PREFACE:

In this lab activity, you will mix 3 unknown substances together in a bag and observe the changes that occur.  There will be both chemical changes and physical changes. Observation skills are crucial for this lab 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.  This is a dangerous experiment do not get any substances on your skin.  We will wear our goggles throughout the entire lab time!

 

MATERIALS:   PLEASE NOTE WHMIS LABELS AND ACCORDING SAFETY

Chemical A (a white solid) Chemical B (a white solid)

Chemical C (a blue liquid) 50 mL graduated cylinders

Plastic bag goggles

 

PROCEDURES:    

GOGGLES ARE DONNED 

& NOT REMOVED UNTIL EVERYONE’S LAB CONCLUSION!!!!

 

Add one spoonful of Chemical A (sodium bicarbonate) on the left side of the zip-lock bag.  Describe and record the properties for Chemical A.  

 

The baking soda is very white and powdery compared to the calcium chloride

What is it’s formula?

NaHC03

List some of the uses of this chemicals?

Baking and cleaning

Add 1 spoonful of Chemical B (Calcium chloride) on the right side of the zip-lock bag.  Do not mix the chemicals.  Describe and record the properties for Chemical B.  

Looks like Styrofoam 

What is it’s formula?

CaC12

List some of the uses of this chemicals?

It’s used for treatment for low levels of calcium

1. How is chemical B different from Chemical A?

Baking soda is used as a leavening tool for baking, but Calcium Chloride absorbs moisture.       

1. Look and describe Chemical C (Bromothymol blue).  Record your observations in the space provided below. 

Its blue and a thicker consistency 

It ended up turning yellow

What is it’s formula?

C27H28Br2O5S

 

List some of the uses of this chemicals?

It’s used for measuring the presence of carbonic acid in a liquid

 

Now you are ready for the observations of change. 

1. Mix a small amount, not all of it, Chemical A with Chemical B in the middle zip-lock bag.  Record observations.  Paste a photograph in the space below.
3. Nothing really happened with chemical A and B together.
10. Add 10 drops of chemical C into a plastic bag.  QUICKLY remove as much air as possible and then seal it up.  In the first 30 seconds, squeeze the bag in various places to mix all of the chemicals. What do you observe? Take a photograph and if possible video recording.

As soon as they all mixed the mixture turned yellow and it started foaming.

 

 

1. Detect any temperature changes with your hand.  What do you feel?

Suddenly the bag was very hot, and then it became very cold.

 

After 2 minutes thoroughly record any new observations. Include a photograph in the space below.   In the space below add at least two photographs of your zip-lock bag.

 

 

 

 

1. When you are finished, open the zip very slightly and discard the plastic bag. Discard the UNSEALED bag in the correct discard.  DO NOT take off your goggles until everyone in the room has completed the lab.

 

1. What evidence of chemical change did you observe in the bag? 

At first adding chemicals a and b did nothing, but after adding the blue liquid the baking soda expanded and the bag filled with air.

1. What physical changes did you see? Answer in complete sentences.  

 When we added both chemicals the substance changed from powder to a yellow liquid putty. It started out more like a powder and as time passed it changed from solid to liquid and blue to yellow. It also got very hot and cold.