lectureplus timberlake1 acids and bases. lectureplus timberlake2 arrhenius acids and bases acids...

LecturePLUS Timberlake 1

Acids and Bases

Acids and Bases

LecturePLUS Timberlake 2

Arrhenius Acids and Bases

Acids produce H+ in aqueous solutions water

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

Bases produce OH- in aqueous solutions

water

NaOH Na+(aq) + OH- (aq)

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Acids

Produce H+ (as H3O+) ions in water

Produce a negative ion (-) too

Taste sour

Corrode metals

React with bases to form salts and water

LecturePLUS Timberlake 4

Bases

Produce OH- ions in water

Taste bitter, chalky

Are electrolytes

Feel soapy, slippery

React with acids to form salts and water

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Learning Check AB1

Describe the solution in each of the following as: 1) acid 2) base or 3)neutral.

A. ___soda

B. ___soap

C. ___coffee

D. ___ wine

E. ___ water

F. ___ grapefruit

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Solution AB1

Describe each solution as:

1) acid 2) base or 3) neutral.

A. _1_ soda

B. _2_ soap

C. _1_ coffee

D. _1_ wine

E. _3_ water

F. _1_ grapefruit

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Learning Check AB2

Identify each as characteristic of an A) acid or B) base

____ 1. Sour taste

____ 2. Produces OH- in aqueous solutions

____ 3. Chalky taste

____ 4. Is an electrolyte

____ 5. Produces H+ in aqueous solutions

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Solution AB2

Identify each as a characteristic of an A) acid or B) base

_A_ 1. Sour taste

_B_ 2. Produces OH- in aqueous solutions

_B_ 3. Chalky taste

A, B 4. Is an electrolyte

_A_ 5. Produces H+ in aqueous solutions

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Some Common Acids

HCl hydrochloric acid

HNO3 nitric acid

H3PO4 phosphoric acid

H2SO4 sulfuric acid

CH3COOH acetic acid

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Learning Check AB3

Give the names of the following

A. HBr (aq) 1. bromic acid

2. bromous acid

3. hydrobromic acid

B. H2CO3 1. carbonic acid

2. hydrocarbonic acid

3. carbonous acid

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Solution AB3

A. HBr 3. hydrobromic acid

The name of a nonoxy acid begins with the prefix hydro- and ends with -ic acid. In a nonoxy acid, the negative anion end in -ide.

B. H2CO3 1. carbonic acid

The name of an oxyacid is named with the stem of the anion (carbonate) changed to

-ic acid

LecturePLUS Timberlake 12

Some Common Bases

NaOH sodium hydroxide

KOH potassium hydroxide

Ba(OH)2 ________________________

Mg(OH)2 ________________________

Al(OH)3 aluminum hydroxide

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Learning Check AB4

Match the formulas with the names:

A. ___ HNO2 1) hydrochloric acid

B. ___ Ca(OH)2 2) sulfuric acid

C. ___ H2SO4 3) sodium hydroxide

D. ___ HCl 4) nitrous acid

E. ___ NaOH 5) calcium hydroxide

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Solution AB4

Match the formulas with the names:

A. _4__ HNO2 1) hydrochloric acid

B. _5__ Ca(OH)2 2) sulfuric acid

C. _2__ H2SO4 3) sodium hydroxide

D. _1__ HCl 4) nitrous acid

E. _3__ NaOH 5) calcium hydroxide

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Learning Check AB5

Acid, Base Nameor Salt

CaCl2 ______ _________________

KOH ______ _________________

Ba(OH)2 ______ _________________

HBr ______ _________________

H2SO4 ______ __________________

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Solution AB5

Acid, Base Nameor Salt

CaCl2 salt calcium chloride

KOH base potassiuim hydroxide

Ba(OH)2 base barium hydroxide

HBr acid hydrobromic acid

H2SO4 acid sulfuric acid

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Bronsted-Lowry Acids

Acids are hydrogen ion (H+) donors

Bases are hydrogen ion (H+) acceptors

HCl + H2O H3O+ + Cl-

donor acceptor + -

+ +

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Chapter 9Acids and Bases

Acid-Base Neutralization

Buffers

Acid-Base Titration

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Neutralization Reactions

When acid and bases with equal amounts of hydrogen ion H+ and hydroxide ions OH- are mixed, the resulting solution is neutral.

