Chemical Equations

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Chemical Equations

• H2 O2 ? H2O

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• Chemical equations are a shorthand way to express
  what happens in chemical reactions.
• Instead of having to write, hydrogen gas reacts
  with oxygen gas to form liquid water, we can
  simply write
• H2 O2 ? H2O

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H2 O2 ? H2O

• reactants the reacting substances on the left
  side of the equation

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H2 O2 ? H2O

• reactants the reacting substances on the left
  side of the equation
• products the resulting substances on the right
  side of the equation

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H2 O2 ? H2O

• reactants the reacting substances on the left
  side of the equation
• products the resulting substances on the right
  side of the equation
• means reacts with

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H2 O2 ? H2O

• reactants the reacting substances on the left
  side of the equation
• products the resulting substances on the right
  side of the equation
• means reacts with
• ? means produces

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Types of Chemical Reactions

• There are four main types of chemical reactions
• synthesis
• decomposition
• single replacement
• double replacement

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Synthesis Reactions

• Two or more substances combine and a reaction
  takes place to produce a compound.
• The general reaction is shown byA B ? AB
• Example Zn S ? ZnS

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Decomposition Reactions

• This is the opposite of synthesis. A compound is
  broken down into simpler parts. It is usually
  done through heat or electrolysis.
• The general reaction is shown by CD ? C D
• Example NaCl ? Na Cl2

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Single Replacement Reactions

• A single element will replace its counterpart in
  a compound. Metals replace metals nonmetals
  replace nonmetals.
• The general reaction is shown byAB C ? CB A
• Example CuSO4 Zn ? ZnSO4 Cu

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Double Replacement Reactions

• Two compounds react and switch partners.
• The general reaction is shown byAB CD ? AD
  CB
• Example AgNO3 NaCl ? AgCl NaNO3