Week 11 Flashcards

1
Q

NaCN

A

The salt of NaOH (strong base) and HCN (weak acid).
* The base “wins”: pH > 7

Overall reaction is:
* H2O(aq) + CN-(aq) ⟺ OH-(aq) + HCN(aq)

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2
Q

NH4Cl

A

Salt of NH4OH (weak base) and HCl (strong acid)
* Acid “wins”: pH < 7 and reaction is
* H2O(aq) + NH4+(aq) ⟺ NH3(aq) + H3O+(aq)

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3
Q

If you add the salt of an acid to a solution of the same acid ….

A

then the equilibrium will shift towards neutral

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4
Q

A buffer solution

A

an acid or a base aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa

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5
Q

Buffer capacity

A

Amount of strong acid or base that can be added without causing significant pH change.
* Depends on amount of acid & conjugate base in solution

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6
Q

Most effective buffers have acid/base ratio…

A

less than 10 and more than 0.1 ⇒ pH range is ±1

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7
Q

pH control is essential because

A

biochemical reactions are very sensitive to pH

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8
Q

Human blood is slightly…

A

Basic - pH ≈ 7.39 – 7.45

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9
Q

Deviations from normal blood pH

A

pH < 7.2, “acidosis”; pH > 7.6, “alkalosis”.

Death occurs if pH < 6.8 or > 7.8

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10
Q

To make up a buffer, we need pH…

A

near pKa

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11
Q

Equivalence point

A

when the amount of added base = initial amount of acid:

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12
Q

strong acids…

A

completely dissociate in solution

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