Transcript COS 3.0 Acids and Bases

• Acid and base are terms used by chemists to categorize
chemicals according to their pH.
•An acid is generally considered to be any material that gives
up a hydrogen ion in solution.
• A base is any material that creates a hydroxide ion in
solution.
•Many of these acids and bases are familiar in everyday life.
A class of compounds whose water
solutions taste sour, turn blue litmus to
red, and react with bases to form salts.
(measures less than 7 on the pH scale)
Acids produce solutions that:
• Taste sour
• Turn blue litmus paper red
• Conduct electricity
• react with metals to liberate a hydrogen gas
• are corrosive (acid rain)
• lose the above properties when reacted with a base.
Examples of acids:
• Vinegar
• Lemon Juice
• Soft Drink
• Battery Acid
• Stomach Acid
• Apple Juice
• Black Tea
A class of compounds that taste
bitter, feel slippery in water solution,
turn red litmus to blue, and react with
acids to form salts.
(measures more than 7 on the pH scale)
Bases produce solutions that:
• taste bitter
• turn red litmus blue
• conduct electricity
• feel slippery
• are corrosive (basic solution in glass container)
• lose the above properties when reacted with an acid.
Examples of bases:
• Detergent
• Baking Soda
• Drain Cleaner
• Ammonia
• Soaps (hand, dish)
• Antacid
• These are items that are neither acids or
bases.
• Neutral items will turn blue and red litmus
paper green.
• The main example of a neutral item is:
Pure Water
(measures exactly 7 on the pH scale)
• Red litmus paper
• Blue litmus paper
• pH
• Red Cabbage Juice
•Robert Boyle discovered litmus paper
•certain plant extracts, such as litmus, can be
used to distinguish acids from bases.
• blue and red litmus paper turn red when
dipped in an acid
• red and blue litmus paper turn blue when
exposed to a base
The pH scale is used to identify
how strong acids and bases are.
• pH is the measure of acids or bases of a
solution.
• The pH scale is numbered from 1 to 14
• 1 through 6 being acids
• 7 is considered neutral
• 8 through 14 being bases
• red cabbage can be used as an acid/base
indicator
• after boiling the red cabbage, pour a small
amount of the juice into a small sample of a
substance your checking
• the juice will turn blue if the substance is a
base
• the juice will turn red if the substance is an
acid
• Proteins
in your hair, nails, cell membranes,
and other parts of you body consist of amino
acids.
• Enzymes that catalyze reactions in your body
are composed of amino acids.
• Hydrochloric acid is in your stomach to aid in
the digestion of food.
• Organic bases are major components of DNA
and products of the digestion of proteins.
• ACID - A class of compounds whose water solutions
taste sour, turn blue litmus to red, and react with bases to
form salts. (measures less than 7 on the pH scale)
• BASE - A class of compounds that taste bitter, feel
slippery in water solution, turn red litmus to blue, and
react with acids to form salts. (measures more than 7 on
the pH scale)
• NEUTRAL - These are items that are neither acids or
bases.
There are 4 main ways to determine if a substance is and
acid or a base. They are: Red litmus paper, Blue litmus
paper, pH, and Red Cabbage Juice.
1. Name an example of an acid that was mentioned on one of the
slides.
2. Name an example of a base that was mentioned on one of the
slides.
3. True or False. The lower the pH number, the stronger the
acidity.
1. Vinegar, Lemon Juice, Soft Drink, Battery Acid, Stomach Acid,
Apple Juice, or Black Tea.
2. Detergent, Baking Soda, Drain Cleaner, Ammonia, Soaps
(hand, dish), or Antacid.
3. True
• Background information on acids and bases.
<http://educ.queensu.ca/~science/main/concept/chem/c10/C10CDMJ1.htm>
• Acids and Bases. <http://www.bookrags.com/research/acids-and-bases-woc/>
• Acids and bases Lab. <http://www. Scribd.com/doc/2977162/Acids-and-Bases-Lab/>
• Smoot, Robert C.; Price, Jack S.; Smith, Richard G. Chemistry A Modern Course.
Chapter 24, Acids, Bases, and Salts.
• Holt, Rinehart, and Winston, Inc. Chemistry Visualizing Matter. Chapter 13, Acids and
Bases.