Chapter 16 Acids & Bases Flashcards
Define Acid
Sour taste; has the ability to dissolve many metals, neutralize bases, turns blue litmus paper red and has a pH under 7
Define Base
Bitter taste and slippery feel; has the ability to neutralize acids, turns red litmus paper blue and has a pH above 7
Define Arrhenius Acid
Acids are substances that produces H+ ions (proton) in an aqueous solution
Define Arrhenius Base
Bases are substances that produces OH- ions in an aqueous solution
Define Neutralization
Acids and bases that combine to form water
Define Bronsted-Lowry Acid
Proton (H+ ion) donor
Define Bronsted-Lowry Base
Proton (H+ ion) acceptor
In the Bronsted-Lowry Acid-Base theory how are Acids and Bases defined?
In this theory acids and bases are defined by the way they react with each other
Define Amphoteric
Substances that can act as acids or bases
What element can be an example of an Amphoteric substance?
H2O
Identify which of the substances are Acids and which are Bases I) KOH (aq) II) HNO3 (aq) III) CH3COOH (aq) IV) HBR (aq) V) NH4+ (aq) VI) Sr(OH)2 (aq) VII) H2SO4 (aq)
I) Base II) Acid III) Acid IV) Acid V) Acid VI) Base VII) Acid
Define Conjugate Acid Base Pair
2 substances related to each other by the transfer of a proton
A Conjugate Acid Base Pair only differs by ____ _______
1 proton
A base accepts a proton and becomes a ___________ ______
Conjugate Acid
An acid donates a proton and becomes a ____________ ______
Conjugate Base
The original base becomes a _________ _______ in the reverse reaction and the original acid becomes a _________ _________ in the reverse reaction
Conjugated acid; conjugated base
Write out the Conjugate Acids for each base I) NH3+ II) OH- III) H2O IV) CO3 2-
I) NH4+
II) H2O+
III) H3O+
IV) HCO3 -
Write out the Conjugate Bases for each acid I) HCl II) HBr III) HNO3 IV) CH3COOH
I) Cl-
II) Br-
III) NO3-
IV) CH3COO-
Write the Conjugate Acids for each base
I) ClO4-
II) HSO4-
III) H2PO4
I) HClO4
II) H2SO4
III) H3PO4
Write the Conjugate Bases for each acid
I) H2SO3
II) HCHO2
III) HF
I) HSO3-
II) HCOO-
III) F-
What does the Lewis definition of acids and bases focus on?
The transfer of electron pairs
Define Lewis Acid
Electron pair acceptor
Define Lewis Base
Electron pair donor
What are the types of Lewis acids and bases?
I) Incomplete octet
II) Molecules that contain double bonds
III) Small and highly charged cations that have empty orbitals allowing them to act as Lewis acids
Identify the following as a Lewis Acid or Base I) Fe3+ II) BH3 III) NH3 IV) F- V) BeCl2 VI) OH- VII) B(OH)3 VIII) CN-
I) Lewis Acid II) Lewis Acid III) Lewis Base IV) Lewis Base V) Lewis Acid VI) Lewis Base VII) Lewis Acid VIII) Lewis Base
Define Strong Acid
An acid that completely ionizes in a solution
In regards to Strong Acids which way does the equilibrium lie?
The equilibrium lies far to the right with a single arrow
What are some examples of Strong Acids?
- Hydrochloric Acid (HCl)
- Hydrobromic Acid (HBr)
- Hyrdoiodic Acid (HI)
- Nitric Acid (HNO3)
- Perchloric Acid (HClO4)
- Sulfuric Acid (H2SO4)
For Strong Acids what is the [H3O+] value?
The [H3O+] value is the same as the acid initial
Define Weak Acid
An acid that only partially ionizes in a solution
In regards to Weak Acids which way does the equilibrium lie?
The equilibrium is double arrowed and lies both ways
What are some examples of Weak Acids?
