SCIENCE 9: Bag of Change

PREFACE:

In this activity, you will mix 3 unknown substances together in a bag and observe the changes that occur noting chemical change and physical change. Observation skills are crucial for this investigation.   Watch for changes in state (solid, liquid, gas), colour (use noun-colour description), volume (mL), temperature, and anything else you can detect.   Do not smell any of this substances please.

MATERIALS:   PLEASE NOTE WHMIS LABELS AND ACCORDINGLY SAFETY

PROCEDURES:    GOGGLES ARE DONNED & NOT REMOVED UNTIL LAB CONCLUSION!!!!

1. Add one spoonful of Chemical A on the left side of the ziplock bag. Describe and record the properties for Chemical A.  Add 1 spoonful of Chemical B on the right side of the ziplock bag.  Do not mix the chemicals.  Look and describe Chemical C.  Record your observations in the spaces provided below. Observations may include the colour or state of each chemical. Add a photograph of each Chemical in second row below.

Chemical A (Sodium bicarbonate)	Chemical B (Calcium chloride)	Chemical C (Bromothymol blue)
It’s a white powder. 10.23 grams were placed into the Ziploc bag. Its starting temperature is room temperature. There were no WHMIS labels.	Looks like small white pearls. WHMIS label says: Harmful if swallowed, irritant, do not inhale.Its starting temperature is room temperature. Once mixed with chemical A, the mixture weighed 15.1 grams. Therefore 4.87 grams of calcium chloride was used.	It appears to be a blue liquid with a consistency of water. There were no labels on this substance.

2. Mix Chemical A with Chemical B in the ziplock bag. Record observations.  Add 10 mL of chemical C into a plastic bag.  QUICKLY remove as much air as possible and then seal it up.
3. In the first 30 seconds, squeeze the bag in various places to mix the chemicals.
4. Detect any temperature changes with your hand.
5. Record as many observations as you can. After 2 minutes record any new observations.
6. Add at least two photographs of your ziplock bag.
7. When you are finished, wash all the chemicals down the drain and rinse out the plastic bag.
8. What evidence of chemical change did you observe in the bag? What physical changes did you see?

 Observations

When chemical A and chemical B were mixed together, the pearls remained intact and the powder remained unaffected. As soon as chemical C, was added hot air came out of the bag. As all three chemicals were mixed together, the white powder started turning into yellow and bubbling mixture. The pearls started to heat up making them almost too hot too touch but did not dissolve. The blue liquid was absorbed by the yellow mixture losing its blue colouring. The yellow mixture seemed to overall stay the same temperature. After two minutes the bag returned back to its normal temperature, pearls stayed intact and the yellow mixture remained the same colour. However it did stop bubbling.

The two chemicals before they were mixed