Acids, Bases,
and pH
Chapter 9, Section 1
Acids
 Foods
such as grapefruits, lemons, limes, and
oranges taste sour because the contain acids.
 With acids dissolve in water, they ionize, which
means they form ions.
 When acids ionize, they form hydrogen ions, H+,
which attach to water molecules to make
hydronium ions, H3O+….this is what gives acids their
properties.
 Acids taste sour, cause indicators to change color,
and conduct electric current.
 They are also corrosive and can damage materials,
including your skin.
Acids
 Strong
acids ionize completely. Ex. Nitric acid, HNO3
 All acids ionize when they are dissolved in water
 A substance that conducts electricity when the
substance is dissolved in water is an electrolyte.
 Stronger the acid, the stronger the electrolyte
 Weak acids do not ionize completely. Ex. Acetic
acid, aka- vinegar
Acids
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Concentrated acid can be dangerous
On page 295, please know each of the acids as either
strong or weak and what they are commonly used for.
Acids are used in many manufacturing processes and
are necessary to many organisms
Strong acids are corrosive and can damage lining
tissues.
Even weak acids are not always safe to handle.
Vapors can be harmful to the eyes, mouth, and lungs,
and can damage your skin.
Bases
 Many
common household
substances contain bases
 Bases have a bitter taste,
and solutions feel slippery.
 Solutions of bases also
conduct electric current,
cause indicators to change
color, and can damage skin.
 When bases dissolve in
water, they form hydroxide
ions, OH-.
Bases
 Many
common bases contain hydroxide ions
 Like strong acids, strong bases produce as many
ions as possible when they dissolve.
 Strong bases are ionic compounds that contain a
metal ion and a hydroxide ion…aka metal
hydroxides (NaOH- Sodium hydroxide)
 When a metal hydroxide is dissolved in water, the
metal ions and the hydroxide ions dissociate, or
separate.
Bases
 Some
bases ionize in water to form hydroxide ions
 This means….some bases already contain OH- while
others ionize to form OH Ammonia is an example of a weak base that ionizes
to create OH-.
 Weak acids are weak electrolytes and strong bases
are strong electrolytes.
 Page 297: know some common bases, whether
they are strong or weak, and their common use
pH
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You can tell if a solution is acidic or basic by using an
indicator, such as litmus paper.
But to know exactly how acidic or basic a solution is, you
must measure the concentration of H3O+
The pH of a solution indicates its concentration of H3O+
ions.
In solutions, the concentrations of H3O+ ions is related to
the concentration of OH- ions.
The pH of a solutions also indicated the concentration of
OH- ions.
pH
 Small
differences in pH mean large differences in
acidity
 There is more than one way to measure pH
Section 1 Review
 Page
300: 1-8; please use complete sentences
Acids, Bases,
and Salts in the
Home
Chapter 9, Section 3
Cleaning Products
 Water
does not mix with grease and oil…why??
 Cleaning products improve water’s ability to clean
because they help water mix with oily substances
 Soaps allow oil and water to mix through forming an
emulsion that can be washed away my rinsing.
Cleaning Products
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Detergents have replaced soap in
many uses
An insoluble salt, called soap scum, is
what settles out on clothing, dishes,
your skin, and your hair.
The scum also makes a ring around
our bathtub or sink
You can prevent this problem by using
detergents instead of soap to wash
clothes.
Most shampoos, liquid hand soaps,
and body washes contain detergents,
not soap.
Detergents are salts of sodium,
potassium, and sometimes
ammonium.
Cleaning Products
 Ammonia
solutions are also good cleaners
 A disinfectant is a substance that kills viruses and
bacteria
 Household bleach, a very strong disinfectant, is a
basic solution of sodium hypochlorite…this is why it
removes colors and stains from objects.
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Bleach does not remove the stain…just removes the
color. This is why using soap is still required.
Personal-Care and Food Products
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Many heathcare, beauty, and food products in your
home, in addition to cleaners, contain acids, bases, or
salts.
Antacids are basic substances that you swallow to
neutralize stomach acid when you have am upset
stomach.
Shampoos are adjusted for an ideal pH…think about
when you shower away from home and the water feels
different and it’s hard to wash the shampoo out of your
hair. Sometimes soap scum can be left. YUCK!!
The appearance of your hair is greatly affected by the
pH of your shampoo. The best hair is when it is either
slightly acidic or neutral. Basic shampoos can cause hair
swell and be frizzy
Personal-Care and Food Products
 Acids
can be used as antioxidants
 To keep a cut apple looking fresh, lemon juice can
be spread over the apple flesh.
 The citric acid in lemon juice acts as an antioxidant
and prevents oxygen from reacting with the
molecules in the apple that form the brown
substances.
Personal-Care and Food Products
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Acids, bases, and salts are used in the kitchen
Vinegar and citrus juices are used to make acidic
marinades that can tenderize meats.
Acids can cause proteins in meat to unravel…making
them more tender! YUMMY!!!
Baking soda is a salt that forms carbon dioxide gas at
high temperatures…this is what makes bread and other
baked good rise! 
Bases are used in the kitchen as cleaners that break
down materials that can cause clogs.
Section 3 Review
 Page
313: 1-7; Please use complete sentences