[Juozukas]

hello,
i had to solve this problem:

Compose the conditional scheme of a Daniell-Jacobi galvanic cell in which the zinc and iron electrodes are immersed into the solutions of their salts(Zn²⁺ and Fe ²⁺). Write the equations of the reactions taking place on the electrodes. Calculate the concentration of the Fe²⁺ ions if the electromotive force is 0 and the concentration of Zn²⁺ is 0,001mol/l.

I tried to solve the problem, unfortunately i did something wrong. Here is how i calculated:

http://img201.imageshack.us/img201/5207/problemzy5.jpg (I'm sorry for making an image, but i don't know any other way to show you how i did it)

The answer 13,9 seems not logical to me, that's why I'm asking you help. Tell me where is the mistake, it would be really nice if you would correct it

[Kryolith]

E_C=-0.44 V + 0.059 V/2*lg [Fe²⁺]
E_A=-0.76 V + 0,059 V/2*lg(0.001) = -0.8485 V

E_C-E_A=-0.44 + 0.0295 lg [Fe²⁺] + 0.8485 = 0
==> lg [Fe²⁺]=-13.847
==> [Fe²⁺]=1.42 * 10^-14 mol/l

[Juozukas]

E_C=-0.44 V + 0.059 V/2*lg [Fe²⁺]
E_A=-0.76 V + 0,059 V/2*lg(0.001) = -0.8485 V

E_C-E_A=-0.44 + 0.0295 lg [Fe²⁺] + 0.8485 = 0
==> lg [Fe²⁺]=-13.847
==> [Fe²⁺]=1.42 * 10^-14 mol/l

where did you get the 1.42 from?

[Kryolith]

lg x = y ==> x=10^y
10^-13.847=1.42 * 10^-14