Conservation of Mass Lab Pt 1

Conservation of Mass Lab—Part 1: Baking Soda & Vinegar

Pre-Lab Questions:

1. What is the Law of Conservation of Matter and how does it relate to chemical reactions?

2.   How does one know if a chemical reaction has occurred? What is your evidence?

Hypothesis:

1. If the Law of Conservation of Matter is related to chemical reactions, then I would find that...               

Explain what you would expect to happen in your laboratory experiment today.

Procedure:

1. Place your Ziploc bag on the scale and zero out the weight.

2. Place 10 grams of baking soda in your Ziploc bag.

3. Fill your plastic container with 15 mL of vinegar and close it.

4. Place the vinegar container in your Ziploc bag, squeeze out the air from the bag and seal it completely.

5. Weigh the bag and all of the contents on the scale and record in your data table.

6. Carefully open the plastic lid to the vinegar container WITHOUT opening the Ziploc bag.

7. Let the vinegar and baking soda react and make observations.

8. Weigh the bag again and record the new mass of the entire bag.

9. Rinse out the plastic container and Ziploc bag with water. Shake out the plastic bag to remove the water.

Data:

Name of group:	Before reaction mass:	After reaction mass:
Your group names
Classmates groups

Observations:

1. Write three observations during your experiment about the vinegar and the baking soda. Note any temperature changes.

Analysis:

1. Calculate your percent error in your experiment using this formula:

                                Mass after – Mass before       x 100   =    percent error

                                            Mass before

2. Based on the Law of Conservation of Mass, what should have been the percent error?

3. Do your results support the Law of Conservation of Mass? Why, or why not?

4. Is the class data accurate/precise? Why, or why not?

5. What experimental errors would account for any differences you observed?

6. The reactants in this chemical reaction are baking soda (NaHCO3) and vinegar (HC2H3O2) and the products are carbon dioxide (CO₂), water (H₂O) and sodium acetate (NaC2H3O2 ). Write the chemical reaction and balance it.