aqueous solutions and solubility equilibria chapter 9
TRANSCRIPT
![Page 1: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/1.jpg)
Aqueous Solutions and Solubility Equilibria
Chapter 9
![Page 2: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/2.jpg)
9.1 The Acid-Base Properties of Salt Solutions
• Salt: any ionic compound that is formed in a neutralization reaction from the anion of an acid and the cation of a base.
E.g. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
![Page 3: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/3.jpg)
• The acid/base property of a salt results from reactions between water and the dissociated ions of the salt. – Ion that react with water produce a solution with
excess H30+ or OH
![Page 4: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/4.jpg)
Salts that form Neutral Solutions
• Salts of strong bases and strong acids dissolve in water and form neutral solutions.– The conjugate bases of strong acids are very
___________.– The conjugate acids of strong bases are very
___________.E.g.
Neither ion will react with water: too weak!
![Page 5: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/5.jpg)
Salts the Dissolve and form Acidic and Basic Solutions
• Salts of weak bases and strong acids dissolve in water and form acidic solutions.
• Salts of strong bases and weak acids dissolve in water and form basic solutions.
(LOOKING AT THE CONJUGATE ACIDS/BASES!)
![Page 6: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/6.jpg)
Salts of Weak Acids and Bases
• Ions in a salt from weak acids and bases BOTH react with water.
• Acidity/basicity depends on relative strength of the ions.
• Determine which ion is stronger by comparing the Ka and Kb associated with the cation and anion.
• If Ka>Kb, acidic. If Kb>Ka, basic.
![Page 7: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/7.jpg)
![Page 8: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/8.jpg)
![Page 9: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/9.jpg)
![Page 10: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/10.jpg)
CLASSWORK/HOMEWORK
Read through SP on pg. 423. Make notes.Do PPs 1-3.
![Page 11: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/11.jpg)
Calculating pH at Equivalence
• Equivalence point: just enough acid and base have been mixed for complete reaction to occur, with no excess of either reactant.
• Acid-base indicator: weak, monoprotic acid. It is in equilibrium between undissociated acid (one colour) and conjugate base (different colour)
• End-point: indicator changes colour.
![Page 12: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/12.jpg)
![Page 13: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/13.jpg)
![Page 14: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/14.jpg)
![Page 15: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/15.jpg)
PPs 8 & 9
![Page 16: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/16.jpg)
SR (pg. 429) #2, 6, 7.
![Page 17: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/17.jpg)
9.2 – Solubility Equilibria
![Page 18: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/18.jpg)
Solubility as an Equilibrium Process
• Change in enthalpy, entropy, and temperature determine whether or not a change is favoured.
• Same is important to determine how much salt will dissolve.
![Page 19: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/19.jpg)
![Page 20: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/20.jpg)
• Change is favoured when G is negative. • When salt dissolves, entropy is increased.
![Page 21: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/21.jpg)
Ex// Barium sulfate crystals in water:
As ions enter solution, rate of reverse change, recrystallisation, increases.
Eventually, rate of recrystallisation becomes equal to the rate of dissolving.
![Page 22: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/22.jpg)
Solubility Equilibria
• Equilibrium exists between the solid ionic compound and its dissociated ions in solution.
![Page 23: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/23.jpg)
Solubility Product Constant
![Page 24: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/24.jpg)
Solubility product constant: Ksp!!!
![Page 25: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/25.jpg)
![Page 26: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/26.jpg)
![Page 27: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/27.jpg)
![Page 28: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/28.jpg)
![Page 29: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/29.jpg)
• PPs 13, 15
![Page 30: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/30.jpg)
Using the Solubility Product Constant
• Use the value of Ksp for a compound to determine the concentration of its ions in a saturated solution.
• Similar to finding equilibrium amounts using Kc for homogeneous equilibria.
![Page 31: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/31.jpg)
![Page 32: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/32.jpg)
WORK ON PPs 17, 18, 19,
![Page 33: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/33.jpg)
The Common Ion Effect
• When ionic compound added to a solution that already contains one of its ions.
• Adding a common ion to a solution increases the concentration of that ion in solution – EQUILIBRIUM SHIFTS AAWY FROM THE ION. – Can form precipitates.
![Page 34: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/34.jpg)
![Page 35: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/35.jpg)
The Effect of a Common Ion on Solubility
![Page 36: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/36.jpg)
• Work on PPs 21-23
![Page 37: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/37.jpg)
9.3Predicting the Formation of a Precipitate
The Ion Product: Qsp: expression that is identical to the solubility product constant, but values are not necessarily at equilibrium.
(Where have we seen this before?)
![Page 38: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/38.jpg)
E.g.
- Adding magnesium sulfate to water. - Initially, all magnesium sulfate dissolves. - Saturation: no more salt will dissolve. - More solid will form.
![Page 39: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/39.jpg)
- Calculate Qsp by substituting the conc. Of each ion into the expression.
![Page 40: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/40.jpg)
Using the Ion Product Expression
• If Qsp > Ksp, compound will form an ionic compound.
• How do we know which ionic compounds are soluble?
![Page 41: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/41.jpg)
![Page 42: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/42.jpg)
E.g.
![Page 43: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/43.jpg)
![Page 44: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/44.jpg)
• PPs 29, 30, 31
![Page 45: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/45.jpg)
![Page 46: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/46.jpg)
• PPs. 33, 34, 35
![Page 47: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/47.jpg)
Test Review
![Page 48: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/48.jpg)
Buffers and the Common Ion Effect
• A buffer consists of a ________________________ and a ________________________ or vise versa.
• Need to consider initial concentration of reactants since homogeneous.
![Page 49: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/49.jpg)
![Page 50: Aqueous Solutions and Solubility Equilibria Chapter 9](https://reader031.vdocuments.us/reader031/viewer/2022013103/56649f145503460f94c295d2/html5/thumbnails/50.jpg)