1. Alka Seltzer Lab

2. Observations:
Alka Seltzer: smells like vinegar, powdery, chalkish, crumbly, triangular, black dots, white, smooth on top, delicate, words, jagged on edges,
Bromothymol Blue: clear, light blue, see through, minty, no bubbles, thin, watery,

3. Observations when you blew in the tube?
Turned green-yellow, stay clear, yellow- green, foamy at top, still watery, no bubbles

4. Observations when you added AS to BB:
Flashed green to yellow
Foamy, fizzed
Dissolved and got bubbly
Powder at bottom, kept bubbling
Less bubbles (tiny)
Clump of powder at bottom.

5. After 5 minutes of shaking?
Yellow to green to blue (turquoise)
Powder was rising, Powder went away
No more bubbles

6. Baking soda (sodium bicarbonate) Citric acid
What is in Alka Seltzer?
Baking soda (sodium bicarbonate)
Citric acid
Aspirin (acetyl salicylic acid)

7. What is Bromothymol Blue?
An acid/base indicator

8. Colors It turns yellow in an acid. It turns blue in a base.
It turns green in a neutral substance.
It turns yellow in an acid.

10. Why does it turn yellow?
Because the Brom Blue is in an acidic liquid.

11. What are the acids?
Citric Acid
Acetyl salicylic acid

12. What was the white powder at the bottom?
Aspirin that did not dissolve yet.

13. Why do people take an acid if their stomach hurts?

14. Why does it turn blue after shaking it?
It helps the aspirin to dissolve.
This causes a reaction.
New chemicals form.
The new chemicals are bases.
So….. Blue!

15. Final chemicals Aspirin --- takes away pain
Sodium citrate --- settles your stomach

16. Conclusion Bromothymol Blue is an acid/base indicator.
It turns yellow in acids, and blue in bases. In a neutral substance, it is green.

17. Active Ingredients in Alka-Seltzer
Baking soda
Aspirin
Citric acid

18. What happens when alka seltzer is put in water?
The baking soda reacts with the citric acid and aspirin.
Carbon dioxide gas is given off. ( causes the fizz).
The acids cause Brom Blue to turn yellow.
The white powder at the bottom is undissolved aspirin.

19. After shaking so that all the solids dissolve and react, you end up with two new compounds. These are bases and cause the Brom Blue to become blue again.

20. The aspirin compound takes away the pain.
The other compound (sodium citrate) settles your upset stomach.