chapter 15 properties of acids & bases. what is an acid? a compound that donates a hydrogen ion...

CHAPTER 15CHAPTER 15PROPERTIES OF ACIDS & PROPERTIES OF ACIDS & BASESBASES

WHAT IS AN ACID?WHAT IS AN ACID?

A compound that A compound that donates a donates a hydrogen ion (H+) hydrogen ion (H+) when dissociatedwhen dissociated

Acids, continuedAcids Generate Hydronium Ions, continued

Section 1 What Are Acids and Bases?Chapter 15

ACID PROPERTIESACID PROPERTIES

1.1. aqueous solutions have a sour aqueous solutions have a sour tastetaste

2.2. change the color of acid-base change the color of acid-base indicatorsindicators

3.3. when reacted with an active metal, when reacted with an active metal, releases hydrogen gasreleases hydrogen gas

Zn Zn (s)(s) + H + H22SOSO44 (aq)(aq) ZnSO ZnSO44 (aq)(aq) + + HH22 (g)(g)

ACID PROPERTIESACID PROPERTIES

4.4. when reacted with base, produces when reacted with base, produces salt and watersalt and water

HCl HCl (aq)(aq) + NaOH + NaOH (aq)(aq) NaCl NaCl (s)(s) + H + H22O O (l)(l)

5.5. conduct electric currentconduct electric current

6.6. Turns litmus paper redTurns litmus paper red

Visual Concepts

Strength and Weakness Strength and Weakness of Acids and Basesof Acids and Bases

Chapter 15

STRONG VS. WEAK ACIDSSTRONG VS. WEAK ACIDS

• Strong acids Strong acids dissociate dissociate completelycompletely

• Every HEvery H++ ion ion breaks offbreaks off

• Weak acids Weak acids dissociate dissociate incompletelyincompletely

• A few HA few H++ ions ions break off then break off then reformreform

WHAT IS A BASE?WHAT IS A BASE?

• A compound that accepts a A compound that accepts a hydrogen ion (H+) hydrogen ion (H+)

OROR• contains OHcontains OH-- ion ion

Bases, continued

Chapter 15Section 1 What Are Acids and Bases?

BASE PROPERTIESBASE PROPERTIES

1.1. aqueous solutions of bases have a aqueous solutions of bases have a bitter tastebitter taste

2.2. bases change the color of acid bases change the color of acid base indicatorsbase indicators

3.3. dilute aqueous solutions of bases dilute aqueous solutions of bases feel slipperyfeel slippery

BASE PROPERTIESBASE PROPERTIES

4.4. when reacted with acid, produces when reacted with acid, produces salt and watersalt and water

5.5. conduct electric currentconduct electric current

6.6. Turns litmus paper blueTurns litmus paper blue

12

Describe the solution in each of the Describe the solution in each of the following as:following as: 1) acid 2) base or 3)neutral1) acid 2) base or 3)neutralA. sodaA. soda

B. soapB. soapC. coffeeC. coffeeD. wineD. wineE. waterE. water

F. grapefruitF. grapefruit

Learning CheckLearning Check

•Relationship of [HRelationship of [H33OO++] and [OH] and [OH--]]

Chapter 15Section 1 What Are Acids and Bases?

DIFFERENT DEFINITIONSDIFFERENT DEFINITIONS

SHOULD BE SHOULD BE MEMORIZEDMEMORIZED

Visual Concepts

Arrhenius Acids and Arrhenius Acids and BasesBases

Chapter 15

ARRHENIUSARRHENIUS

ACIDACID• A chemical A chemical

compound that compound that increases the increases the concentration of concentration of HH++ ions in solution ions in solution

• Good for Good for calculating pHcalculating pH

BASEBASE• A chemical A chemical

compound that compound that increases the increases the concentration of OHconcentration of OH-- ions in solutionions in solution

• Good for calculation Good for calculation pOHpOH

• Limited to bases Limited to bases containing OHcontaining OH--

17

Arrhenius Definition Arrhenius Definition • In aqueous solution…In aqueous solution…

