1. Aqueous Solutions

2. Ionic Reactions
General Rules for dissolution (dissociation) of ionic compounds
Only 1 cation and 1 anion are formed
Monoatomic ions = subscripts become coefficients for the ions
Polyatomic ions = only subscripts outside of parentheses become coefficients
Charges of all ions must add up to zero (because compounds are neutral

3. Examples of Ionic Compounds dissolving in water
NaBr (s)  Na+(aq) Br- (aq)
Cr(NO3)3 (s)  Cr3+ (aq) NO3- (aq)

4. Practice K2S (s)  FeCl3 (s)  MgBr2 (s)  AlCl3 (s)  Na2Cr2O7 (s) 
(NH4)2S (s) 
K3PO4 (s) 

5. Answers K2S (s)  2 K+ (aq) + S2- (aq)
FeCl3 (s)  Fe3+ (aq) Cl- (aq)
MgBr2 (s)  Mg2+ (aq) Br- (aq)
AlCl3 (s)  Al3+ (aq) Cl- (aq)
Na2Cr2O7 (s)  2 Na+ (aq) + Cr2O72- (aq)
(NH4)2S (s)  2 NH4+ (aq) + S2- (aq)
K3PO4 (s)  3 K+ (aq) + PO43- (aq)

6. Will it dissolve in water?
Soluble: Alkali metals, NH4+, ClO3-, ClO4-, acetates, NO3-, and strong acids
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Strong Acids = HCl, HBr, HI, HNO3, H2SO4, HClO3, HClO4
All other acids are weak

7. Will it dissolve in water?
Sometimes Soluble:
Cl-, Br-, I- except with Ag+, Hg22+, and Pb2+
Sulfate except with Hg22+, Pb2+, Ca2+, and Ba2+

8. Will it dissolve Insoluble:
CO32-, CrO42-,Cr2O72-, PO43-, P3- except with Alkali Metals and ammonium
S2- except with Alkali Metals, Alkaline Earth Metals and ammonium
OH- and O2-except with Alkali Metals and ammonium (slightly soluble with Ca2+, Sr2+, and Ba2+)

9. Will a rxn occur? Chemical Driving Force
Formation of water is the strongest driving force
Formation of a precipitate (insoluble compound)
Formation of a covalent compound. Many of these are organic acids or gases
H2CO3 (aq)  CO2 (g) + H2O (l)
H2SO3(aq)  SO2 (g) + H2O (l)
NH4OH  NH3 (g) + H2O (l)
H2S (aq)  H2S (g)

10. Practice: Formation of water
HCl (aq) + NaOH (aq) 
CaO (s) + 2 HCl (aq) 

11. Practice: Predicting Products
Solubility Rules
Practice Reactions
Always Soluble: Alkali metals, NH4+, ClO3-, ClO4-, acetates, NO3-, and strong acids
Cl-, Br-, I- except with Ag+, Hg22+, and Pb2+
KCl + Pb(NO3)2 

12. Practice: Predicting Product
Solubility Rules
Practice Reaction
Always Soluble: Alkali metals, NH4+, ClO3-, ClO4-, acetates, NO3-, and strong acids
Sulfate except with Ag+, Hg22+, Pb2+, Ca2+, Sr2+, and Ba2+
Na2SO4 + Ba(NO3)2 

13. Practice: Formation of a Gas
Gases From Aqueous Soln
Practice Reaction
H2CO3 (aq)  CO2 (g) + H2O (l)
H2SO3(aq)  SO2 (g) + H2O (l)
NH4OH  NH3 (g) + H2O (l)
H2S (aq)  H2S (g)
K2SO3 + HNO3 

14. Practice: Formation of a Gas
Gases from Aqueous Soln:
Practice Reaction:
H2CO3 (aq)  CO2 (g) + H2O (l)
H2SO3(aq)  SO2 (g) + H2O (l)
NH4OH  NH3 (g) + H2O (l)
H2S (aq)  H2S (g)
HCl + CaCO3 

15. Equations Molecular Equation = show chemical formulas
HCl (aq) + NaOH (aq)  NaCl (aq) + H2O (l)

16. Equations (Complete) Ionic Equation =
show ions for strong electrolytes
insoluble compounds (precipitates), gases, and covalent compounds are written as molecules
H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq)  Na+(aq) + Cl-(aq) + H2O (l)

17. Equations
Net Ionic Equation = Only show substances that are not present on both reactant and product sides.
Ex: (Complete) Ionic Equation
H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq)  Na+(aq) + Cl-(aq) + H2O (l)
Ex: Net Ionic Equation
H+(aq) + OH-(aq)  H2O (l)

18. Net Ionic Equations
Allows chemists to identify active components of the reaction. Ions not included are considered “spectator ions”
H+(aq) + OH-(aq)  H2O (l)
So Na+ and Cl- are spectator ions

19. Net Ionic Equations
If all ions cancel on reactant and products side, then there is no driving force and therefore no reaction will occur
Ex: Will potassium chloride and sodium nitrate react?

20. Will potassium chloride and sodium nitrate react?
Molecular Equation
KCl (aq) + NaNO3 (aq)  NaCl (aq) + KNO3 (aq

21. Will potassium chloride and sodium nitrate react?
Molecular Equation
KCl (aq) + NaNO3 (aq)  NaCl (aq) + KNO3 (aq)
(Complete) Ionic Equation
K+(aq) + Cl-(aq) + Na+(aq) + NO3-(aq)  Na+(aq) + Cl-(aq) + K+(aq) + NO3-(aq)

22. Will A Reaction Occur?
Potassium sulfate is mixed with Barium nitrate

23. Potassium Sulfate with Barium Nitrate
K2SO4(aq) + Ba(NO3)2(aq)  BaSO4(s) + 2 KNO3 (aq)

24. Potassium Sulfate with Barium Nitrate
K2SO4(aq) + Ba(NO3)2(aq)  BaSO4(s) + 2 KNO3 (aq) 2K+(aq) + SO42-(aq) + Ba2+(aq) + 2NO3-(aq)  BaSO4(s) + 2K+(aq) + 2NO3-(aq)

25. Potassium Sulfate with Barium Nitrate
2K+(aq) + SO42-(aq) + Ba2+(aq) + 2NO3-(aq)  BaSO4(s) + 2K+(aq) + 2NO3-(aq) Net Ionic Equation: SO42-(aq) + Ba2+(aq)  BaSO4(s)