Properties of acidsProperties of acids Taste Sour (kids, don’t try this at Taste Sour (kids, don’t try this at

home).home). Conduct electricity.Conduct electricity. Some are strong, some are weak Some are strong, some are weak

electrolytes.electrolytes. React with metals to form hydrogen React with metals to form hydrogen

gas.gas. Change indicators (litmus red).Change indicators (litmus red). React with hydroxides to form water React with hydroxides to form water

and a salt.and a salt.

Properties of basesProperties of bases React with acids to form water and React with acids to form water and

a salt.a salt. Taste bitter.Taste bitter. Feel slippery (Don’t try this either).Feel slippery (Don’t try this either). Can be strong or weak Can be strong or weak

electrolytes.electrolytes. Change indicators (litmus blue).Change indicators (litmus blue).

WaterWater Water ionizes- falls apart into ions.Water ionizes- falls apart into ions.

HH22O O H H++ + OH + OH--

Called the self ionization of water.Called the self ionization of water. Only a small amount.Only a small amount. [H[H++ ] = [OH ] = [OH--] = 1 x 10] = 1 x 10-7-7MM A neutral solution.A neutral solution. In water Kw = [HIn water Kw = [H++ ] x [OH ] x [OH--] = 1 x 10] = 1 x 10-14-14

Kw is called the ion product constant.Kw is called the ion product constant.

Ion Product ConstantIon Product Constant HH22O O H H++ + OH + OH--

Kw is constant in every aqueous. Kw is constant in every aqueous. solution [Hsolution [H++] x [OH] x [OH--] = 1 x 10] = 1 x 10-14-14MM22

If [HIf [H++] > 10] > 10-7-7 then [OH then [OH--] < 10] < 10-7-7 If [HIf [H++] < 10] < 10-7-7 then [OH then [OH--] > 10] > 10-7-7

If we know one, we can determine If we know one, we can determine the other.the other.

If [HIf [H++] > 10] > 10-7-7 acidic [OHacidic [OH--] < 10] < 10-7-7 If [HIf [H++] < 10] < 10-7-7 basic [OHbasic [OH--] > 10] > 10-7-7

LogarithmsLogarithms Powers of ten.Powers of ten. A shorthand for big, or small A shorthand for big, or small

numbers.numbers. pH = -log[HpH = -log[H++]] in neutral pH = - log(1 x 10in neutral pH = - log(1 x 10-7-7) = 7) = 7 in acidic solution [Hin acidic solution [H++] > 10] > 10-7-7

pH < -log(10pH < -log(10-7-7)) pH < 7pH < 7 in base pH > 7in base pH > 7

pH and pOHpH and pOH pOH = - log [OHpOH = - log [OH--] ] [H[H++] x [OH] x [OH--] = 1 x 10] = 1 x 10-14-14MM22

pH+pOH = 14pH+pOH = 14

0 1 3 5 7 9 11

13

140135791

113

14

Basic

100

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Basic

100

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Acidic Neutral

[OH-]

pH

[H+]

pOH

Types of Acids and BasesTypes of Acids and Bases

Several DefinitionsSeveral Definitions

Arrhenius DefinitionArrhenius Definition Acids produce hydrogen ions in Acids produce hydrogen ions in

aqueous solution.aqueous solution. Bases produce hydroxide ions Bases produce hydroxide ions

when dissolved in water.when dissolved in water. Limits to aqueous solutions.Limits to aqueous solutions. Only one kind of base.Only one kind of base. NHNH33 ammonia could not be an ammonia could not be an

Arrhenius base.Arrhenius base.

Polyprotic AcidsPolyprotic Acids Some compounds have more than Some compounds have more than

1 ionizable hydrogen.1 ionizable hydrogen. HNOHNO3 3 nitric acid - monoproticnitric acid - monoprotic

HH22SOSO44 sulfuric acid - diprotic - 2 H sulfuric acid - diprotic - 2 H++

HH33POPO44 phosphoric acid - triprotic - phosphoric acid - triprotic -

3 H3 H++

Bronsted-Lowry DefinitionsBronsted-Lowry Definitions And acid is an proton (HAnd acid is an proton (H++) donor and a ) donor and a

base is a proton acceptor.base is a proton acceptor. Acids and bases always come in pairs.Acids and bases always come in pairs. HCl is an acid.HCl is an acid. When it dissolves in water it gives its When it dissolves in water it gives its

proton to water.proton to water.

HCl(g) + HHCl(g) + H22O(l) O(l) HH33OO++ + Cl + Cl--

Water is a base makes hydronium ion.Water is a base makes hydronium ion.

Come in PairsCome in Pairs General equation General equation HA(aq) + HHA(aq) + H22O(l) O(l) H H33OO++(aq) + A(aq) + A--(aq)(aq)

Acid + Base Acid + Base Conjugate acid +Conjugate acid + Conjugate base Conjugate base

This is an equilibrium.This is an equilibrium. B(aq) + HB(aq) + H22O(l) O(l) BH BH++(aq) + OH(aq) + OH--(aq)(aq)

Base + Acid Base + Acid Conjugate acid +Conjugate acid + Conjugate base Conjugate base

NHNH33(aq)+H(aq)+H22O(l) O(l) NH NH44++(aq)+OH(aq)+OH--(aq)(aq)

How StrongHow Strong

StrengthStrength Strong acids and bases are strong Strong acids and bases are strong

electrolyteselectrolytes They fall apart completely.They fall apart completely. Weak acids don’t completely ionize.Weak acids don’t completely ionize. Concentrated much dissolved.Concentrated much dissolved. Strong forms may ions when Strong forms may ions when

dissolved.dissolved. Mg(OH)Mg(OH)22 is a strong base- it falls is a strong base- it falls

completely apart when dissolved. completely apart when dissolved. Not much dissolves.Not much dissolves.

