Solubility Unit III Lesson 1

Solubility is a measure of the maximum amount of solid that will dissolve in a volume of water. Units: g/L mol/L g/100mL Or even: mL/L for CO2(g) in water The unit must have an amount on the top and volume on the bottom! In order to determine the solubility you must completely fill or saturate the solution! To saturate the solution you must add weighed portions of the solid to a given volume of water and stir until no more will dissolve. A small amount of excess solid will be present in the saturated solution.

Determining The Solubility of NaCl Add measured portions of NaCl and stir to dissolve NaCl 10.0 g Take 100 mL of water

Determining The Solubility of NaCl

Determining The Solubility of NaCl The solution is stirred and it all dissolves NaCl

Determining The Solubility of NaCl The solution is stirred and it all dissolves NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Rate of dissolving > Rate of crystallization Na+ Cl-

Determining The Solubility of NaCl Add more since the solution is not full Amount NaCl Dissolved 10.0 g NaCl 10.0 g Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g NaCl Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Rate of dissolving > Rate of crystallization Na+ Cl-

Determining The Solubility of NaCl Add more since the solution is not full Amount NaCl Dissolved 10.0 g NaCl 10.0 g Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g NaCl Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Rate of dissolving > Rate of crystallization Na+ Cl-

Determining The Solubility of NaCl Add more since the solution is not full Amount NaCl Dissolved 10.0 g NaCl 3.0 g Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g NaCl Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g The solution is stirred and it all dissolves Na+ Cl- NaCl

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g 3.0 g The solution is stirred and it all dissolves Rate of dissolving > Rate of crystallization Na+ Cl-

Determining The Solubility of NaCl Add more since the solution is not full Amount NaCl Dissolved 10.0 g 3.0 g NaCl 1.0 g Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g 3.0 g NaCl Na+ Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g 3.0 g Na+ NaCl Cl-

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g 3.0 g 33.0 g/100 mL The solution is stirred and it does not dissolve! The solution is full or saturated. Na+ Cl- A bit of solid (1 g) sits on the bottom NaCl(s) Rate of dissolving = Rate of crystallization

Determining The Solubility of NaCl Amount NaCl Dissolved 10.0 g 3.0 g 33.0 g/100 mL The solution is stirred and it does not dissolve! The solution is full or saturated. Na+ Cl- NaCl(s) A bit of solid sits on the bottom This tells you that the solution is saturated and that it is in equilibrium Rate of dissolving = Rate of crystallization

Calculate the solubility in units of g/L and mole/L. Solubility = 33.0 g 0.100 L = 330. g/L s = molar solubility = the molarity to saturate = 33.0 g x 1 mole 58.5 g = 5.60 M

Na+ Cl- NaCl(s) 33.0 g/100 mL A bit of solid sits on the bottom This tells you that the solution is saturated and that it is in equilibrium Since this is an equilibrium lets write the Equilibrium Equation: NaCl(s) ⇌ Na+ + Cl- Expression: Keq = [Na+][Cl-] do not count a solid! Because this Keq is special and based on the solubility of a solid it is called a solubility product or Ksp. Ksp = [Na+][Cl-]

This unit is all about the Ksp and the solubility of saturated solutions.

Equilibrium Expressions for Saturated Solutions Write the equation for equilibrium present in a saturated solution of Al2(SO4)3 solution. Al2(SO4)3(s) ⇌ 2Al3+ + 3SO42- Write the equilibrium expression or solubility product Solubility Product = Ksp = [Al3+]2[SO42-]3

Equilibrium Expressions for Saturated Solutions Write the equation for equilibrium present in a saturated solution of Al2(SO4)3 solution. Ca3(PO4)2(s) ⇌ 3Ca2+ + 2PO43- Write the equilibrium expression or solubility product Solubility Product = Ksp = [Ca2+]3[PO43-]2

There are three types of solutions.   Unsaturated Contains less than the maximum amount of dissolved solid Not at equilibrium Add more solid and it will dissolve The rate of dissolving > the rate of crystallizing

There are three types of solutions. Saturated Contains the maximum amount of dissolved solid At equilibrium Add more solid and it does not dissolve The rate of dissolving is equal to the rate of crystallization

There are three types of solutions. Supersaturated   Contains more than the usual maximum amount of dissolved solid Not at equilibrium Add more solid and more solid precipitates The rate of dissolving is less than the rate of crystallization

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4 High H2SO4

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4 High H2SO4 High Ca(NO3)2  

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4 High H2SO4 High Ca(NO3)2 High CaSO4

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4 High H2SO4 High Ca(NO3)2 High CaSO4 Low FeSO4

What we just calculated was exact solubility. The data book page 4 gives us relative solubility. High Solubility means > .1 M Low Solubility means  .1M   Classify as high or low solubility. Na3PO4 High H2SO4 High Ca(NO3)2 High CaSO4 Low FeSO4 High

Classify as high or low solubility.   Ag2SO4

Classify as high or low solubility.   Ag2SO4 low CuSO4

Classify as high or low solubility.   Ag2SO4 low CuSO4 high CuCl2

Classify as high or low solubility.   Ag2SO4 low CuSO4 high CuCl2 high CuCl

Classify as high or low solubility.   Ag2SO4 low CuSO4 high CuCl2 high CuCl low BaS

Classify as high or low solubility.   Ag2SO4 low CuSO4 high CuCl2 high CuCl low BaS high K2CO3  

Classify as high or low solubility.   Ag2SO4 low CuSO4 high CuCl2 high CuCl low BaS High K3CO3   high

See notes “Solubility Charts/Qualitative Analysis” Do Hebden p. 81-83 #21, 22, 24 Hebden p. 90 #26, 27,31,32,35, 37,38”