Chapter 9 Acids and Bases - Download as PowerPoint by lt56JX


									   Chapter 9
Acids and Bases
  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
  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
    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
      Sulfuric Acid—H2SO4
      Nitric Acid—HNO3
      Hydrochloric Acid—HCl
      Strong acids are good electrolytes.
  Weak Acids
      Acetic Acid—HC2H3O2
      Carbonic Acid H2CO3
      Boric Acid—H3BO3
      Weak acids are poor electrolytes.
Properties of Bases
    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
Common Bases
 Strong Bases
     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:

 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       Acid          Base
Litmus paper    Red           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
  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 

To top