Chapter 16 Lecture Outline
16.1 The Danger of Antifreeze
16.2 Buffers: Solutions That Resist pH Change
Introduction to Buffers
16.3 Buffer Effectiveness: Buffer Range and Buffer Capacity
- Calculate for a 0.1 M acetic acid/0.1 M sodium acetate buffer. Solution
- Effect of adding a base to a generic weak acid. (mathcad)
- Add 0.05 moles of sodium hydroxide to 1 liter of acetic acid buffer. (Solution)
- Add 0.05 moles of sodium hydroxide to 1 liter of water.
- Formic acid buffer
- 10.0 mL of 1.0 M formic acid is mixed with 1.00 g of sodium formate and diluted to 250.0 mL.
- Add 5.0 mL of 1.0 M sodium hydroxide to the formic acid/sodium formate solution.
- Add 5.0 mL of 2.0 M hydrochloric acid to the formic acid/sodium formate solution.
- Solutions
- Graph results of adding acid or base to a buffer with spreadsheet
16.4 Titrations and pH Curves
Acid base titration video clip (internet © Saunders, 1997)
Strong Acid-Strong Base Titration
- Strong Acid Titration Problem
- Start with 50.0 mL of 0.100 M HCl, Calculate pH (on board)
- Add 1 mL 0.200 M NaOH, Calculate pH (on board)
- Add 5 mL 0.200 M NaOH, Calculate pH (Group 1)
- Add 10 mL 0.200 M NaOH, Calculate pH (Group 2)
- Add 15 mL 0.200 M NaOH, Calculate pH (Group 3)
- Add 20 mL 0.200 M NaOH, Calculate pH (Group 4)
- Add 25 mL 0.200 M NaOH, Calculate pH (Class first, then on board)
- Add 26 mL 0.200 M NaOH, Calculate pH (Class first, then on board)
- Add 30 mL 0.200 M NaOH, Calculate pH (Group 1)
- Add 50 mL 0.200 M NaOH, Calculate pH (Group 2)
- Summerize results
mL 0.100 M HCl |
mL 0.200 M NaOH |
pH |
50 |
0 |
1.00 |
50 |
1 |
1.03 |
50 |
5 |
1.14 |
50 |
10 |
1.30 |
50 |
15 |
1.51 |
50 |
20 |
1.84 |
50 |
25 |
7.00 |
50 |
26 |
11.42 |
50 |
30 |
12.10 |
50 |
50 |
12.70 |
- Show graph in spreadsheet.
- Solutions
Titration of a weak acid
- Calculate for 100.0 mL of 0.1 M acetic acid solution.
- Add 1 mL of 0.1 M sodium hydroxide.
- Add 10 mL of 0.1 M sodium hydroxide.
- Add 50 mL of 0.1 M sodium hydroxide.
- Add 75 mL of 0.1 M sodium hydroxide.
- Add 100 mL of 0.1 M sodium hydroxide.
- Add 110 mL of 0.1 M sodium hydroxide.
- Graph results with Spreadsheet
- Solutions
Graphical Review of titrations
- Effect of concentration and Ka on Titration curves
- 0.1 M Strong Acid, 0.1 M Weak acid (Ka = 1.8x10-5, 0.1 M NaOH)
- 0.1 M Strong Acid, 0.1 M Weak acid (Ka = 1.8x10-7, 0.1 M NaOH)
- 0.1 M Strong Acid, 0.1 M Weak acid (Ka = 1.8x10-9, 0.1 M NaOH)
- 0.01 M Strong Acid, 0.01 M Weak acid (Ka = 1.8x10-5, 0.1 M NaOH)
- Spreadsheet
16.5 Solubility Equilibria and the Solubility Product Constant
- Introductiion to Solubility
- Soluble Salts: NaCl (s) --> Na1+ (aq) + Cl1- (aq) (
internet
© Saunders, 1997)
- Insoluble Salts: Pb2+(aq) + 2 I1-(aq) --> PbI2(s). (
internet
© Saunders, 1997)
- Equlibrium: PbCl2(s) <--> Pb2+(aq) + 2 Cl1-(aq). (
internet
© Saunders, 1997)
- Measuring Pb2+ ions by AA (
internet
© Saunders, 1997)
- Shifting Equlibrium
- Dilute Ag1+ and Cl1-(
internet
© Saunders, 1997)
- Concentrated Ag1+ and Cl1-(
internet
© Saunders, 1997)
- Adding Cl1- stepwise to Pb2+ (
internet © Saunders, 1997
- Qualitative Analysis:
internet
© Saunders, 1997
- Conversion of PbCl2 to PbCrO4 (
internet
© Saunders, 1997
Animation
internet
© Saunders, 1997)
Solubility Equlibrium Problems
- Molar Solubility. 9.3x10-3 g of CaCO3 dissolves in 1 L of water. What is the "molar solubility" Solutions
- What is Ksp for CaCO3? Solutions
- How much AgCl will dissolve in 500 mL of water? Ksp = 1.56 x 10-10 Solutions
- How much PbCl2 will dissolve in 500 mL of water? Ksp = 1.6 x 10-5. Solutions
- Given Ksp = 1.5 x 10-11 for Mg(OH)2
- Calculate the mass of Mg(OH)2 that will dissolve in 250 mL of water.
- Calculate the mass of Mg(OH)2 that will dissolve in 250 mL of water with the pH buffered to 13.
- Calculate the mass of Mg(OH)2 that will dissolve in 250 mL of water with the pH buffered to 4.
- Solutions
- For AgCl, Ksp = 1.56 x 10-10
- What is the solubility in water
- What is the solubility in 0.10 M NaCl
- What is the solubility in 1.0 M NaCl
- What happens when 50 mL of 1.0 x10-4 M NaCl is added to 50 mL of 1.0x10-6 M AgNO3.
- Increase the concentration of NaCl to 0.50 M and repeat.
- Solutions
- For PbCl2, Ksp = 1.6 x 10-5
- What is the solubility in water
- What is the solubility in 0.10 M NaCl
- What is the solubility in 1.0 M NaCl
- What happens when 50 mL of 0.20M NaCl is added to 50 mL of 1.0x10-4 M Pb(NO3)2.
- Increase the concentration of NaCl to 2.0 M and repeat.
- Solutions
- Given a solution containing Ba2+ and Fe2+, Start at pH 1 and adjust the pH so that:
- The first ion begins to precipitate
- The second ion begins to precipitate
- How much of the first has precipitated at this point?
- How much of the second ion has precipitated at pH 14?
- Solutions
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Widener University
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This page has been accessed
times since 5/30/97.
Last Updated Friday, May 25, 2001 1:59:43 PM