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 Br-1

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 Br-1 I C E

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

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

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

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

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

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

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

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

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

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

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 IO3-
Ksp = [Cu+2][IO3-]2
Ksp = [x][2x]2
1.4 x 10-7 = [x][2x]2

24. 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 IO3-
Ksp = [Cu+2][IO3-]2
Ksp = [x][2x]2
1.4 x 10-7 = [x][2x]2
1.4 x 10-7 = 4x3

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

26. 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 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

27. Ksp Calculations – Your Turn
The Ksp of mercury (II) sulfide is x Find its molar solubility.

28. 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!

29. Ksp Calculations What does it all mean?
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 5.0x x x10-10
Appendix A25

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

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

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