Acids, Bases, and SaltsAcids, Bases, and Salts

Chapter 23Chapter 23

Acids and Bases – Section 1Acids and Bases – Section 1

What do you think of when you hear acid?What do you think of when you hear acid?

Acids have at least 1 hydrogen atom that Acids have at least 1 hydrogen atom that can be removedcan be removed

Acid:Acid: produces H produces H++ in a water solution. in a water solution.

HH++ reacts w/ H reacts w/ H22O to form HO to form H33OO++

hydronium ionhydronium ion

Properties of AcidsProperties of AcidsTaste sourTaste sourBurns on skinBurns on skinCorrosive – irreparable damageCorrosive – irreparable damageReact strongly w/ certain metals and React strongly w/ certain metals and produce Hproduce H22 gas gas

React w/ indicators to produce different React w/ indicators to produce different colorscolorsIndicator:Indicator: organic compound that organic compound that changes color in an acid or base.changes color in an acid or base.

Common AcidsCommon Acids

BasesBases

Ex: baking powder, Mallox and antacids Ex: baking powder, Mallox and antacids are basesare bases

Soaps: clean greasy, fatty substances Soaps: clean greasy, fatty substances (bases)(bases)

Base:Base: produce hydroxide ion,OH produce hydroxide ion,OH--, in , in HH22O solution. Also, accepts HO solution. Also, accepts H++ ion. ion.

Properties of BasesProperties of BasesOpposites of acidsOpposites of acids

Many are crystalline solidsMany are crystalline solids

Most are ionic compoundsMost are ionic compounds

Feel slippery and have bitter tasteFeel slippery and have bitter taste

Corrosive and cause severe burnsCorrosive and cause severe burns

React w/ indicators to produce different React w/ indicators to produce different colorscolors

Common BasesCommon Bases

Strengths of Acids and Strengths of Acids and BasesBases

Section 2Section 2

Strong and Weak AcidsStrong and Weak Acids

Strength depend on how many particles Strength depend on how many particles dissociate into ionsdissociate into ions

Strong Acid:Strong Acid: nearly all molecules nearly all molecules dissociate into ionsdissociate into ions

Ex: HCl, HNOEx: HCl, HNO33, H, H22SOSO44

Strong and Weak AcidsStrong and Weak Acids

Weak Acids:Weak Acids: only small amount dissolves only small amount dissolves in waterin water

Ions do the damage – more ions more Ions do the damage – more ions more damage!!damage!!

Ex: Acetic Acid and Carbonic AcidEx: Acetic Acid and Carbonic Acid

Strong and Weak AcidsStrong and Weak Acids

Strong vs. WeakStrong vs. Weak

Strong:Strong: All ProductsAll Products

Weak:Weak: Some Reactants and Some ProductsSome Reactants and Some Products

Strong and Weak BasesStrong and Weak Bases

Most bases are ionic compoundsMost bases are ionic compounds

Strong Base: Strong Base: dissociate completely to its dissociate completely to its ions. Ex: sodium hydroxide, NaOHions. Ex: sodium hydroxide, NaOH

Weak Base:Weak Base: does NOT dissociate does NOT dissociate completely. Ex: ammonia, NHcompletely. Ex: ammonia, NH33

Dilute and ConcentrationDilute and Concentration

DiluteDilute: more water than acid: more water than acid

ConcentratedConcentrated: more acid than water: more acid than water

Can have Can have concentrated weak acidconcentrated weak acid and and dilute strong aciddilute strong acid

Measuring StrengthMeasuring Strength

pH:pH: measure of concentration of H measure of concentration of H++

More HMore H++ the lower the pH the lower the pH

Scale from 0 – 14Scale from 0 – 14

7 = neutral, concentration of OH7 = neutral, concentration of OH-- = = concentration of Hconcentration of H++

Below 7 = acidic, more HBelow 7 = acidic, more H++

Above 7 = basic, more OHAbove 7 = basic, more OH--

pH ScalepH Scale

BuffersBuffers

Def:Def: solutions containing ions that react solutions containing ions that react with additional acids or bases to minimize with additional acids or bases to minimize effects on pHeffects on pH

SaltsSalts

Section 3Section 3

NeutralizationNeutralization

Def:Def: rxn between an acid and a base that rxn between an acid and a base that takes place in a water solution.takes place in a water solution.

2 rxns occur: HCl(2 rxns occur: HCl(aqaq) + NaOH() + NaOH(aqaq) ) HH33OO++((aqaq) + OH) + OH--((aqaq) ) H H22O(O(ll) ) waterwater NaNa++((aqaq) + Cl) + Cl--((aqaq) ) NaCl( NaCl(aqaq)) saltsalt

Salt FormationSalt Formation

Salt:Salt: compound formed when (-) ion from compound formed when (-) ion from acid combines with (+) ion from baseacid combines with (+) ion from base

Ex: NaClEx: NaCl

Acid Base RxnsAcid Base Rxns

acid + base acid + base salt + water salt + water2HCl(2HCl(aqaq) + Ca(OH)) + Ca(OH)22((aqaq) ) CaCl CaCl22((aqaq) + 2H) + 2H22O(O(ll))

Soaps and DetergentsSoaps and DetergentsPolar(water) and Nonpolar(grease fat) Polar(water) and Nonpolar(grease fat) substancessubstances

““Like dissolves Like”Like dissolves Like”

Polar dissolves Polar, etc.Polar dissolves Polar, etc.

Soaps have both Soaps have both PolarPolar and and NonpolarNonpolar endsends Mix with water and greaseMix with water and grease Hydrocarbon Chain is 12 - 18 carbonsHydrocarbon Chain is 12 - 18 carbons

Soap ScumSoap Scum

Salts form that are insoluble in waterSalts form that are insoluble in water

DetergentsDetergents do NOT make insoluble salts do NOT make insoluble salts can be used in cold watercan be used in cold water