NaOH (aq) + HCl(aq) NaCl + H2O

base acid salt water

Ca(OH)2 + 2 HCl CaCl2 + 2H2Obase acid salt water

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Neutralization

H3O+ and OH- combine to produce water

H3O+ + OH- 2 H2O

from acid from base neutral

Net ionic equation:

H+ + OH- H2O

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Ionic Equations for Neutralization

Write strong acids, bases, and salt as ions

H+ + Cl- + Na+ + OH- Na+ + Cl- + H2O

Cross out matched ions

H+ + Cl- + Na+ + OH- Na+ + Cl- + H2O

Write a net ionic reaction

H+ + OH- H2O

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Balancing Neutralization Equations

Write the equation for the neutralization

between magnesium hydroxide and nitric acid.

1. Write the formulas of the acid and base

Mg(OH)2 + HNO3

2. Balance to give equal OH- and H+

Mg(OH)2 + 2 HNO3

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3. Write the products:

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

salt water

(metal and nonmetal)

4. Balance products

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

LecturePLUS Timberlake 24

Learning Check N2

Select the correct group of coefficients for the

following neutralization equations

A. __ HCl + __ Al(OH)3 __AlCl3 + __

H2O

1) 1, 3, 3, 1 2) 3, 1, 1, 1 3) 3, 1, 1 3

B.__ Ba(OH)2 + __H3PO4 __Ba3(PO4)2 + __ H2O

1) 3, 2, 2, 2 2) 3, 3, 1, 6 3) 2, 3, 1, 6

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Solution N2

A. 3HCl + 1Al(OH)3 1AlCl3 + 3H2O

B. 3Ba(OH)2 + 2H3PO4 1Ba3(PO4)2 +

6H2O

LecturePLUS Timberlake 26

Learning Check N3

Write a balanced equation and calculate

the mL of 2.00 M H2SO4 required to

neutralize 50.0 mL of 1.00 M KOH?

___H2SO4 + ___KOH ___K2SO4 + H2O

1) 12.5 mL 2) 50.0 mL 3) 200. mL

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Solution N3

How many mL of 2.00 M H2SO4 are required to

neutralize 50.0 mL of 1.00 M KOH?

H2SO4 + 2KOH K2SO4 + 2H2O

0.0500 L x 1.00 mole KOH x 1 mole H2SO4 x

1 L 2 mole KOH

1 L x 1000 mL = 12.5 mL

2 mole KOH 1 L

LecturePLUS Timberlake 28

Learning Check N4

A 25 mL sample of phosphoric acid is neutralized by 40. mL of 1.5 M NaOH. What is the molarity of the phosphoric acid solution?

3NaOH + H3PO4 Na3PO4 + 3H2O

1) 0.45 M 2) 0.80 M 3) 7.2 M

LecturePLUS Timberlake 29

Solution S4

0.040 L x 1.5 mole NaOH x 1 mole H3PO4

1 L 3 mole NaOH

x 1 = 0.80 mol/L = 0.80 M

0.025 L

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Acids and Bases

Ionization of Water

The pH Scale

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Ionization of Water

Occasionally, in water, a H+ is transferred between H2O molecules

. . . . . . . .H:O: + :O:H H:O:H + + :O:H-

. . . . . . . . H H H

water molecules hydronium hydroxide ion (+) ion (-)

LecturePLUS Timberlake 32

Pure Water is Neutral

Pure water contains small, but equal amounts of ions: H3O+ and OH-

H2O + H2O H3O+ + OH-

hydronium hydroxide

ion ion

1 x 10-7 M 1 x 10-7 MH3O+ OH-

LecturePLUS Timberlake 33

Ion Product of Water Kw

[ ] = Molar concentration

Kw = [ H3O+ ] [ OH- ]

= [ 1 x 10-7 ][ 1 x 10-7 ]

= 1 x 10-14

LecturePLUS Timberlake 34

Acids

Increase H+

HCl (g) + H2O (l) H3O+ (aq) + Cl-

(aq)

More [H3O+] than water > 1 x 10-7M

As H3O+ increases, OH- decreases

[H3O+] > [OH-]H3O+

OH-

LecturePLUS Timberlake 35

Bases

Increase the hydroxide ions (OH-)

H2O

NaOH (s) Na+(aq) + OH- (aq)

More [OH-] than water, [OH-] > 1 x 10-7M

When OH- increases, H3O+ decreases

[OH] > [H3O+]

H3O+OH-

LecturePLUS Timberlake 36

Using Kw

The [OH- ] of a solution is 1.0 x 10- 3 M. What is the

[H3O+]?

