an introduction to the properties of acids, bases, and the ph scale
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ACIDS, BASES, AND PH OH MY!!
An introduction to the properties of acids, bases, and the pH scale
COMPLETE THE FOLLOWING TABLE
Element Atomic #
Mass # Protons Electrons
Neutrons
Ion, Isotope,
or Neutral?
82 209
16 18
Uranium 238 92
MONDAY, SEPTEMBER 17TH
Pick up the two pieces of paper from the front table.
ACIDS
Taste sour Very reactive Contain H+ (hydrogen ions) Examples:
Hydrochloric Acid (HCl) Sulfuric Acid (H2SO4) Citric Acid (citrus fruits) Acetic Acid (vinegar)
BASES
Taste Bitter Feel slippery (soap) Contain OH- (hydroxide ions) Examples:
Soap Sodium Hydroxide (NaOH) Ammonia
ACIDS VS. BASES
If the number of H+ ions in a solution is greater than number of OH- ions, the solution is an acid
If the OH- ions are greater than the H+ ions, the solution is a base
pH SCALE
Indicates hydrogen ion (H+) concentration
Ranges from 0-14 Acids are found in the 0-6 range Bases are found in the 8-14 range 7 is NEUTRAL!!
1 2 3 4 5 6 7 8 9 10 11 12 13 14 strongest acid neutral strongest base
MONDAY, SEPTEMBER 17TH
Do Now: Get out your pH notes from Friday.
Testing Day
Tomorrow!!!
pH SCALE
H+ concentration increasesOH- concentration increases
pH SCALEAs you move from pH 0 to pH 14, the concentration of H+ DECREASES (10 times each number)
As you move from pH 0 to pH 14, the concentration of OH- INCREASES (10 times each number)
PRACTICE
1. As you move from pH 7 to pH 4 what happens to H+ concentration?
2. As you move from pH 2 to pH 8 what happens to OH- concentration?
3. How much more acidic is a solution with a pH 1 vs. pH 5?
TESTING pH
pH paper OR litmus paper
BUFFERS
Neutralize acids and bases Keep the pH from undergoing large
changes
PRACTICE AND LAB
Practice: Read the entire article. Write the main point for each paragraph under the paragraph.
Lab: Make a prediction for each substance. Move around to each station and dip
the pH paper into the solution. Use the scale to determine the pH of
each substance.
LAB Liquid Prediction Actual
pH 1. White milk ________ ________ 2. V-8 Juice ________ ________ 3. Comet cleaner ________ ________ 4. Vinegar ________ ________ 5. Baking Soda ________ ________ 6. Water ________ ________ 7. Egg ________ ________ 8. Lime Juice ________ ________
POST LAB QUESTIONS
1. Which solution was the strongest acid? The strongest base?
2. Which solution was the weakest acid? The weakest base?
3. Did you predict that any solution would be neutral? Was your prediction correct? Explain.
4. How many of your predictions were confirmed during the lab? Explain.
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