1. pH

2. What is pH? pH is the scale that tells you whether a substance is acidic, basic, or neutral. pH=“p” stands for percent and “H” stands for hydrogen The values correspond to the concentration of the hydronium ions.

3. What is an acid? An acid is a substance that donates hydrogen ions (H+) to form additional hydronium ions when dissolved in water. Therefore, there is a larger concentration of hydronium ions versus hydroxide ions. What is the formula for a Hydronium ion? Just add an H+ to water (H 2 O) = H 3 O + (hydronium ion)

4. What is a base? A base is a substance that either contains hydroxide ions or reacts with water to form additional hydroxide ions. Therefore, there is a larger concentration of hydroxide ions versus hydronium ions. What is the formula for a Hydroxide ion? Just take an H+ from water (H 2 O) = OH - (No HO’s in Science) Do you remember any compounds that had an OH? NaOH Sodium Hydroxide

5. Properties: ACIDS Sour taste Can burn skin Contains more H 3 O+ than OH- BASES Bitter taste Can burn skin Contains more OH- than H 3 O+ Feels slippery/soapy What is a common property of Acids and Bases? They both can burn!

6. The pH Scale… The pH scale ranges from 0-14. 0 = most acidic 7 = neutral (Distilled H 2 O) 14 = most basic But you can also have… Diluted acids= 4,5,6 on the pH scale and Diluted bases = 8,9,10 on the pH scale!

7. Diluted vs. Concentrated Diluted means to weaken with the addition of water. Concentrated means to strengthen with the absence of water. Think about when you made Kool-Aid and added too much water and what it tasted like. Too much water = it was too diluted = Does not taste good!

8. Copy pH scale in Notebook

9. pH Scale Diluted= weak Concentrated=strong

10. During the Lab… Find the pH level using the pH probe. (dip it for about 30 seconds and record) Remember to dip the probe into the clean water BEFORE you dip it into the next chemical! Clean up any spills. Do not waste time talking. Pay attention to the lab because of the chemicals! Leave the pH probe at the table!!! Move clockwise after 3 minutes / table.

11. Post-Lab Questions 1.Which items were the is most acidic? 2.Which items were the most basic? 3.Which items on your scale were neutral? 4.Which items on your scale were weakest acids? 5.Which items on your scale were the weakest bases? 6.Why would you take an antacid if your stomach was upset? 7. Label your pH scale with the different substances according to the pH you found!

12. Fill in pH ScalepH Scale

13. Acids and Bases We can have weak acids and bases. Likewise, we can have strong acids and bases. Neutralize- to add an acid to a basic solution or a base to an acidic solution until the resulting solution is chemically neutral or safe. (pH = 7). So…how would you neutralize a strong base like a laundry detergent spill on your skin? Pour large amounts of a weak acid on your skin like vinegar

14. Very Acidic Very Basic Neutral

15. What’s wrong with Soda? Prolonged exposure to soft drinks can lead to significant enamel loss (tooth decay)! The erosive potential of colas is 10 times that of fruit juices in just the first three minutes of drinking!!!