Review of Acids, Bases, & Review of Acids, Bases, & SaltsSalts

Arrhenius AcidArrhenius Acid

•Has H in the formula•Produces H+ as the only positive ion in solution

Formula of an AcidFormula of an Acid

•Inorganic – formula starts with H•Organic – formula ends with COOH

Properties of AcidsProperties of Acids

•Sour Taste•Electrolytes

•React with bases to form a salt + H2O

•Turn litmus RED•React with most metals to produce H2(g)

Ionization of an AcidIonization of an Acid

HCl H+ + Cl-

HCl + H2O H3O+ + Cl-oror

Arrhenius BaseArrhenius Base

•Has OH in the formula•Produces OH- as the only negative ion in solution

Formula of a BaseFormula of a Base

•Has format MOH•M is a metal

Properties of BasesProperties of Bases

•Bitter Taste•Slippery Feel•Electrolytes•React with acids to form a salt + H2O•Turn litmus BLUE

Ionization of a BaseIonization of a Base

NaOH Na+ + OH-

Ionization of NHIonization of NH33

NH3 + H2O NH4+ + OH-

Formula of a SaltFormula of a Salt

Metal + Nonmetal

Write the formula of Write the formula of potasium sulfatepotasium sulfate

K+ & (SO4)2-

KK22SOSO44

ElectrolytesElectrolytes

•Solutions conduct – they contain ions•Acids (HX), bases (MOH), & salts (MX) are electrolytes

NONNONelectrolyteselectrolytes

Solutions of covalent compounds (all nonmetals). They do NOT

conduct.

Identify the electrolytes Identify the electrolytes

• LiOH• CH3COOH• C6H12O6

• NaNO3

• H2SO4

• CH3OH• Ca(OH)2

• HCl• C8H18

• Al(OH)3

• HNO3

• CH3CH2COOH• K2SO4

• CH3CHOHCH3

• CH3OCH3

• H3PO4

• Mg(OH)2

• CH3CH2OH

Yes - BYes - BYes - AYes - A

NNooYes - SYes - S

Yes - AYes - A

NoNoYes - BYes - B

Yes - AYes - A

NoNo

Yes - BYes - BYes - AYes - A

Yes - AYes - A

Yes - SYes - SNoNo

NoNoYes - AYes - A

Yes - BYes - BNoNo

pH scalepH scale

0-14Acidic: 0 to 7,

Neutral: 7Basic: 7-14

Most acidic on pH scaleMost acidic on pH scale

pH = 0

Most basic on pH scaleMost basic on pH scale

pH = 14

OHOH--

Hydroxide ion

HH++

Hydrogen ionor

Proton

HH33OO++

Hydronium ion. Interchangeable with H+.

Acidic SolutionAcidic Solution

[H+] [OH-]

Basic SolutionBasic Solution

[OH-] [H+]

If the pH changes from 3 If the pH changes from 3 to 5, how does the [Hto 5, how does the [H++] ]

change?change?

The pH changes by 2, so the [H+] changes by 102 or 100X. Since the

pH went up, it became LESS acidic. The new solution has a [H+] 100

times less than the original solution.

How can pH be safely How can pH be safely tested?tested?

Instrumental – use pH meterIndicators – use a series of indicators to narrow down the pH rangeTest acids with metals (NOTNOT Cu, Ag, or Au)

Bronsted-Lowry AcidBronsted-Lowry Acid

Proton Donor

Bronsted-Lowry BaseBronsted-Lowry Base

Proton Acceptor

Bronsted-Lowry Acids & Bronsted-Lowry Acids & BasesBases

HCl + H2O H3O+ + Cl-

Strong Acids & BasesStrong Acids & Bases

Complete or almost complete ionization.

Weak Acids & BasesWeak Acids & Bases

Ionization occurs only to a slight extent, a few

percent.

Reactions of Acids with Reactions of Acids with MetalsMetals

Metal + Acid H2(g) + salt

Zn(s) + HCl Zn(s) + HCl ? ?

Zn(s) + 2HCl Zn(s) + 2HCl H H22(g) + ZnCl(g) + ZnCl22

Al(s) + HCl Al(s) + HCl ? ?

2Al(s) + 6HCl 2Al(s) + 6HCl 3H 3H22(g) + 2AlCl(g) + 2AlCl33

Neutralization ReactionsNeutralization Reactions

Acid + Base Salt + H2O

Net Ionic Equation for Net Ionic Equation for Neutralization ReactionsNeutralization Reactions

H+ + OH- H2O

At neutralizationAt neutralization

Moles H+ = Moles OH-

Molarity (M)Molarity (M)

Molarity = Moles solute Liters of soln

Titration EquationTitration Equation

MaVa = MbVb

This equation works when the This equation works when the number of H’s on the acid number of H’s on the acid EQUALS the number of OH’s on EQUALS the number of OH’s on the base!the base!

Titration EquationTitration Equation

naMaVa = nbMbVb

This equation works when the This equation works when the number of H’s on the acid does NOT number of H’s on the acid does NOT equal the number of OH’s on the equal the number of OH’s on the base!base!nnaa = number of acidic H’s in acid. = number of acidic H’s in acid.nnbb = number of OH’s in base. = number of OH’s in base.

pHpH

-log[H+] or –log[H3O+]

pOHpOH

-log[OH-]

pOH + pH = pOH + pH =

14

[OH[OH--] X [H] X [H++] = ] =

1.0 X 10-14

If the [HIf the [H++] = 1 X 10] = 1 X 10-3-3

1.The pH =2.The pOH =3.The [OH-] =

33

1111

1 X 101 X 10-11-11

IndicatorIndicator

Substance that changes color over a narrow

pH range.

Molarity HMolarity H22SOSO44 Vs. Molarity H Vs. Molarity H++

H2SO4 2H+ + SO42-

[H+] = 2[H2SO4]

2M H2SO4 4M H+

What is the concentration of a What is the concentration of a hydrochloric acid solutionhydrochloric acid solution if 50.0 mL50.0 mL

of a 0.250 M KOH0.250 M KOH solution are needed to neutralize 20.0 mL20.0 mL of the of the

HClHCl solution solution of unknown concentration?

MaVa = MbVb

X(20.0 mls) = .250M(50.0mls)

Acid1.50 M

Base? M

Final Volume 16.07 24.25

Initial Volume 5.45 4.05

Amount Used

(1.50 M)(10.62 mls) = X(20.20 (1.50 M)(10.62 mls) = X(20.20 mls)mls)

10.62 20.20