Balancing Chemical Equations(3) by pptfiles


									                     Balancing Chemical Equations
• A chemical reaction is the process by which the atoms the atoms of one or more
   substances are rearranged to form different substances.
• Some chemical reactions are hard to see while others are very obvious as they release
   large amounts of energy or there is a color change.
• The starting substances in a chemical reaction are the reactants and the ending
   substances are the products.
• A chemical equation is one in which the chemical formulas of the reactants and the
   products are shown separated by an arrow pointing to the products (right).
• The Law of Conservation of Matter states that matter cannot be created or destroyed in
   a chemical reaction. Therefore, the same number of each element must be present in
   the reactants and the products.
• This is called a balanced equation. Coefficients are numbers placed in from of the
   different compounds in the chemical equation to balance it.
Balancing Equations
Step 1 – Write the skeleton equation. Be sure to put the reactants on the left and the
   products on the right.
   NaOH + CaBr2                       Ca(OH)2 + NaBr
Step 2 – Count the atoms of each element of each side.
Reactant: Na – 1               Product: Na - 1
         OH – 1                        OH - 2
         Ca – 1                        Ca - 1
          Br – 2                       Br – 1
Step 3 – Adjust the coefficients.
   2NaOH + CaBr2                      Ca(OH)2 + 2NaBr
Step 4 – Check to see that the coefficients are at the lowest possible ratio.
Step 5 – Recount the atoms
Reactant: Na – 2               Product: Na - 2
         OH – 2                       OH - 2
         Ca – 1                        Ca - 1
          Br – 2                       Br – 2

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