The document discusses solubility equilibria and the solubility product constant (Ksp). It defines Ksp as the product of the equilibrium concentrations of ions from a dissolving salt. Examples are provided to demonstrate calculating Ksp from solubility data and vice versa. The key points are that according to Ksp, all salts are slightly soluble, and Ksp values can be used to compare the relative solubilities of different salts that produce the same or different number of ions.

1. Solubility & Equilibrium
Ksp

2. Solubility & Equilibrium
• The beginning
XY(s) ==> X+ + Y-

3. Solubility & Equilibrium
• The beginning
XY(s) ==> X+ + Y-
As time continues the [ions] begins to
increase.

4. Solubility & Equilibrium
Greater the chance that they will collide
and reform
• XY(s) <== X+ + Y-
• When it becomes saturated it reaches
equilibrium.
XY(s) <==> X+ + Y-

5. Solubility & Equilibrium
Equilibrium Constant for Solubility-Ksp
Ksp = [X+]x [Y-]y
 Solubility = molar solubility = mol/L
• Be careful ~ sometimes given g/L or have to solve
for g/L

6. Solubility & Equilibrium
Equilibrium Constant for Solubility-Ksp
Ksp = [X+]x [Y-]y
1) Just ions, no solids

7. Solubility & Equilibrium
Equilibrium Constant for Solubility-Ksp
Ksp = [X+]x [Y-]y
2) It doesn’t matter if you have stuff on
the bottom.

8. Solubility & Equilibrium
Equilibrium Constant for Solubility-Ksp
Ksp = [X+]x [Y-]y
3) Not solubility - that’s an equilibrium
position(Q) (will more dissolve or not?)

9. Solubility & Equilibrium
Equilibrium Constant for Solubility-Ksp
Ksp = [X+]x [Y-]y
4) Equilibrium so remember ICE

10. Ksp Calculations
The solubility of copper (I) bromide is 2.0
x 10-4 mol/L at 25 C. Calculate Ksp.

11. Ksp Calculations
The solubility of copper(I) bromide is 2.0
x 10-4 mol/L at 25°C. Calculate Ksp.
CuBr(s) <==> Cu+1 + Br-1
I 0 0
C + x + x
E 2.0 x10-4 2.0 x 10-4

12. Ksp Calculations
The solubility of copper(I) bromide is 2.0
x 10-4 mol/L at 25°C. Calculate Ksp.
CuBr(s) <==> Cu+1 + Br-1
Ksp = [2.0 x10-4][2.0 x 10-4]
= 4.0 x 10-8 (no units for K)

13. Ksp Calculations – Your Turn
• The solubility of silver phosphate is
1.60 x 10-5 M. Calculate its Ksp.

14. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
I

15. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
I 0 0
C

16. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
I 0 0
C +x +2x
E

17. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
I 0 0
C +x +2x
E +x +2x

18. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
Ksp = [Cu+2][IO3
-]2

19. Ksp Calculations
The Ksp value of copper(II) iodate is
1.4 x 10-7 at 25°C. Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
Ksp = [Cu+2][IO3
-]2
Ksp = [x][2x]2

20. Ksp Calculations
The Ksp value of copper(II) iodate is 1.4 x 10-7 at 25°C.
Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
Ksp = [Cu+2][IO3
-]2
Ksp = [x][2x]2
1.4 x 10-7 = [x][2x]2

21. Ksp Calculations
The Ksp value of copper(II) iodate is 1.4 x 10-7 at 25°C.
Calculate its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
Ksp = [Cu+2][IO3
-]2
Ksp = [x][2x]2
1.4 x 10-7 = [x][2x]2
1.4 x 10-7 = 4x3

22. Ksp Calculations
The Ksp value of copper(II) iodate is 1.4 x 10-7 at 25°C. Calculate
its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
Ksp = [Cu+2][IO3
-]2
Ksp = [x][2x]2
1.4 x 10-7 = [x][2x]2
1.4 x 10-7 = 4x3
x = 3.3 x 10-3 mol/L

23. Ksp Calculations
The Ksp value of copper(II) iodate is 1.4 x 10-7 at 25°C. Calculate
its solubility.
Cu(IO3)2(s) <==> Cu+2 + 2 IO3
-
[Cu+2] = 3.3 x 10-3 mol/L
[IO3
-] =2(3.3 x 10-3 mol/L) = 6.6 x 10-3 mol/L

24. Ksp Calculations – Your Turn
• The Ksp of mercury (II) sulfide is
1.6 x 10-54. Find its molar solubility.

25. Ksp Calculations
What does it all mean?
According to Ksp, EVERYTHING is at least very, very,
very, very slightly soluble.
Looking at the Ksp can help you figure out the solubility
of compounds compared to each other – with a couple
key rules about doing it!

26. Ksp Calculations
What does it all mean?
1) Salts that produce the same # of ions can
be compared to see which one is the
most/least soluble.
AgBr vs AgI vs AgCl
Ksp values 5.0x10-13 1.5x10-16 1.6x10-10
Appendix A25

27. Ksp Calculations
What does it all mean?
2) If the salts break into different # of ions,
you can’t just look. Must calculate.

28. Ksp Calculations
2 example problems:
Which is more soluble:
copper (II) carbonate or cadmium carbonate?
Ksp = 2.5 x 10-10 Ksp = 5.2 x 10-12

29. Ksp Calculations
2 example problems:
Which is more soluble:
tin (II) hydroxide or strontium phosphate?
Ksp = 3.0 x 10-27 Ksp = 1.0 x 10-31