HCl H+(aq) + Cl-(aq)

– AcidsAcids form hydrogen ions (H+)

In aqueous solution…In aqueous solution…

•BasesBases form hydroxide ions (OH-)

NaOH Na+(aq) + OH-

(aq)

water

water

Brønsted-Lowry Classification, continuedBrønsted-Lowry Acids Donate Protons, continued

Section 1 What Are Acids and Bases?Chapter 15

Visual Concepts

BrBrøønsted-Lowry Acids nsted-Lowry Acids and Basesand Bases

Chapter 15

BRONSTED-LOWRYBRONSTED-LOWRY

ACIDACID• A molecule or ion A molecule or ion

that is a proton that is a proton (H(H++) donor) donor

BASEBASE• A molecule or ion A molecule or ion

that is a proton that is a proton (H(H++) acceptor) acceptor

• Includes Includes compounds w/o compounds w/o OHOH--

21

Brønsted-LowryBrønsted-Lowry

HCl + H2O Cl– + H3O+

– AcidsAcids are proton (H+) donors– BasesBases are proton (H+) acceptors

conjugate acidconjugate base

baseacid

Acids and bases come in Acids and bases come in pairs...pairs...

• A A conjugate baseconjugate base is the remainder of the original is the remainder of the original acid, after it donates it’s hydrogen ionacid, after it donates it’s hydrogen ion

• A A conjugate acidconjugate acid is the particle formed when the is the particle formed when the original base gains a hydrogen ionoriginal base gains a hydrogen ion

• General equation is: General equation is:

HAHA(aq)(aq) + H + H22OO(l)(l) H H33OO++(aq)(aq) + A + A--

(aq)(aq)

Acid Base Acid Base Conj acid Conj base Conj acid Conj base

LEWISLEWIS

ACIDACID• Electron pair Electron pair

acceptoracceptor

BASEBASE• Electron pair donatorElectron pair donator

Why don’t we like this definition?Why don’t we like this definition?

24

Hydronium Ion HHydronium Ion H33OO++

• Often the term HOften the term H++ for for convenience, it is more accurate convenience, it is more accurate to use to use HH33OO++

HClHCl(aq)(aq) + H+ H22OO(l)(l) HH33OO++(aq)(aq) + Cl + Cl––(aq)(aq)

H

HH H H

H

ClClO O

–+

Ex.1- Ex.1- Water as a baseWater as a base

H2O + HNO3 H3O+ + NO3–

CBCAAB

(ex. water)

Amphoteric - can be an acid or a base - can be an acid or a base

26

Ex. 2- Water as an acidEx. 2- Water as an acid

NH3 + H2O NH4+ + OH-

CA CBB A

Acid-Base Titrations and pHAcid-Base Titrations and pH

pHpH

• pH < 7 is acidicpH < 7 is acidic

• pH = 7 is neutralpH = 7 is neutral

• pH > 7 is basicpH > 7 is basic

Calculating pHCalculating pH

pH = - log [HpH = - log [H++]]

pH = power of HydrogenpH = power of Hydrogen

[H[H++] = concentration in Normality] = concentration in Normality

Calculating pOHCalculating pOH

pOH = - log [OHpOH = - log [OH--]]

pOH = power of HydroxidepOH = power of Hydroxide

[OH[OH--] = concentration in Normality] = concentration in Normality

pH + pOH = 14pH + pOH = 14

CALCULATING pH FROM CALCULATING pH FROM CONCENTRATIONCONCENTRATION

SAMPLE PROBLEM ASAMPLE PROBLEM A

What is the pH of a 1 x 10What is the pH of a 1 x 10-3-3 M HCl M HCl solution?solution?


What is the pH of a 1.0 x 10What is the pH of a 1.0 x 10-3-3 M HCl M HCl solution?solution?Step 1:Convert from M to N.