- Chlorous Acid (HClO2)
- Nitrous Acid (HNO2)
- Hydroflouric Acid (HF)
- Formic Acid (HCHO2)
- Benzoic Acid (HC7H5O2)
- Acetic Acid (HC2H3O2)
- Hypochlorous Acid (HClO)
- Hydrocyanic Acid (HCN)
- Phenol (HC6H5O)
- Sulfurous Acid (H2SO3)
- Carbonic Acid (H2CO3)
- Phosphoric Acid (H3PO4)
For Weak Acids what is the [H3O+] value?
The [H3O+] value is smaller than the initial concentration of the acid
Strong Acids have ______ attractions and __________ ionization, Weak Acids have _______ attractions and ___________ ionization
Weak; complete, strong; partial
Define Acid Ionization (Dissociation) Constant (Ka)
The equilibrium constant for the ionization reaction of the weak acid
Larger Ka = ?
Smaller Ka = ?
Larger Ka = stronger weak acid
Smaller Ka = weaker weak acid
Define Autoionization
When a molecular can act as an acid and a base with itself
Define Ion Product Constant for Water (Kw)
The equilibrium constant for the Autoionization of water
Kw = ?
Kw = [H3O+][OH-] = 1.0x10^-14
The concentration of H3O+ times the concentration of OH- is always _____________ at ______ degrees celsius
1.0x10^-14, 25 degrees celsius
In acidic solutions is [H3O+] less than or greater than [OH-]
[H3O+] > [OH-]
In basic solutions is [H3O+] less than or greater than [OH-]
[H3O+] < [OH-]
If the concentration of [H3O+] increase what happens to the concentration of [OH-]
Concentration of [OH-] decreases
What are the equations used to find pH?
- Kw = [H3O+][OH-]
- pH = -log [H3O+]
- pOH = -log [OH-]
- pH + pOH = 14.00
What is the equation for finding pKa?
pKa = -logKa
The larger the Ka the ________ the pKa and the __________ the weak acid
Smaller, stronger
The smaller the Ka the __________ the pKa and the __________ the weak acid
Larger, weaker
How do you find [H3O+] and pH for a Strong Acid?
The concentration of [H3O+] for a strong acid = the concentration of the strong acid
How do you find [H3O+] and pH for a Weak Acid?
The concentration of [H3O+] for a weak acid does not equal the concentration of the strong acid, you must use an ICE Table to find [H3O+]
T/F Strong Acids completely ionize in solutions however we must not ignore the contribution of the Autoionization of water
False; strong acids do completely ionize in solutions and we can also ignore the contribution of Autoionization of water
T/F Weak acids are not equal to the concentrations of the weak acid since it does not ionize completely
True
Define Percent Ionization
The ratio of the ionized acid concentration to the initial acid concentration, multiplied by 100%
For 2 weak acids of the same initial concentration which one results in the higher Percent Ionization value?
The stronger weak acid results in higher Percent Ionization
If the initial acid concentration increases what happens to the [H3O+] equilibrium and Percent Ionization?
[H3O+] equilibrium increases and Percent Ionization decreases
If you have a Strong and a Weak Acid, which would you use to solve for pH?
The Strong Acid
If you have 2 Weak Acids, which would you use to solve for pH?
You would use the stronger Weak Acid (the weak acid with the higher Ka)
Define Strong Base
A base that completely dissociates in a solution
T/F There are 2 groups of Strong Bases
True
What is the difference between group 1 and group 2 Strong Bases?
Group 1: highly soluble
Group 2: slightly soluble
What are the common Strong Bases in both group 1 and group 2?
Group 1 - Lithium Hydroxide (LiOH) - Sodium Hydroxide (NaOH) - Potassium Hydroxide (KOH) Group 2 - Strontium Hydroxide (Sr(OH)2) - Calcium Hydroxide (Ca(OH)2) - Barium Hydroxide (Ba(OH)2)
Define Weak Base
A base that produces OH- by accepting protons from water (ionizing water to form OH-)
What is the main difference between Strong and Weak Bases?
Weak bases must accept protons from water to produce OH- whereas strong bases already contain OH and dissociate into water
For Weak Bases is the [OH-] smaller, larger, or the same as the initial concentration of the base?
