Law of Conservation of Mass Inquiry Lab
Purpose:
To design and complete a laboratory experiment that proves the law of conservation of mass.
Background Information:
Alka-Seltzer® is made up of baking soda (sodium bicarbonate, NaHCO3) and citric acid C6H8O7. To use the tablets, as
intended medically, they must be fully dissolved in a glass of water, where they famously undergo a chemical reaction that
produces lots of carbon dioxide (CO2) bubbles. As the tablets dissolve, the sodium bicarbonate splits apart to form
bicarbonate ions (HCO3-). This reacts with hydrogen (H +) from citric acid, another ingredient in the tablets. This chemical
reaction forms water and carbon dioxide gas.
Materials: You do NOT need to use all of them
Flask
Balloon
Balance/Scale
Water
Alka-Seltzer Tablet
(ONLY 2 per group)
Graduated Cylinder
Plastic bag
Test tube
Water
Beakers
Procedure: (Write your actual procedures)
Steps should be directives, with no personal pronouns.
ie: 1. Pour 10mL of water into beaker.
Data/Observations:
-
Include a data table.
Include qualitative observations as well as measurements (quantitative).
Analysis: (Be sure to include any calculations you made)
Answers should be 1-2 sentences each.
1. Compare the differences in mass before and after the reaction. Explain any discrepancies in the masses.
2. Address any possible sources of error you made.
And NO, saying “human error” does not count! BE SPECIFIC
3. Explain how you could improve the experiment.
Conclusion:
Answer should only be 1-2 sentences.
1. Did the experiment justify the law of conservation of mass? Why or Why not? Use your data to explain.