Conservation of Mass
Introduction:
A chemical change occurs when substances change into different substances
The Law of Conservation of Mass states that matter can be neither created nor
destroyed, but that it can change its form.
Mixing vinegar and baking soda produces water and carbon dioxide.
CH3COOH + NaHCO3 ---> H2O (L) + CO2 (G)
vinegar
baking soda
water carbon dioxide
The CO2 bubbles in this reaction because it is a gas.
Purpose:
When vinegar and baking soda are mixed together what happens to the mass of
the mixture in an open container?
Hypothesis: _______________________________________________
__________________________________________________________
__________________________________________________________
Procedures:
1) Measure and record the mass of the flask. Measure 2 g of
baking soda and pour into the flask.
2) Measure and record the mass of the graduated cylinder.
3) Measure 50 ml of vinegar and record the total mass of the
graduated cylinder and vinegar. Calculate the mass of the
vinegar by subtracting the mass of the cylinder from the total
mass.
4) Add the total mass of the flask, baking soda and vinegar.
5) Calculate the mass of the baking soda and vinegar.
6) Add the 50 ml of vinegar to the 2 g baking soda into the flask.
7) Swirl the flask to mix until the bubbling action stops.
8) Record the total mass of the flask with the vinegar and baking
soda after the chemical reaction has stopped bubbling.
9) Calculate the mass of the baking soda and vinegar after the
chemical reaction took place by subtracting the mass of the
flask.
Table: Mass of reactants and products
Object
Mass (g)
Flask
Baking Soda
Graduated Cylinder
Vinegar and Graduated Cylinder
Determine: Vinegar
Total: Flask, Baking Soda, Vinegar
(before the chemical reaction)
Total: Baking Soda and Vinegar
(before the chemical reaction)
Flask, Baking Soda, Vinegar (after the
chemical reaction)
Determine: Baking Soda and Vinegar
mixture (after the chemical reaction)
Determine: Carbon Dioxide
Analysis:
Answer using COMPLETE SENTENCES
1. What
is produced as a result of mixing baking soda and
vinegar?
2. How much did the total mass of the flask, baking soda,
and vinegar decrease after the chemical reaction took
place?
3. Why did the total mass of the flask with its contents
decrease after the chemical reaction?
4. How many grams of Carbon Dioxide (CO2) was produced
as a result of this chemical reaction?
5. Explain the Law of Conservation of Mass in your own
words.
6. Explain how this lab relates to the Law of Conservation of
Mass.
7. Determine the mass for each reactant and product based
upon the data collected from this lab. Remember that the
total mass of the reactants = the total mass of the products.
CH3COOH + NaHCO3 ---> H2O (L) + CO2 (G)
vinegar
baking soda water
carbon dioxide
____g
____g
____g
____g