N = (1.0 x 10-3) (1)

N = 1.0 x 10-3


What is the pH of a 1.0 x 10What is the pH of a 1.0 x 10-3-3 M HCl M HCl solution?solution?Step 2:Plug-in.

pH = - log [H+]

pH = - log (1.0 x 10-3)

pH = 3

SAMPLE PROBLEM BSAMPLE PROBLEM B

What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M HH22SOSO44 solution? solution?


What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M HH22SOSO44 solution? solution?Step 1:Convert from M to N.

N = (0.025) (2)

N = 0.050


What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M HH22SOSO44 solution? solution?Step 2:Plug-in.

pH = - log [H+]

pH = - log (0.050)

pH = 1.3

SAMPLE PROBLEM CSAMPLE PROBLEM C

What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M NaOH solution?NaOH solution?


What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M NaOH solution?NaOH solution?Step 1:Convert from M to N.

N = (0.025) (1)

N = 0.025


What is the pH of a 2.5 x 10What is the pH of a 2.5 x 10-2-2 M M NaOH solution?NaOH solution?Step 2:Plug-in.

pOH = - log [OH-]

pOH = - log (0.025)

pOH = 1.6


What is the pH of a 0.025 M NaOH What is the pH of a 0.025 M NaOH solution?solution?Step 3:Solve for pH.

pH + pOH = 14

pH + 1.6 = 14 -1.6 -1.6

pH = 12.4

CALCULATING CALCULATING CONCENTRATION FROM pHCONCENTRATION FROM pH

[H[H33OO++]]

[H[H33OO++] = 10] = 10-pH-pH

[H[H33OO++] = concentration of acid (N)] = concentration of acid (N)

Look for your log button.Look for your log button.Above it – 10Above it – 10xx

To access it, To access it, hit 2hit 2ndnd F key F keyHit log keyHit log key

The Self-Ionization of Water, continuedThe Self-Ionization Constant of Water, continued

Section 2 Acidity, Basicity, and pHChapter 15

[OH[OH--]]

[OH[OH--] = 10] = 10-pOH-pOH

[OH[OH--] = concentration of base (N)] = concentration of base (N)

[H[H33OO++] [OH] [OH--] = 1.0 x 10] = 1.0 x 10-14-14

SAMPLE PROBLEM DSAMPLE PROBLEM D

What is the concentration of a HCl What is the concentration of a HCl solution with pH of 5.6?solution with pH of 5.6?

SAMPLE PROBLEM DSAMPLE PROBLEM D

What is the concentration of a HCl What is the concentration of a HCl solution with pH of 5.6?solution with pH of 5.6?

Plug into equation & calculator.

[H+] = 10-5.6

[H+] = 2.5 x 10-6

SAMPLE PROBLEM ESAMPLE PROBLEM E

What is the concentration of a What is the concentration of a Mg(OH)Mg(OH)22 solution with pH of 5.6? solution with pH of 5.6?



Step 1:Plug into equation & calculator.

[H+] = 10-5.6

[H+] = 2.5 x 10-6



Step 2:Convert from H to OH.

[H+] = 2.5 x 10-6

[H+] [OH-] = 1.0 x 10-14

(2.5 x 10-6) [OH-] = 1.0 x 10-14

[OH-] = 4.0 x 10-9

NEUTRALIZATION NEUTRALIZATION REACTIONSREACTIONS

Visual Concepts

Neutralization ReactionNeutralization Reaction

Chapter 15

NEUTRALIZATION NEUTRALIZATION REACTIONSREACTIONS

• The reaction of an acid and a base The reaction of an acid and a base to form salt & waterto form salt & water

• H+ ions react with OH- to form H+ ions react with OH- to form waterwater

• Predict products as in a double Predict products as in a double replacement rxn (partner swap)replacement rxn (partner swap)

HCl HCl (aq)(aq) + NaOH + NaOH (aq)(aq) HH22OO (l)(l) + + NaCl NaCl (s)(s)

