Transcript Chapter 9 Acids and Bases

Chapter 9
Acids and Bases
Vocabulary
 Acid—a hydrogen containing compound
that ionizes in water to produce
hydrogen ions and is a proton donor
 Base—a hydroxide containing
compound that ionizes in water to
produce hydroxide ions and is a proton
acceptor.
 Indicator—compounds that show a
definite color change when mixed with
an acid or base.
 Electrolytes—a substance whose water
solution conducts an electric current.
 Emulsify—dissolves fats and oils
 Salt—compound formed from the positive
ion of a base and the negative ion of an
acid. The compound is neutral.
 Neutralization—the name of a reaction
between an acid and a base.
 Insoluble—will not dissolve in water.
Acids and Bases Around Us
 Acids and bases are all around us every day.
 Acids are in aspirin, vitamin C, oranges,
grapes, lemons, grapefruit, apples, milk, tea,
pickles, vinegar, and carbonated beverages
 Bases are in lye, milk of magnesia,
deodorant, ammonia, and soaps.
 Acid is necessary for digestion and bases,
such as antacids help when our stomach
hurts.
 Industry depends on acids and bases as
well. Metals are cleaned with acids. Bases
are used for making fertilizer and synthetic
fibers. Both are used to make medicine.
Turn to your partner and
name two common things
in which you find acids
and two common things in
which you find bases.
Properties of Acids
 Acids taste sour.
 Acids affect the color of indicators Litmus
paper changes from blue to red.
 Acids react with metals for form H2 and a
metal compound. The acid corrodes the
metal and produces a residue.
 All acids contain hydrogen, but not
everything that contains hydrogen is an acid.
When an acid is mixed with water, acids
ionize to produce hydrogen ions (H+). This
ion is rapidly surrounded by water to form a
hydronium ion H3O.
Common Acids
 Strong Acids
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Sulfuric Acid—H2SO4
Nitric Acid—HNO3
Hydrochloric Acid—HCl
Strong acids are good electrolytes.
 Weak Acids
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Acetic Acid—HC2H3O2
Carbonic Acid H2CO3
Boric Acid—H3BO3
Weak acids are poor electrolytes.
Properties of Bases
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Bases taste bitter.
Bases are slippery to the touch.
Bases turn litmus paper from red to blue.
Bases emulsify
All bases contain the hydroxide ion (OH-).
When dissolved in water, bases produce
this ion. Because the hydroxide ion can
combine with the hydrogen ion and form
water, bases are referred to as proton
acceptors.
Common Bases
 Strong Bases
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Strong bases are good electrolytes.
Potassium hydroxide—KOH
Sodium hydroxide—NaOH
Calcium hydroxide—Ca(OH)2
 Weak Bases
 Weak bases are poor electrolytes.
 Ammonium hydroxide—NH4OH
 Aluminum hydroxide—Al(OH)3
Turn to your partner and list
two characteristics of an
acid and a base. Then try to
name one acid and one base.
Acids and Bases in Solution:
Salts
 To measure the acidity of a solution, the
pH scale is used. This measures the
concentration of H3O (hydronium).
 pH is a scale from 0 – 14. Seven is
neutral; 0 – 6 is acidic; 8 – 14 is basic.
 Strong acids have low pH values. Strong
bases have high pH values.
Determining pH
 pH is determined by using an indicator.
 Litmus
 Phenolphthalein
 pH paper
 Methyl orange
 Bromthymol blue
 Red cabbage juice
 Grape juice
Incidator
Litmus paper
Acid
Red
Base
Blue
Phenolphthalein Colorless
Pink
pH paper
Red to pink
Blue to green
Methyl orange
Red
Yellow
Bromthymol blue Yellow
Blue
Red cabbage
Pink
Blue to green
Grape juice
Pink
Yellow
Formation of Salts
 When acids react chemically with bases
they form salts. The process is called
neutralization.
 The reaction produces a salt and water.
 Many of the salts formed are insoluble.
 The insoluble substance that crystallizes
is called a precipitate because they fall
out of the solution.
 Example:
 HCl + NaOH  H2O + NaCl
Exercise your brain!!!
 Write the chemical equation to
demonstrate the neutralization of sulfuric
acid and sodium hydroxide.
 Here is a hint:
 Sulfuric acid is H2SO4
 Sodium hydroxide is NaOH
 When you think you have it, come write it
on the board 