8.5F BALANCING EQUATIONS And the Law of Conservation of
Mass
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MAIN IDEA 8.5F - Recognize whether a chemical equation
containing coefficients is balanced or not and how that relates to
the law of conservation of mass.
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NOTES A chemical equation joins two separate chemical formulas
together. 2H 2 + O 2 2H 2 O The whole thing is a chemical equation
2H 2 + O 2 2H 2 O Chemical Formulas
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NOTES Rats Eat Poop = reactants, equals, products 2H 2 + O 2 2H
2 O reactants equals products To keep from blowing up the world we
have to make sure that all equations are balanced. When they are
unbalanced you have a chemical reaction This is why we learned to
count atoms
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NOTES The Law of Conservation of Mass Mass can neither be c nor
it can just change forms. You have to know this term forever and
ever now. States that what is the reactant side of the equation has
to be on the product side (so you dont blow up the world) Very
similar to the Law of Conservation of Energy createddestroyed,
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NOTES To balance an equation you have to count the atoms on the
reactant side and the product side. 2H 2 + O 2 2H 2 O H= H= O= O=
Is this equation balanced? 4 4 22 YES
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NOTES How to balance an equation: 1.Count the atoms on both
sides H 2 + O 2 2H 2 O H= H= O= O= So what now? 2.What can we add
to make them even? (what number could you multiply the atoms by to
even out the numbers?) WARNING!!! You can only change the Co-
effiecient. NEVER the subscript. 2 4 22
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NOTES It will take you a little bit of trail and error to
figure it out. It takes patience. Practice one: _____ Fe + _____
AgNO3 _____ Fe(NO3)2 + _____ AgFe=Ag=N=O=
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BRAIN BREAK
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NOTES Practice: 1.____ Na 3 PO 4 + ____ KOH ____ NaOH + ____ K
3 PO 4 2.____ P 4 + ____ O 2 ____ P 2 O 3 3.____ CF 4 + ____ Br 2
____ CBr 4 + ____ F 2 4.____ Al + ____ HCl ____ H 2 + ____ AlCl
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