s8pe-31003-ca
11/9/05
5:06 PM
MAZER
Page 322
KEY CONCEPT
Solutions can be acidic,
basic, or neutral.
CALIFORNIA
Content Standard
8.5.e Students know
how to determine
whether a solution
is acidic, basic, or
neutral.
BEFORE, you learned
NOW, you will learn
• Substances dissolved in solutions
can break apart into ions
• Concentration is the amount
of a substance dissolved in
a solution
• Water is a common solvent
• What acids and bases are
• How to determine if a solution
is acidic or basic
• How acids and bases react with
each other
EXPLORE Acids and Bases (8.5.e)
VOCABULARY
What happens when an antacid mixes
with an acid?
acid p. 323
base p. 323
pH p. 326
neutral p. 326
PROCEDURE
1
Fill the cup halfway with vinegar.
2 Observe the vinegar in the cup.
Record your observations.
3 Crush two antacid tablets and place them
MATERIALS
• clear plastic
cup
• vinegar
• 2 antacid
tablets
in the vinegar.
4 Observe the contents of the cup for
5 minutes. Record your observations.
WHAT DO YOU THINK?
• What did you observe before adding the
antacid tablets?
• What happened after you added the tablets?
Acids and bases have distinct properties.
Many solutions have certain properties that make us call them acids or
bases. Acids are found in many foods, such as orange juice, tomatoes,
and vinegar. They taste slightly sour when dissolved in water and
produce a burning or itchy feeling on the skin. Strong acids should
never be tasted or touched. These solutions are used in manufacturing
and are dangerous chemicals.
reading tip
The prefix ant- means
“against,” so an antacid
is a substance that works
against an acid.
322 Unit 3: Chemical Interactions
Bases are the chemical opposite of acids. They tend to taste bitter
rather than sour and often feel slippery to the touch. Bases are also found
in common products around the home, including soap, ammonia, and
antacids. Strong bases, like the lye used for unclogging drains, are also
dangerous chemicals.
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