Pick up the PPT notes and the practice paper off the front

demo table.

Pick up the PPT notes and the practice paper off the front

demo table.

PAP CHEMISTRYPAP CHEMISTRY

ACIDS AND BASESACIDS AND BASES

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PAP ChemChapter 1:Intro to Chem

PropertiesProperties

electrolytes electrolytes

turn litmus red

sour taste

react with metals to form H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar, milk, soda, apples, citrus fruits

ammonia, lye, antacid, baking soda

Acids are Proton (H+ ion) DonorsAcids are Proton (H+ ion) Donors

Strong acids are assumed to be 100% ionized in solution (good H+ donors).

Weak acids are usually less than 5% ionized in solution (poor H+ donors).

HCl

H2SO4 HNO3

H3PO4 HC2H3O2Organic acids

StrengthStrength

Strong Acid/Base• 100% ionized in water• strong electrolyte

- +

HCl

HNO3

H2SO4

HBr

HI

HClO4

NaOH

KOH

Ca(OH)2

Ba(OH)2

StrengthStrength

Weak Acid/Base• does not ionize completely• weak electrolyte

- +

HF

CH3COOH

H3PO4

H2CO3

HCN

NH3

Acids Have a pH less than 7

Acids Have a pH less than 7

Acids Taste SourAcids Taste Sour

Citric acid in citrus fruit Malic acid in sour apples Lactic acid in sour milk

and sore muscles

Butyric acid in rancid butter

Organic acids are weak acids. Some are used as flavoring agents in food.

Acids Effect

Indicators

Acids Effect

Indicators

Blue litmus paper turns red in contact with an acid.

Methyl orange turns red with addition of an acid

Acids React with Active MetalsAcids React with Active Metals

Acids react with active metals to form salts and hydrogen gas.

Mg + 2HCl MgCl2 + H2(g)

Zn + 2HCl ZnCl2 + H2(g)

Mg + H2SO4 MgSO4 + H2(g)

Acids React with CarbonatesAcids React with Carbonates

2HC2H3O2 + Na2CO3

2 NaC2H3O2 + H2O + CO2

Effects of Acid Rain on Marble(calcium carbonate)

Effects of Acid Rain on Marble(calcium carbonate)

George Washington:BEFORE

George Washington:AFTER

Acids Neutralize BasesAcids Neutralize Bases

HCl + NaOH NaCl + H2O

Neutralization reactions ALWAYS produce a salt and water.

H2SO4 + 2NaOH Na2SO4 + 2H2O

2HNO3 + Mg(OH)2 Mg(NO3)2 + 2H2O

OH- (hydroxide) in base combines with H+ in acids to form water

H+ + OH- H2O

DefinitionsDefinitions

Arrhenius - In aqueous solution…

HCl + H2O H3O+ + Cl–

• Acids form hydronium ions (H3O+)

H

HH H H

H

ClClO O

–+

acid

DefinitionsDefinitions

Arrhenius - In aqueous solution…

• Bases form hydroxide ions (OH-)

NH3 + H2O NH4+ + OH-

H

H

HH H

H

N NO O–+

H

H

H H

base

DefinitionsDefinitions

Brønsted-Lowry

HCl + H2O Cl– + H3O+

• Acids are proton (H+) donors. • Bases are proton (H+) acceptors.

conjugate acidconjugate base

baseacid

DefinitionsDefinitions

H2O + HNO3 H3O+ + NO3–

CBCAAB

DefinitionsDefinitions

Amphoteric - can be an acid or a base.

NH3 + H2O NH4+ + OH-

CA CBB A

DefinitionsDefinitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following:• (these are acids)

Polyprotic - an acid with more than one H+

DefinitionsDefinitions

Br -

HSO4-

CO32-

HBr

H2SO4

HCO3-

Give the conjugate acid for each of the following:• (these are bases-accept protons)

DefinitionsDefinitions

Lewis• Acids are electron pair acceptors. • Bases are electron pair donors.

Lewis base

Lewis acid

Acid/Base DefinitionsAcid/Base Definitions

Type Acid Base

Arrhenius H+ producer OH- producer

Bronsted-Lowry

H+ donor H+ acceptor

Lewis Electron-pair acceptor

Electron-pair donor

Anion Ending Acid Name

-ide hydro-(stem)-ic acid

-ate (stem)-ic acid

-ite (stem)-ous acid

Acid NomenclatureAcid Nomenclature

HBr

H2CO3

H2SO3

• 2 elements, -ide

• 3 elements, -ate

• 3 elements, -ite

hydrobromic acid

carbonic acid

sulfurous acid

Acid NomenclatureAcid Nomenclature

hydrofluoric acid

sulfuric acid

nitrous acid

• 2 elements

• 3 elements, -ic

• 3 elements, -ous

HF

H2SO4

HNO2

Acid NomenclatureAcid Nomenclature

H+ F-

H+ SO42-

H+ NO2-

Properties of BasesProperties of Bases

Bases are proton (hydrogen ion, H+) acceptors

Bases have a pH greater than 7 Bases taste bitter Bases effect indicators

Red litmus turns blue Phenolphthalein turns purple

Solutions of bases feel slippery Bases neutralize acids

Bases are Proton (H+ ion) Acceptors

Bases are Proton (H+ ion) Acceptors

Sodium hydroxide (lye), NaOH Potassium hydroxide, KOH Magnesium hydroxide, Mg(OH)2

Calcium hydroxide (lime), Ca(OH)2

Bases have a

pH greater than 7

Bases have a

pH greater than 7

Bases Effect Indicators

Bases Effect Indicators

Red litmus paper turns blue in contact with a base.

Phenolphthalein turns bright pink in a base.

Bases Neutralize Acids

Bases Neutralize Acids

Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.

2 HCl + Mg(OH)2 MgCl2 + 2 H2O