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1
Acids and Bases
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)
3
Acids
þ Produce H+ (as H3O+) ions in water
þ Produce a negative ion (-) too
þ Taste sour
þ Corrode metals
þ React with bases to form salts and water
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. ___soapC. ___coffeeD. ___ wineE. ___ 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_ soapC. _1_ coffeeD. _1_ wineE. _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 acidThe 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 acidThe name of an oxyacid is named with the stem of the anion (carbonate) changed to -ic acid
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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 acidB. _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 AB5Learning 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 chlorideKOH base potassiuim hydroxideBa(OH)2 base barium hydroxideHBr acid hydrobromic acidH2SO4 acid sulfuric acid
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Bronsted-Lowry Acids
Acids are hydrogen ion (H+) donorsBases are hydrogen ion (H+) acceptors
HCl + H2O H3O+ + Cl-
donor acceptor + -
+ +
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pH
Indicates the acidity [H3O+] of the solution
pH = - log [H3O+]
From the French pouvoir hydrogene
(“hydrogen power” or power of hydrogen)
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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
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Some [H3O+] and pH
[H3O+] pH
1 x 10-5 M 5
1 x 10-9 M 9
1 x 10-11 M 11
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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
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pH of Some Common Bases
blood 7.4
tears 7.4
seawater 8.4
milk of magnesia 10.6
household ammonia 11.0
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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
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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
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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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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 acidsSO3 + H2O ⎯→ H2SO4 sulfuric acid
NO + H2O ⎯→ HNO2 nitrous acid
HNO2 + H2O ⎯→ HNO3 nitric acid
4. Effects of Acid RainDecline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rainExtensive 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 bacteriaCorrodes metals, textiles, paper and leather
28
Acid Rain continued...Sources of Acid Rain
Power stations
Oil refineries
Coal with high S content
Car and truck emissions
Bacterial decomposition, and lighting
hitting N2
29
SO2 26 million tons in 1980
NO and NO2 22 million tons in 1980Mt. St Helens (1980) 400,000 tons SO2
Reactions with oxygen in air form SO3
2SO2 + O2 2 SO3
Reactions with water in air form acidsSO3 + H2O H2SO4 sulfuric acid
NO + H2O HNO2 nitrous acid
HNO2 + H2O HNO3 nitric acid
30
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