Material
Mass (g)
Flask
Balloon
Vinegar
Baking soda
Total Mass of all objects
A)Total mass of all objects after the reaction
occurred
-------------------------------------- gram
B) Compare the mass of your all your objects before
the reaction and after the reaction. Are they the
same?
____________________________________
C) Mass of the system after the Carbon dioxide gas
escaped._______________
D) How much gas escaped?________________
Analysis Questions:
1. What was the evidence to indicate that a chemical reaction occurred?
2. How did the final (products) mass of the system compare with the initial (reactants) mass of the system for
each trial? How did your result support or violated the Law of Conservation of Mass?
3. List the reactants and indicate its state of matter
4. List the products and list its state of matter
5. How else could you have tested the law of conservation of matter for this reaction? What other experimental
designs could you have implemented? Write a different procedure that can be used to test this law.
Name:_________________________________________Date___________________Period_________
Law of Conservation of Mass Lab
Purpose: To attempt to verify & observe the Law of Conservation of Mass - In any chemical reaction, the total
mass of the reactants is always equal to the mass of the products.
Materials:
• balance
• 1 balloon
• weighing paper
• 125 mL flask
•
•
•
50ml graduated cylinder
~5 g baking soda
~15 mL vinegar
Introduction: The word equation for the following reaction is as follows:
vinegar + baking soda → sodium acetate + water + carbon dioxide
The chemical equation for the reaction is:
CH3COOH + NaHCO3 → NaC2H3O2 + H2O + CO2
Reactants
Products
Procedure:
1. Record the mass of the empty flask and the balloon separately.
2. Pour about 15 mL of vinegar into the flask. Weight the flask & vinegar, subtract the flask weight to
find the weight of your vinegar.
3. Put about 5g of baking soda into the balloon, make sure you weigh the empty balloon first so you
know exactly how much baking soda was put in. Record the exact mass of baking soda that is in the
balloon by subtracting the mass of the balloon.
4. While one student holds the flask, another must slip the open end of the
balloon over the mouth of the flask, while keeping the baking soda from
entering the flask.
5. Weigh the whole system and record the mass.
6. Tip the balloon upright, allowing the baking soda to drop into the flask and
allow the reaction to fully complete. Swirl your reaction a little bit to make
sure all of the baking soda reacted. Record the mass of the full system
(balloon, flask and products).
7. Touch the bottom of the flask.
-How does it feel?_____________________________
-What kind of reaction is in this chemical change?______________________________
-Describe the heat flow___________________________________________________
8. After the reaction is completed, weight the mass of the balloon, flask, baking soda and vinegar
(Do not let any gas escape from the system that you set up)
9. Open the balloon to let the gas escape and reweight the system. Record
10. Return the empty balloon to me and rinse everything down the drain.
Data: Mass table