Chemistry – Feb 22, 2018 P3 – Nomenclature quiz 5 Pick up 2 handouts when done. Objective – Driving forces Assignment: Driving forces worksheet 1 Agenda Homework Review (types) Types of driving forces Precipitation reactions Solubility rules WB Word Equation practice

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 than one driving force. But if it has none, it will not happen.

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

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.

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+

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

Solubility Rules (all in one view) Soluble Insoluble (Precipitates) Li+, Na+, K+, NH4+ (primary rule) NO3-, C2H3O2-, ClO3- Cl-, Br-, I- Ag+, Hg22+ , Pb2+ SO42- Ba2+, Ca2+, Sr2+ CO32-, O2-, PO43- OH- Ba2+, Ca2+, Sr2+, Mg2+ S2-

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 displacement reactions between ionic compounds. If no product is a solid, 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 Soluble Insoluble (Precipitates) Li+, Na+, K+, NH4+ (primary rule) NO3-, C2H3O2-, ClO3- Cl-, Br-, I- Ag+, Hg22+ , Pb2+ SO42- Ba2+, Ca2+, Sr2+ CO32-, O2-, PO43- OH- Ba2+, Ca2+, Sr2+, Mg2+ S2-

Exit Slip - Homework Exit Slip: none What’s Due? (Pending assignments to complete.) Start the Driving Forces Worksheet (Page 1 only determine aq/s then state if no reaction occurs) What’s Next? (How to prepare for the next day) Read p473, p286-288, p548-549, p280-282