Reactions in aqeous solutions

1. 8.3 Reactions in Aqueous Solutions
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2. 2
General Properties of Aqueous
Solutions
• Solution - a homogeneousmixture
– Solute:the component that is dissolved
– Solvent: the component that does the dissolving
Generally, the component present in the greatest quantity is
considered to be the solvent. Aqueous solutions are
those in which water is the solvent.

3. • Electrolytes andNonelectrolytes
– Electrolyte: substance that dissolved in water produces a
solution that conducts electricity
• Containsions
– Nonelectrolyte: substance that dissolved in water produces a
solution that does not conduct
electricity
• Does not containions
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4. • Dissociation- ionic compounds separate into
constituent ionswhen dissolved in solution
• Ionization- formation of ions by molecular
compounds whendissolved
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• Strong and weak electrolytes
– StrongElectrolyte: 100% dissociation
• All water soluble ionic compounds, strong acids
and strong bases
– Weakelectrolytes
• Partially ionized in solution
• Exist mostly as the molecular form in solution
• Weak acids and weak bases

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7. • Examples of weak electrolytes
– Weakacids
HC2H3O2(aq) C2H3O2
-(aq) + H+
(aq)
– Weakbases
NH3 (aq) + H2O(l) NH4
+
(aq) + OH− (aq)
(Note: double arrows indicate a reaction that occurs in
both directions - a state of dynamic equilibrium exists)
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8. Method to Distinguish Types of Electrolytes
nonelectrolyte
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weakelectrolyte strongelectrolyte

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Classify the following as nonelectrolyte, weak electrolyte or
strongelectrolyte
– NaOH : strong electrolyte
– CH3OH : nonelectrolyte
– H2CO3 : weak electrolyte

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Types of reactions in aqueous solutions
• Reactionsthatformprecipitate
• Precipitation(formation of a solid from two aqueous solutions)
occurs when product is insoluble
• Produce insoluble ionic compounds

11. o Precipitation reaction
⁻ Reaction between aqueous sodium hydroxide and copper chloride solution.

12. Mixing Solutions of Pb(NO3)2 andNaCl
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Identify the Precipitate
Pb(NO3)2 (aq) + 2NaI (aq)  2NaNO3 + PbI2

15. • Molecularequation:shows all compounds represented by their
chemical formulas
• Ionicequation:shows all strong electrolytes as ions and all other
substances (non- electrolytes, weak electrolytes, gases) by their
chemical formulas
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16. o Molecular equation:
o Ionic equation:
• NetIonicequation: shows only the reacting species in the
chemical equation
– Eliminates spectator ions
o Net ionicequation:
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o Steps in writing a net ionicequation
∙ Write the balanced molecular equation.
∙ Predict products by exchanging cations and anions in
reactants.
∙ Separate strong electrolytes into ions.
∙ Cancel spectator ions.
∙ Use the remaining species to write the net ionic equation.

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Aqueous solutions of silver nitrate and sodium sulfate are
mixed. Write thenet ionic reaction.
∙ Step 1:
2AgNO3(aq) + Na2SO4 (aq)  2NaNO3(?) + Ag2SO4 (?)

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∙ Step 2:
Use solubility table; all nitrates are soluble but silver
sulfate isinsoluble
2Ag+(aq) + 2NO3
(aq) + 2Na+(aq) +SO4
2 (aq) 2Na+(aq)+ 2NO3
(aq) + Ag2SO4(s)

20. ∙ Step 3: Cancelspectators
2Ag+ (aq) + 2NO3
 (aq) + 2Na+ (aq) + SO4
2  (aq) 2Na+(aq) + 2NO3
(aq) +
Ag2SO4(s)
∙ Step 4: Write the net ionicreaction
2Ag+ (aq) + SO4
2  (aq)  Ag2SO4 (s)
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