LAB: Red Cabbage Indicators by 5r7y0Np

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									                        LAB: Red Cabbage Indicators
Indicators are compounds that change color in the presence of acids
or bases (according to the pH). Red cabbage contains a natural
indicator that turns specific colors at specific pHs.
Purpose: You will extract the indicator from red cabbage and use it
to determine the pH of several liquids.
Data Table:
    Liquid                   Color with            Color with pH   pH number
                             Indicator                paper        from p. 619
     Control
     Vinegar
    Ammonia
    HCl Acid
 Baking Soda
   Rainwater

Analysis:
1. What purpose does the control serve?


2. What is the pH of the control?

3. When using the red cabbage indicator, what colors are associated
   with acids?

4. When using the red cabbage indicator, what colors are associated
   with bases?

5. Why is red cabbage juice considered a good indicator?



6. Which do you think would be more useful to help identify an
   unknown liquid – pH paper or red cabbage juice? Why?


Unit 4 (Ch. 10) – Reactions/Chem. Living Systems     Bach                 11/24/09

								
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