7. Calculate the solubility of Cu(N3)2 in water in grams per litre, where the Ksp = 6.3 x 10-10.

Equilibrium equation:

Cu(N3)2 (s) Cu2+ (aq) + 2 N3- (aq)

6.3 x 10-10 = (x)(2x)2 = 4x3

After solving for x we get x = 5.4 x 10-4 = [ Cu2+ ], which also equals [ Cu(N3)2 ].

To find the solubility of Cu(N3)2 in grams per litre, we need to change {moles} / {L} to {g} / {L}. To do this, we multiply the molarity of Cu(N3)2 by:

a) the solubility of Cu2+
b) the molarity of Cu2+
c) the molecular weight of Cu(N3)2
d) the density of (N3-)2