Introduction to Introduction to Acids, BasesAcids, Bases

Arrhenius Definition of Arrhenius Definition of Acids and BasesAcids and Bases

Acids dissociate to produce Acids dissociate to produce HH++ ionsions in aqueous (water) in aqueous (water) solutionssolutions HCl HCl H H+ + (aq) + Cl(aq) + Cl- - (aq)(aq)

Bases dissociate to produce Bases dissociate to produce OHOH-- ions ions in aqueous (water) in aqueous (water) solutionssolutions

NaOHNaOH Na Na+ + (aq) + OH(aq) + OH--(aq)(aq)

DissociationDissociationDissociation:Dissociation: when a compound splits when a compound splits

apart into ions in solution.apart into ions in solution.

How might these dissociate?How might these dissociate?

HH22SOSO44

KOHKOHDO NOW:

Packet page 3, #7

Practice Writing Dissociation Equations

Note: Note: Acids and Bases are only reactive if their Acids and Bases are only reactive if their

ions are dissociated (when aqueous)ions are dissociated (when aqueous)

HCl (l) = hydrogen chlorideHCl (l) = hydrogen chlorideHCl (aq) = hydrochloric acidHCl (aq) = hydrochloric acid

Getting to Know Some AcidsGetting to Know Some Acids

6

Some Common AcidsSome Common AcidsSee Table KSee Table K

HClHCl hydrohydrochlorchloric acidic acid

HNOHNO33 nitr nitric acidic acid

HH33POPO44 phosphor phosphoric acidic acid

HH22SOSO44 sulfursulfuric acidic acid

HCHC22HH33OO22 acet acetic acidic acid

The Hydronium Ion (HThe Hydronium Ion (H3300++)) Acids produce the HAcids produce the H++ ion ion

This is just a “bare proton” This is just a “bare proton” and is very reactive.and is very reactive.

It immediately forms a It immediately forms a coordinate covalent bond coordinate covalent bond with nearby water with nearby water molecules to form (Hmolecules to form (H3300++).).

Do Now:

Draw the formation of the Hydronium Ion

Organic AcidsOrganic AcidsContain carbon Contain carbon Only one of the hydrogens is “acidic” and Only one of the hydrogens is “acidic” and

dissociates in solutiondissociates in solutionEx:Ex: Acetic AcidAcetic Acid

HCHC22HH33OO22 or or CHCH33COOHCOOH

Naming Acids (Honors)Naming Acids (Honors)Binary AcidsBinary Acids

(Contain 2 elements only)(Contain 2 elements only)

Ex:Ex: HCl, HBr, HHCl, HBr, H22S, HFS, HF

Hydro __________ ic AcidHydro __________ ic Acid

Naming Acids (Honors)Naming Acids (Honors)Ternary AcidsTernary Acids

(Contain hydrogen and a polyatomic ion)(Contain hydrogen and a polyatomic ion)Do NOT start with “Hydro”Do NOT start with “Hydro”

Look at name of polyatomic ionLook at name of polyatomic ion If it ends in “ate” the acid ends in “ic”If it ends in “ate” the acid ends in “ic”

If it ends in “ite” the acid ends in “ous”If it ends in “ite” the acid ends in “ous”

Name These Acids (Honors)Name These Acids (Honors)

HBrHBrHNOHNO33

HH33POPO44

HNOHNO22

HH22CC22OO44

HClOHClOHBrOHBrOHClOHClO44

HH22SSHIOHIO33

Name These Acids (Honors)Name These Acids (Honors)HBr = hydrobromic acidHBr = hydrobromic acid

