Chemistry
Mr. Ross
 If
acids and bases are mixed together in
the proper amounts, they neutralize each
other to produce water and a new
compound, called salt.
 Acid
 Ex:
+ Base  Water + Salt
HCl + NaOH  H2O + NaCl
 titration=
a base is added one drop at a
time until the acid is neutralized.
 A color change in the indicator indicates
when neutralization has occurred.
 The more drops required to neutralize
the acid the strong the original acid
 An
ion is an atom that loses or gains an
electron so the number does not equal
the number of protons
 An acid has a high concentration of
positive hydrogen ions
 A base has a high concentration of
negative hydroxide ions
 How
do you think titration can be
accomplished?
 What is the difference between titration
and neutralization?
•


Your stomach secretes hydrochloric acid, the pH
of your stomach varies, from 1-2 up to 4-5. When
you eat, the stomach releases proteases and
hydrochloric acid to aid in digestion.
After the meal has been digested, your stomach
pH returns to a resting level of about 4 or 5.
Your stomach secretes acid in response highprotein meal, your stomach pH may drop to as
low as 1 to food, so first thing in the morning you
can expect a slightly acidic stomach pH, but not
an acidic level representative of pure
hydrochloric acid.
Antacids are medicines that help
correct the pH balance in your
stomach. Your stomach has its own
natural acids and sometimes these
acids become too much for your
stomach to handle.
 This is caused when you don’t eat
on time and you have an empty
stomach.
 What the antacid does is to
neutralize this affect. They buffer
the stomach’s gastric acid since
they are basic in nature.

 Human
blood normally has a pH of 7.35
and this pH is maintained even when
small amounts of acid or base are added.
 A solution that resists changes in pH
when an acid or base is added is called a
buffer. Aspirin often contains a buffer.
 The
point at which there are
stoichiometrically equivalent amounts of
acid and base.
 [H+]
= [OH-]
Buret
Valve
Acid with
Phenolpthalein
End-Point
 Indicators
are chosen, such that they change
colors at the range of the pH of interest.

The solution itself at the end-point may be:
• Basic, if the reaction involves a strong base and a
weak acid.
• Neutral, if the reaction involves a strong acid and a
strong base.
• Acidic, if the reaction involves a strong acid and a
weak base.