Reactions in Aqueous Solutions

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• Chapter 8
• Reactions in Aqueous Solutions

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Predicting Whether a Reaction Will Occur

• If two chemical are going to react with each
  other it is often because there is a "driving
  force" to produce one or more of the following
• Solid is formed (precipitate)
• Water is formed (H2O)
• Gas is formed (fizz/bubbles)
• Electrons are transferred

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Reactions in Which a Solid Forms

• Ionic Compound - a compound that results when a
  metal reacts with a nonmetal to form cations and
  anions.
• Another name for all ionic compounds is Salts.
  The most famous salt is NaCl.

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• When an ionic compound is dissolved in water, the
  ions separate and move around independently. A
  solution of a dissolved ionic compound will
  conduct electricity. It will allow electric
  current to flow through it.

Ionic Compounds that dissolve in water are
called electrolytes.
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Ions separate when the solid dissolves.
Ba2
K
NO3-
CrO42-
NO3-
K
Ba(NO3)2(aq) K2CrO4(aq) ?
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2K(aq) CrO42-(aq) Ba2(aq) 2NO3-(aq)
Ba2
K
NO3-
CrO42-
NO3-
K
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What are the possible combinations of ions?

• K(aq) CrO42-(aq)
• K(aq) NO3-(aq)
• Ba2(aq) CrO42-(aq)
• Ba2(aq) NO3-(aq)

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Write the formulas of the products.

• BaCrO4 KNO3

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Complete the equation.

• Ba(NO3)2(aq) K2CrO4(aq) ? BaCrO4 2KNO3

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Figure 8.3 Solubilities of common compounds.
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Driving Forces for Chemical Reactions

• Formation of a solid
• Formation of H2O
• Transfer of e-
• Formation of a gas

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Predict the possible reaction between lead (II)
nitrate and sodium sulfate.

• Write the formulas for the reactants.
• Exchange cations to give 2 products.
• Use solubility rules to determine precipitate.
• Complete and balance equation.

Pb(NO3)2(aq) Na2SO4(aq) ?
NaNO3(aq) PbSO4(s)
2
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Practice

• Try Self-Check p. 223
• Try Focus Questions p. 223 2-3