Question

What is the Keq ? ?

Answer 1

`sf(K=2.2xx10^6)`

Explanation:

We can reverse both equations then add:

`sf(Cu(NH_3)_4^(2+)rightleftharpoonsCu^(2+)+4NH_3)`

`sf(K_1=1/K_(f)=1/(2.1xx10^(13))=0.476xx10^(-13))`

`sf(Cu^(2+)+2OH^(-)rightleftharpoonsCu(OH)_2)`

`sf(K_2=1/K_(sp)=1/(2.2xx10^(-20))=0.4545xx10^(20))`

Adding the two equations give us the one we want:

`sf(Cu(NH_3)_4^(2+)+cancel(Cu^(2+))+2OH^(-)rightleftharpoonscancel(Cu^(2+))+4NH_3+Cu(OH)_2)`

For which we can say:

`sf(K=K_1xxK_2=0.476xx10^(-13)xx0.4545xx10^(20)=2.16xx10^(6))`