PRACTICE REACTIONSPRACTICE REACTIONS

1.1. HCl + LiOH HCl + LiOH

2.2. HNOHNO33 + Ca(OH) + Ca(OH)22

3.3. HH22SOSO44 + Al(OH) + Al(OH)33

PRACTICE REACTIONSPRACTICE REACTIONS

1.1. HCl + LiOH HCl + LiOH H H22O + LiClO + LiCl

2.2. 2 HNO2 HNO33 + Ca(OH) + Ca(OH)22 2 H 2 H22O + O + Ca(NOCa(NO33))22

3.3. 3 H3 H22SOSO44 + 2 Al(OH) + 2 Al(OH)33 6 H 6 H22O + O + AlAl22(SO(SO44))33

NORMALITYNORMALITY

AN ACIDS/BASES UNITAN ACIDS/BASES UNIT

NORMALITY (N)NORMALITY (N)

N = (MOLARITY) ( # OF H’s)N = (MOLARITY) ( # OF H’s)

What is N equal to in a monoprotic acid?What is N equal to in a monoprotic acid?

N = MN = M

What is N equal to in a diprotic acid?What is N equal to in a diprotic acid?

N = 2 MN = 2 M

TITRATIONSTITRATIONS

NNAA V VAA = N = NBB V VBB

Visual Concepts

TitrationTitrationChapter 15

NORMALITY & NEUTRALIZATION NORMALITY & NEUTRALIZATION REACTIONSREACTIONS

NNA A VVA A = N= NBB V VBB

Where:Where:

NNAA = normality of acid = normality of acid

VVA A = volume of acid= volume of acid

NNBB = normality of base = normality of base

VVB B = volume of base= volume of base


What volume of a 0.25 M HCl What volume of a 0.25 M HCl solution is needed to neutralize 36 solution is needed to neutralize 36 mL of 0.30 Mg(OH)mL of 0.30 Mg(OH)22 M? M?

Step 1: Start with what you know.Step 1: Start with what you know.

NNAA = (0.25 M) (1) = 0.25 N = (0.25 M) (1) = 0.25 N

VVAA = X mL = X mL

NNBB = (0.30 M) (2) = 0.60 N = (0.30 M) (2) = 0.60 N

VVBB = 36 mL = 36 mL


What volume of a 0.25 M HCl What volume of a 0.25 M HCl solution is needed to neutralize 36 solution is needed to neutralize 36 mL of 0.30 Mg(OH)mL of 0.30 Mg(OH)22 M? M?

Step 2: Substitute & Solve.Step 2: Substitute & Solve.

NNAA V VAA = N = NBB V VBB

(0.25) (X) = (0.60) (36)(0.25) (X) = (0.60) (36)

0.25 X = 21.60.25 X = 21.6

X = 86.4 mLX = 86.4 mL

Multiple ChoiceMultiple Choice

1.1. Which of the following is not a characteristic of Which of the following is not a characteristic ofan acid?an acid?

A.A. An acid changes the color of an indicator.An acid changes the color of an indicator.

B.B. An acid has a bitter taste.An acid has a bitter taste.

C.C. An acid ionizes in water.An acid ionizes in water.

D.D. An acid produces hydronium ions in waterAn acid produces hydronium ions in water..

Multiple ChoiceMultiple Choice1.1. Which of the following is not a characteristic of Which of the following is not a characteristic of

an acid?an acid?

A.A. An acid changes the color of an indicator.An acid changes the color of an indicator.

B.B. An acid has a bitter taste.An acid has a bitter taste.

C.C. An acid ionizes in water.An acid ionizes in water.

D.D. An acid produces hydronium ions in water.An acid produces hydronium ions in water.

Multiple ChoiceMultiple Choice2.2. When an acid reacts with an active When an acid reacts with an active metalmetal,,

A.A. the hydronium ion concentration the hydronium ion concentration increases.increases.

B.B. the metal forms anions.the metal forms anions.

C.C. hydrogen gas is produced.hydrogen gas is produced.

D.D. carbon dioxide gas is produced.carbon dioxide gas is produced.

Multiple ChoiceMultiple Choice2.2. When an acid reacts with an active When an acid reacts with an active

metal,metal,

A.A. the hydronium ion concentration the hydronium ion concentration increases.increases.

