How do I calculate the cell potential?

1 Answer

E_(cell)^@=E_(red)^@+E_(Ox)^@Ecell=Ered+EOx

Explanation:

For an in-depth explanation see Ernest Z's answer.

To calculate standard cell potential, you use the formula:

E_(cell)^@=E_(red)^@+E_(o x)^@Ecell=Ered+Eox,

where E_(cell)^@Ecell is the cell potential, E_(red)^@Ered is the reduction potential and E_(o x)^@Eox is the oxidation potential. These are at 25^@ "C"25C and "1 atm"1 atm.

To calculate cell potential in non-standard conditons, the equation is:

E_(cell)= E_(cell)^@- (RT)/(nF)lnQEcell=EcellRTnFlnQ,

where

  • E_(cell)Ecell = cell potential at non-standard state conditions
  • E_(cell)^@Ecell = standard state cell potential
  • RR = universal gas constant ("8.314472 J/mol" cdot "K"8.314472 J/molK)
  • TT = absolute temperature (Kelvin scale)
  • FF = Faraday's constant ("96485 C/mol e"^-96485 C/mol e)
  • nn = number of moles of electrons transferred in the balanced equation for the reaction occurring in the cell
  • Q = reaction quotient for the reaction

aA + bB -> cC + dDaA+bBcC+dD,

so Q=([C]^c [D]^d)/([A]^a [B]^b)Q=[C]c[D]d[A]a[B]b

This is the [Nernst equation.](http://www.chem.purdue.edu/gchelp/howtosolveit/Electrochem/Electrochemical_Cell_Potentials.htm)

I hope I helped!