Smaller
What are the common Weak Bases?
- Methylamine (CH3NH2)
- Ethylamine (C2H5NH2)
- Pyridine (C5H5N)
- Aniline (C6H5NH2)
- Carbonate Ion (CO3 2-)
- Bicarbonate Ion (HCO3-)
- Ammonia (NH3)
What is the Ionization Reaction of Methylamine (CH3NH2)
CH3NH2 (aq) + H2O (l) –> CH3NH3 (aq) + OH- (aq)
What is the Ionization Reaction of Ethylamine (C2H5NH2)
C2H5NH2 (aq) + H2O (l) –> C2H5NH3 (aq) + OH- (aq)
What is the Ionization Reaction of Pyridine (C5H5N)
C5H5N (aq) + H2O (l) –> C5H5NH (aq) + OH- (aq)
What is the Ionization Reaction of Aniline (C6H5NH2)
C6H5NH2 (aq) + H2O (l) –> C6H5NH3 (aq) + OH- (aq)
What is the Ionization Reaction of Carbonate Ion (CO3 2-)
CO3 2- (aq) + H2O (l) –> HCO3 (aq) + OH- (aq)
What is the Ionization Reaction of Bicarbonate Ion (HCO3-)
HCO3- (aq) + H2O (l) –> H2CO3 (aq) + OH- (aq)
What is the Ionization Reaction of Ammonia (NH3)
NH3 (aq) + H2O (l) –> NH4 (aq) + OH- (aq)
What do all of the Weak Base pairs have in common?
All of the bases have a nitrogen atom and a lone pair
Lone pairs act as a what?
Acts as a proton acceptor
Define Base Ionization Constant (Kb)
The equilibrium constant for the ionization of a weak base
The larger the Kb, the ___________ the pKb, and the ___________ the weak base
Smaller, stronger
The smaller the Kb, the __________ the pKb, and the ___________ the weak base
Larger, weaker
Define Salt
A chemical compound consisting of an assembly of cations and anions
A cation can potentially serve as a __________ and an anion can potentially serve as a __________
Acid, base
Think of any anion as the __________ ________ of an acid
Conjugate Base
An anion thats conjugate base is weak acid =
Weak base
An anion thats conjugate base is strong acid =
pH neutral
Classify each anion as a strong or weak acid and then identify the conjugate base I) Cl- II) F- III) NO3- IV) C2H3O2-
I) HCl, strong acid, pH neutral
II) HF, weak acid, weak base
III) HNO3, strong acid, pH neutral
IV) HC2H3O2, weak acid, weak base
Classify each anion as a strong or weak acid and then identify the conjugate base
I) NO3-
II) C2H3O2-
III) I-
I) HNO3, strong acid, pH neutral
II) HC2H3O2, weak acid, weak base
III) HI, strong acid, pH neutral
Which of the following anions CANNOT act as a base? I) F- II) NO2- III) C2H3O2- IV) CN- V) I-
I) HF, weak acid II) HNO2, weak acid III) HC2H3O2, weak acid IV) HCN, weak acid V) HI, strong acid (can't act as a base)
What is the equation for finding pKb?
pKb = -logKb
Which statement is false about acids and bases?
I) Arrhenius acid is a substance that produces H+ ions in aqueous solutions
II) Arrhenius base is a substance that produces OH- ions in aqueous solutions
III) Bronsted bases are considered as OH- acceptors
IV) H2O can act as an acid
V) H2O can act as a base
III is false; Bronsted bases are considered proton (H+ ion) acceptors
What is the conjugate acid of C17H19NO3?
C17H20N03+
Which of the following is a conjugate acid-base pair? I) HI, NaOH II) H3O+, OH+ III) H3PO4, PO4 3- IV) H2SO4, HSO4- V) NH3, NH4-
IV ; H2SO4, HSO4-
How many of these compounds are considered as Lewis Acids? I) Al3+ II) H2O III) NH4+ IV) CN- V) FeCl3 VI) NH3
4 ; Al3+, H2O, NH4+ and FeCl3
What is the most accurate and complete description of a Lewis Acid and Lewis Base respectively?
