Chem 113 1st Edition Lecture 41 Outline of Last Lecture I. Redox chemistry revisitedII. Half-reaction method for balancing redox reactionsIII. Steps in the half-reaction methodIV. Balancing redox reactions in basic solutionsOutline of Current Lecture V. Electrochemical cellsVI. Comparing E°half-cell valuesVII.Current LectureI. Electrochemical cellsa. A voltaic cell uses a spontaneous redox reaction (ΔG<0) to generate electrical energyi. The system does work on the surroundingsb. An electrolytic cell uses electrical energy to drive a nonspontaneous reaction (ΔG>0)i. Surroundings do work on the systemc. Both types of cell are constructed using two electrodes placed in an electrolyte solutioni. The anode is the electrode at which oxidation occursii. The cathode is the electrode at which reduction occursII. Comparing E°half-cell valuesa. Standard electrode potentials refer to the half-reaction as a reductionb. E° values therefore reflect the ability of the reactant to act as an oxidizing agentThese 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.c. The more positive the E° value, the more readily the reactant will act as an oxidizing agentd. The more negative the E° value, the more readily the product will act as a reducing agentIII. Cell Potential: output of a voltaic cella. A voltaic cell converts the ΔG of a spontaneous redox reaction into the kinetic energy of electronsb. LOOK AT POWERPOINTIV. Standard electrode potentialsa. The standard electrode potential is the potential of a given half-reaction when allcomponents are in their standard statesb. By convention, all standard electrode potentials refer to the half-reaction written at reductionc. The standard cell potential depends on the difference between the abilities of the two electrods to act as reducing agentsi. E°cell=E°reduction (cathode)-E°oxidation(anode)V. Writing spondaneous redox reactionsa. Each half-reaction contains both a reducing agent and an oxidizing agentb. The stronger oxidizing and reducing agents react spontaneously to form the weaker onesc. A spontaneous redox reaction (E°cell>0) will occur between an oxidizing agent andany reducing agent that lies below it in the emf series (one that has a less positive value for E°)d. The oxidizing agent is the reactant from the half-reaction with the more positive
View Full Document
Unlocking...