Chemical Reactions and Equations

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Chemical Reactions and Equations
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The Equation

• Reactants Products
• Used to describe what is occurring in the
  reaction.

3
Symbols

• used to separate reactants and/or
  products.
• yields separates reactants and
  products.
• reversible reaction at equilibrium.
• (s) or (cr) solid state of matter
  (crystalline).
• (l) liquid state of matter.

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Symbols

• (g) gaseous or vapor state of matter.
• (aq) (aqueous) dissolved in H2O, a homogeneous
  solution.

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The Process

• When balancing an equation the number of atoms of
  each element on each side of the yield sign must
  be equal. This ensures the Law of Conservation
  of Matter is obeyed.

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Diatomic Molecules
71 st Rule

• H2
• N2
• O2
• F2
• Cl2
• Br2
• I2

Start with element 7 Forms the shape 7 When you
add hydrogen, there are 7
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The Process

• List the elements on both sides of the yield
  sign.
• List the number of atoms for each subscript
• distribute the subscript through the ( ).
• If they do not match determine the common
  multiple that will make them equal.
• Whatever you multiply by becomes the coefficient
  in front of the substance.

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• Change any other element that is changed.
• Continue the process until every element is
  equal.
• If any blank is not filled, place the number one,
  even though it is understood.

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The Process

• When balancing an equation the number of atoms of
  each element on each side of the yield sign must
  be equal. This ensures the Law of Conservation
  of Matter is obeyed.

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Chemical Reaction Types

• Combination or Synthesis
• Element Element Compound
• There is only one product formed.
• 2Al N2 2AlN
• Decomposition
• Compound Element Element
• There can only be one reactant.
• Cu(CO3) CuO CO2
• 2Fe2O3 4Fe 3O2

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• Single Replacement or Single Displacement
• Element Compound Element Compound
• Metals only replace metals, and nonmetals only
  replace nonmetals.
• Cu 2Ag(NO3) Cu(NO3) 2Ag
• 2KCl Br2 2KBr Cl2

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• 4. Double Replacement or Double Displacement
• Compound Compound Compound Compound
• Combine the outside two elements, and combine the
  inside two elements (foil method).
• KCl Ag(NO3) K(NO3) AgCl

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• Combustion
• Organic Compound Oxygen Carbon
  Dioxide Water
• When balancing a combustion reaction assume that
  the coefficient in front of the organic compound
  is one. Balance the carbon, hydrogen, then
  oxygen. If you come out with a fraction multiply
  everything by two.
• Examples
• C2H6
• C5H12