1. DO NOW….. 1.Write down today’s objective in your binder. 2.Using your notes from our Homeostasis: Investigating Breathing Rate Lab, answer the question: “What two respiratory gases affect breathing rate?” “Which gas changes the condition of the blood?”

2. LAB: DETERMINING A LIQUID AS ACIDIC, BASIC OR NEUTRAL OBJECTIVE IS TO DETERMINE THE PH OF COMMON HOUSEHOLD SUBSTANCES AND USE THIS INFORMATION TO IDENTIFY THE SUBSTANCE AS AN ACIDIC, BASIC OR NEUTRAL SOLUTION.

3. VOCABULARY BUILDING: BE SURE THAT YOU CAN DEFINE THESE TERMS BEFORE DOING THE LAB Ion Dissociate Hydrogen ion Hydroxide ion Neutral Acidic Basic

4. WATER IN A GLASS HOW DO THE MOLECULES APPEAR? Above is a diagram of the way in water molecules can look in the glass to the left. The water molecules breaks into ions, hydroxide and hydrogen. Diagram below shows Water molecules with 2 hydrogen Atoms and 1 oxygen atom

5. PAPER INDICATOR - Called pH paper - Indicates the presence and amount of H +

6. SET UP FOR THE LAB Test tubes contain various household substances

7. Above he pH paper is the light yellow colored as shown by the arrow. This is the paper you used to id the acid and base or neutral liquid. The red and blue paper are something else. A beaker of distilled water is available to clean the stirring rod after each application of a substance on the paper. Preventing contamination of solutions is very important.

8. LiquidpH paper color pH #Acid, Base, or Neutral VinegarAcid MilkNeutral or acid DetergentBase AmmoniaBase GatoradeAcid WaterNeutral Baking soda waterBase Spray cleanerBase Orange juiceAcid SodaAcid Data Table indicates if the liquid is and acid, a base, or neutral liquid. Your results may or may not be the same. These are the expected results. You would not be marked wrong if the data correctly matches with the type of liquid.

9. USE THIS SLIDE TO HELP YOU COMPARE THE MAKEUP OF TWO SOLUTIONS (QUESTION #2 IN ANALYSIS OF EXPERIMENT) Rule: As you move from right to left, the number of Hydrogen ions decreases. How does a pH of 3 and a pH of 5 compare? How does a pH of 8 and a pH of 12 compare? Does a neutral liquid have hydrogen ions? Does a pH of 9 have hydrogen ions?

10. Strong Acid Weak Acid NeutralWeak Base Strong Base Vinegarx Milkx Detergentx Ammoniax Gatoradex Waterx Baking soda x Spray cleaner x Orange juice x Sodax Data Table indicates the expected answers. Yours may be different but would be correct if your data matches your answer.

11. CHALLENGE: People usually say that the blood is neutral. A pH of 7 denotes neutral. Fr 7 can be called acidic or basic (alkaline) when talking about the condition of human blood. Why?