Solving the Nernst Equation for Zn^2+ Concentration

[morgan8222]

I built a cell with one side containing the solution 0.10 M CuSO4 with Cu(s) in it. The other side has 1 M NH3 and 0.05 M ZnSO4 with Zn(s) in it. The measured cell potential was 1.31.

I am using the Nernst equation. I need to find the concentration of Zn^2+.

E=E"-(0.059/2)logQ

1.31 = 1.10 -(0.059/2) log Q

Q = 7.61E-8

I am confused about what Q is. I know its definition, but I am not sure about the reaction and which concentrations to use.
Could someone help me out?

 

[Borek]

On both sides you have metal electrode submerged in the solution of its own ions. In both cases reaction is identical (although metal is different).