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ACIDS & BASESACIDS & BASES
Acid Nomenclature Acid Nomenclature FlowchartFlowchart
h yd ro - p re fix-ic en d in g
2 e lem en ts
-a te en d in gb ecom es-ic en d in g
-ite en d in gb ecom es
-o u s en d in g
n o h yd ro - p re fix
3 e lem en ts
AC ID Ss ta rt w ith 'H '
Binary
-ide
Oxyacids or Ternary
-ite
-ate
NAMES AND FORMULASA Review
HX means HX means AcidAcid
If anion ends in If anion ends in “–ide”“–ide”
Acid name begins withAcid name begins with “hydro-”“hydro-”
Ends with Ends with “–ic“–ic”” , followed by , followed by “Acid”
HCl – HCl – HydroHydrochlorchloricic Acid (Chloride)Acid (Chloride)
HBr – HBr – HydroHydrobrombromicic Acid (Bromide)Acid (Bromide)
HCN – HCN – HydroHydrocyancyanic Acid (Cyanide)ic Acid (Cyanide)
NAMES AND FORMULAS
If anion ends in If anion ends in “–ite”“–ite”
Acid ends with Acid ends with “–ous”,“–ous”, followed by followed by “Acid”“Acid”
HH22SOSO33 – Sulfur – Sulfurousous AcidAcid
HNOHNO22 – Nitr – Nitrousous AcidAcid
HH33POPO33 – Phosphor – Phosphorousous AcidAcid
NAMES AND FORMULAS
If anion ends in “–ate“–ate””
Acid ends with “–ic“–ic”” ,followed by “Acid”“Acid”
H2SO4 – Sulfuric Acid
HNO3 – Nitric Acid
H3PO4 – Phosphoric Acid
NAMES AND FORMULAS
Bases Bases named same as ionic compound
NaOH –Sodium HydroxideHydroxide (Lye)Ca(OH)2 – Calcium HydroxideHydroxide (Lime)
Pb(OH)2 – Lead Hydroxide Hydroxide
KOH – Potassium HydroxideHydroxide
WATER IONIZATIONWATER IONIZATION
Water molecules in continuous random motion
Collisions between two molecules
Result in transfer of hydrogen ion
H2O + H2O HH33OO++ + OHOH--
HH33OO++ = hydronium ion
OHOH-- = hydroxide ion
3 Theories3 TheoriesAcid-Base TheoriesAcid-Base Theories
3 Theories Acid/Base3 Theories Acid/Base
Theory #1: Arrhenius (traditional) Theory #1: Arrhenius (traditional)
a) a) Acids – Acids – produce Hproduce H++ ions (or ions (or hydronium ions Hhydronium ions H33OO++) in aqueous solution) in aqueous solution
b) b) BasesBases – – produces OHproduces OH-- ions in aqueous ions in aqueous solutionssolutions
i: Monoprotic Acid gives up 1 H+ (HCL)
ii: Diprotic Acid gives up 2 H+ (H2SO4)
iii: Triprotic Acid gives up 3 H+ (H3PO4)
Arrhenius acid is a substance that produces H+ (H3O+) in water
Arrhenius base is a substance that produces OH- in water
Brønsted – LowryBrønsted – Lowry Theory #2: Brønsted – Lowry
a) Acids – proton (H+) donora) Acids – proton (H+) donor (H+ is given away)(H+ is given away)
b) Bases – proton (H+) acceptorb) Bases – proton (H+) acceptor (H+ gained)(H+ gained)
A A “proton“proton” is really just a ” is really just a hydrogen atom that has lost it’s hydrogen atom that has lost it’s electron!electron!
