Unit 9 Notes
Acids, Bases, and Salts
Acids
An acid is a substance
that produces Hydrogen
ion H+ or hydronium H3O+
in solution
Properties of Acids
1. taste sour
2. electrolytes – conduct
electricity because of ions
3. corrosive – eat away at metals
as metallic compounds and
hydrogen gas is produced
Different Acids
Acid
Formula
Where Found
Hydrochloric
(strong)
HCl
Stomach, cleaning
supplies, “muriatic
acid”
Sulfuric
(strong)
Nitric (strong)
H2SO4
Car batteries,
fertilizer
HNO3
Explosives,
fertilizers
Phosphoric
H3PO4
Detergents,
fertilizers
Carbonic
H2CO3
Soda (carbonated)
Ascorbic
H2C2H6O6
Vitamin C (fruits and
vergetables
Acetylsalicylic
HOOC-C6H4-OOCCH3
aspirin
Acetic (weak)
CH3COOH
vinegar
The most widely used chemical in the
world is sulfuric acid. It can cause
severe burns because it is a
dehydrating agent. This means that it
takes all of the water out of
materials, including skin.
STRONG ACIDS
A Strong Acid completely ionizes
(breaks apart) in water and
releases a lot of H+.
Example: sulfuric acid (battery
acid)
Weak Acids
A Weak acid only partially beaks down
in water, so it doesn’t release much
H+.
Example: acetic acid (vinegar)
Bases
A BASE is a substance that
produces hydroxide ions OH- in
solution. AKA=Alkine
Properties of Bases
1. feel slippery
2. taste bitter
3. electrolytes
4. corrosive
Most bases contain a metal and OH(hydroxide)
The exception is ammonia, NH3, but it
still produces OH- when mixed with
water
NH3 + H2O
NH4+ + OH-
BASE
Sodium
hydroxide
Formula
NaOH
Where Found
Soap, drain
cleaner
(strong)
Aluminum
Al(OH)2
hydroxide (weak)
Magnesium
Mg(OH)2
hydroxide
Deodorant,
antacid
Laxative,
antacid
Calcium
hydroxide
Ca(OH)2
Mortar,
plaster, lime
ammonia
NH3
Cleaners,
fertilzer, rayon,
nylon
(strong)
(strong)
(weak)
Strong Bases
A strong base completely dissociates
(breaks apart) in solution and releases
lots of OH-.
Example: sodium hydroxide
Weak Base
A weak base does not completely
break apart in solution and does not
release as much OHExample: Aluminum hydroxide
pH Scale
pH is the measure of H3O+ in a
solution
pH is used to measure the strength of
acids and bases. It ranges from 0 to
14.
Substances with a pH lower than 7
are acidic
Substances with a pH higher than 7
are basic
Substances with a pH of 7 are neutral
Indicators
Substances that change color in the
presence of acids and bases
Examples:
1. bromythymol blue turns yellow for acid
and blue for base
2. phenylthalein turns clear for acid and
pink for base
pH Scale
Strong
Acids
Weak
Acids
Neutral
(pure water)
Weak
Bases
Strong
Bases
Neutralization
If you want to NEUTRALIZE
an acid or base, you add a
BUFFER.
Buffers
Buffers are ACIDS, BASES, or
SALTS that are mixed with acids or
bases to make their pH closer to 7.
If you want to neutralize an acid, your
buffer must be a BASE
If you want to neutralize a base, your
buffer must be an ACID
Buffers in your body help keep your
blood’s pH at 7.4. This is necessary
because most of your food contains
ACIDS
Titration
Process that can be used to
determine the concentration of
an acid or base
Neutralization is a chemical reaction
between an acid and a base
H+ from the acid combine with OHfrom the base to form water
Metals from the base combine with
nonmetals from the acid to form a salt
Example:
HCl + NaOH
NaCL + H2O
Salts
Most SALTS are formed with a METAL
and a NONMETAL other than OXYGEN.
Some salts are formed with a METAL
and a POLYATOMIC ION.
Salt
Formula
Uses
Sodium chloride
NaCl
Food preparation
Sodium
bicarbonate
NaHCO3
Baking soda
Calcium
carbonate
CaCO3
Chalk
Ammonium
chloride
NH4Cl
Batteries
Sodium
phosphate
Na2PO4
Detergents
Acid Rain
 Unpolluted rain typically has a pH value
of 5.6 which is acidic, but not harmful
 Any rain that is below 5.6 is
considered acid rain
 Acid Rain Can:
1. Dissolve marble in buildings and statues
2. Corrode metal (buildings, cars)
3. Kill plankton (then fish die)
Ways Acid Rain can Occur
Burning coal releases sulfur – sulfur
combines with water in the air – sulfuric
acid forms
Car exhaust releases nitrogen oxide –
combines with water – nitric acid forms
Ways to Prevent Acid Rain
“scrubbers on smokestacks”
Nuclear power
Cleaner fuel
Soaps
Soaps are organic salts, this means that
they contain carbon.
Soaps are made by reacting fats or oils
with sodium hydroxide or potassium
hydroxide.
Soaps made with NaOH are solids
Soaps made with KOH are liquids
Glycerin is another product of this
reaction which is used in lotion
The process of making soap is called
SAPONIFICATION
Detergents
Detergents are similar to soaps, but fo
not form soap scum which is a
precipitate that forms when soap is
used in hard water (lots of minerals)
This is why most laundry products are
detergents, not soaps
Esters
An ESTER is an organic compound
formed by the reaction of an organic
acid with an alcohol
Esters are responsible for the odors
and flavors of flowers, fruits, and other
foods. Esters are added to jello and
candy to give the flavors of
strawberry, banana, or apple.
Organic acids are also used to make
polyester fibers