Chapter 10: Acids and Bases Flashcards

(23 cards)

1
Q

Arrhenius acids and bases?

A

Dissociate to form an excess of H+ and OH- in solution respectively

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2
Q

Bronsted-Lowry acids and bases?

A

Donate and accept a proton respectively

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3
Q

Lewis acids and bases?

A

Accept and donate an electron pair, respectively

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4
Q

What is an amphoteric species?

A

One that acts like an acid in a basic environment and a base in an acidic environment. Amphiprotic in a bronsted-lowry sense. Eg water, zwitterionic AAs

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5
Q

Nomenclature for:
anions ending in -ide?
anion ending in -ite?
anion ending in -ate?

A

hydro- -ic acid

  • ous acid
  • ic acid
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6
Q

What is autoionization? example?

A

When a compound reacts with itself to form ions. Ex water reacts with itself to form hydronium and hydroxide

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7
Q

What is Kw? Value?

A

Water dissociation constant. Kw = [H3O][OH] = 10^-14 at 298K

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8
Q

What does pH equal? pOH? How do they relate to each other?

A

pH = -log[H+]
pOH = -log[OH-]
At 298K, pH + pOH = 14

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9
Q

Quick math:
pH if [H+] = 0.0001? pOH?
if [H+] = 0.1? pOH?

A

10^-4, therefore pH = 4 and pOH = 10.

pH = 1 and pOH = 13

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10
Q

Approximate value for the log of a decimal between 1 and 10, eg. -log 1.8x10^-5?

A

-log (n x 10^m) = m - 0.n

so -log 1.8 x10^-5 = 5 - 0.18 = 4.82

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11
Q

Common strong acids encountered on the MCAT? Strong bases?

A
  • HCl, HBr, HI, H2SO4, HNO3, HClO4

- NaOH, KOH and other Group IA metals with OH

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12
Q

Acid dissociation constant formula? Smaller Ka means?

A

Ka = [H3O+][A-] / [HA]

weaker the acid, less it will dissociate

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13
Q

Base dissociation constant formula? Smaller Kb means?

A

Kb = [B+][OH-] / [BOH]

weaker the base, less it will dissociations

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14
Q

What values generally characterize and weak acid and a weak base?

A

A Ka or Kb which is less than 1

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15
Q

What is Kw also equal to?

A

Ka x Kb, therefore a large Ka leads to a conjugate base with a very low Kb and vice versa

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16
Q

Normality of a polyprotic acid? eg of 2M H2SO4

A

H2SO4 has 2 acid equivalents x 2M, so 4N

17
Q

Titrant vs Titrand?

A

small amount of solution with known concentration (titrant) is added to known volume of solution with unknown concentration (titrand) until equivalence point

18
Q

Where is the equivalence point for a strong acid/strong base titration? For other titrations?

A

At pH 7. At whatever point the acid equivalents equal the base equivalents

19
Q

Formula which allows for the calculation of the titrand concentration?

A

NaVa = NbVb, where Na and Nb are the normality of the acid and base and Va and Vb are the volumes

20
Q

What are indicators? Color change point referred to as?

A

Weak acids and bases which have different colors in their protonated and deprotonated states. Must be a weaker acid or base than the acid or base being titrated, or they would change color immediately. Endpoint, should be very close to equivalence point

21
Q

What does the half-equivalence point correspond to?

A

The pKa of an acid, when half is in its protonated state

22
Q

What is the Henderson-Hasselbach Equation?

A

pH = pKa + log [A-]/[HA], therefore when [A-] = [HA] the pH = pKa -> the half-equivalence point. can be used for weak acid or weak base solutions: pOH = pKb + log [B+]/[BOH]

23
Q

General buffering capacity of a buffer solution?

A

+/- 1 pH unit from the pKa