solubility equlibrium 18.4. so what can the k expression be used for?

SOLUBILITY EQULIBRIUM

18.4

18.4So what can the K expression be used for?

18.4The K expression is used for any reversible

reaction: Kw is used for the ionization of water into

H3O+ and OH-

Ka is used for the ionization of weak acids

Kb is used for the ionization of weak bases

Ksp is used for the dissolving of a solid

18.4In all cases: K = products/reactants Only ions in solution or gases are part of

the equation The larger the K value, the more products

are produced and the more the forward reaction is favored.

18.4What is Ksp?

AgCl(s) Ag1+(aq) + Cl1-(aq)

So if the Ksp is large, is it more or less soluble?

18.4Ksp is the solubility product constant.

It is used to quantitatively determine how much of a solid will dissolve.

It also gives the concentrations of ions in a saturated solution.

The larger the K value, the more ions form and the more it dissolves in water.

18.4Ksp is the solubility product constant.

p. 615 What ions are missing from this chart? Why?What connection is there between this chart

and the pink sheet solubility rules?The bigger the Ksp the more soluble or less

soluble?If a solution’s ions are at Ksp what word can

be used to describe it?

18.4Example 1: Write Ksp expressions for the

solvation of the following salts.MgCO3

Fe(OH)3

Ag2CO3

18.4Example 2: Which of the above is the most

soluble? Least soluble?

18.4Example 3: It is determined that 0.0781

g/L of BaC2O4 dissolves in water. What is the Ksp?

18.4Example 4: The solubility of Pb(IO3)2 is 4.0

x 10-5 mol/L. What is the Ksp of this salt?

18.4Example 5: What is the molarity of the ions

of AgCl in water?

18.4Example 6: What is the molar solubility of

Ag2CrO4 in water? Ksp of Ag2CrO4 is 1.9 x 10-12.

18.4Example 7: The solubility of Ag2SO4 in

water is 4.99 g/L. What is the Ksp of this salt?

18.4Example 8: How many grams of CaSO4 can

dissolve in 600 mL of water?

18.4The real value of Ksp comes in determining

if there are enough ions present to form a precipitate.

18.4The real value of Ksp comes in determining

if there are enough ions present to form a precipitate.

If a precipitate forms then the solution must be saturated.

18.4What is the ion product?

18.4The ion product is a measurement of the

ions dissolved in solution.

18.4The ion product is a measurement of the

ions dissolved in solution.

If the ion product is larger than Ksp then there are more ions than should be and a precipitate will form.

If the ion product is smaller than Ksp then there are not enough ions dissolved and no precipitate will form.

If the ion product equals Ksp then the solution is exactly saturated.

18.4Example 9: Would a precipitate form if 5.0

x 10-2 mol of AgNO3 and 1.0 x 10-3 mol of NaC2H3O2 are dissolved in 1.0 L of solution?

18.4Example 10: Would a precipitate form if a

0.010 M solution of Pb(NO3)2 is mixed with a 0.010 M HCl solution?

18.4Example 11: Will a precipitate form when

0.025 M CaCl2 is mixed with 0.0050 M Na2CO3?

18.4Example 12: Will a precipitate form when

100 mL of a 0.0030M Pb(NO3)2 solution is mixed with 400 mL of 0.040 M Na2SO4?

CHAPTER 18 TEST NOTES20 multiple choice (3 points each)8 problems (5 points each)1 extra credit (5 points)

CHAPTER 18 TEST NOTESLe Chatelier’s Principle

Use it to predict which way the system will move to

compensate for being stressedTemperatureConcentrationpressure

Figuring K values (K, Ka, Kb, Ksp, or ion product) gases and aqueous solutions only included [ ] = M bigger the K value, the more products are

formed coefficients become powers Don’t forget to use ICE box for Ka or Kb

CHAPTER 18 TEST NOTESWriting equations

acid/base conjugate pairsBuffers

Use equations to explain how they workComparing ion product to Ksp