HNOHNO3 3 = nitric acid= nitric acid

HH33POPO4 4 = phosphoric acid= phosphoric acid

HNOHNO22 = nitrous acid = nitrous acid

HH22CC22OO4 4 = oxalic acid= oxalic acid

HClO = hypochlorous acidHClO = hypochlorous acid

HBrO = hypobromous acidHBrO = hypobromous acid

HClOHClO4 4 = perchloric acid= perchloric acid

HH22S = hydrosulfuric acidS = hydrosulfuric acid

HIOHIO3 3 = iodic acid= iodic acid

Getting to Know Some BasesGetting to Know Some Bases

Naming BasesNaming Bases

All Arrhenius bases contain the hydroxide ionAll Arrhenius bases contain the hydroxide ion

Name ends in “hydroxide”Name ends in “hydroxide”Ex: LiOH = lithium hydroxideEx: LiOH = lithium hydroxide

Note: Note: There are “Non” Arrhenius Bases, more on them There are “Non” Arrhenius Bases, more on them

laterlater

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Some Common BasesSome Common BasesSee Table LSee Table L

NaOHNaOH sodium hydroxidesodium hydroxide

KOHKOH potassium hydroxidepotassium hydroxide

Ba(OH)Ba(OH)22 barium hydroxidebarium hydroxide

Mg(OH)Mg(OH)22 magnesium hydroxide magnesium hydroxide

Al(OH)Al(OH)33 aluminum hydroxidealuminum hydroxide

Important NoteImportant NoteThere are no “organic bases” (containing There are no “organic bases” (containing

carbon).carbon).

CC22HH55OH for example is not a base.OH for example is not a base.

It is an alcohol. It is an alcohol.

The OH on this molecule does not The OH on this molecule does not dissociate to form OHdissociate to form OH- - (hydroxide ion)(hydroxide ion)

SaltsSalts ““Salts” are ionic compounds that are not Salts” are ionic compounds that are not

acids or bases.acids or bases.

Metal cation (+) & nonmetal anion (-)Metal cation (+) & nonmetal anion (-)Ex: NaCl, MgSOEx: NaCl, MgSO44, Li, Li22SS

18

Learning Check Learning Check

Acid, Base Acid, Base NameNameor Saltor Salt

CaClCaCl2 2 ____________ ______________________________

KOHKOH ____________ ______________________________

Ba(OH)Ba(OH)2 2 ____________ _______________ _______________

HBrHBr ____________ ______________________________

HH22SOSO44 ____________ ________________________________

AnswersAnswers

Acid,Base Nameor Salt

CaCl2 salt calcium chloride

KOH base potassium hydroxide

Ba(OH)2 base barium hydroxide

HCl acid hydrochloric acid

H2SO4 acid sulfuric acid

ElectrolytesElectrolytesAcids & Bases & Salts are electrolytesAcids & Bases & Salts are electrolytes

Produce free ions when dissolved Produce free ions when dissolved Solutions will conduct.Solutions will conduct.More concentrated = more conductive.More concentrated = more conductive.

Do Now:

Practice Ditto on Identifying Electrolytes

http://www.kentchemistry.com/links/AcidsBases/Electrolytes.htm

Taste & FeelTaste & Feel

AcidsAcids: taste sour and give a burning : taste sour and give a burning sensation if touchedsensation if touched

BasesBases: taste bitter and feel slippery if : taste bitter and feel slippery if touchedtouched

DO NOT attempt to determine an acid or base by taste or touch ever in the lab!

Which substance, when dissolved in water, Which substance, when dissolved in water, forms a solution that conducts an electric forms a solution that conducts an electric current?current?

(1) C(1) C22HH55OH     OH    

(3) C(3) C1212HH2222OO1111

(2) C(2) C66HH1212OO66         

(4) CH(4) CH33COOH COOH

Let’s ReviewLet’s Review

A solid substance was tested in theA solid substance was tested in thelaboratory. The test results are listed below.laboratory. The test results are listed below.

