Solubility Lesson 7 Changing solubility

SolubilityLesson 7

Changing solubility

When to and When not to Multiply the Molarity 1. The molar solubility of Ba(OH)2 is 2. Equal volumes of 0.0010 M Ba(NO3)2 and 0.0010 M. Ksp = ? 0.0010 M NaOH are mixed. Will a

precipitate occur?

Ba(OH)2(s) ⇌ Ba2+ + 2OH- Ba(OH)2(s) ⇌ Ba2+ + 2OH-

s s 2s 10.0010 1 0.0010 M 2 2

0.00050 M 0.00050 M

Multiply by 2 because of Ba(OH)2(s) Do not multiply by 2 because of NaOH

Ksp = [Ba2+][OH-]2 TIP = [Ba2+][OH-]2

Ksp = [s][2s]2 TIP = [0.00050][0.00050]2

Ksp = 4s3

Ksp = 4[0.0010]3 TIP = 1.25 x 10-10

Ksp = 4.0 x 10-9 TIP < Ksp No ppt.

3. AgNO3(s) is added to 1.0 L of a solution containing Cl- in order to precipitate out the Cl- as AgCl(s). After the AgCl(s) is filtered out what is the remaining concentration of Cl-?

AgCl(s) ⇌ Ag+ +Cl-

s s s

Ksp = s2

1.8 x 10-10 = s2

s = [Cl-] = 1.3 x 10-5 M

Changing the Solubilty of a Salt

energy + AgCl(s) ⇄ Ag+ + Cl-



The molar solubility is the amount of AgCl(s) in moles per litre that dissolves into ions to form a saturated solution.



The molar solubility is the amount of AgCl(s) in moles per litre that dissolves into ions to form a saturated solution. If this equilibrium shifts to the right, the molar solubility increases.



The molar solubility is the amount of AgCl(s) in moles per litre that dissolves into ions to form a saturated solution. If this equilibrium shifts to the right, the molar solubility increases. If this equilibrium shifts to the left, the molar solubility decreases.



The molar solubility is the amount of AgCl(s) in moles per litre that dissolves into ions to form a saturated solution. If this equilibrium shifts to the right, the molar solubility increases. If this equilibrium shifts to the left, the molar solubility decreases. Like all equilibriums, only changing the temperature changes the Ksp.



The molar solubility is the amount of AgCl(s) in moles per litre that dissolves into ions to form a saturated solution. If this equilibrium shifts to the right, the molar solubility increases. If this equilibrium shifts to the left, the molar solubility decreases. Like all equilibriums, only changing the temperature changes the Ksp. Most solid equilibriums are endothermic.

Changing the Solubility of a Salt


Substance Added Effect on Molar Solubility Effect on Ksp AgNO3



Substance Added Effect on Molar Solubility Effect on Ksp AgNO3

Increases the [Ag+] and shifts the equilibrium left



Substance Added Effect on Molar Solubility Effect on Ksp AgNO3 Decrease none

NaCl




NaCl

Increases the [Cl-] and shifts the equilibrium left




NaCl Decrease none

Na2SIncreases the [Cl-] and shifts the equilibrium left




NaCl Decrease none

Na2S S2- is low solubility with Ag+ so they react and [Ag+] decreases




NaCl Decrease none

Na2S Increase none

Pb(NO3)2




NaCl Decrease none

Na2S Increase none

Pb(NO3)2Pb2+ is low solubility with Cl- so they react and [Cl-] decreases




NaCl Decrease none

Na2S Increase none

Pb(NO3)2 Increase none

H2O




NaCl Decrease none

Na2S Increase none


H2OThe molar solubility is the number moles per litre and therefore does not change when more water is added.




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl

AgCl is a solid that the solution is already saturated with and it does not change the solubility




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl none none

Increase Temperature




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl none none


Shifts to the right and increases the ksp




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl none none

Increase Temperature Increase Increase

Decrease Temperature




NaCl Decrease none

Na2S Increase none


H2O none none

AgCl none none






NaCl Decrease none

Na2S Increase none


H2O none none

AgCl none none


Decrease Temperature Decrease Decrease


Ca(OH)2(s) ⇄ Ca2+ + 2OH- Substance Added Effect on Molar Solubility Effect on Ksp Ca(NO3)2


Ca(OH)2(s) ⇄ Ca2+ + 2OH- Substance Added Effect on Molar Solubility Effect on Ksp Ca(NO3)2 Decrease none

Na2SO4



Na2SO4



Na2SO4 Increase none

NaOH




NaOH Decrease none

HCl




NaOH Decrease none

HCl Increase none

NaCl




NaOH Decrease none

HCl Increase none

NaCl none none

Ca(OH)2




NaOH Decrease none

HCl Increase none

NaCl none none

Ca(OH)2 none none





NaOH Decrease none

HCl Increase none

NaCl none none

Ca(OH)2 none none






NaOH Decrease none

HCl Increase none

NaCl none none

Ca(OH)2 none none


Decrease Temperature Decrease Decrease

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Solubility Lesson 7 Changing solubility