Chemical Equilibrium Systems Including Acids and Bases Flashcards

1
Q

Static Equilibrium:

A

Equal and opposite forces are applied. Like a stand-still game of tug-of-war.

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2
Q

Dynamic Equilibrium:

A

The rate of both processeses are occurring equally.

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3
Q

Gas equilibrium must be contained in a…

A

sealed container/closed system.

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4
Q

Aqueous equilibrium (for Chem 30) can occur in an open beaker because…

A

the rate of evaporation is insignificant.

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5
Q

How do you recognize the products in an equilibrium graph?

A

They start at 0 mol/L.

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6
Q

How do you recognize the reactants in an equilibrium graph?

A

They start at a given concentration. (not 0 mol/L)

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7
Q

How do you infer the coefficients in equilibrium equations from a graph?

A

The rate of change = slope, and the slope relates to the coefficient. The larger the coefficient, the steeper the slope.

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8
Q

When can you tell equilibrium is reached on a graph?

A

When the concentrations stop changing.

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9
Q

What two things is the rate of reaction affected by?

A

Concentration of reactants, pressure in the equation (changes coefficients).

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10
Q

If Kc>1:

A

Products are favoured, reaction proceeds > 50%

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11
Q

If Kc<1:

A

Reactants are favoured, reaction proceeds < 50%

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12
Q

What is not included in a Kc expression?

A

Pure solids, water (in aqueous equilibrium), and pure liquids (in gaseous equilibrium).

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13
Q

How do you complete an ICE chart step-by-step?

A
  1. Label.
    I = [initial] mol/L
    C = [change] mol/L
    E = [equilibrium] mol/L
  2. Place in given values, if the initial [ ] of a substance is not given, assume it is 0.
  3. Find the change value and use it to find the change value of everything else, multiplying by coefficients if necessary.
  4. Find final equilibrium values and use them in sub and solve equations.
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14
Q

Le Chatelier’s Principle:

A

If stress is applied to a system at equilibrium, the system responds to minimize that stress. Any stress that causes a response will change concentration.

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15
Q

What effect do catalysts have on equilibrium?

A

They do not effect the position of equilibrium, they only cause the system to reach equilibrium more rapidly. (Kc is unaffected)

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16
Q

What type of equilibrium system(s) does pressure affect?

A

Gaseous equilibrium.

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17
Q

What will adding or removing a reactant or product do to equilibrium?

A

It will shift equilibrium away from what is added or towards what is removed.

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18
Q

How will increasing/decreasing pressure affect equilibrium?

A

An increase in pressure will shift the equilibrium towards the side that has fewer gaseous mols. A decrease in pressure will shift the equilibrium towards the side the has more gaseous moles. If the gaseous mols are equal, there will be no effect.

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19
Q

How does temperature affect equilibrium?

A

Follows the add-away rule. With an increase in temperature (exothermic), the rate of reverse reaction increases and equilibrium shifts left. Kc will get smaller. With a decrease in temperature (exothermic), the rate of reverse reaction decreases and the equilibrium shifts right. Kc will get larger.

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20
Q

Acid:

A

A substance that donates protons (H+(aq)).

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21
Q

Strong Acid:

A

Ionizes 100%.

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22
Q

Weak Acid:

A

Ionizes partially at most concentrations

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23
Q

Base:

A

Dissolves in water, bitter, slippery, litmus turns blue, conductive, and neutralizes acids. Accepts protons (H+(aq)) and dissociates 100% at all concentrations.

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24
Q

When strong acids are put at equilibrium, which side is favoured?

A

Products.

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25
Q

What makes an acid organic?

A

It has carbon and oxygen

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26
Q

What type of arrow are strong acid/base equations written with?

A

One-way.

27
Q

What type of arrow are weak acid/base equations written with?

A

Double-sided.

28
Q

When weak acids are put at equilibrium, which side is favoured?

A

Reactants

29
Q

What is used to measure the strength of an acid? What does the number tell us specifically?

A

Equilibrium constant: if >1, strong acid, if <1, weak acid.

