CHEM1112 Lecture Notes - Lecture 23: Lead, Chemical Equation, Sodium Chloride
19 May 2018
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Professor
Identify what determines solubility in terms of bonding forces
23.1
Sunday, 29 October 2017
12:18 AM
23. Solubility Equilibrium Page 1
Construct Ksp from the chemical equation for dissolution
Calculate solubility from Ksp values for salts according to their
formula
Solution is saturated
○
Solubility is maximum amount that will dissolve
○
When dissolving a solid in solution, equilibrium refers to as much solid has dissolved as
possible
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>0.1M = soluble
➢
<1.0 x 10-3 = insoluble
➢
Intermediate cases = moderately soluble
➢
If solubility
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e.g. solubility of magnesium hydroxide is 9.63 g/L or 1.65 x 10-3 M
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Screen clipping taken: 2/11/2017 9:06 AM
Equilibrium
Solubility equilibria presented as dissolution processes
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e.g.
Screen clipping taken: 2/11/2017 9:08 AM
Since the conc of a pure solid is taken to be constant, the equilibrium constant is
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Ksp = [product A]a[product B]b
High Ksp value = high solubility
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So in this case
Screen clipping taken: 2/11/2017 9:09 AM
Pb2+ and Cl- are present in the same solution at the same time, their concs can NEVER
be large enough so Q > Ksp
➢
Ksp
Solubility from Ksp
23.2, 23.3
Sunday, 29 October 2017
12:18 AM
23. Solubility Equilibrium Page 2
Solubility from Ksp
Screen clipping taken: 2/11/2017 9:11 AM
From chem eqn let [Pb] = x and [Cl-]2= 2x
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So…
At times may need to use quadratic eqn, or cancel out small values of x
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23. Solubility Equilibrium Page 3
Document Summary
Identify what determines solubility in terms of bonding forces: solubility equilibrium page 1. Construct ksp from the chemical equation for dissolution. Calculate solubility from ksp values for salts according to their formula. When dissolving a solid in solution, equilibrium refers to as much solid has dissolved as possible. Intermediate cases = moderately soluble e. g. solubility of magnesium hydroxide is 9. 63 g/l or 1. 65 x 10-3 m. Solubility equilibria presented as dissolution processes e. g. screen clipping taken: 2/11/2017 9:08 am. Since the conc of a pure solid is taken to be constant, the equilibrium constant is. Pb2+ and cl- are present in the same solution at the same time, their concs can never be large enough so q > ksp. Solubility from ksp: solubility equilibrium page 2. From chem eqn let [pb] = x and [cl-]2 = 2x. At times may need to use quadratic eqn, or cancel out small values of x: solubility equilibrium page 3.
