Buffer Capacity (College)

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Buffer Capacity

Instructions: The following questions require the use of a calculator.

Which of the following correctly defines a buffer?

A solution that resists changes in pH when an acid is added
A solution that resists changes in pH when a base is added
A solution that allows changes in pH when an acid or a base is added
A solution that resists changes in pH when an acid or a base is added

Which of the following correctly defines buffering capacity?

The amount of protons a buffer can absorb without a change in pH
The amount of hydroxide ions a buffer can absorb without a change in pH
The amount of protons or hydroxide ions a buffer can absorb without a change in pH
None of the above

Which of the following equations represents the pH of the buffer?

[math][HA]/[A^-][/math]
1
[math][HA], only[/math]
[math][A^-]/[HA][/math]

At which of the following values for the pH of the buffer does optimal buffering occur?

Which of the following represents a viable buffer?

HCl and its salt
NaOH and its salt
Ammonia and its salt
None of the above

Which of the following does NOT represent a viable buffer solution?

Citric Acid/Sodium Citrate
Boric Acid/Borax
Carbonic Acid/Sodium Hydrogen Carbonate
None of the above

Which of the following equations can be used to calculate the concentration of hydrogen ions in a buffer solution?

[math][H^+] = K_a xx [[HA]]/[[A^-]][/math]
[math][H^+] = K_a xx [[A^-]]/[[HA]][/math]
[math][H^+] = {K_a xx [A^-]}/{[A^-] xx[HA]}[/math]
None of the above

Which of the following correctly represents the equation used to calculate the pH value of the buffer, based on the [math]K_a value[/math]?

[math]pH=pK_a+{log} [[A^-]]/[[HA]][/math]
[math]pH=pK_a-{log} [[A^-]]/[[HA]][/math]
[math]pH=pK_a+{log} [[HA]]/[[A^-]][/math]
[math]pH=pK_a-{log} [[HA]]/[[A^-]][/math]

If [math]K_b=1.81xx10^-5[/math] and a solution contains 6.00 mol of ammonia and 4.00 mol of ammonium chloride, determine the pH value of this solution.

10.

If [math]K_a=1.8xx10^-5[/math] for a buffer solution containing acetic acid, [acetate]=1.2 M, and [acetic acid]=0.82 M, determine the pH value of the buffer solution.