B.B. the metal forms anions.the metal forms anions.

C.C. hydrogen gas is produced.hydrogen gas is produced.

D.D. carbon dioxide gas is produced.carbon dioxide gas is produced.

Multiple ChoiceMultiple Choice3. 3. Which of the following is a Brønsted-Which of the following is a Brønsted-

Lowry base?Lowry base?

A. A. an electron pair donoran electron pair donor

B. B. an electron pair acceptoran electron pair acceptor

C. C. a proton donora proton donor

D. D. a proton acceptora proton acceptor

Multiple ChoiceMultiple Choice4. 4. What is the formula for acetic acid?What is the formula for acetic acid?

A. A. CHCH33COOHCOOH

B. B. HNOHNO33

C. C. HClOHClO44

D. D. HCNHCN

Multiple ChoiceMultiple Choice5. 5. Identify the salt that forms when a Identify the salt that forms when a

solution of Hsolution of H22SOSO44 is titrated with a is titrated with a solution of Ca(OH)solution of Ca(OH)22..

A.A. calcium sulfatecalcium sulfate

B.B. calcium hydroxidecalcium hydroxide

C.C. calcium oxidecalcium oxide

D.D. calcium phosphatecalcium phosphate

Short AnswerShort Answer

6. 6. How does a strong acid differ How does a strong acid differ from a weak acid? Give one from a weak acid? Give one example of each.example of each.

Short AnswerShort Answer6. 6. How does a strong acid differ from a weak How does a strong acid differ from a weak

acid? Give one example of each.acid? Give one example of each.

Answer:Answer: A strong acid is 100% ionized; a A strong acid is 100% ionized; a weak acid is less than 100% ionized. weak acid is less than 100% ionized. Possible strong acids are HCl, HI, HBr, HNOPossible strong acids are HCl, HI, HBr, HNO33, , HH22SOSO44, HClO, HClO44, and HClO, and HClO33. With very few . With very few exceptions, any other acid will be a weak exceptions, any other acid will be a weak acid.acid.

Multiple ChoiceMultiple Choice1.1. Distilled water contains Distilled water contains

A.A. H H22O.O.

B.B. H H33OO++..

C.C. OH OH..

D.D. All of the above All of the above

Multiple ChoiceMultiple Choice1.1. Distilled water contains Distilled water contains

A.A. HH22O.O.

B.B. HH33OO++..

C.C. OHOH..

D.D. All of the above All of the above

Multiple ChoiceMultiple Choice2.2. What is the pH of a 0.0010 M HNO What is the pH of a 0.0010 M HNO33??

A.A. 1.0 1.0

B.B. 3.0 3.0

C.C. 4.0 4.0

D.D. 5.0 5.0

Multiple ChoiceMultiple Choice2.2. What is the pH of a 0.0010 M HNO What is the pH of a 0.0010 M HNO33??

A.A. 1.01.0

B.B. 3.0 3.0

C.C. 4.04.0

D.D. 5.05.0

Multiple ChoiceMultiple Choice3. 3. Which of the following solutions Which of the following solutions

would have a pH value greater than would have a pH value greater than 7?7?

A.A. [OH [OH] = 2.4 ] = 2.4 10 1022 M M

B.B. [H [H33OO++] = 1.53 ] = 1.53 10 1022 M M

C.C. 0.0001 M HCl 0.0001 M HCl

D.D. [OH [OH] = 4.4 ] = 4.4 10 109 9 MM

Multiple ChoiceMultiple Choice3. 3. Which of the following solutions Which of the following solutions

would have a pH value greater than would have a pH value greater than 7?7?

A.A. [OH [OH] = 2.4 ] = 2.4 10 1022 M M

B.B. [H[H33OO++] = 1.53 ] = 1.53 10 1022 M M

C.C. 0.0001 M HCl0.0001 M HCl

D.D. [OH[OH] = 4.4 ] = 4.4 10 109 9 MM

Multiple ChoiceMultiple Choice4.4. If the pH of a solution of the strong base NaOHIf the pH of a solution of the strong base NaOH

is known, which property of the solution can is known, which property of the solution can be be calculated?calculated?