A Brønsted-Lowry acid is a proton donorA Brønsted-Lowry base is a proton acceptor
acid conjugate
basebase conjugate
acid
LewisLewis
a)a) Lewis acid –Lewis acid – electron pair electron pair acceptoracceptor
b) Lewis base –b) Lewis base – electron pair donorelectron pair donor
Theory #3 – Lewis Theory #3 – Lewis
WATER DISSOCIATION,SIMPLIFIED
Dissociation of water:
H2O H+ + OH-
One H+ and one OH- produced, so
[H+] = [OH-]
[ X ] = concentration (Molarity)
PROPERTIES OF ACIDS• Sour or tart taste in foodsSour or tart taste in foods
• Strong Acid = Strong Strong Acid = Strong ElectrolyteElectrolyte
• Release Release H+H+ ions in water ions in water
• Turn blue litmus paper RedTurn blue litmus paper Red
Hydrogen Ion in WaterHydrogen Ion in Water
Water + a proton Hydronium Ion
H2O + H+ H3O +1
The H+ ion has no electrons so it attached itself to a water molecule to share its electrons
ARRHENEIUS ACIDSARRHENEIUS ACIDS
Theory developed by Arrhenius (1859-1927)rrhenius (1859-1927)
Defined acids and bases as compounds that ionize to produce HDefined acids and bases as compounds that ionize to produce H++ and and OHOH--
HCl + H2O (1) H3O+ (aq) + Cl - (aq) monoprotic
H2SO4 + H2O (2) H3O
+ (aq) + SO4-2 (aq)
diprotic H3PO4 + H2O - (3) H3O
+ (aq) + PO4-3 (aq)
triprotic
ARRHENIUS ARRHENIUS ACIDSACIDS Theory: substance that contains hydrogen,
and releases the H+ in water
Types of Arrhenius AcidsTypes of Arrhenius Acids
Triprotic acids contain 3 ionizable protons
H3PO4
Monoprotic acids contain 1 ionizable proton HCl, HBr, HF, HI
Diprotic acids contain 2 ionizable protons
H2SO4
PROPERTIES OF BASES• Feels slipperyFeels slippery• Bitter tasteBitter taste• Strong Base = Strong ElectrolyteStrong Base = Strong Electrolyte• Produce Produce hydroxide ionshydroxide ions in water in water• Red litmus turns Blue in a Base Red litmus turns Blue in a Base
(RBB)(RBB)
EX: LYE USED IN SOAPMAKINGEX: LYE USED IN SOAPMAKING AMMONIA USED IN CLEANINGAMMONIA USED IN CLEANING
ARRHENIUS BASESARRHENIUS BASESSubstance that contains OH and
releases the OH-OH- in water.
NaOH + H2O Na+1 (aq) + OHOH-- (aq)
Mg(OH)2 + H2O Mg +2 (aq) + 2 OHOH--
(aq)
Some DefinitionsSome Definitions Arrhenius acids and basesArrhenius acids and bases
Acid:Acid: Substance that, when Substance that, when dissolved in water, increases the dissolved in water, increases the concentration of hydrogen ions concentration of hydrogen ions (protons, H(protons, H++).).
Base:Base: Substance that, when Substance that, when dissolved in water, increases the dissolved in water, increases the concentration of hydroxide ions.concentration of hydroxide ions.
Complete book practice problemsComplete book practice problems Pg 609Pg 609 #34,43,44,45,46#34,43,44,45,46 Or check your Power packet ( Acids Or check your Power packet ( Acids
+ Bases) pg 9+ Bases) pg 9
WhoWhoTheory:Theory:
Acid=Acid=WhenWhen
ArrheniusArrhenius increases increases HH++ 1880’s1880’s
Brønsted & Brønsted & LowryLowry
proton proton donordonor 19231923
LewisLewisElectron-Electron-pair pair acceptoracceptor
19231923
Three definitions of acid
ALTERNATE THEORIESALTERNATE THEORIESNot all materials with acidic/basic properties
in aqueous solution contain H or OH.
Don’t fit Arrhenius definition of acids & base
Thomas Lowry (1874-1936) independently proposed a new definition.
