Question

Here is short-hand cell notation for an electrochemical cell involving copper and zinc.

Zn/Zn²⁺//Cu²⁺/Cu

If the [Cu²⁺] is 6 M and the [Zn²⁺] 0.09 M, find the cell potential under NON-standard conditions using the Nernst equation.

Answer 1

SOLUTION:

The following electrochemical equation takes place in this cell

Zn(s) + Cu²⁺(aq) -------> Zn²⁺ (aq) + Cu(s)

Ecell is given as

E_cell = E^o_cell - 0.0591/n {log[Zn²⁺]/[Cu²⁺]}

n = number of electrons involved in balanced chemical equation, here n = 2

[Zn²⁺] = 0.09M, [Cu²⁺] = 6M

E^o_cell = E^o_R - E^o_L

E^o_R -= standard electrode potential of cathode. Here cathode is Cu and E^o_R = 0.34V

E^o_L -= standard electrode potential of Anode. Here anode is Zn and E^o_L = -0.76V

Therefore E^o_cell = 0.34 -(-0.76) = 1.1V

Therefore

E_cell = 1.1 - 0.0591/2 {log[0.09]/[6]}

E_cell = 1.1 - 0.029 X (-1.82)

E_cell = 1.154V