acids and bases Flashcards

1
Q

State the arrhenius definition

A

Acids produce hydrogen ions in aq solutions and bases produce hydroxide ions in aq solutions

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2
Q

State the bronsted-lowry definition

A

An acid is a proton donor and a base is a proton acceptor

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3
Q

According to the bronsted-lowry definition what are acidic protons often attached to

A

Oxygen
Halogens
Nitrogen atoms

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4
Q

According to the bronsted-lowry definition what do bases need

A

Lone pair electrons to act as a proton acceptor

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5
Q

Acids and bases occur as what

A

Acid-base pairs
Base –> conjugate acid
Acid –> conjugate base

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6
Q

What is ka

A

Acidity constant

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

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7
Q

Describe strong acids

A
Most of acid is dissociated (ionized, strong electrolyte) 
Ka = large 
Equilibrium lies far right 
[H+]=[HA]initial 
A- much weaker base than H20
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8
Q

State strong acids

A
HCl 
HI
HBR 
HNO3 
H2SO4 
HClO4
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9
Q

Describe weak acids

A

Ka = small
Equilibrium lies far left
[H+] < [HA]initial
A- much stronger base than a H2O

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10
Q

State weak acids

A

HF
CH3COOH (acetic acid)
HCOOH (formic acid)
HOOCCH2CCH2COOHCOOHOH (citric acid)

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11
Q

Describe relationship between acid and base conjugate pairs

A

Inverse relationship
Strong acid –> doesn’t react as base (spectator)
Weak acid –> weak base
Doesn’t react as acid –> strong base

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12
Q

What is water

A

Amphoteric

Acts as an acid or base

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13
Q

What is Kw

A

Ion product constant of water

Kw=[H3O+][HO-] = 1.0x10^-14 @ 25degrees c

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14
Q

What is Kw in neutral

A

[H30+]=[HO-] = x

Kw=x^2 –> x=1.0x10^-7

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15
Q

What is Kw in acidic

A

[H30+]>[OH-]

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16
Q

What is Kw in basic

A

[H30+] IS LESS THAN [OH-]

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17
Q

State relationship between H+ and pH

A

As [H+] increases pH decreases

As [H+] decreases or [HO-] increases pH increases

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18
Q

State formulas for the pH scale

A
Kw=[H3O+][HO-] = 1.0x10^-14 
pH = -log [H+]
pOH = -log [HO-]
-logKw = -log [H+]-log[HO-] = 1.0x10^-14 
Pkw = pH + pOH / pH+pOH = 14.00
[H+]= 10^-pH
[pOH] = 10^-pOH
*2 decimal places, 2 sig figs*
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19
Q

State what percent dissociation is and the formula

A

Extent of ionization for a weak acid

%diss= (molarity of H+ at equil / initial concentration) x 100

20
Q

How is percent dissociation affected as weak acid becomes more dilute

21
Q

Formulas for pka, ka, kb and pkb

A
  • logpka=pka pka goes down ka goes up

- logpkb=pkb pkb goes down kb goes up

22
Q

State formula for Kb

A

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

23
Q

State strong bases

A
LiOH 
KOH 
NaOH 
RbOH 
CsOH 
Mg(OH)2
Ca(OH)2
Ba(OH)2
Sr(OH)2
24
Q

State weak bases

A

Amines = ammonia, methylamine, ethylamine, aniline and pyridine
Hydroxylamines

25
What are polyprotic acids
Molecules that have more than one acidic proton
26
What is special about polyprotic acids
Product of 1st reaction = reactant of 2nd reaction | Each dissociation step has a Ka associated with it
27
How to solve weak polyprotic acids
Must do 2 ice tables and carry down [H+] from first table
28
How do we deal with something - x in acid base chemistry
Use 5% rule, approximation | If doesn't work then use quadratic formula
29
State the generalizations about WEAK polyprotic acids
All of [H+] comes from first dissociation step Very little of HA- dissociates, assume [H+]=[HA-] Concentration of [A2-]=ka2
30
How to solve strong polyprotic acids
Don't need ka1 --> first dissociation (first ice table) goes to completion Concentration of H+ carries down to the second ice table
31
What are salts
Ionic compounds that are products of acid-base neutralizations
32
Which salts do not affect pH
Salts of the cations of strong bases | Salts of the anions of strong acids
33
Which salt produces basic solutions
Salts containing cation (with neutral properties) and an anion that is the conjugate base of a weak acid
34
Which salt produces acidic solutions
Salts containing anion (with neutral properties) and a cation that is the conjugate acid of a weak base
35
State the relationship for any conjugate acid base pair
Inverse relationship between ka of acid and kb of base Ka x Kb = Kw PKa + PKb = 14.00
36
What do highly charged metal ions form
Complex ions and produce acidic solutions
37
What happens when both ions in a salt have acid-base properties
Competition between K's Ka>Kb pH < 7 acidic Ka=Kb pH = 7 neutral Ka is less than Kb ph is less than 7 = basic
38
What are covalent oxides
They produce acidic solutions | SO3, SO2, CO2, NO2, etc
39
What are ionic oxides
They produce basic solutions | CaO, K2O, etc
40
What is the relationship between acidity and increasing electronegativity
Proportional | Acidity increases when going down a column in periodic table
41
Describe hydrogen halides
Weak acid = strong bond | Strong acid = weak bond
42
Describe oxyacids
Electron withdrawing effect (inductive) of electronegative atoms makes the O-H bond more acidic
43
State lewis model definition
Lewis acid is an electron pair acceptor and a lewis base is an electron pair donor (Includes bronsted lowry acids and bases) Lewis base = e- pair donor Lewis acid = e- pair acceptor
44
Acid-base properties of salts: neutral salts
Cation is neutral (alkali metal or alkaline earth metal) Anion is conjugate base of a strong acid Ex = NaCl, KNO3
45
Acid-base properties of salts: basic salts
Cation is neutral (alkali metal or alkaline earth metal) Anion is conjugate base of a weak acid Ex = CH3COOHNa, NaCN
46
Acid-base properties of salts: acidic salts
Cation is conjugate acid of a weak base (or highly charges metal cation) Anion is the conjugate base of a strong acid Ex = NH4Cl, AlCl3