Kw = [H3O+ ] [OH- ] = 1.0 x 10-14

[H3O+] = 1.0 x 10-14

[OH-]

[H3O+] = 1.0 x 10-14 = 1.0 x 10-11 M

1.0 x 10- 3

LecturePLUS Timberlake 37

Learning Check pH1

The [H3O+] of lemon juice is 1.0 x 10-3 M.

What is the [OH-] of the solution?

1) 1.0 x 103 M

2) 1.0 x 10-11 M

3) 1.0 x 1011 M

LecturePLUS Timberlake 38

Solution pH1

The [H3O+] of lemon juice is 1.0 x 10- 3 M.

What is the [OH-]?

[OH- ] = 1.0 x 10 -14 = 1.0 x 10-11 M 1.0 x 10 - 3

LecturePLUS Timberlake 39

Using the Calculator

1.0 x 10 -14

4.0 x 10-5

Enter 1.0 EE +/- 14 4.0 EE +/- 5

= 2.5 x 10 -10

LecturePLUS Timberlake 40

Learning Check pH2

The [OH-] of a solution is 5 x 10 -5 M. What is the [H3O+ ] of the solution?

1) 2 x 10- 5 M

2) 1 x 1010 M

3) 2 x 10-10 M

LecturePLUS Timberlake 41

Solution pH2

The [OH-] of a water solution is 5 x 10-5 M.

What is the [H3O+] in the solution?

[ H3O+] = 1.0 x 10 -14

5 x 10- 5

On some calculators:

1.0 EE +/- 14 5 EE +/- 5 = 2 x 10 -10 M

LecturePLUS Timberlake 42

Learning Check pH3

A.The [OH-] when [H3O+ ] of 1 x 10- 4 M

1) 1 x 10-6 M

2) 1 x 10-8 M

3) 1 x 10-10 M

B.The [H3O+] when [OH- ] of 5 x 10-9 M

1) 1 x 10- 6 M

2) 2 x 10- 6 M

3) 2 x 10-7 M

LecturePLUS Timberlake 43

Solution pH3

Kw = [H3O+ ][OH-] = 1.0 x 10 14

A. (3) [OH- ] = 1.0 x 10 -14 = 1.0 x 10 -10

1.0 x 10- 4

B. (2) [H3O+] = 1.0 x 10 -14 = 2 x 10 - 6

5 x 10- 9

LecturePLUS Timberlake 44

pH

Indicates the acidity [H3O+] of the solution

pH = - log [H3O+]

From the French pouvoir hydrogene

(“hydrogen power” or power of

hydrogen)

LecturePLUS Timberlake 45

In the expression for [H3O+]

1 x 10-exponent

the exponent = pH

[H3O+] = 1 x 10-pH M

pH

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pH Range

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Neutral

[H+]>[OH-] [H+] = [OH-] [OH-]>[H+]

Acidic Basic

LecturePLUS Timberlake 47

Some [H3O+] and pH

[H3O+] pH

1 x 10-5 M 5

1 x 10-9 M 9

1 x 10-11 M 11

LecturePLUS Timberlake 48

pH of Some Common Acids

gastric juice 1.0

lemon juice 2.3

vinegar 2.8

orange juice 3.5

coffee 5.0

milk 6.6

LecturePLUS Timberlake 49

pH of Some Common Bases

blood 7.4

tears 7.4

seawater 8.4

milk of magnesia 10.6

household ammonia11.0

LecturePLUS Timberlake 50

Learning Check pH4

A. The [H3O+] of tomato juice is 1 x 10-4 M.

What is the pH of the solution?

