w^{ xIWo v* . Ftrn llermodynemics: 1t. ., = AG = . Uder standard conditions: | *" | .f Positive cell pot#tfll %lU"*.rs reaction Can determine AG experimentallY (htr n€ed infinitesimally small current flow) 3 LG:-nFEntt Number of electons transferred per mole ofreacfion Electrical Work Galvanic cell reaction = Work is done Because: Electric charges (e-s) are moved The total amount of work done depends on: 1) Work done on each electron
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Unformatted text preview: : the potential difference: .E&quot;&quot;o Porerfrbl diftrerrce 19= work(r) Charge (C) 2) Number of moles electrons moved = n 3) Charge on each electron: -e: -1.602 x l0-le C number of moles of electrons Maximum cell potential (E*u), as calculated theoretically, excluding resistance in wires etc. Maximum workthat can be done Negative becausf.gg$ flows out ofsystem---1-(lt reacfion $ spontaneous e E is positive) Faraday's constant = charge on I mole of electrons=F:exNo ,F :96,485 C/mol 2 \^^/k -) Dependence of Cell Potential on Concentration . For non-standard conditions: LG: AGo + RTIIQ . Since: LG: -nFEuy and AGo : -nFEoun = -nFEut : -nFEoo' * RTIrQ at25&quot;C: 0.0257 L'=L. : Nernst equation hlQ Eun= E*u-#^n . Commonly written in terms of log (base-10) ln(x):2.303 x log(x) at25&quot;C E = E&quot; - o'otnt to*g n Calculate cell potential under non-standard conditions...
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