Topic: Reactions in Aqueous Solution
Do Now:
Label the following at (aq) or (s)
1. NaBr
2. PbNO3
3. KOH
4. CuSO4
5. Ba2S
Formation of a precipitate
2 aqueous solutions mixing to
produce a new compound that is
insoluble (a solid)
Demo
• KI + PbNO3  KNO3 + PbI
• AgNO3 + NaCl  AgCl + NaNO3
Reactions in aqueous solution
• Many reactions, esp. many double replacement
reactions, occur in water.
• What happens when substances dissolve in
water?
• Depends on if they are ionic or covalent.
Dissolving an Ionic Substance in water
 it splits into the ions that make up
the compound
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Example:
NaCl(s)  Na+(aq) + Cl-(aq)
CaCl2(s)  Ca2+(aq) + 2Cl-(aq)
AlCl3(s)  Al3+(aq) + 3Cl-(aq)
The ions are spread out among the water molecules.
Lets check to see if there are really
ions
• Conductivity = conduct electricity
– Need charged particles (ions) to travel
Electrolytes
• = compounds that conduct electricity
• Ionic compounds that dissolve in water are
electrolytes
Dissolving a Covalent Substance in water
 split into individual molecules NOT IONS
• Ex: sucrose
• C12H22O11(s)  C12H22O11(aq)
• The sugar molecules are spread out among
the water molecules.