Chapter 9
Section 1
 Explain the chemical composition of acids and bases,
and explain the change of pH in neutralization
reactions.
 I can differentiate between acids and bases.
 When dissolved in water, they ionize (form ions)
 Form H+ (Hydrogen) ions, which attach to water
molecules to form hydronium ions, H3O+
 Properties:
 Taste sour
 Blue litmus paper turns red
 Conduct electric current
 Corrosive
Chemical Equation
Reactants
Products
 Complete ionization in water
 High concentration of hydronium ions in the
liquid
 Strong acid
 Conducts electricity
 Strong electrolyte
 Weak acids
 Low concentration of hydronium ions in the
liquid
 Do not conduct electricity well
 Weak electrolyte
 Double headed arrow
 Corrosive
 Can damage living tissues
 Vapors can be harmful to eyes, mouth and
lungs
 Wear safety goggles, gloves, lab apron
 When dissolved in water form OH- (hydroxide ions)
 Properties
 Tastes bitter
 Solution feels slippery
 Turn red litmus paper blue
 Like acids, bases can also damage the skin
 When bases dissolve in water, they ionize.
Na+
NaOH
+
OH-
 Not all bases contain OH Some will react with water to form hydroxide ion
NH3
+
H2O
NH4+
+
OH-
 High concentration of OH- in the solution
Ba(OH)2
Ba2+
 Complete ionization in water
 Good conductor of electricity
 Strong electrolyte
+
2OH-
 Low concentration of OH- in solution
NH3 + H2O
NH4+
 Do not ionize completely
 Not a good conductor of electricity
 Weak electrolyte
+
OH-
 Bases are corrosive and can damage living tissue
 Wear safety goggles, gloves and a lab apron!!
 What ions do acids produce?
 What ions do bases produce?
 What is the difference between a strong acid and a
weak acid?
 What is the difference between a strong base and a
weak base?
 Why should we observe lab safety rules when working
with acids and bases?
Learning Target Checkpoint
 How do you differentiate between acids and bases?
 I can explain pH.
 You can determine if a substance is an acid or a base by
using an indicator.
 An indicator is a substance that changes color in the
presence of an acid or base.
 Indicators measure the level of hydronium ions. The
level determines if a substance is acidic or basic.
 Cabbage juice can be used as an
indicator
 Litmus paper is a common
indicator
catalog.flatworldknowledge.com
 Acids turn blue litmus paper red
 Bases turn red litmus paper blue
 Only indicates if a substance is
an acid or a base
 To determine strength or
weakness, pH values are used
profmarsolais.com
 A measure of the concentration of H3O+
ions in solution
 Acidity or basicity of a solution can be
critical
 Enzymes in your body will not function
properly if your blood is too basic or acidic
 Fish cannot survive in waters that are too
acidic or basic
hapnotes.wikidot.com
ck12.org
• Small differences in pH
mean large differences in
acidity
• Example:
pH of coke = 3
pH of coffee = 5
Coke is 102 , or 100, times more
acidic than coffee.
ch302.cm.utexas.edu
gizmodo.com
Lemon juice has
a pH of 2.2. Is it
an acid or a
base?
Detergents such
as Tide have a
pH of about 10.
Is Tide an acid
or a base?
Seawater has a
pH of 8.2. Is
seawater an acid
or a base?
The inside of
your mouth has
a pH of 7. Is it
an acid or a
base?
409 cleaner
contains
ammonia that
has a pH of 12.
What will 409
do to red litmus
paper?
A soft drink has
a pH of 3.2.
What will it do
to a piece of red
litmus paper?
 You can find pH from the concentration of a strong
acid.
 pH is the negative power of 10 that is used to describe
the concentration of H3O+ ions.
The concentration of H3O+ in pure water is 1 x 10-7.
The pH of pure water = 7
 The concentration of H3O+ ions in a solution of a
strong acid is the same as the concentration of the
acid.
 Determine the pH of a 0.0001 M (Molar) solution of
the strong acid HCl.
concentration of H3O+ ions = concentration of HCl
concentration of H3O+ ions = 0.0001 M = 1 x 10-4 M
pH = -(-4) = 4
 What is pH?
 How do you determine the pH of a substance?