1. Do now
Pollutants have the ability to cause the pH of a substance to change especially in aqueous solutions.
Why do you think pH is related to water quality especially within an ecosystem?

2. Substance that dissolves
Aqueous solution?
Any solute + a water solvent
pH: “Power of Hydrogen”
measure of the concentration of H+ ion in a solution
Substance that dissolves
Dissolving Agent

3. Why do you think pH is related to water quality?
Water determines what kinds of plants and animals can live there.
Water that is too acidic or alkaline will kill the plants and animals.
In a lake or pond, the waters pH is effected by its age and the chemicals discharged by communities and industries.

4. pH Scale Acids- Release Hydrogen Ions (H+)
–Ex: HCl
Bases- Release Hydroxide Ions (OH-) (a.k.a Alkaline)
Ex: NaOH
Neutral – Number of H+ = Number of OH+

5. What is the pH of water?

6. What about pH of blood?
What regulates the pH of blood?

7. Pre-Lab Take a few minutes to read the lab and answer the questions:
What is the purpose of the lab?
Define “acid” and “base” using the terms hydrogen ions and hydroxide ions
What indicators will be used in this lab?
What must you do to the stirring rod between testing substances and why?

8. Lab: pH
Objective:
Determine the pH of common household substances and use this information to identify the substance as an acidic, basic or neutral solution.

9. Need an “indicator” which is something that detects the presence of a certain substance
pH Paper: Indicates the number of H+ ions by means of a number value.
•Litmus Paper:
–Red:
Stays red in a Acid
Turns Blue in a Base
Blue:
Stays Blue in Base
Turns Red in Acid

10. How to set up

11. Do Now
ph is a logarithmic scale. Use the picture above to help you compare the solutions below:
1. How does a pH of 3 and a pH of 5 compare?
2. How does a pH of 8 and a pH of 12 compare?
3. Does a neutral liquid have hydrogen ions?
4. Does a pH of 9 have hydrogen ions?
Rule: As you move from right to left, the number of Hydrogen ions increases.
Each time you move one pH value, it is a 10x increase or decrease

12. Data table indicates the name of solution, its pH and whether it is an acid or a base
Neutral
Milk 6 X
Vinegar 2
Ammonia 11
Lemon Juice
Dish Soap
7-8
Baking Soda
8-9
Water
6-8
Veggie Wash