30
Q

The weaker the acid, the (more/less) it affects pH.

A

less

31
Q

Ka:

A

The equilibrium constant for acids.

32
Q

What type of arrow are acid-base equilibrium equations drawn with?

A

Double-sided.

33
Q

Strong acids have conjugate bases, They (are/aren’t) a stronger base than water.

A

aren’t

34
Q

Weak acids have conjugate bases, They (are/aren’t) a stronger base than water.

A

are

35
Q

What makes an acid inorganic?

A

H is in the front of the compound.

36
Q

When you calculate the pH of a polyprotic acid, the first Ka is much (less/greater) than the second Ka

A

greater

37
Q

In net ionic equations strong acids are written as:

A

H3O+(aq)

38
Q

In net ionic equations weak acids are written as:

A

Their mollecular form, ie. CH3COOH(aq)

39
Q

In net ionic equations strong bases are written as:

A

OH-(aq)

40
Q

In net ionic equations weak bases are written as:

A

Their ionic form, ie. NaNO2(aq)

41
Q

Kw =

A

Ka * Kb

42
Q

Products are favoured if:

A

The acid is above the base.

43
Q

Reactants are favoured if:

A

The base is above the acid.

44
Q

How do you calculate the pH of a weak acid?

A

Use ICE chart or pH = -log√([WA]*ka)

45
Q

How do you calculate the pH of a weak base?

A

pH = -log√([WB]*(kw/ka)) or ICE chart

46
Q

What do you do when finding Ka if given a pH?

A

Use an ICE chart, [H3O+] = 10^(-pH)

47
Q

Acid-base indicators are (in/organic) (strong/weak) (acid/bases).

A

organic, weak, acids

48
Q

Protonated:

A

Has H+(aq) - primary colour.

49
Q

De-protonated

A

Lost H+(aq) - primary colour.

50
Q

What is an inert gas, and how is it used in equilibrium?

A

Noble, unreactive gasses will be added to a system in equilibrium to increase pressure. There is no change in concentration or partial pressures of the individual molecules, though. Therefore, there is no shift in equilibrium.

51
Q

What stress changes Kc?

A

Temperature increase/decrease

52
Q

Equilibrium favours…

A

The side with the weaker acid.

53
Q

Will a colour change occur if a weaker indicator is added to a stronger acid?

A

No.

54
Q

Will a colour change occur if a stronger indicator is added to a weaker acid?

A

Yes

55
Q

What represents a weak base system at equilibrium?

A

An aqueous solution of a weak base in a state of equilibrium would consist mainly of the unionized form of the base and only a small amount of hydroxide ions and the cation (conjugate acid) of the weak base.
B(aq) + H2O(l) <-> BH+(aq) + OH-(aq)

56
Q

What happens to equilibrium when an acid is added to a weak acid system?

A

If hydrochloric acid were added to the equilibrium mixture, hydrogen ions (H +) and chloride ions (Cl -) would be added. Hydrogen ions are on the right-hand side of the equilibrium; therefore, the equilibrium will shift to the left-hand side to compensate, resulting in a higher concentration of reactants but no change in pH.

57
Q

What happens to equilibrium when a base is added to a weak acid system?

A

While neither sodium ions (Na+) nor hydroxide ions (OH-) are present on either side, the hydroxide ions will remove H+ ions, and the equilibrium will shift to the right-hand side to replace the hydrogen ions that were removed.

58
Q

How do you find the pH of a weak acid using WAB and Kc values?

A

pH = -log√(WA x ka)

59
Q

How do you find [H3O+] of a weak acid using WAB and Kc values?

A

√(WA x Ka)

60
Q

How do you find the pH of a weak base using WAB and Kc values?

A

pH = 14.00 + log√(WB x (KW/KA))

61
Q

What does a Ka value mean?

A

An acid’s ability to ionize in water

62
Q

What pH constitutes a strong base?

A

13-14

63
Q

What pH constitutes a strong acid?

A

0-1

64
Q

What is not an indication that a system has reached equilibrium?

A

Constant mass