Reactions in a Bag

Purpose: The purpose of this experiment is to miss several chemicals in a plastic bag, observe evidence of a reaction, then try to determine which chemicals are responsible for the changes.

Materials:

• Calcium Chloride

• Silicon Dioxide

• Bromthymol blue solution

• Zipper-close bag

• 10 mL graduated cylinder

• Sodium hydrogen carbonate

• Plastic spoons

Class Procedure:

1. Examine each of the materials provided.

2. Blindfold one of the lab partners. This student should hold the bag during step 3.

3. Place one spoonful of each of the solids and 10 mL of the liquid in the zip-lock bag. Quickly zip the bag shut. Observe any evidence that a reaction takes place. Include the observations by both lab partners.

4. Devise an experiment to determine which combination of chemicals is responsible for each of the changes that occur. In other words, which material(s) could be left out and still have each change occur? You may use laboratory glassware for your experiment, but you must have your experimental design approved by the teacher before you start.

Results:

We observed many reactions in this experiment, such as the mixture of chemicals became warm and hot. It also gave off gas causing the bag to expand. It bubbled, turned yellow, foamed and fizzed.

Group Procedure:

1. Take one spoonful of calcium chloride and put it in the plastic bag and pour 10mL of the blue solution, Bromthymol blue, and label the bag accordingly.

2. Do the same for each chemical and record observations.

3. Combine Calcium Chloride and Silicon dioxide and pour one spoonful of each in the bag and pour 10mL of the blue solution in it and record observations.

4. Do the same for the combination of Calcium Chloride and Sodium Hydrogen carbonate. Observe results.

5. Then do the Silicon Dioxide and Sodium Hydrogen Carbonate in a different bag, add 10mL the blue solution and observe results.

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