Ch 9- Acids, Bases, Buffers Flashcards

1
Q

A system is at equilibrium when the ratio of concentrations of the products to the reactions are _______.

A

equal

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2
Q

strong acids are _____% ionized in water

A

100%

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3
Q

what is the Kw value @ 25C

A

1 * 10 ^-14

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4
Q

How does the pH of a solution relate to pOH

A

pH + pOH = 14

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5
Q

What is the Henderson-Hasselbalch equation used for?

A

Calculating the pH of a buffer solution

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6
Q

Which of the following is a strong acid?
A) Acetic acid
B) Hydrochloric acid
C) Carbonic acid
D) Formic acid

A

B) Hydrochloric acid

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7
Q

what does Le Chatelier’s principle state?

A

if a system is no longer at equilibrium, it will react to re-establish equilibrium state

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8
Q

large K value means?

A

equilibrium favors products

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9
Q

K value less than one means?

A

equilibrium favors reactants

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10
Q

what is an amphiprotic species AND which is the most common?

A

can react as acid or base… WATER :)

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11
Q

The equilibrium constant for a reaction is denoted as
𝐾 and depends on the ____________ of the reaction.

A

temperature

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12
Q

What happens to the pH of a solution when a strong base is added?

A) It decreases
B) It remains the same
C) It increases
D) It becomes neutral

A

C) It increases

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13
Q

The equilibrium constant for a base equilibrium reaction is denoted as _____________.

A) 𝐾𝑎
B) 𝐾𝑏
C) 𝐾𝑤
D) 𝐾𝑝

A

B) 𝐾𝑏

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14
Q

In a buffer solution, the weak acid reacts with added ____________ to maintain pH.

A

base

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15
Q

The concentration of hydroxide ions in water is related to the ____________ constant 𝐾𝑤.

A

ionization

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16
Q

The Henderson-Hasselbalch equation calculates the pH of a buffer using the ratio of ____________ to weak acid.

A

conjugate base

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17
Q

Which of the following does NOT affect the pH of a solution?

A) Na⁺
B) Cl⁻
C) OH⁻
D) H⁺

A

A) Na⁺

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18
Q

What is the conjugate base of hydrochloric acid (HCl)?

A

Cl-

19
Q

Why is the conjugate base of a strong acid considered to be very weak?

A

Because strong acids completely ionize, leaving very little of the conjugate base to affect pH.

20
Q

How do weak acids behave in water compared to strong acids?

A

Weak acids establish an equilibrium between ionized and un-ionized forms, while strong acids fully ionize.

21
Q

How can you determine the concentration of hydroxide ions in a solution?

A

[OH −]=10 ^−pOH

22
Q

Which of the following is a characteristic of a weak base?

A) It ionizes completely in water
B) It partially ionizes in water
C) It does not affect the pH of the solution
D) It forms a strong conjugate acid

A

B) it partially ionizes in water

23
Q

Which statement best describes a buffer solution?

A) It changes pH rapidly when small amounts of acid or base are added.
B) It maintains a stable pH when small amounts of acid or base are added.
C) It neutralizes all added acids and bases.
D) It only works for strong acids and bases.

A

B) It maintains a stable pH when small amounts of acid or base are added.

24
Q

What does a low 𝑝𝐾𝑎 value indicate about an acid?

A) The acid is weak.
B) The acid is strong.
C) The acid is neutral.
D) The acid is not ionizable.

A

B) The acid is strong.

25
Q

what does it mean if K is higher than 1?

A

reaction favors product

25
Q

what does it mean if K is less than 1?

A

reaction favors reactants

26
Q

what are some examples of strong acids?

A

HCl, HBr, HI, HNO3, H2SO4, HClO4 (all others weak!)

27
Q

what are some examples of strong bases?

A

first 2 columns of periodic table & OH-

28
Q

the ______ the acid, the _____ the conjugate base

A

stronger, weaker

29
Q

the ___ the base, the ______ the conjugate acid

A

stronger, weaker

30
Q

Do Na+, Li+, K+ impact pH of solution?

A

no

31
Q

how to make a buffer (3 key factors)

A
  1. must have conjugate acid/base pair 2.must be weak 3. must have relatively significant amount
32
Q

if the conjugate base and conjugate acid concentrations are equal– what is the pH of the buffer?

A

pH = pKa

33
Q

For conjugate acid/base pairs– what does Ka * Kb =

A

1 * 10^-14

34
Q

how to determine pH from [H+] concentration

A

pH = - log [H+]

35
Q

POH from OH- concentration

A
  • log [OH-]
36
Q

acid/bases react to form ______ and _____

A

salt, water

37
Q

what is the henderson-hasselbach equation

A

PH = PKa + log [molar concentration of conj base]/ [molar concentration of weak acid]

38
Q

main difference between bronsted and arrhenius defintions of acids/bases

A

Bronsted: H+ donator/acceptor
Arrhenius, H3O+ acid and OH- base

39
Q

what is the most common nonmetal oxide

A

CO2

40
Q

what does polyprotic mean

A

more than 1 hydrogen atom
First ionization is the most complete
The amount of hydrogens it has does not equal # of reactions

41
Q

pH of an effective buffer must be within ____ pH unit of pKa of weak aci

A

one

42
Q

What does it mean if a salt is basic?

A

It has NO acidic component (group 1 or group 2)

43
Q

What does it mean if a salt is acidic?

A

It has NO basic component
(Chlorine,
Bromide,
Iodide,
Sulfate,
ClO4- –Perchlorate,
NO3– Nitrate)