Transcript Acids and Bases

Acids, Bases, &
Salts
Acid:
A substance that produces
hydrogen ions, H+, in
solution.
Base:
A substance that produces
hydroxide ions, OH-, in
solution.
Indicator:
An organic compound that
changes color in an acid
or base.
Litmus paper: red in acid
blue in base
Properties of Acids:
 Acids
taste sour (never taste!!)
 Acids are electrolytes (contain
ions)
 Acids are corrosive
 Acids react with indicators to
cause a predictable color
change.
List of important
acids on page 193 in
your book.
Properties of Bases:
 In
undissolved state most bases are
crystalline solids
 In solution most bases:
– feel slippery (never touch)
– taste bitter (never taste)
– bases are also corrosive, and can
cause severe burns
List of important
bases on page 195
of your book.
pH
A measure of the
concentration of
hydronium ions.
The pH scale ranges
from 0 - 14
0 - 6 = acidic (the lower the
value the more acidic)
8 - 14 = basic (the higher the
value the more basic)
pH = 7 is neutral
Water is typically neutral.
Neutralization of
Acids and Bases
Neutralization:
A chemical reaction between an
acid and a base.
 Forms water and a salt
 Neutralization reactions = ionic

Example:
HNO3 + KOH -->
H2O(l) + K+ + NO3Water
Salt
Neutralization Reaction Video

http://www.marymount.k12.ny.us/marynet/s
twbwk03/03hchem/emreaction/emreaction.
html
Salt:
A salt is a compound
formed when the negative
ions from an acid
combine with the positive
ions from a base.
List of some salts on
page 203 of your
book.
Titration:
A process in which a
solution of known
concentration is used to
determine the
concentration of another
solution.
Strength of Acids and
Bases
Strong acid:
ionizes almost
completely in a
solution.
Weak acid:
only partly ionizes in
a solution.
Strong Base:
dissociates completely
in solution.
Weak Base:
only partly dissociates
(produces very few
ions)
pH & Digestion: Mouth
 The
1st place food goes is mouth.
 Saliva contains amylase.
 Amylase helps to break down food.
 Saliva is near pH 7 (best pH for amylase
to work.
pH & Digestion: Stomach
 Stomach
is lined with enzymes &
hydrochloric acid (HCl).
 Enzymes work to break down food into
macromolecules the body can use.
 pH is about 2. (These enzymes work
best at this pH.)
pH & Digestion: Small Intestine
 Digestion
is completed mostly in small
intestine.
 Important molecules pass into
bloodstream from here.
 pH is about 8 (these enzymes work
best at this pH.)