1. Solubility and Precipitation Rules

2. Solubility
The ability to dissolve or break down into its component ions in a liquid
Example:
NaCl is soluble
Completely dissolves in water
AgCl is insoluble
Stays a solid in water

3. Solubility Rules Li, Na, K, NH4, NO3 are all soluble
Therefore, anything that contains these ions are soluble
Cl, Br, and I are soluble except when paired with Ag, Hg2, and Pb
SO4 is soluble except with Sr, Ba, Pb, or Ca
OH, S, CO3, PO4 are insoluble except when paired with Li, Na, K, NH4

4. Let’s Try
Determine whether each of the follow compounds is soluble or insoluble:
AgBr
Insoluble – Br is normally soluble but not when its with Ag
CaCl2
Soluble
Pb(NO3)2
Soluble – NO3 is always soluble
NH4Cl
Soluble - NH4 and Cl are both soluble

5. Precipitation Reactions
A reaction in which a solid is formed upon mixing two aqueous solutions
Example:
Potassium Iodide + Lead Nitrate
2 KI (aq) + Pb(NO3)2 (aq) -> 2 KNO3 (aq) + PbI2 (s)

6. Your Turn
Write an equation for the precipitation reaction that occurs (if any) when solutions of sodium carbonate and copper (II) chloride are mixed.
Write an equation for the precipitation reaction that occurs (if any) when solutions of lithium nitrate and sodium sulfate are mixed.
Na2CO3 (aq) + CuCl2 (aq) ->
Li2NO3 (aq) + Na2SO4 (aq) ->

7. Writing Chemical Equations
Molecular Formula
An equation that shows the complete neutral formula for every compound
Complete Ionic Equation
An equation that shows the reactants and products as they are present in solution
AgNO3 (aq) + NaCl (aq) -> AgCl (s) + NaNO3 (aq)
Ag+ (aq) + NO3- (aq) + Na+ (aq) + Cl- (aq) ->
AgCl (s) + Na+ (aq) + NO3- (aq)

8. Writing Chemical Equations cont.
Spectator Ions
Ions that are present on both the reactant and product side.
They do not participate in the reaction
Net Ionic Equation
An equation that eliminates the spectator ions and shows only the elements or compounds that are participating
Ag+ (aq) + NO3- (aq) + Na+ (aq) + Cl- (aq) ->
AgCl (s) + Na+ (aq) + NO3- (aq)
Ag+ (aq) + Cl- (aq) -> AgCl (s)

9. You Try Consider the following reaction:
What is the complete ionic equation?
Which ions are the spectators?
What is the net ionic equation?
HCl (aq) + NaOH (aq) -> H2O (l) + NaCl (aq)