Johannes Brønsted (1879-1947) and
Some DefinitionsSome Definitions BrønstedBrønsted––Lowry: must have Lowry: must have bothboth
1. an Acid:1. an Acid: Proton donorProton donor
andand
2. a Base:2. a Base: Proton acceptorProton acceptor
BrBrøønsted – Lowry Acids and Basesnsted – Lowry Acids and Bases
B/L Acid is a hydrogen ion donor
B/L base is a hydrogen ion acceptor
Arrhenius acids and bases fit into the Brønsted – Lowry Theory
The Brønsted-Lowry acid donates a proton,
while the Brønsted-Lowry base accepts it.
Brønsted-Lowry acids and bases are always paired.
Which is the acid and which is the base in each of these rxns?
BrBrøønsted – Lowry Acids and Bases nsted – Lowry Acids and Bases
NH3 + H2O NH4+ + OH-
Ammonia is a base accepts hydrogen ion
Water is an acid donates hydrogen ion
What Happens When an Acid What Happens When an Acid Dissolves in Water?Dissolves in Water?
Water acts as a Water acts as a BrønstedBrønsted––Lowry base Lowry base and abstracts a and abstracts a proton (Hproton (H++) from the ) from the acid.acid.
As a result, the As a result, the conjugate baseconjugate base of of the acid and a the acid and a hydronium ionhydronium ion are are formed.formed.Movies…
A BrønstedA Brønsted––Lowry acid…Lowry acid…
……must have a removable (acidic) proton.must have a removable (acidic) proton.
HCl, HHCl, H22O, HO, H22SOSO44
A BrønstedA Brønsted––Lowry base…Lowry base…
……must have a pair of nonbonding must have a pair of nonbonding electrons.electrons.
NHNH33, H, H22OO
Conjugate Acids and Bases:Conjugate Acids and Bases: From the Latin word From the Latin word conjugareconjugare, meaning , meaning
“to join together.”“to join together.” Reactions between Reactions between acidsacids and and basesbases always always
yield their yield their conjugate basesconjugate bases and and acids.acids.
BrBrøønsted – Lowry Acids and Bases nsted – Lowry Acids and Bases
Conjugate Acid Conjugate Acid
Formed when a base gains a hydrogen ion.
NH4+ is the Conjugate Acid
Conjugate BaseConjugate Base
What remains when an acid has donated the hydrogen ion.
OH- is the Conjugate Base
BrBrøønsted – Lowry Acids and Basesnsted – Lowry Acids and Bases
)()()()( 423 aqOHaqNHlOHaqNH
Base
Acid Conjugate Acid
Conjugate Base
Conjugate acid / base pair
Brønsted – Lowry Acids and Bases Brønsted – Lowry Acids and Bases
Two substances that are related by the loss or gain of a hydrogen ion.
Water is Amphoteric - Acts as both Acid and Base
HCl + HHCl + H22O O H H33OO++ + Cl + Cl--
In General:Conjugate Base of a Strong Acid is weak
HCl (acid) has a weak conjugate base in Cl-
Brønsted – Lowry Acids and Bases Brønsted – Lowry Acids and Bases
Conjugate Acid of a Strong Base is weakNaOH (base) has a weak conjugate acid in Na+
ALTERNATE THEORIESALTERNATE THEORIESGilbert Lewis (1875-1946) focused
on the donation or acceptance of electrons.
Remember the Lewis Dot Structure?This is the same guy…
Lewis acid acceptsaccepts electrons to form a covalent bondLewis base donatesdonates electrons to form a covalent bond
Acid-Base DefinitionsAcid-Base Definitions
TypeType AcidAcid BaseBase
ArrheniusArrhenius HH++ producer producer OHOH-- producer producer
BrBrønsted-ønsted-LowryLowry
HH++ donor donor HH++ acceptor acceptor
LewisLewis Electron-pair Electron-pair acceptoracceptor
Electron-pair Electron-pair donordonor