1. Differentiate the following: a. pH from pOH ____________________________________________________________________________________________________________________________________________________________ b. Ka from Kb ____________________________________________________________________________________________________________________________________________________________ c. Pka from Pkb ____________________________________________________________________________________________________________________________________________________________ d. Kw from pKw
1. Differentiate the following:
a. pH from pOH
____________________________________________________________________________________________________________________________________________________________
b. Ka from Kb
____________________________________________________________________________________________________________________________________________________________
c. Pka from Pkb
____________________________________________________________________________________________________________________________________________________________
d. Kw from pKw
____________________________________________________________________________________________________________________________________________________________
2. What is the importance of buffer systems in the human body?
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
3. What is the Henderson-Hasselbalch equation?
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4. What are the approximate pH ranges and color changes of the following dyes?
|
Indicator |
pH range |
Color change |
|
Thymol blue (acid range) |
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Bromphenol Blue |
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Bromcresol Green |
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Bromcresol Purple |
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Phenol Red |
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Thymol Blue (Alkaline range) |
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Methyl red – Methylene Blue |
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Methyl orange |
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Phenolphthalein |
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5. How is the assigned buffer prepared? Write your computations and encircle the amount of solute needed.
6. Determination of buffer capacity
|
Buffer solution |
Desired pH |
Volume added |
Buffer capacity |
||
|
0.10 M HCl |
0.10M NaoH |
Acid added |
Base added |
||
|
1 |
3.0 |
|
|
|
|
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2 |
4.0 |
|
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3 |
6.0 |
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4 |
8.0 |
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5 |
9.50 |
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6 |
9.0 |
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7 |
13.0 |
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a. What is the most effective buffer against acids?
____________________________________________________________________________________________________________________________________________________________________________
b. What is the most effective buffer against bases?
____________________________________________________________________________________________________________________________________________________________________________
c. What is the most effective buffer against either acids or bases?
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