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					Acids, Bases, and pH

      Notes #7
    Forming & Breaking Down Water

 Chemical Reaction Formula of Water
   a. H2O H+ + OH-

 Water breaks down into 1 Hydrogen ion
 (H+) and 1 Hydroxide ion (OH-).
           Why is water neutral?
ANS: Ratio of H+ and OH- is equal
     *1 positive H+ balances out the 1
      negative OH-
                       The pH Scale
 What does the pH scale measure?
ANS: Measures the amount of H+
     in a solution.
     -And it ranges from a scale of 0-14
     A Closer Look at the pH Scale
a.  Acids: Concentration of H+>OH-
          -And ranges from 0-6 in the pH
           scale.
           - lower the #, stronger the
             acid; higher the #, weaker the acid
b. Neutral: Concentration of H+=OH-
            -Scale ranges around 7
c. Bases: Concentration of H+<OH-
           -Ranges from 8-14
           -lower the #, weaker the
             base; higher the #, stronger the base
                              Quick Check
1. If you have a solution with a pH of 7. It is
  considered ___________.
 a. Basic     b. Acidic       c. Neutral

2). If you have a solution with a pH of 5, then
  it is a ____________ acid.
  a. strong            b. weak

3) If you have a solution with a pH of 13,then it
  is a ____________ base.
 a. strong             b. weak.
                       The pH Scale


         QuickTime™ an d a
TIFF (Uncompressed) decompressor
   are need ed to see this picture .
   What are Acid-Base Indicators?

 ANS: Helps estimate the acid or base
   level of a chemical solution.
3 Types of Acid-Base Indicators
1. Blue Litmus Paper:
    -In acid it turns from blue to red
    -In bases it stays blue
       Acid-Base Indicators Cont’d

2. Red Litmus Paper:
   -In acid it stays red
   -In bases it turns from red to blue
Blue & Red litmus Paper
Testing Unknown Substance
      Acid-Base Indicators Cont’d
3. pH paper:
   -Accurately measures the pH level
    (0-14) of the chemical solution
                What are buffers?
ANS: Weak acids or bases that
 neutralizes strong acids or bases.

Ex. Pepcid AC or Tums are Ant-acids that
  neutralize the over production of
  stomach acids.
      pH Lab Pre-Lab Write Up
    Write this on your own sheet of
     paper
Title (from handout)
I.   Purpose (Summarize into one
     sentence)
II. Hypotheses (Copy and complete the
     sentences)
III. Materials
                            III.Materials
1.   Litmus Paper (Blue   8. Soda
     & Red)               9. Rubbing alcohol
2.   pH paper & color     10. Antacid
     decoder
3.   Apple juice          11. Baking Soda
4.   NaOH                 12. Shampoo
5.   Vinegar              13. Bleach
6.   HCL                  14. Detergent
7. Orange juice           15. Keppel water
                          16) Milk
                      IV. Procedure
 Summarize Procedure or bullet main
 points



HW: Draw, label, and color the pH scale
Use page 43; Fig 2-10
                Quiz 1 Scores
 A = 22-25
 B = 19-21
 C = 17-18
 D = 14.5-16
 F = 0 - 14
                                      #20
 Oxygen-16
 Neutrons= Atomic Mass - # protons
          = 16-8
           = 8 neutrons
 Carbon-14
         Atomic Mass - # protons
        = 14 -6
        = 8 neutrons

				
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posted:12/3/2011
language:English
pages:18