CHEM 122 1st Edition Lecture 37 Outline of Last LectureI. Balancing redox reactionsII. Electrochemical cellsa. ElectrodesIII. Cell VoltageOutline of Current Lecture I. Electrode PotentialsII. Free Energy from Electrochemical cellsa. Spontaneityb. Concentration and cell potentialCurrent LectureElectrode Potentials:- The larger/ more positive Ered, the greater the tendency for the reduction to occur- The smaller/more negative Ered, the more difficult it is for reduction process to form- The more Positive Er the stronger the oxidizing agent- The more negative Er, the stronger the reducing agent.Free Energy from Electrochemical cells- Gibbs Free energy Change:o∆ G=−nF Ecell n: moles of electrons transferred F: faraday’s constant, 96,500 C/mole e- E: cell potential in volts- Spontaneity:o Spontaneous: Change in G is (-) and Ecell is (+)o Nonspontaneous: change in G is (+) and Ecell is (-)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best Used as a supplement to your own notes, not as a substitute.- Relationship between Ecell and K:oEcell°=RTnFlnKChang in G K E cell Reaction at standard state conditions<0 > 1 > 0 Spontaneous0 1 0 Spontaneous at Equilibrium> 0 < 1 < 0 Non spontaneous- concentration and cell potential:o reaction concentration is increased then cell potential increaseso product concentration is increased then cell potential decreases.- Nernst EquationoE=E°−RTnFlnQ- as the reaction in the battery continues, the reactant ions are consumed and the product ion concentrations increase. Eventually the cell potential will drop to zero and that’s when the cell is at equilibrium and change in G is
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