A. A. molar concentrationmolar concentration

B. B. [OH[OH]]

C. C. [H[H33OO++]]

D. D. All of the aboveAll of the above

Multiple ChoiceMultiple Choice5.5. A neutral aqueous solutionA neutral aqueous solution

A. A. has a 7.0 M Hhas a 7.0 M H33OO++ concentration. concentration.

B. B. contains neither hydronium ions nor contains neither hydronium ions nor hydroxidehydroxide ions.ions.

C. C. has an equal number of hydronium ions andhas an equal number of hydronium ions and hydroxide ions.hydroxide ions.

D. D. None of the aboveNone of the above

Multiple ChoiceMultiple Choice6.6. Identify the salt that forms when a Identify the salt that forms when a

solution of Hsolution of H22SOSO44 is titrated with a is titrated with a solution of Ca(OH)solution of Ca(OH)22..

A. A. calcium sulfatecalcium sulfate

B. B. calcium hydroxidecalcium hydroxide

C. C. calcium oxidecalcium oxide

D. D. calcium phosphatecalcium phosphate

Multiple ChoiceMultiple Choice7.7. The pH of a solution is 6.32. What is the The pH of a solution is 6.32. What is the

pOH?pOH?

A. A. 6.326.32

B. B. 4.8 4.8 10 1077

C. C. 7.687.68

D. D. 2.1 2.1 10 1088

Multiple ChoiceMultiple Choice8.8. Which of the pH levels listed below is the Which of the pH levels listed below is the

most acidic?most acidic?

A.A. pH = 1pH = 1

B.B. pH = 5pH = 5

C.C. pH = 9pH = 9

D.D. pH = 13pH = 13

Short AnswerShort Answer9.9. A solution has a pH of 4.75. What A solution has a pH of 4.75. What

is the hydronium ion concentration? is the hydronium ion concentration? Is the solution acidic or basic?Is the solution acidic or basic?

Short AnswerShort Answer9.9. A solution has a pH of 4.75. What A solution has a pH of 4.75. What

is the hydronium ion concentration? is the hydronium ion concentration? Is the solution acidic or basic?Is the solution acidic or basic?

Answer:Answer: [H[H33OO++] = 1.8 ] = 1.8 10 1055 M; M; acidicacidic

Extended ResponseExtended Response10.10. The hydroxide ion The hydroxide ion

concentration in a solution is 1.6 concentration in a solution is 1.6 10 101111 M. What are the [H M. What are the [H33OO++], ], the pH, and the pOH of the the pH, and the pOH of the solution?solution?

Extended ResponseExtended Response10.10. The hydroxide ion concentration in The hydroxide ion concentration in

a solution is 1.6 a solution is 1.6 10 101111 M. What are the M. What are the [H[H33OO++], the pH, and the pOH of the ], the pH, and the pOH of the solution?solution?

Answer:Answer: [H[H33OO++] = 6.3 ] = 6.3 10 104 4 MM

pH = 3.20pH = 3.20

pOH = 10.80pOH = 10.80

Extended ResponseExtended Response11.11. Write the balanced equation Write the balanced equation

that represent the reaction that that represent the reaction that takes place when milk of magnesia takes place when milk of magnesia (magnesium hydroxide) reacts with (magnesium hydroxide) reacts with hydrochloric acid in your stomach.hydrochloric acid in your stomach.

Extended ResponseExtended Response13.13.Write the balanced equation that represent Write the balanced equation that represent

the reaction that takes place when milk of the reaction that takes place when milk of magnesia (magnesium hydroxide) reacts magnesia (magnesium hydroxide) reacts with hydrochloric acid in your stomach.with hydrochloric acid in your stomach.

Answer:Answer:

s + aq aq aq2 2 2Mg(OH) ( ) 2HCl( ) MgCl ( ) 2H O( )

chapter 15 properties of acids & bases. what is an acid? a compound that donates a hydrogen ion...

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