• dissolves in water• dissolves in water• is an electrolyte• is an electrolyte• melts at a high temperature• melts at a high temperature

Based on these results, the solid substanceBased on these results, the solid substancecould becould be

(1) Cu               (1) Cu               (3) C(3) C(2) CuBr(2) CuBr22                    (4) C(4) C66HH1212OO66

The compound HNOThe compound HNO33 can be described as an can be described as an

(1) Arrhenius acid and an electrolyte(1) Arrhenius acid and an electrolyte

(2) Arrhenius acid and a nonelectrolyte(2) Arrhenius acid and a nonelectrolyte

(3) Arrhenius base and an electrolyte(3) Arrhenius base and an electrolyte

(4) Arrhenius base and a nonelectrolyte (4) Arrhenius base and a nonelectrolyte

Based on Reference Table F, which of Based on Reference Table F, which of these salts is the best electrolyte?these salts is the best electrolyte?

A. sodium nitrateA. sodium nitrate

B. magnesium carbonateB. magnesium carbonate

C. silver chlorideC. silver chloride

D. barium sulfateD. barium sulfate

A substance that conducts an electrical A substance that conducts an electrical current when dissolved in water is calledcurrent when dissolved in water is called

(1) a catalyst  (1) a catalyst                 

(2) a non-electrolyte(2) a non-electrolyte

(3) a metalloid   (3) a metalloid            

(4) an electrolyte(4) an electrolyte

Which compound is an Arrhenius acid?Which compound is an Arrhenius acid?

(1) CaO (1) CaO 

(2) K(2) K22OO

(3) HCl   (3) HCl  

(4) NH(4) NH33

When one compound dissolves in water, When one compound dissolves in water, the only positive ion produced in the the only positive ion produced in the solution is Hsolution is H33OO++(aq). This compound is (aq). This compound is classified asclassified as

(1) a salt(1) a salt

(2) a hydrocarbon(2) a hydrocarbon

(3) an Arrhenius acid(3) an Arrhenius acid

(4) an Arrhenius base (4) an Arrhenius base

Which substance is an Arrhenius acid?Which substance is an Arrhenius acid?

(1) Ba(OH)(1) Ba(OH)22    

                  (2) H(2) H33POPO44

(3) CH(3) CH33COOCHCOOCH33     

(4) NaCl (4) NaCl

Which compound releases hydroxide ions Which compound releases hydroxide ions in an aqueous solution?in an aqueous solution?

(1) CH(1) CH33COOH  COOH     

(2) HCl(2) HCl

(3) CH(3) CH33OH   OH                

(4) KOH (4) KOH

An Arrhenius base yields which ion as the An Arrhenius base yields which ion as the only negative ion in an aqueous solution?only negative ion in an aqueous solution?

(1) hydride ion (1) hydride ion                  

(2) hydronium ion(2) hydronium ion

(3) hydrogen ion     (3) hydrogen ion        

(4) hydroxide ion (4) hydroxide ion

The compound NaOH(s) dissolves in water The compound NaOH(s) dissolves in water to yieldto yield

(1) hydroxide ions as the only negative ions(1) hydroxide ions as the only negative ions

(2) hydroxide ions as the only positive ions(2) hydroxide ions as the only positive ions

(3) hydronium ions as the only negative ions(3) hydronium ions as the only negative ions

(4) hydronium ions as the only positive ions (4) hydronium ions as the only positive ions

How are HNOHow are HNO33(aq) and CH(aq) and CH33COOH(aq) similar?COOH(aq) similar?

(1) They are Arrhenius acids and they turn blue (1) They are Arrhenius acids and they turn blue litmus red.litmus red.

(2) They are Arrhenius acids and they turn red litmus (2) They are Arrhenius acids and they turn red litmus blue.blue.

(3) They are Arrhenius bases and they turn blue (3) They are Arrhenius bases and they turn blue litmus red.litmus red.

(4) They are Arrhenius bases and they turn red (4) They are Arrhenius bases and they turn red litmus blue. litmus blue.