1) - 4 2) 4 3) 8

B. The [OH-] of an ammonia solution is

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

1) 3 2) 11 3) -11

LecturePLUS Timberlake 51

Solution pH4

A. pH = - log [ 1 x 10-4] = -(- 4) = 4

B. [H3O+] = 1 x 10-11

pH = - log [ 1 x 10- 11] = -(- 11) = 11

LecturePLUS Timberlake 52

Learning Check pH5

The pH of a soap is 10. What is the [H3O+] of the soap

solution?

1) 1 x 10 - 4 M

2) 1 x 1010 M

3) 1 x 10 - 10 M

LecturePLUS Timberlake 53

Solution pH5

The pH of a soap is 10. What is the [H3O+]

of the soap solution?

[H3O+] = 1 x 10-pH M

= 1 x 10-10 M

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pH on the Calculator

[H3O+] is 4.5 x 10-6 M

pH = 4.5 x EXP(or EE) 6+/- LOG +/-

= 5.35

LecturePLUS Timberlake 55

Learning Check pH6

A soap solution has a [H3O+] = 2 x 10-8 M. What is the pH of

the solution?

1) 8

2) 7.7

3) 6

LecturePLUS Timberlake 56

Solution pH6

A soap solution has a [H3O+] = 2.0 x 10-

8 M. What is the pH of the solution?

B) 2.0 EE 8 +/- LOG +/- = 7.7

LecturePLUS Timberlake 57

Learning Check pH7

Identify each solution as

1. acidic 2. basic 3. neutral

A. _____ HCl with a pH = 1.5

B. _____ Pancreatic fluid [H+] = 1 x 10-8 M

C. _____ Sprite soft drink pH = 3.0

D. _____ pH = 7.0

E. _____ [OH- ] = 3 x 10-10 M

F. _____ [H+ ] = 5 x 10-12

LecturePLUS Timberlake 58

Solution pH7

Identify each solution as

1. acidic 2. basic 3. neutral

A. _1__ HCl with a pH = 1.5

B. _2__ Pancreatic fluid [H+] = 1 x 10-8 M

C. _1__ Sprite soft drink pH = 3.0

D. _3__ pH = 7.0

E. _1__ [OH-] = 3 x 10-10 M

F. _2__ [H+] = 5 x 10-12

LecturePLUS Timberlake 59

Acid RainUnpolluted rain has a pH of 5.6

Rain with a pH below 5.6 is “acid rain“

CO2 in the air forms carbonic acid

CO2 + H2O H2CO3

Adds to H+ of rain

H2CO3 H+ (aq) + HCO3-(aq)

Formation of acid rain:

1. Emission of sulfur and nitrogen oxides from the burning of fuels expecially coal with high S content, power stations, oil refineries, vehicles as well as bacterial decomposition, and lighting hitting N2

SO2 26 million tons in 1980

NO and NO2 22 million tons in 1980

Mt. St Helens (1980) 400,000 tons SO2

2. Reactions in the atmosphere form SO3

2SO2 + O2 2 SO3

3. Reactions with atmosphere water form acids

SO3 + H2O H2SO4 sulfuric acid

NO + H2O HNO2 nitrous acid

HNO2 + H2O HNO3 nitric acid

4. Effects of Acid Rain

Decline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rain

Extensive fish kills in spring from runoff due to accumulation of large amounts of acid on the snow

Dissolves minerals Mg, Ca, and K from the soil and waxy coatings that protect leaves from bacteria

Corrodes metals, textiles, paper and leather

LecturePLUS Timberlake 60

Sources of Acid Rain

Power stations

Oil refineries

Coal with high S content

Car and truck emissions

Bacterial decomposition, and lighting

hitting N2

LecturePLUS Timberlake 61

SO2 26 million tons in 1980

NO and NO2 22 million tons in 1980

Mt. St Helens (1980) 400,000 tons SO2

Reactions with oxygen in air form SO3

2SO2 + O2 2 SO3

Reactions with water in air form acids

SO3 + H2O H2SO4 sulfuric acid

NO + H2O HNO2 nitrous acid

HNO2 + H2O HNO3 nitric acid

LecturePLUS Timberlake 62

Effects of Acid Rain

Leaches Al from soil, which kills fish

Fish kills in spring from runoff due to

accumulation of large amounts of acid in

snow

Dissolves waxy coatings that protect leaves

from bacteria

Corrodes metals, textiles, paper and leather

LecturePLUS Timberlake 63

Chapter 9Acids and Bases

Strengths of Acids and Bases

Making Dilutions

LecturePLUS Timberlake 64

Strengths of Acids and Bases

Strong acids completely ionize (100%) in

aqueous solutions

HCl + H2O H3O+ + Cl- (100 % ions)

Strong bases completely (100%) dissociate into ions in aqueous solutions.