I) A proton donor and proton acceptor
II) A proton acceptor and proton donor
III) Electron donor and electron acceptor
IV) Electron acceptor and electron donor
IV ; Electron acceptor and electron donor
How many of the following are weak acids? I) CH3COOH II) HF III) HCl IV) HI V) H2SO4 VI) HCOOH
3 ; CH3COOH, HF and HCOOH
How many of the following is/are weak bases? I) CH3NH2 II) NH3 III) LiOH IV) C5H5N V) NaCl
3 ; CH3NH2, NH3 and C5H5N
Which statement is incorrect about bases?
I) Strong bases completely dissociate in water and donate OH-
II) Weak bases produce OH- by accepting protons from water, ionizing water to form OH-
III) Most weak bases contain a lone pair and a nitrogen atom
IV) For weak bases, OH- is equal to the initial concentration of the base
IV
What are the different ways of categorizing Cations?
- Cations of strong bases
- Cations of conjugated acids
- Cations of highly charged metals
Define Cations of Strong Bases
Cations that are the counterions of strong bases; results in pH neutral
Define Cations of Conjugated Acids
Cations that are the conjugate acid of a weak base; results in weak acid
Define Cations of Highly Charged Cations
Cations that are small and highly charged metals; results in weak acid
What is an example of Highly Charged Cations?
Al3+ and Fe3+
Classify each of the following as a weak acid or pH neutral
I) Ca2+
II) C5H5NH+
III) Cr3+
I) pH neutral
II) Weak acid
III) Weak acid
What is the equation comparing the strength of Conjugate Acid-Base Pairs?
Ka x Kb = Kw
The ____________ the acid, the ____________ the conjugate base (vise versa)
Stronger ; weaker
Conjugate acid of a weak base results in a ________ Cation, paired with conjugate base of a strong acid results in a _________ Anion. Together resulting in __________
Acidic ; neutral ; acidic
Small highly charged metal ion results in a ________ Cation, paired with conjugate base of a strong acid results in a _________ Anion. Together resulting in __________
Acidic ; neutral ; acidic
Counterion of strong base results in a __________ Cation, paired with conjugate base of a strong acid results in a _________ Anion. Together resulting in __________
Neutral ; neutral ; neutral
Conjugate acid of a weak base results in a _________ Cation, paired with conjugate base of a weak acid results in a _________ Anion. Together resulting in __________
Acidic ; basic ; would be acidic or basic depending on the relative strength
Small highly charged metal ion results in a __________ Cation, paired with conjugate base of a weak acid results in a _________ Anion. Together resulting in __________
Acidic ; basic ; would be acidic or basic depending on the relative strength
Counterion of strong base results in a __________ Cation, paired with conjugate base of a weak acid results in a _________ Anion. Together resulting in _________
Neutral ; basic ; basic
Define Monoprotic Acid
Acid containing one ionizable proton
What are some examples of Monoprotic Acids?
HF, HCl and HCOOH
Define Diprotic Acids
Acids containing two ionizable protons
What are some examples of Diprotic Acids?
H2SO4, H2SO3 and H2CO3
Define Triprotic Acids
Acids containing three ionizable protons
What are some examples of Triprotic Acids?
H3PO4
Define Polyprotic Acids
Acids containing two or more ionizable protons
In regards to Polyprotic Acids, will the successive Ka value following the first be smaller, larger or the same?
Smaller than the first Ka value
Define Binary Acids
Acids that contain a Hydrogen and only one other element (nonmetal)
What is the acid strength of Binary Acids?
Increases LEFT to RIGHT and TOP to BOTTOM
Define Oxyacids
Acids that contain a Hydrogen atom bonded to an oxygen atom that is bonded to another element
What is the acid strength of Oxyacids?
The GREATER the number of OXYGEN atoms bonded to the same Y the STRONGER the Oxyacid
How do you determine the strength of Oxyacids with the same number of Oxygen atoms?
The MORE ELECTRONEGATIVE (to the right or to the top) the element Y, the STRONGER the Oxyacid