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.

MATERIALS:   PLEASE NOTE WHMIS LABELS AND ACCORDING SAFETY

PROCEDURES:    

GOGGLES ARE DONNED 

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

2. 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.  

What is it’s formula?

NaHCO3

List some of the uses of these chemicals?

Cooking and it’s in toothpaste

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.  

Small white pebbles 

What is its formula?

CaCl2

List some of the uses of these chemicals?

In plastic, wastewater treatment plants and blast furnaces 

How is chemical B different from Chemical A?

Chemical B is a rock type of texture/material while chemical A is a powder type of texture/ material 

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

What is its formula?

C27H28Br205S

List some of the uses of these chemicals?

Measuring the presence of carbonic acid in a liquid 

Now you are ready for the observations of change. 

Mix a small amount, not all of it, Chemical A with Chemical B in the middle zip-lock bag.  Record observations.  

Nothing happened 

Add 10 mL 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 the chemicals. What do you observe? Take a photograph and if possible video record.

Detect any temperature changes with your hand.

It became very warm while you held your hand on it for a good 5 seconds 

After 2 minutes thoroughly record any new observations.

In the space below add at least two photographs of your zip-lock bag.

  When you are finished, wash all the chemicals down the drain and rinse out 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.

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

It produced gas and filled the bag like a balloon

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

 a physical change I saw was that it became a think liquid or paste and dissolved most of chemical B

 POST THIS LAB ON YOUR EDUBLOG

BE SURE TO INCLUDE YOUR VIDEO IF POSSIBLE!!