Ch 14 Flashcards
(100 cards)
1
Q
What is a Lewis Acid?
A
A Lewis Acid is an electron pair acceptor.
2
Q
What is a Lewis Base?
A
A Lewis Base is an electron pair donor.
3
Q
What do cations indicate in reactions?
A
Cations indicate loss of electrons in reactions.
4
Q
What do anions indicate in reactions?
A
Anions indicate gain of electrons in reactions.
5
Q
What is a conjugate acid-base pair?
A
A conjugate acid-base pair consists of two substances related to each other by donating and accepting a single proton.
6
Q
What is a conjugate base?
A
A conjugate base is formed by the removal of a proton from the acid.
7
Q
What is a conjugate acid?
A
A conjugate acid is formed by the addition of a proton to the base.
8
Q
What does Ka represent?
A
Ka is the equilibrium constant for a reaction in which a proton is removed from an acid by water to form the conjugate base and the hydronium ion.
9
Q
What are strong acids?
A
Strong acids completely dissociate in an aqueous solution to produce a H+ ion and a weak conjugate base.
10
Q
What is a weak base?
A
A weak base is one that has a low affinity for a proton.
11
Q
What is a weak acid?
A
A weak acid is an acid that dissociates only slightly in aqueous solution.
12
Q
What are oxyacids?
A
Oxyacids are acids where the acidic protons are attached to an oxygen atom.
13
Q
What is an organic acid?
A
An organic acid contains a carboxylic acid functional group.
14
Q
What is the nature of water in acid-base chemistry?
A
Water is amphoteric; it behaves either as an acid or as a base.
15
Q
What is autoionization?
A
Autoionization is a reaction in which two like molecules react to give ions.
16
Q
What is Kw?
A
Kw is the ion product constant or dissociation constant, Kw = [HO-][H3O+] = 1.0 x 10-14 at 25°C.
17
Q
How is pH calculated?
A
pH = -log [H+] and pOH = -log [OH-].
18
Q
What is pKw at 25°C?
A
pKw = 14.00 at 25°C.
19
Q
How do you calculate the pH of strong acid solutions?
A
Strong acids completely dissociate in water.
20
Q
Why is H+ from HCl important?
A
H+ from HCl is important for calculating pH in solutions.
21
Q
What is the significance of autoionization of water?
A
Autoionization of water produces negligible H+ compared to strong acids like 0.10M HCl.
22
Q
What is the pH of 1.0 M HCl?
A
The pH of 1.0 M HCl is calculated as pH = -log[1.0], resulting in pH = 0.
23
Q
What are strong bases?
A
Strong bases completely dissociate in water and are strong electrolytes.
24
Q
What are Group 1A strong bases?
A
Group 1A strong bases include NaOH, KOH, LiOH, RbOH, and CsOH.
25
What are Group 2A strong bases?
Group 2A strong bases include Ca(OH)2, Ba(OH)2, and Sr(OH)2 with limited solubility.
26
How do strong bases produce hydroxide?
Strong bases produce two moles of hydroxide per one mole of metal.
27
What does Kb represent?
Kb is the base dissociation constant.
28
What are monoprotic acids?
Monoprotic acids have one acidic proton.
29
What are diprotic acids?
Diprotic acids have two acidic protons.
30
What are triprotic acids?
Triprotic acids have three acidic protons.
31
How does the acid strength of phosphoric acid compare?
The acid strength of phosphoric acid is H3PO4 > H2PO4 > HPO4²-.
32
Which proton removal is easier in polyprotic acids?
The first proton removal is easier from a polyprotic acid than the second proton.
33
What does Ka x Kb equal?
Ka x Kb equals Kw, the ion product of water.
34
What does pKa x pKb equal?
pKa x pKb equals pKw, which is 14.00.
35
What are neutral salts?
Neutral salts consist of cations from strong bases and anions from strong acids.
36
What are examples of neutral salts?
Examples of neutral salts include KCl, NaCl, NaNO3, and KNO3, which have pH = 7.
37
How are basic solutions from salts produced?
Basic solutions from salts are produced when a base reacts with water to generate hydroxide ions.
38
How are acidic solutions from salts produced?