Acids “Corrode” Certain MetalsAcids “Corrode” Certain MetalsSee Reference Table JSee Reference Table J

Metals above Hydrogen on the table will react Metals above Hydrogen on the table will react with acids to form a salt and Hwith acids to form a salt and H22 gas gas

Single Replacement ReactionSingle Replacement Reaction

2Zn(s) + 2HCl(aq) ZnCl2Zn(s) + 2HCl(aq) ZnCl22(aq) + H(aq) + H22(g)(g)

Will an acid react with these metals?Will an acid react with these metals?

If so complete and balance the single If so complete and balance the single replacement reaction.replacement reaction.

Mg + HNOMg + HNO33

Cu + HClCu + HCl

Ca + HCa + H22SOSO44

AnswersAnswers

Mg + 2HNOMg + 2HNO33 Mg(NOMg(NO33))22 + H + H22

Cu + HClCu + HCl No reaction Cu in below No reaction Cu in below hydrogen on Table Jhydrogen on Table J

Ca + HCa + H22SOSO44 Ca(SOCa(SO44) + H) + H22

Bases DO NOT corrode metalsBases DO NOT corrode metals

Interactive:Interactive: Acid, Bases and Metals BBC (good for Indicators)Acid, Bases and Metals BBC (good for Indicators) http://www.bbc.co.uk/schools/ks3bitesize/science/chemical_materialhttp://www.bbc.co.uk/schools/ks3bitesize/science/chemical_material

_behaviour/acids_bases_metals/activity.shtml_behaviour/acids_bases_metals/activity.shtml

DO NOW:

Packet page 2 and 3, # 4, #5

pH ScalepH ScaleUsed to help determine how acidic or basic Used to help determine how acidic or basic

something is.something is.

pH = 7 pH = 7 NeutralNeutral

pH < 7pH < 7 AcidicAcidic

pH > 7 pH > 7 BasicBasic

Acids & Bases Neutralize Each Acids & Bases Neutralize Each OtherOther

HH++ ion and OH ion and OH-- ions will join together to form ions will join together to form neutral water.neutral water.

Reaction is slightly exothermic (See Table I)Reaction is slightly exothermic (See Table I)

HH+ + (aq) + OH(aq) + OH-- (aq) (aq) →→ H H22O (l)O (l)

Determining if it is an Acid or Base Determining if it is an Acid or Base

How can you tell if something is acidic or How can you tell if something is acidic or basic?basic?

Use an electronic pH meterUse an electronic pH meter

Use an indicator such as Use an indicator such as litmuslitmus

Use pH paper containing universal indicatorUse pH paper containing universal indicator

Acid/Bases IndicatorsAcid/Bases IndicatorsUsing Table MUsing Table M

LitmusLitmus pH range for color changepH range for color change

(4.5 – 8.3)(4.5 – 8.3) Color change: red to blue Color change: red to blue

PhenolphthaleinPhenolphthalein pH range for color change pH range for color change

(8 - 9)(8 - 9) Color change: colorless to Color change: colorless to

pinkpinkWhat color would these be What color would these be

if if pH = 10? pH = 10? pH = 3?pH = 3?

Based on the results of testing colorless solutions with Based on the results of testing colorless solutions with indicators, which solution is most acidic?indicators, which solution is most acidic?

(1) a solution in which bromthymol blue is blue(1) a solution in which bromthymol blue is blue

(2) a solution in which bromcresol green is blue(2) a solution in which bromcresol green is blue

(3) a solution in which phenolphthalein is pink(3) a solution in which phenolphthalein is pink

(4) a solution in which methyl orange is red (4) a solution in which methyl orange is red

Let’s ReviewLet’s Review

According to Reference Table M, what is According to Reference Table M, what is the color of the indicator methyl orange in a the color of the indicator methyl orange in a solution that has a pH of 2?solution that has a pH of 2?

(1) blue (1) blue              

(2) orange(2) orange

(3) yellow (3) yellow      

(4) red (4) red

Which indicator would best distinguish Which indicator would best distinguish between a solution with a pH of 3.5 and a between a solution with a pH of 3.5 and a solution with a pH of 5.5?solution with a pH of 5.5?

