Name:_______________________________
Period:_______
Conservation of Mass Lab
 Prelab
1. Alka Seltzer Tablets fizz when placed in water. Is this a chemical or physical change? How do you know?
2. Balance the following equation which represents the Alka Seltzer reaction.
__ H3C3H5O7 (aq) + __NaHCO3(aq)
__Na3C3H5O7 (aq) + __H2O(l) + __CO2(g)
3. The law of conservation of mass states that matter cannot be _______________ or _____________________. If
this is true, how can you prove this by doing this lab?
 Lab:
You will do two Alka Seltzer reactions to prove weather mass is conserved. First do the lab without a lid on the
container. Second do the lab while quickly placing the lid on the container.
 Procedures:
You will use ¼ of a tablet and a glass vial ½ full of water.
Make a two data tables (one for lid off, the other for lid on) that will help you prove weather mass was lost, gained, or
conserved. Think ahead to what you will need to mass. Label your data table thoroughly.
Data Table 1: Reaction 1 with No Lid
Data Table 2: Reaction 2 with Lid On
4. Did reaction 1 with the lid off gain mass, lose mass, or remain the same? Explain why.
5. Did reaction 2 with the lid on gain mass, lose mass, or remain the same? Explain why.
6. Classify the following as Element, Compound, Homogeneous Mixture or Heterogeneous Mixture.
a. Sodium Bicarbonate dissolved in water [NaHCO3 (aq)] ____________________
b. Carbon Dioxide [CO2 (g)]:______________________
c. The water, alkaseltzer tablet and bubbles together: _________________________