Measuring strengthMeasuring strength Ionization is reversible.Ionization is reversible. HAHA HH++ + A + A- -

makes an equilibrium.makes an equilibrium. Equilibrium constant for an Equilibrium constant for an

acid(acid dissociation constant.acid(acid dissociation constant. KKaa = [H = [H++ ][A ][A- - ] ]

[HA][HA] Stronger acid- more products.Stronger acid- more products. larger Klarger Kaa (pg 450) (pg 450)

What about bases?What about bases? Strong bases dissociate completely.Strong bases dissociate completely.

B + HB + H22OO BH BH++ + OH + OH--

Base dissociation constant.Base dissociation constant. KKbb = [BH = [BH++ ][OH ][OH--]] [B][B]

we can ignore the waterwe can ignore the water Stronger base more dissociated.Stronger base more dissociated. Larger KLarger Kb.b.

PracticePractice Write the expression for HNOWrite the expression for HNO22

Write the KWrite the Kbb for NH for NH33

Neutralization reactionsNeutralization reactions

Neutralization Reactions Neutralization Reactions Acid + Base Acid + Base Salt + water Salt + water Salt = an ionic compoundSalt = an ionic compound Water = HOHWater = HOH HNOHNO33 + KOH + KOH

HCl + Mg(OH)HCl + Mg(OH)22

HH22SOSO44 + NaOH + NaOH

Really just double replacement.Really just double replacement.

Reactions Happen in Moles Reactions Happen in Moles How many moles of HNOHow many moles of HNO33 are need are need

to neutralize 0.86 moles of KOH?to neutralize 0.86 moles of KOH? How many moles of HCl are How many moles of HCl are

needed to neutralize 3.5 moles of needed to neutralize 3.5 moles of Mg(OH)Mg(OH)22 ? ?

Usually happen in solutionsUsually happen in solutions If it takes 87 mL of an HCl solution If it takes 87 mL of an HCl solution

to neutralize 0.67 moles of to neutralize 0.67 moles of Mg(OH)Mg(OH)22 what is the concentration what is the concentration

of the HCl solution?of the HCl solution? If it takes 58 mL of an HIf it takes 58 mL of an H22SOSO44

solution to neutralize 0.34 moles of solution to neutralize 0.34 moles of NaOH what is the concentration of NaOH what is the concentration of the Hthe H22SOSO44 solution? solution?

TitrationTitration

Determining an unknownDetermining an unknown

TitrationTitration When you add the same number of When you add the same number of

moles of acid and base, the solution is moles of acid and base, the solution is neutral.neutral.

By measuring the amount of a base By measuring the amount of a base added you can determine the added you can determine the concentration of the acid.concentration of the acid.

If you know the concentration of the If you know the concentration of the base.base.

This is a titration.This is a titration.

NormalityNormality Want moles of HWant moles of H++ and OH and OH--

molarity x liters = moles of acid or molarity x liters = moles of acid or basebase

Don’t want moles of acid or baseDon’t want moles of acid or base Want moles of HWant moles of H++ and OHand OH-- Moles HMoles H++ = Molarity x liters x # of H= Molarity x liters x # of H++

Normality = Molarity x # of HNormality = Molarity x # of H++

Normality x Liters = Moles of HNormality x Liters = Moles of H++

Same process for base yieldsSame process for base yields

Titration equationsTitration equations MMaa x V x Vaa x # of H x # of H++ = M = Mbb x V x Vbb x # of x # of

OHOH-- NNaa x V x Vaa = N = Nbb x V x Vbb

really moles of Hreally moles of H++= moles of OH= moles of OH--

PracticePractice What is the normality of the What is the normality of the

following.following. 2.0 M hydrofluoric acid2.0 M hydrofluoric acid 0.18 M phosphoric acid0.18 M phosphoric acid 4.0 M potassium hydroxide4.0 M potassium hydroxide 0.0020 calcium hydroxide 0.0020 calcium hydroxide

More PracticeMore Practice If it takes 45 mL of a 1.0 M NaOH If it takes 45 mL of a 1.0 M NaOH

solution to neutralize 57 mL of HCl, solution to neutralize 57 mL of HCl, what is the concentration of the HCl ?what is the concentration of the HCl ?

If it takes 67 mL of 0.500 M HIf it takes 67 mL of 0.500 M H22SOSO44 to to

neutralize 15mL of Al(OH)neutralize 15mL of Al(OH)33 what was what was

the concentration of the Al(OH)the concentration of the Al(OH)33 ? ?

How much of a 0.275 M HCl will be How much of a 0.275 M HCl will be needed to neutralize 25mL of .154 M needed to neutralize 25mL of .154 M NaOH?NaOH?