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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 3