(1) bromthymol blue (1) bromthymol blue        

(2) litmus(2) litmus

(3) bromcresol green   (3) bromcresol green   

(4) thymol blue (4) thymol blue

Which indicator is blue in a solution that Which indicator is blue in a solution that has a pH of 5.6?has a pH of 5.6?

(1) bromcresol green (1) bromcresol green    

(2) methyl orange(2) methyl orange

(3) bromthymol blue  (3) bromthymol blue    

(4) thymol blue (4) thymol blue

Which indicator is yellow in a solution with Which indicator is yellow in a solution with a pH of 9.8?a pH of 9.8?

(1) methyl orange(1) methyl orange              (2) bromcresol green(2) bromcresol green

(3) bromthymol blue (3) bromthymol blue     (4) thymol blue (4) thymol blue

In which solution will thymol blue indicator In which solution will thymol blue indicator appear blue?appear blue?

(1) 0.1 M CH(1) 0.1 M CH33COOHCOOH

      (2) 0.1 M HCl(2) 0.1 M HCl

(3) 0.1 M KOH   (3) 0.1 M KOH                      

(4) 0.1 M H(4) 0.1 M H22SOSO4 4

Properties of Acids (Summary) Properties of Acids (Summary)

Produce HProduce H++ (as H (as H33OO++) ions in water) ions in water

Electrolytes (conduct in solution)Electrolytes (conduct in solution)

Taste sour Taste sour

pH is < 7 pH is < 7

Corrode metals (see Table J)Corrode metals (see Table J)

React with bases to form salts and waterReact with bases to form salts and water

(Neutralization)(Neutralization)

Properties of Bases (Summary)Properties of Bases (Summary)

Produce OHProduce OH-- ions in water ions in water

Electrolytes (conduct in solution)Electrolytes (conduct in solution)

Taste bitter, chalkyTaste bitter, chalky

pH is >7pH is >7

Feel soapy, slipperyFeel soapy, slippery

React with acids to form salts and waterReact with acids to form salts and water

(Neutralization)(Neutralization)

53

Learning CheckLearning CheckDescribe the solution in each of the following Describe the solution in each of the following as: as: 1) acid 2) base or 3)neutral.1) acid 2) base or 3)neutral.A. ___sodaA. ___soda

B. ___soapB. ___soapC. ___coffeeC. ___coffeeD. ___ wineD. ___ wineE. ___ waterE. ___ water

F. ___ grapefruitF. ___ grapefruit

54

SolutionSolutionDescribe each solution as: Describe each solution as: 1) acid 2) base or 3) neutral.1) acid 2) base or 3) neutral.A. A. _1__1_ soda soda

B. B. _2__2_ soap soapC. C. _2__2_ coffee coffeeD. D. _1__1_ wine wineE. E. _3__3_ water water

F. F. _1__1_ grapefruit grapefruit

55

Learning CheckLearning Check

Identify each as characteristic of an Identify each as characteristic of an A) acid or B) baseA) acid or B) base____ 1. Sour taste ____ 1. Sour taste ____ 2. Produces OH____ 2. Produces OH-- in aqueous solutions in aqueous solutions

____ 3. Chalky taste____ 3. Chalky taste____ 4. Is an electrolyte____ 4. Is an electrolyte____ 5. Produces H____ 5. Produces H++ in aqueous solutions in aqueous solutions

56

SolutionSolution

Identify each as a characteristic of anIdentify each as a characteristic of an A) acid or B) baseA) acid or B) base__AA__ 1. Sour taste 1. Sour taste

__BB__ 2. Produces OH 2. Produces OH-- in aqueous solutions in aqueous solutions

__BB__ 3. Chalky taste 3. Chalky taste

A, BA, B 4. Is an electrolyte4. Is an electrolyte

__AA__ 5. Produces H 5. Produces H++ in aqueous solutions in aqueous solutions