Acids and Bases The pH scale What do vinegar, lemons, and orange juice have in common?
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Transcript of Acids and Bases The pH scale What do vinegar, lemons, and orange juice have in common?
Acids and BasesThe pH scale
What do vinegar, lemons, and orange juice have in
common?
Characteristics of Acids
• Taste Sour• React with
metals• Often produce
hydrogen gas• Can burn your
skin
What do milk, Comet, and Tums have in common?
Characteristics of Bases
• Taste Bitter• Feel Slippery• Neutralize
Acids– Antacids
• Dissolve grease
But, what exactly are acids and
bases?
•Substance that ionizes in water to give hydrogen ions (H+)
Acid
Examples of Acids
• HCl
• H2SO4
• HNO3
• HF• Juices
•Substance that ionizes in water to give hydroxide ions (OH-)
Base
Examples of Bases
• NaOH
• Ca(OH)2
• KOH• Soap,
Ammonia, Baking Soda
The pH Scale
•Measurement system that indicates the concentration of H+ ions in solution.–The pH scale ranges from 0 to 14.
The pH Scale
•pH = “power of hydrogen”–Each step increases by a power of ten
pH Scale
Acidic Solutions
• Solutions with a pH below 7 are called acidic because they have more H+ ions than OH- ions.
• The lower the pH, the greater the acidity.
Basic Solutions
• Solutions with a pH above 7 are called basic because they have more OH- ions than H+ ions.
• The higher the pH, the more basic the solution.
pH
Sca
le
pH and Water
• Why does water have a pH of 7?– Hydronium ions = hydroxide ions – (H+) = (OH-)
H20 H+ + OH-
pH paper
Litmus paper
Litmus paper
Interesting fact…
Water can act as an acid or a base!!!
Video Clip