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
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PROCEDURES:
QUESTIONS:
GOGGLES ARE DONNED & NOT REMOVED UNTIL EVERYONE’S LAB CONCLUSION!!!!
1. Add one spoonful of Chemical A () on the left side of the zip-lock bag. Describe and record the properties for Chemical A.
Chemical A is a white coloured powder. The chemical was at room temperature when we used it.
What is it’s formula?
The formula for sodium bicarbonate is NaHCO₃.
List some of the uses of this chemicals?
- Relieves heartburn
- Used in baking and cooking
- Relieves acid indigestion
2. 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.
Chemical B is tiny shaped sphere, no bigger than 3 mm. The spheres were the colour white and the chemical was at room temperature.
What is it’s formula?
The formula for Calcium chloride is CaCl2.
List some of the uses of this chemicals?
- De-icing roads in winter
- Preserves food
- Used in food
- Swimming pool chemical
How is chemical B different from Chemical A?
Chemical B is shaped as spheres and chemical A is a powder, also they are both used for different things an example is Chemical A is used for baking.
Look and describe Chemical C (Bromothymol blue). Record your observationin the space provided below.
Chemical C has a very pigmented blue colour and its state is a liquid. The liquid was at a room temperature when we were using it.
What is it’s formula?
The formula for bromothymol is C27H28Br2O5S.
List some of the uses of this chemicals?
- for measuring the presence of carbonic acid in a liquid
- Used for science experiments
Now you are ready for the observations of change.
3. 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.
Nothing happened when we mixed chemicals A and B together.
4. 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.
When we added the ten drops of chemical C there was immediate change of colour to orange and the chemicals started to fizz. The bag inflated, and chemical A and B reacted differently with temperature. Chemical B made the chemicals heat up and chemical A cooled it down. At the end the fizzing died down but we were left with an orange liquid with one side warm and the other side cold.
Detect any temperature changes with your hand. What do you feel?
I believe the chemicals A and B caused the different temperature changes in the plastic bag. The side where chemical B was, was warm, and the side where chemical A was, was cold. All the solutions were room Temperature when we started this lab.
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.
the bag deflated after two minutes, the cold temperature on one side of bag started to go back to room temperature. The fizzing stopped at the end of the experiment and the texture of the chemicals mixed together felt like paste.
5. 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.
What evidence of chemical change did you observe in the bag?
The chemicals mixed together created liquid but when they were separate they were a liquid and solid. The mixture produced gas and change of colour. The chemical reaction also created fizzing and temperature change.
What physical changes did you see? Answer in complete sentences.
The mixture produced gas and fizzing. The colour also changed from white to orange.