Acidic solutions from salts are produced when the anion is not a base and the cation is the conjugate acid of a weak base.
39
What is the Bronsted-Lowry definition of an acid?
An acid is a proton (H+) donor.
40
What is the Bronsted-Lowry definition of a base?
A base is a proton (H+) acceptor.
41
How is percent dissociation of weak acids calculated?
Percent dissociation of weak acids is calculated as (amount dissociation / initial concentration) x 100%.
42
What is the effect of dilution on weak acids?
Percent dissociation increases as the acid becomes more dilute.
43
What is a weak acid?
A weak acid is an acid that partially dissociates in solution, leading to a decrease in [H+] as [HA] decreases.
44
What is % dissociation?
The percentage of the original acid that dissociates into ions, which increases as [HA] decreases.
45
What is a highly charged metal ion?
A highly charged metal ion, such as AlCl3, produces an acidic solution when dissolved in water.
46
What is a hydrated ion?
A hydrated ion is an ion surrounded by water molecules, where the charge on the metal ion polarizes the O-H bonds in the water.
47
What is acid-base behavior?
Acid-base behavior is the ability of a substance to donate H+ (acid) or accept H+ (base) when dissolved in water.
48
What is electronegativity?
Electronegativity is the tendency of an atom to attract electrons, which affects the acidity of a molecule.
49
How does oxyacid strength change?
Oxyacid strength increases with the number of oxygen atoms attached to the central atom.
50
What is the common ion effect?
The common ion effect is the phenomenon where the addition of a common ion shifts the equilibrium, making a solution less acidic or basic.
51
What is a buffer solution?
A buffer solution is a solution of a weak acid and its conjugate base that resists changes in pH upon the addition of small amounts of strong acid or base.
52
What is buffer capacity?
Buffer capacity is the amount of acid or base a buffer can neutralize before the pH begins to change significantly.
53
What is buffer composition?
Buffer composition is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid.
54
What is the Henderson-Hasselbalch equation?
The Henderson-Hasselbalch equation is pH = pKa + log([A-]/[HA]), used to calculate the pH of a buffer solution.
55
How should a buffer be prepared?
When preparing a buffer, [A-]/[HA] should equal one to maintain the desired pH.
56
What is pKa?
pKa is the negative logarithm of the acid dissociation constant, used to determine the strength of an acid.
57
What is acid-base neutralization?
Acid-base neutralization is the reaction between an acid and a base that produces water and a salt.
58
What is a conjugate base?
A conjugate base is the species that remains after an acid donates a proton.
59
What is a conjugate acid?
A conjugate acid is the species formed when a base accepts a proton.
60
What happens to pH with large amounts of CH3COOH and CH3COO-?
A small change in pH occurs when the amounts of CH3COOH and CH3COO- are large compared to the added OH- or H+.
61
What is buffer action?
Buffer action is the ability of a buffer to resist changes in pH when acids or bases are added.
62
What is an acidic solution?
An acidic solution has a higher concentration of H+ ions than OH- ions.
63
What is a basic solution?
A basic solution has a higher concentration of OH- ions than H+ ions.
64
65
Arrhenius Definition of Acids & Bases?
Produces H+ in solution, OH- in solution. Limited definition.
66
Lewis Definition of Acids & Bases?
Electron acceptor, electron donor.
67
Bronsted Lowry Definition of Acids & Bases?
Proton donor, acceptor.
68
What are conjugate acid-base pairs?
Every acid forms a conjugate base; every base forms a conjugate acid.
## Footnote
A strong acid/base forms a weak conjugate acid; a weak acid/base forms a stronger conjugate acid.
69
What is the formula for Ka?
HA -><- H+ + A-
Ka = [A-][H+]/[AH]
70
Strong acids ____ dissociate in an aqueous solution.
Completely.
71
What is titration?
Addition of a measured volume of base of known molarity into an acid to be analyzed. Base is titrant, acid is analyte.
72
What is the equivalence point vs. endpoint?
Equivalence point: enough titrant has been added to react 1:1 with analyte. Endpoint: 1 drop beyond that point, indicated by an indicator.
73
What is Normality (N)?
Equivalents/Liter.
## Footnote
For a mono/di/triprotic acid in respect to molarity: = molarity, 2 * M, 3 * M.