NaOH Na+ (aq) + OH-(aq) (100 % ions)

LecturePLUS Timberlake 65

NH3, A Bronsted-Lowry Base

When NH3 reacts with water, most of the reactants remain dissolved as molecules, but a few NH3 reacts with water to form NH4

+ and hydroxide ion.

NH3 + H2O NH4+(aq) + OH- (aq)

acceptor donor

+ +

LecturePLUS Timberlake 66

Strong and Weak Acids and Bases

Strong acids

HCl, HNO3 , H2SO4

Most other acids are weak.

Strong bases

NaOH, KOH, and Ca(OH)2

Most other bases are weak.

LecturePLUS Timberlake 67

Learning Check SW1

Identify each of the following as a

1) strong acid or base 2) weak acid

3) weak base

A. ___ HCl (aq)

B. ___ NH3(aq)

C. ___ NaOH (aq)

D. ___ H2CO3 (aq)

LecturePLUS Timberlake 68

Solution SW1

Identify each of the following as a

1) strong acid or base 2) weak acid

3) weak base

A. _1__ HCl (aq)

B. _3__ NH3(aq)

C. _1__ NaOH (aq)

D. _2__ H2CO3 (aq)

LecturePLUS Timberlake 69

Antacids

Used to neutralize stomach acid (HCl)

Many contain one or more weak bases

Alka-Seltzer: NaHCO3, citric acid, and aspirin

Di-gel: CaCO3 and Mg(OH)2

Gelusil: Al(OH)3 and Mg(OH)2

Maalox: Al(OH)3 and Mg(OH)2

Mylanta: Al(OH)3 and Mg(OH)2

LecturePLUS Timberlake 70

More Antacids

Milk of Magnesia: Mg(OH)2

Rolaids: AlNa(OH)2CO3

aluminum sodium dihydroxy carbonate

Tums: CaCO3

Tempo: CaCO3, Al(OH)3, Mg(OH)2

LecturePLUS Timberlake 71

Dilutions

Add water Volume increases. New concentration is less than initial

LecturePLUS Timberlake 72

Concentration of A Diluted Solution

A 25 mL sample of a 6.0 M KOH is diluted by adding 75 mL of water. Calculate the new concentration of the KOH solution.

Moles KOH = 0.025 L x 6.0 moles = 0.15 moles

1 L

New volume = 25 mL + 75 mL = 100. mL = 0.100 L

New molarity = 0.15 moles = 1.5 M

0.100 L

LecturePLUS Timberlake 73

Learning Check SW 2

A 125 mL sample of a 3.0 M HCl is diluted by adding 250 mL of water. The new concentration of the HCl solution is

1) 8.0 M

2) 1.5 M

3) 1.0 M

LecturePLUS Timberlake 74

Solution SW 2

3) 1.0 M

moles HCl = 0.250 L x 3.0 moles = 0.75 mole 1 L

new M = 0.75 mole 1.0 M HCl 0.750 L(new volume)

LecturePLUS Timberlake 75

Learning Check SW 3

A 50.0 mL sample of 15% sucrose solution is diluted by adding 200. mL of water. The new concentration of the sucrose solution is

1) 3.0 %

2) 7.5 %

3) 10. %

LecturePLUS Timberlake 76

Learning Check SW 3

A 50.0 mL sample of 15% sucrose solution is diluted by adding 200. mL of water. The new concentration of the sucrose solution is

1) 3.0 %

g sucrose = 50.0 mL x 15 g sucrose = 7.5 g

100 mL

new % = 7.5 g sucrose = 3.0 % sucrose

250 mL

(new volume)