Chemistry Unit- Lesson 10

Lesson 10:

Chemical Changes

Objective: To see a color change as evidence of a chemical change
To see fizzing/bubbling as evidence of a chemical change


Supplies:
3 tubes, labeled #1-3
bleach
vinegar
hydrogen peroxide
3 tubes half full with water
food coloring

Procedure:
Place the bleach, peroxide, and vinegar in each of the tubes labeled #1-#3.
Drop one drop of food coloring in each of the water-filled tubes.

Place one dropper full of solution #1 into one water-filled tube. Observe. Continue for each of the 3 solutions.

The bleach will produce an immediate color change. The vinegar will produce none.

Over the next few minutes the tube with bleach added will become more and more colorless. I added the peroxide on this one. I thought it would produce some sort of change, considering it is used to bleach some things....but no change occurred. Even after adding more than one dropper full.

Experiment 2:

We've done this one before. But it was a hit then, and this time we talked a little more about the why behind it and what was taking place.

Step 1: Fill up a bottle/tube about half way with vinegar
Step 2: Funnel a couple of tablespoons of baking soda into a balloon.

Step 3: carefully stretch the neck of the balloon over the bottle. Be sure not to allow the baking soda to fall into the bottle yet.
Step 4: Lift the balloon to allow the baking soda to fall into the bottle and mix with the vinegar. You may want to hold on to the neck of the bottle/balloon just in case.
Step 5: Watch! The balloon will inflate as the reaction between the vinegar and baking soda produces carbon dioxide.