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Title: Acids and Bases


1
Acids and Bases
2
ACIDS
BASES
  • electrolytes ?electrolytes
  • Produces H30 in water ?produces OH- in water
  • bitter taste, chalky
  • sour taste
  • turn litmus red
  • turn litmus blue
  • react with metals to form H2 gas
  • slippery feel
  • ammonia, antacid, baking soda
  • vinegar, soda, apples, citrus fruits

3
Acids
  • Arrhenius - In aqueous solution
  • Acids form hydronium ions (H3O)

HCl H2O ? H3O Cl
acid
4
Base
  • Arrhenius - In aqueous solution
  • Bases form hydroxide ions (OH-)

NH3 H2O ? NH4 OH-
base
5
Bronsted-Lowry Acids
  • Acids are proton (H) donors
  • Bases are proton (H) acceptors
  • HCl H2O H3O Cl-
  • donor acceptor

6
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

7
Acid, Base Definitions
8
Learning Check AB1
  • Describe the solution in each of the following
    as 1) acid 2) base or 3)neutral.
  • A. ___soda
  • B. ___soap
  • C. ___ wine
  • D. ___ water
  • E. ___ grapefruit

1
2
1
3
1
9
Learning Check
  • 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

A
B
B
Both
A
10
15.1 Acids Generate Hydronium Ions
  • Strong Acids completely ionizes in water
  • HNO3 H2O ? H3O NO3-
  • Weak Acids partially ionizes in water
  • HOCl H2O ? H3O ClO-
  • Strong Acids MEMORIZE
  • If it is not a strong acid then it is a weak
    acid!!
  • HCl H2SO4 HNO3
  • HBr HI HClO4

hydrochloric
sulfuric
nitric
hydroiodic
perchloric
hydrobromic
11
strong acid vs. weak acid
12
Bases Generate Hydroxide Ions
  • Strong bases ionizes completely in water
  • NaOH ? Na OH-
  • Weak bases releases few hydroxide in water
  • NH3 H2O ? NH4 OH-
  • Strong Bases Memorize
  • LiOH NaOH KOH
  • Ca(OH)2 Ba(OH)2 Sr(OH)2
  • If it is not a strong base then it is a weak
    base!!

Lithium hydroxide
Sodium hydroxide
Potassium hydroxide
Calcium hydroxide
Barium hydroxide
Strontium hydroxide
13
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)

1
3
1
2
14
Acid, Base Conjugates
  • Acids are proton (H) donors.
  • Bases are proton (H) acceptors.
  • Conjugate acid base pair The pair of acid and
    base that differ by a H.
  • Acid- conjugate base base- conjugate acid

HCl H2O ? Cl H3O
base
acid
15
Bronsted-Lowry Acids and Bases
  • Acid Substance that donate a proton (H)
  • Base Substance that accept a proton (H)
  • Acid Base reaction H is transferred from the
    acid to the base.
  •   Ex.
  •  
  • Conjugate acid base pair The pair of acid and
    base that differ by a H. Ex. ACID \ BASE

?
HX
Y
HY
X
Acid
Base
F
HF
Conjugate Acid add H
NO2
HNO2
C2H3O2
HC2H3O2
Conjugate Base subtract H
Memorize NH3 Base
Memorize NH4 Acid
16
  • Amphoteric substance Substance that can either
    donate or accept a hydrogen ion.
  •   Ex. H2O
  •  
  • Example Label the acids and bases, draw lines
    to connect the conjugate pairs.
  • (1) NH3 H2O ? NH4 OH- (2) HF H2O
    ? F- H3O
  •  

H
H
H2O
?
?
HSO4
HCO3
Acid
Base
Acid
Base
17
  • Categorize each of the following as an Acid,
    Base, or Amphoteric and below each, write the
    conjugate acid or base.
  • H2SO4 H2PO4- NH3 NO2- HSO4-

Acid
Ampho
base
Base
Ampho
HSO4
H3PO4
NH4
HNO2
H2SO4
HPO42
SO42
18
15.2 Acidity and Bascitiy and pH
  • Water is both an acid and a base.

acid
base
C.A
C.B
  • In pure water, the two ions must share the same
    concentration.
  • Experiments show that this concentration is1.00
    10-7 M at 25C.
  • H3O OH- 1.00 10-7 M

19
Acidity and Bascitiy
  • The concentration of hydronium ions in a solution
    expresses its acidity.
  • The concentration of hydroxide ions in a solution
    expresses its basicity.
  • When the concentration of H3O goes up, the
    concentration of OH- goes down, and vice versa.

