[hotvince]

Calculate the concentration of Cu⁺² in 1.0 L of a solution that contains a total of 1 x 10^-3 mol of copper(II) ion and that is 0.10 M in NH3.

Cu⁺² + 4NH₃ --> Cu(NH₃)₄⁺² K_f= 5.0 x 10¹²

[Rabn]

Let us know what your approach is and post any work you have done thus far.  Getting the answer isn't as important as understanding the reasoning behind it.

[hotvince]

First, I switched the equation.

So my new equation is : Cu(NH₃)₄⁺²--> Cu⁺²+4NH₃⁺

and my new K_f is 2 x 10 ^-13

Then I attempted to solve for [Cu⁺²] by using the following equation

K_f=[NH₃]⁴[Cu⁺²]                                                   

     [Cu(NH₃)₄⁺²]

So I did (2 x 10^-13) = (0.10)⁴(x)
                            (1 x 10^-13 -x)

The answer I got was 2 x 10 ^-22, but the correct answer is 2 x 10^-12

[Rabn]

If you used the equation you posted you need to double check your numbers for correctness. Otherwise your good.