1. Unit 7: Reactions In Aqueous Solution
Introduction

2. Combining Solutions for Chemical Reaction
Solutions formed from ionic compounds dissolved in water are called aqueous solutions
When mixed they can have reactions occur depending on the chemical that are being combined
3 combinations will be discussed in this unit

3. Precipitate Reactions
Often referred to as exchange reactions or double replacement
Follow the basic formula below where cations are exchanged and create 2 new ionic compounds.
A2B (aq) + XZ (aq)  AZ (aq) + X2B (s)

4. KI (aq) + Pb(NO3)2 (aq)  _________+ _______
Demonstration
Potassium iodide solution is added to lead nitrate solution.
KI (aq) + Pb(NO3)2 (aq)  _________+ _______
This reaction occurs because the lattice energy between lead and iodide ion is too strong for it to dissolve in the water. So on the product side we see it as a solid.
KNO3 (aq)
PbI2 (s)

5. KI (aq) + Pb(NO3)2 (aq)  KNO2 (aq) + PbI2 (s)
Common Notations
KI (aq) + Pb(NO3)2 (aq)  KNO2 (aq) + PbI2 (s)
After the chemicals we write the state of matter so that we may better understand what is occurring.
Solid (s) Liquid (l) Gas (g) Aqueous (aq)
The product that forms from 2 chemicals reacting and forming an insoluble salt is called the precipitate.

6. Neutralization Reactions
This is called neutralization because the resulting solution has no characteristics of the acid or base solutions.
Often called acid/base reactions
Also follows the pattern of the exchange reactions

7. HCl (aq) + Ca(OH)2 (s)  _______ + _________
Demonstration
The reaction in the video is not the exact same chemicals but is the same type of reaction.
Hydrochloric acid neutralizes calcium hydroxide.
HCl (aq) + Ca(OH)2 (s)  _______ + _________
This reaction occurs because the hydrogen from the acid and the hydroxide from the base combine to form water. The other product is a soluble salt in this case.
H2O (l)
CaCl2 (aq)

8. Oxidation-Reduction Reactions
This is called oxidation-reduction because one element reduces its charge and the other increases its charge by exchanging electrons.
Often called Redox reactions or single replacements reactions because one element replaces another in a compound.
Follow the basic formula below where one ion is replaced and creates a new ionic compound.
A2B (aq) + Z (s)  AZ (aq) + B(s)

9. Cu (s) + AgNO3 (aq)  Ag (s) + Cu(NO3)2 (aq)
Demonstration
Copper metal is added to a solution of silver nitrate.
Cu (s) + AgNO3 (aq)  Ag (s) + Cu(NO3)2 (aq)
This reaction occurs because the copper gives up its valence electrons to silver causing silver to become a solid and the copper to become ions.
This is called replacement reaction because the copper replaces the silver in the compound.