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Describing Chemical Reactions

Chemical equations:  shorter, easier way to show chemical reactions, using symbols instead of words

WRITING CHEMICAL EQUATIONS
    Chemical formulas
        Symbols of elements
        Ratio of element in compound
                H2O     2 to 1 ratio
                H2O2   1 to 1 ration

                    subscript - numbe of atoms of an element in a molecule
 
      Structure of an equation
            Begins with reactants     yields  products  - new material

                reactant +  reactant --->   product + Product

CONSERVATION OF MASS
    Amount of matter in a chemical reaction  does not change, so the total mass of the reactants must equal the total mass of the product.

BALANCING CHEMICAL EQUATIONS
 
                H2      +      O2      --->   H2O
            Hydrogen         Oxygen          Water

            Count the number of atom on the left side.  Count the number on the right side.  If they are not equal you need to add coefficient
 
                H2      +      O2      --->   2H2O

            Now the oxygen is balanced we need to look at hydrogen.  It is now 4 hydrogen atoms.

                 2 H2      +      O2      --->   2H2O

            Now there are 4 hydrogen atoms and two oxygen atoms.
                  2H2      +      O2      --->   2H2O