20
Water dissociation constant
OH (aq)
H2O(l) H2O (l)
?
H3O (aq)
Base
Acid
Keq H3OOH
Equilibrium constant
Kw H3OOH
Water dissociation constant
H3O OH- 1.00 10-7 M
Kw H3OOH 1 x 10 -14
In impure water (contains an acidic or basic
substance) If H3O gt 1.0 x 10-7 M, solution
is acidic. If H3O lt 1.0 x 10-7 M, solution
is basic If H3O 1.0 x 10-7 M, solution is
neutral.
21
  • 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
  • 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
  • 2) 2 x 10- 6 M

22
What is OH- in a 3.00 10-5 M solution of HCl?
  • HCl H2O ? H3O Cl-

3.00x10-5M
3.00x10-5M
H3O 3.00 10-5 M Kw H3OOH- 1.00
10-14
23
pH
  • How Acidic Is an Acid?
  • power of hydronium ion (pH) measure of the
    hydronium ion concentration in a solution
  • 7
  • less than 7 is acidic neutral greater than 7
    is basic
  • Each unit of pH represents 10
  • Ex. The difference between 3 and 5 is 100 times

24
pH and pOH
  • H3O OH- Kw 1 x 10-14
  • pH -log H3O pOH -log OH-
  • pH pOH 14 10-pH H3O
  • pH lt 7 acidic 10 pOH OH-
  • pH gt 7 basic
  • pH neutral

25
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



26
Solution pH4
  • A. pH - log 1 x 10-4 4
  • B. OH- 1 x 10-3
  • H3O 1 x 10-11
  • pH - log 1 x 10- 11 11

27
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
  • H3O 10-pH M 10-10 M
  • Acidic or Basic? . . .
  • Basic

28
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

Steps . . .
29
Solution pH6
  • A soap solution has a H3O 2.0 x 10-8 M.
    What is the pH of the solution?
  • pH -log H3O so . . .
  • B) /- LOG 2.0 EE /- 8 7.7
  • Acidic or Basic? . . .
  • Basic

30
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

1
2
1
3
1
2
31
pH on the Calculator
  • H3O is 4.5 x 10-6 M
  • pH /- LOG 4.5 EXP(or EE) /- 6 ENTER
  • 5.35

32
  • Given H3O1 3.02 x 10-8 and pOH 6.48,
  • both just calculated, what is OH1-?
  • OH- 10-pOH ? . . .
  • 2nd log 6.48 3.31 x 10-7
  • Can also do by Kw H3O1OH1-
  • OH- 1.0 x 10-14/3.02 x 10-8 . . .?
  • 1 EE 14 3.02 EE 8
  • 3.31 x 10-7

33
Neutralization
  • Neutralization Reactions
  • Strong acids and strong bases react to form a
    salt and water
  • HCl NaOH ? _____ _____
  • Depends on the strength and amount of acids and
    bases used
  • Neutralization does not mean pH 7.
  • When acid and bases with equal amounts of
    hydrogen ion H and hydroxide ions OH- are mixed,
    the resulting solution is neutral.

NaCl H2O
34
Ionic Equations for Neutralization
  • HCl NaOH HOH NaCl
  • Write strong acids, bases soluble salts 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

35
  • Equal volumes of 1 molar hydrochloric acid
  • (HCl) and 1 molar sodium hydroxide base
  • (NaOH) are mixed. After mixing, the
  • solution will be
  • A strongly acidic.
  • B weakly acidic.
  • C nearly neutral.
  • D weakly basic.
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