CHEM 102 1nd Edition Lecture 34Outline of Last Lecture I. Calculate E° of a CellII. Cell PotentialIII. Is Redox Reaction SpontaneousIV. Voltaic Cell DiagramOutline of Current Lecture I. ElectrolysisII. OvervoltageIII. RelationshipCurrent LectureI. Electrolysis- What are the products of KI electrolysis? What is in the container? Reductions possible: 2H2O +2e- H2 + 2OH- ; E = -0.83V K+ + e- K ; E = -2.93 V Oxidations possible: 2H2O O2 + 4H+ + 2e- ; E = -1.23V 2I- I2 + 2e- ; E = -0.53V Pick 1 of each reaction based on the smaller amount of voltage that must be added. Predict that H2 and I2 gas would be formed -0.83V and -1.23V- If an anode was connected to battery and the battery connected to a cathode, the e- will travel from the anode to the battery- The e- will then travel from the battery to the cathodeII. Overvoltage- Products predicted for electrolysis of aqueous ionic solutions are not always correct- Production H2 and O2 gas at metal electrodes seems to need additional voltage- This overvoltage results from kinetics factorsIII. RelationshipsThese 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.- G° is related to E°- When spontaneous G° is negative and E° is positive- ΔG° = - constant E° The constant is F (Faraday) 96,500 J/mol e- V ΔG° = - nFE°- Earlier we stated ΔG° = -RTlnK- So, they are all related -nFE = -RTlnK OR E° = RT/nF (times) ln
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