Chemical Reactions

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Chemical Reactions
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Objectives

• 1) Write and balance equations
• 2) Identifying the types of reactions

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Reactants and Products

• Gallium Sulfuric acid ? Gallium Sulfate
  Hydrogen
• Reactants- left side of the arrow
• -starting materials
• Products-right side of the arrow
• -the substance made, produced
• The number of atoms on the reactant side must
  equal the number of atoms on the product side.

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Balancing

• Rules
• 1) Write the correct chemical formula for the
  reactants and the products.
• 2) Adjust the coefficients (the numbers that
  appear in front of the formulas) only and evenly.
• 3) Never change the subscripts (the small numbers
  in a formula)
• 4) When counting atoms, multiply the coefficients
  by the subscript for each element.
• 5) There are seven elements, that when left
  alone, exist as diatomic molecules.
• Br2 I2 N2 Cl2 H2 O2 F2

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Balancing Example

• Ga H2SO4 ? Ga2(SO4)3 H2
• Balanced
• 2Ga 3H2SO4 ? Ga2(SO4)3 3H2

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Identifying Reactions

• The five types of reactions
• -Synthesis or Combination
• -Single Replacement
• -Double Replacement
• -Combustion
• -Decomposition (6 types)

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Synthesis
A B AB

• element element ? compound
• Occurs when two or more elements are combined to
  form a new substance
• Also called Combination

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Synthesis or Combination

• Example
• 2 Na Cl2 ? 2NaCl

Jayhawk says Heres an example of
synthesis
Rivalry
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Single Replacement

• Occurs when one element displaces another in a
  compound.
• A BC ? B AC
• element compound ? element compound

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Single Replacement

• Example
• Na LiCl ? NaCl Li

Listen up ,class, its time for an example.
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Double Replacement

• Occurs when the positive and negative ions of the
  two reactants are interchanged
• AB CD ? AD CB
• compound compound?compound compound
• Never put two metals together

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Double Replacement

• Example
• 2NaCl Li2O ? Na2O 2LiCl

Did you know? Double replacement is also referred
to as metathesis.
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Combustion

• Hydrocarbon O2 ? H2O CO2

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Combustion

• Example
• C4H8 O2 ?H2O CO2

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Decomposition

• Occurs when energy in the form of heat, light,
  electricity, or mechanical shock is supplied. A
  compound may decompose to form simpler compounds
  and/or elements.
• compound ? 2 or more substances
• ?

AB A B
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Decomposition

• There are 6 different types of decomposition

Did you know? You might also know decomposition
by analysis.
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Electrical Decomposition

• AB ? A B
• 2NaCl ? 2Na Cl2

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Decomposition Oxy-Acid

• Oxy-Acid ? Water Nonmetal Oxide
• H2SO4 ? H2O SO3
• Examples
• HNO3
• H3PO4
• HClO2

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Decomposition Metallic Hydroxide

• Metallic Hydroxide ? Metal Oxide Water
• 2LiOH ? Li2O H2O
• Fe(OH)2 ? FeO H2O

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Decomposition Metallic Carbonate

• Metallic Carbonate ? Metal Oxide Carbon Dioxide
• MgCO3 ? MgO CO2
• Fe2(CO3)2 ? Fe2O3 3CO2

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Decomposition Metallic Chlorate

• Metallic Chlorate ? Metal Chloride Oxygen
• 2LiClO2 ? 2LiCl 3O2
• Ca(ClO3)2 ? CaCl2 3O2

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Decomposition Metallic Oxide

• Metallic Oxide ? Metal Oxygen
• 2Li2O ? 4Li O2
• 2BaO ? 2Ba O2

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THE END