1. Chemistry – Feb 21, 2019 _____Pb(NO3)2  _____PbO + _____NO2 + _____O2
P3 – Do one mastery quiz and then answer this question:
Balance the following chemical equation:
_____Pb(NO3)2  _____PbO + _____NO2 + _____O2
Then identify it’s type with a S, D, SR, DR, or C.
Pick up 2 handouts when done.
Objective –
Driving forces
Assignment:
Driving forces worksheet 1
Agenda
Mastery Quiz and P3 question
Homework Review (types)
Types of driving forces
Precipitation reactions
Solubility rules
WB Word Equation practice
Get out your reaction classifications
for a HMK check.

2. Driving Force
We can write many kinds of reactions on paper, but for them to actually occur, there must be some kind of driving force. Otherwise a simple mixture will happen with no reaction.
Driving Forces:
Formation of a solid
Formation of water
Formation of a gas
Transfer of electrons
Determines a second classification
Note: Any given reaction may have more thanne driving force. But if it has none, it will not happen.

3. 1) Formation of a solid When two ionic solutions are mixed…
Sometimes a solid forms. Reaction happens.
Solid formation is a driving force. Called a precipitation reaction.
Sometimes no reaction happens.
How do you know which? Experiments.
Patterns: Solubility rules
Chapter 7, Unnumbered Figure 1, Page 219

4. Solubility Rules – Observations
All common compounds of alkali and ammonium ions are soluble.
All nitrates, acetates, and chlorates are soluble.
All binary compounds of the halogens with metals are soluble,
except those of Ag, Hg(I), Pb(II).
All sulfates are soluble, except those of Ba, Ca, Sr, Ag, Hg(I), Pb(II).
Carbonates, hydroxides, oxides, and phosphates are insoluble, except for alkali and ammonium ions.
Sulfides are insoluble except for Ba, Ca, Sr, Mg, alkali and ammonium.

5. Solubility Rules: Soluble Ionic (aq)
Compounds Containing:
Important exceptions
NO3-
None
C2H3O2-
ClO3-
Cl-
Ag+, Hg22+ , Pb2+
Br- I-
SO42-
Ag+, Hg22+ , Pb2+, Ba2+, Ca2+, Sr2+

6. Solubility Rules: Insoluble Ionic (s)
Compounds Containing:
Important exceptions
CO32-
NH4+ and alkali ions (Li+, Na+, K+, Rb+…)
O2-
NH4+ and alkali ions
PO43-
OH-
Ba2+, Ca2+, Sr2+, NH4+ and alkali ions
S2-
Ba2+, Ca2+, Sr2+, Mg2+ , NH4+ and alkali ions

7. Summary Solubility Rules

8. Using solubility rules
Use to determine whether a written reaction will actually happen or not by providing the state descriptors
Precipitates are usually a driving force for double replacement reactions between ionic compounds.
If all substances are aqueous, the reaction does not happen.
Ex: CaCl2 + K2SO4  2 KCl + CaSO4
Ex: 2 LiNO3 + Pb(C2H3O2)2  2 LiC2H3O2 + Pb(NO3)2
Ex: (NH4)2O + AlCl3  NH4Cl + Al2O3
Ex: BaI2 + Na2S  2 NaI + BaS

9. Net Ionic Equations
For precipitation reactions, there are three ways to represent the equation.
Molecular equation
Complete ionic equation
Net ionic equation
Ions not participating in the net ionic equation are called spectator ions
Ex: KI(aq) Pb(NO3)2  PbI2 (s) KNO3 (aq)

10. Exit Slip - Homework What’s Next? (How to prepare for the next day)
Exit Slip: Determine the state descriptors for:
NaOH CaO AgClO AgCl
What’s Due? (Pending assignments to complete.)
Start the Driving Forces Worksheet (Pages 1 and 3. On pg 3 only determine type and balance. )
What’s Next? (How to prepare for the next day)
Read p473, p , p , p