Solubility & Equilibrium Ksp

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

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

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-

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

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

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

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?)

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

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

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 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 E

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

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

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)

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

Ksp Calculations Cu(IO3)2(s) <==> Cu+2 + 2 IO3- I 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

Ksp Calculations Cu(IO3)2(s) <==> Cu+2 + 2 IO3- I 0 0 C 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

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 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

Ksp Calculations Cu(IO3)2(s) <==> Cu+2 + 2 IO3- I 0 0 C +x +2x 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

Ksp Calculations Cu(IO3)2(s) <==> Cu+2 + 2 IO3- 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 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

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

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

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+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

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

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

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!

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 5.0x10-13 1.5x10-16 1.6x10-10 Appendix A25

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

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

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