74
What is equivalent mass?
Weight of acid used/# of acid equivalents.
75
What are oxyacids?
Acidic proton attached to an oxygen.
76
What are organic acids?
Contains a carboxylic acid functional group (COOH).
77
What is amphoteric?
Can behave like an acid or base.
78
What is autoionization?
A reaction in which 2 like molecules react to form ions, often done by water.
79
What is Kw and its formula?
1.0 * 10^-14 for H2O ⇔ H+ + OH-
Kw = [H+][OH-].
80
What is the formula for pH and pOH?
This is easy.
81
What is the rounding rule for pH?
The number of places after the decimal point in the pH equals the number of significant figures in the concentration of H+.
82
How to calculate pH of strong acids?
Easy asf. Acids completely dissociate and you can easily calculate [H+] from this.
83
Practice calculating pH of weak acids…
Problem #73a, interactive example 14.9, problem #83.
84
What is the 5% rule for approximations?
(x/[Reactant]0)*100. If it is 5% or larger, solve quadratic!
85
% dissociation of weak acids formula?
[Amount dissociated]/[Initial concentration] * 100.
## Footnote
For a given weak acid, % diss becomes larger as acid dilutes more and [H+] decreases.
86
Strong bases ____ dissociate and are ____ electrolytes.
Completely, strong.
87
List all strong acids and bases.
Acids: HCl, HBr, HI, H2SO4, HNO3, HClO4.
Bases: Group 1A: NaOH, KOH, LiOH, RbOH, CsOH (all group but not Fr); Group 2: Ca(OH)2, Ba(OH)2, Sr(OH)2.
88
What are weak bases?
Do not completely dissociate and form an equilibrium.
## Footnote
B(aq) + H2O(l) ⇔ BH+(aq) + OH-(aq)
Kb = [BH+][OH-]/[B].
89
What happens in weak base reactions?
All of our weak base reactions will be reacting with water to produce BH+ which is the conjugate acid and OH- which is the conjugate base. This is called hydrolysis (destruction/removal of water).
90
How to calculate pH of a strong base?
They fully dissociate, so we will do this the same way as a strong acid.
91
What is Ka * Kb = ___?
Kw = 1.0 * 10^-14.
## Footnote
pKa = -log(Ka), pKb = -log(Kb), pKw = -log(Kw) = 14.00.
92
Properties of salts that produce neutral solutions?
Consist of cations of strong bases and the anion of strong acids and have 0 effect on [H+].
## Footnote
Because strong acids and bases completely dissociate in water.
93
Properties of salts that produce basic solutions?
Cation has neutral properties (strong base) and whose anion is the conjugate base of a weak acid. Aqueous solution is basic.
## Footnote
Sometimes you have to calculate Kb from Ka and Kw if you have the Ka from the acid in the products side.
94
Effect of structure on acid-base behaviors?
A molecule containing H+ will donate if its bond is polar due to electronegativity difference. HF is a very polar molecule, but will not donate due to its strong bond. CH4 will not donate due to strong and non-polarity.
## Footnote
For oxyacids, acid strength increases as oxygens on central atom increase.
95
For polyprotic acids, what happens during the first dissociation?
The first dissociation makes the problem greatly simplified.
## Footnote
However, know how to calculate the concentrations of the anion with no H+. There are cases where you do have to calculate the [H+] contributed in the 2nd dissociation.
96
What are acidic metal salts?
They do not directly act as an acid, but will dissociate to form hydrated ions. The hydrated ion can act as a weak acid.
## Footnote
Example: AlCl3 -> Al(H2O)63+ and 3Cl-.
97
Salts that produce acidic solutions?
Anion is not a base/conjugate base of a strong acid and cation is conjugate acid of a weak base.
98
How to calculate Ka from Kb and vice versa?
Pretty easy. Ka * Kb = Kw.
## Footnote
Rearrange as needed for conjugate acids & bases in aqueous solutions.
99
Salts with acidic and basic ions?
Cation is conjugate acid of a weak base, and anion is conjugate base of a weak acid.
## Footnote
Acidic if Ka of acid formed by salt is larger than Kb of base formed by salt.
100
What should you memorize?
Table 14.6.
