the ph scale is a substance an acid or a base?. acids an acid is a compound that increases the...
TRANSCRIPT
The pH Scale
Is a substance an acid or a base?
ACIDS• An acid is a compound that
increases the number of hydrogen ions when dissolved in water (H+)
• An acid solution tastes sour• An acid can change the color of
certain compounds
What is an ion?
An ion is an atom that has lost or gained an electron giving it a
positive (+) or negative (-) charge.
USES OF ACIDS• Citric acid and ascorbic acid (Vitamin C)
are found in orange juice• Carbonic acid and phosphoric acid give a
“bite” to soft drinks• Acids in your stomach aid in digestion• Sulfuric acid is the most widely used
industrial acid in the world. It is used in making metals, paper, paints, and fertilizers.
BASES• A base is any compound that increases
the number of hydroxide ions (OH-) when mixed with water
• A base solution tastes bitter• A base solution feels slippery• A base can change the color of certain
compounds
Uses of Bases• Bases are used in soaps
(remember, bases are slippery)• Bases are used to make paper, in
oven cleaners, and to unclog drains• Ammonia is a base and is used in
many household cleaners
Detecting Acids and Bases
• You can detect an acid using an indicator.
• INDICATOR - A substance that changes color in the presence of an acid or a base.
INDICATORS• Litmus paper is an indicatorAn acid turns blue litmus paper redA base turns red litmus paper blue
• Cabbage juice can be used as an indicator The juice should turn pink in acidic solutions, and green in basic solutions.
HOW DO WE MEASURE pH?
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
ACID BASE
NEUTRAL
The pH Scale
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
ACID BASE
NEUTRAL
The pH Scale
• Solutions are groups of molecules that are mixed up in a completely even distribution.
• Uniform Distribution.• Example: Sugar and Water
Images are from http://www.chem4kids.com
• The substance to be dissolved. Will have less solute than solvent in a solution.
• The one doing the dissolving. Will have more solvent than solute in a solution Images are from
http://www.chem4kids.com
Question #1
• Lemon juice has a pH of 2.2. Is it an acid or a base?
Question #2• Detergents
such as Tide have a pH of about 10. Is Tide an acid or a base?
Question #3• Seawater has
a pH of 8.2. Is seawater an acid or a base?
Question #4• The inside of
your mouth has a pH of 7. Is it an acid or a base?
Question #5• How do you
think we came up with the term “acid rain”?
Question #6• 409 cleaner
contains ammonia that has a pH of 12. What will 409 do to red litmus paper?
Question #7• A soft drink
has a pH of 3.2. What will it do to a piece of red litmus paper?
pH of Everyday Substances
Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings