If given the following solubilities, how do you calculate the #K_(sp)# for each compound?

Question

(a) #CuSCN#, 5.0 mg/L
(b) #SnS#, 2.0 x #10^-5# g/L
(c) #Co(OH)_2#, 3,2 x #10^3# g/L
(d) #Ag_2CrO_4#, 3.4 x #10^-2# g/L?

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Answer 1 · 2018-06-02T20:40:19

I will do you ONE example.....#d.#

We examine the solubility equilibrium...

#Ag_2CrO_4(s) stackrel(H_2O)rightleftharpoons2Ag^+ + CrO_4^(2-)#

For which we write the solubility expression....

#K_"sp"=[Ag^+]^2[CrO_4^(2-)]#

But if #S="solubility of silver chromate..."#, then #[Ag^+]=2S#, and #[CrO_4^(2-)]=S#...thus #K_"sp"=(2S)^2S=4S^3#...

Now #S=((3.4xx10^-2*g)/(331.73 *g*mol^-1))/(1*L)=1.0025xx10^-4*mol*L^-1#...

#K_"sp"=4xx(1.0025xx10^-4)^3=4.03xx10^-12#.

When you do the others perhaps you might post the solutions in this thread?