Lab: Conservation of
Mass
Law of Conservation of Matter: Matter can neither be created nor destroyed, however,
it may change forms.
Chemical changes produce new materials and there is usually a temperature
change - the temperature of the reaction either goes up or down.
Materials:
Citric Acid, baking soda, food coloring, Gallon-size Zip-loc Bag, 1 plastic
cup, 50 mL of water, triple-beam balance, metric cup.
Procedures:
1. Measure 2 level teaspoons of baking soda
and place in the plastic cup.
2. Measure 1 level teaspoon of citric acid
and place in the cup with baking soda.
3. Mix the two powders thoroughly.
4. Measure 50 mL of water into the metric
cup.
5. Add two drops of food coloring to the
water in the metric cup.
6. Place the powders from the plastic cup
into the zip-loc bag.
7. Mass all materials (zip-loc bag with powders
and empty metric cup). Mass _____________
8. Close the zip-loc bag leaving only a small
opening at one side.
9. When the instructor tells you to do so,
pour the water from the metric cup into the bag through the small opening
and quickly zip it shut.
10. Record what is happening inside.
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10.After the reaction has stopped, please
mass the zip-loc bag and its contents and the original metric cup. Mass_________________
11. Did you observe a temperature change?
Did the temperature go up?______ go down?_____
12.Please answer the following questions.(use
back as necessary)
a. What physical changes did you observe?
b. What chemical changes did you observe?
c. What is the gas produced?
d. What would happen if you opened the bag?
e. What other reaction might produce the
same result?
f. Was there a change in mass?
Baking Soda
URL________________________________
Safety Precautions
Citric Acid
URL_______________________________
Safety Precautions
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