Book: KE & R: 21 Flashcards
Relating the spontaneity of a process to the sign of the cell potential.
E_cell > 0 for a spontaneous process
Relating electric potential to energy and charge in SI units.
Potential = energy / charge or 1 V = 1 J / C
Relating standard cell potential to standard electrode potentials in a voltaic cell.
Eº_cell = Eº_cathode(reduction) - Eº_anode(oxidation)
Defining the Faraday constant.
F = 9.65×10⁴ J / V mol e⁻
Relating the free energy change to the cell potential.
∆G = -n F E_cell
Finding the standard free energy change from the standard cell potential.
∆Gº = -n F Eº_cell
Finding the equilibrium constant from the standard cell potential.
Eº_cell = ( R T ln( K ) ) / ( n F )
Substituting known values of R, F, and T into equation Eº_cell = ( R T ln( K ) ) / ( n F ) and converting to a common logarithm.
Eº_cell = ( 0.0592 V / n ) log K or log K = n Eº_cell / 0.0592 V
Calculating the nonstandard cell potential (Nernst equation).
E_cell = Eº_cell - RT ln Q / n F
Substituting known values of R, F, and T into the Nernst equation and converting to a common logarithm.
E_cell = Eº_cell - ( 0.0592 V / n ) log Q
Relating current to charge and time.
current ( A ) = charge ( C ) / time ( s )