A Cool Chemical Reaction
A Cool ChemicalReaction
Verifyingthe Law of Conservationof Mass
I
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The law of conservation of mass statesthat the mass of the reactants in any chemical reaction equals the
mass of the products. Matter can be neither creatednor destroyed. Sometimesthe productsof a
chemical reaction are very different in color, texture, and physical state than the reactants. If a gas is
produced its mass also contributesto the mass of the products. The law of conservationof mass is an
important law of chemistry. This law holds true for all chemical reactions.
When the two reactants are mixed the following reaction occurs between baking soda and vinegar.
+NaHCOr("q) *
HzOCI+ COzigy*NaC2H3O216qy
HCzH:Oz1aq1
If using HCI insteadof vinegar, the reaction is:
HzOtrl+ COz1gl+ NaCllaql
HCllaqy+ NaHCO:(aq)
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PURPOSE
of mafferusingthefollowingmaterials.
to verifuthelaw of conservation
Designanexperiment
MATERIALS
balance
zipperedfreezerbag
plasticpipet
baking soda (sodium bicarbonate, NaHCOT)
vine-qar(acetic acid, HCzHrOz)
OR 3M hydrochloric acid, HCI
Safety Alert
l. Gogglesand apronsare required. Acids usedin this experimentcould causedamageto
eyes,clothing and skin.
2. Washhandsthoroughlybeforeleavingthe laboratory.
PROCEDURE
l. Using an "if-then" format,write a hypothesisfor your experimentthat describesthe relationship
betweenthe massof the reactantsandthe massof the productsof this chemicalreaction. Record
your hypothesison the studentanswerpage.
2. Usingyour knowledgeof the scientificmethod,designan experimentto verifu the law of
conservationof matter. Pointsto remember:
r Selectyour equipmentfrom the list above'
. Createan appropriatedatatable.
r Use only small quantities.
o Repeatthis experimentif time allows'
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A Cool Chemical Reaction
3. On a piece of notebook paper, record the steps you will use to perform this experiment. Have your
teacherapprove and initial your procedurebefore beginning.
4. In the spaceprovided on the student answer page,record all data and observations.
5. Flush the contents of the bag in the sink with plenty of water. Dispose of the plastic bag and pipet in
the waste container.
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Laying the Foundation in Middle Grades Chemistry and Physics
l
@2004Laying the Foundation,Inc. All rights reserved.Visit: www.layingthefoundation.org
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