In: Chemistry
Given the following reaction, Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(aq) E° = 1.10 V.
Use the Nernst equation to calculate the cell potential for the cell described with standard line notation below.
Zn|Zn2+(0.5082 M)||Cu2+(0.2699 M)|Cu
Units are not required. Report answer to three decimal places.
Please explain all of your steps! Thanks!
Oxidation Half cell
Zn(s) --------> Zn2+(aq) + 2e Anode E°red= -0.762V
Reduction Half cell
Cu2+(aq) + 2e --------> Cu(s) Cathode E° red = 0.337V
overall reaction is
Cu2+(aq) + Zn(s) -------> Cu(s) + Zn2+ (aq)
E°cell = E°red(Cathode) - E°red(Anode)
= 0.337V - (-0.762V)
= 1.10V
Nernst equation is
Ecell = E°cell - (RT/nF)lnQ
where,
R= 8.314(J/mol K )
T = 298K ( standard temperature )
number of electron transfer , n =2
Faraday constant, F = 96485C/mol
So, at standard temperature Nernst equation is
Ecell = E°cell - (0.0592V/n)logQ
Q = [ Zn2+ ] / [ Cu2+ ]
= 0.5082M/0.2699M
= 1.8829
So,
Ecell = 1.10V - (0.0592/2) log 1.8829
= 1.10 V - 0.0081V
= 1.092V
So, the cell potential is 1.092V