Net Ionic Equations

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Net Ionic Equations
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Net Ionic Equations

• describe a chemical reaction in solution
  recognizing the role of dissociation.

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3 steps

• Non Ionic equation (aka balanced chemical
  equation)
• Total ionic equation
• Net ionic equation

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Example

• Solutions of lead (II) nitrate and potassium
  iodide are mixed.

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Non ionic equation
Pb(NO3)2 KI ---gt
PbI2 KNO3
2
2
(aq)
(aq)
(aq)
(s)
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Total ionic equation

• Dissociate or ionize everything that is
• Aqueous and ionic
• Aqueous and acid

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Total ionic
Dissociate
Pb2(aq) 2NO3(aq)
2K(aq) 2I(aq) ---gt
PbI2(s)
2K(aq) 2NO3(aq)
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Spectator species (entities)

• A spectator species is a species (entity) that
  does not change in the reaction, ?is not involved
  in the reaction.

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Cancel spectator species
Total ionic equation
Pb2(aq) 2NO3(aq)
2K(aq) 2I(aq) ---gt
PbI2(s)
2K(aq) 2NO3(aq)
What remains is the net ionic equation.
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Net ionic equation
Pb2(aq) 2I(aq) ---gt PbI2(s)
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Example
Chlorine gas is bubbled through a solution of
sodium fluoride.
Non ionic equation
Cl2(g) 2NaF(aq) ---gt F2(g) 2NaCl(aq)
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Total ionic equation
Dissociate everything that is Aqueous and ionic
or aqueous and acid
Cl2(g) 2NaF(aq) ---gt F2(g) 2NaCl(aq)
Cl2(g)
2Na(aq) 2F(aq) ---gt
F2(g)
2Na(aq) 2Cl(aq)
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Net Ionic Equation
Cancel all spectator species
What remains is the net ionic equation
Cl2(g) 2F(aq) ---gt F2(g) 2Cl(aq)
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Watch for

• Occasionally there are no spectator species. Then
  the total and the net are the same.
• Occasionally all species in the total ionic
  equation are spectators, ?everything cancels.
  What does this mean??