16.4 Potential, Free Energy, and Equilibrium - Chemistry_ Atoms First 2e _ OpenStax.pdf

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/Learning ObjectivesBy the end of this section, you will be able to:Explain the relations between potential, free energy change, and equilibrium constantsPerform calculations involving the relations between cell potentials, free energy changes, and equilibriumUse the Nernst equation to determine cell potentials under nonstandard conditionsSo far in this chapter, the relationship between the cell potential and reactionspontaneityhas been described,suggesting a link to the free energy change for the reaction (see chapter on thermodynamics). The interpretation ofpotentials as measures of oxidantstrengthwas presented, bringing to mind similar measures of acid-base strength asreflected in equilibrium constants (see the chapter on acid-base equilibria). This section provides a summary of therelationships between potential and the related thermodynamic propertiesΔG and K.E° andΔThe standard free energy change of a process,ΔG°, was defined in a previous chapter as the maximum work that couldbe performed by a system,w. In the case of a redox reaction taking place within a galvanic cell under standard stateconditions, essentially all the work is associated with transferring the electrons from reductant-to-oxidant,w:The work associated with transferring electrons is determined by the total amount of charge (coulombs) transferred andthe cell potential:wherenis the number of moles of electrons transferred,FisFaraday’s constant, andE°is the standard cellpotential. The relation between free energy change and standard cell potential confirms the sign conventions andspontaneity criteria previously discussed for both of these properties: spontaneous redox reactions exhibit positive

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Term
Spring
Professor
N/A
Tags
Electrochemistry, Cell Potentials, Standard Cell Potentials

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