Warm-Up
Find
the Molarity of the following.
1.
If 22.4 g of NaOH is contained
in 700. mL of solution
2.
If 600. mL of 6.0 M HCl is
diluted to 1.5 L
What are
Acids & Bases?
Follow along in your text
Chapters 14 & 15
Properties
electrolytes
electrolytes
sour taste
bitter taste
turn litmus red
turn litmus blue
react with metals
to form H2 gas
slippery feel
vinegar, milk, soda,
apples, citrus fruits
ammonia, lye,
antacid, baking soda
ChemASAP
Definitions
Arrhenius
- In aqueous solution…
Acids form hydronium ions (H3O+)
HCl + H2O
+
H3O
H
H
Cl
acid
O
H
H
–
+
O
H
+
Cl
H
–
Cl
Definitions
Arrhenius
- In aqueous solution…
• Bases form hydroxide ions (OH-)
NH3 + H2O
+
NH4
H
H
H
N
H
base
O
H
H
–
+
O
N
H
+
OH
H
H
H
Definitions
Brønsted-Lowry
• Acids are proton (H+) donors.
• Bases are proton (H+) acceptors.
HCl + H2O
acid
–
Cl
+
+
H3O
base
conjugate base
conjugate acid
Definitions
H2O + HNO3 H3O+ + NO3–
B
A
CA
CB
Definitions
NH3 + H2O
B
A
Amphoteric
+
NH4
CA
+
OH
CB
- can be an acid or a base.
Definitions
Give the conjugate base for each of the following:
-
HF
F
H3PO4
H2PO4
+
H3O
H2O
Polyprotic
- an acid with more than one H+
Definitions
Give the conjugate acid for each of the following:
Br
-
HBr
HSO4
H2SO4
2CO3
HCO3
Definitions
Lewis
• Acids are electron pair acceptors.
• Bases are electron pair donors.
Lewis
base
Lewis
acid
Strength
Strong
Acid/Base
• 100% ionized in water
• strong electrolyte
HCl
HNO3
H2SO4
HBr
HI
HClO4
-
+
NaOH
KOH
Ca(OH)2
Ba(OH)2
Strength
Weak
Acid/Base
• does not ionize completely
• weak electrolyte
HF
CH3COOH
H3PO4
H2CO3
HCN
-
+
NH3
The pH Scale
Follow along in your text
Chapter 15 Section2
Pages 539 -547
Ionization of Water
Hydronium
Ion
H 2O + H 2 O
Kw =
+
[H3O ][OH ]
H3
+
O
+
= 1.0
OH
-14
10
Ionization of Water
Find
the hydroxide ion concentration of
3.0 10-2 M HCl.
[H3O+][OH-] = 1.0 10-14
[3.0 10-2][OH-] = 1.0 10-14
[OH-] = 3.3 10-13 M
Acidic or basic? Acidic
Hint: [H3O+] > [OH-]
pH Scale
14
0
7
INCREASING
ACIDITY
pH =
NEUTRAL
+
-log[H3O ]
pouvoir hydrogène (Fr.)
“hydrogen power”
INCREASING
BASICITY
pH Scale
pH of Common Substances
pH Scale
pH = -log[H3O+]
pOH =
-log[OH ]
pH + pOH = 14
[H3
+
O]
[OH ]
=
=
-pH
10
-pOH
10
pH Scale
What
is the pH of 0.050 M HNO3?
pH = -log[H3O+]
pH = -log[0.050]
pH = 1.3
Acidic or basic? Acidic
pH Scale
What
is the molarity of HBr in a solution
that has a pOH of 9.6?
pH + pOH = 14
pH = -log[H3O+]
pH + 9.6 = 14
So [H3O+] = 10-pH
pH = 4.4
[H3O+] = 10-4.4
Acidic
[H3O+] = 4.0 10-5 M HBr
Neutralization
Chemical
reaction between an acid and
a base.
Products are a salt (ionic compound)
and water.
ACID + BASE SALT + WATER
• Neutralization does not mean pH = 7.
Neutralization
• Salts can be neutral, acidic, or basic.
HCl + NaOH NaCl + H2O
strong
strong
neutral
HC2H3O2 + NaOH NaC2H3O2 + H2O
weak
strong
basic
Titration
Titration
standard solution
• Analytical method
in which a standard
solution is used to
determine the
concentration of an
unknown solution.
unknown solution
Titration
Equivalence
point (endpoint)
• Point at which equal
amounts of H3O+ and OHhave been added.
• Determined by…
• indicator color change
• dramatic change in pH
pH Indicators
Indicator Type
Methyl Violet
Thymol Blue
pH Range Color Changes
-2 – 3
Yellow to Violet
0 – 4.5
Red to Yellow
6 – 11
Yellow to Blue
Methyl Orange
2–6
Red to Yellow
Methyl Red
4–8
Red to Yellow
Litmus
3.5 – 9.5
Red to Blue
Bromothymol Blue 4 – 8.5
Yellow to Blue
Phenolphthalein
6 – 11
Colorless to
Pink
Alizarin Yellow R
8 – 13
Yellow to Red
Titration
Titration
+
O
moles H3 = moles
MVn = MVn
OH
M: Molarity
V: volume
n: # of H+ ions in the acid or
# of OH- ions in the base
Titration
42.5
mL of 1.3M KOH are required to
neutralize 50.0 mL of H2SO4. Find the
molarity of H2SO4.
H3O+
OH-
M=?
M = 1.3M
V = 50.0 mL
n=2
V = 42.5 mL
n=1
MV# = MV#
M(50.0mL)(2)
=(1.3M)(42.5mL)(1)
M = 0.55M H2SO4
0
