1. Double Replacement Reactions
In detail

3. Ionic Compounds in Water
Because the ions in ionic compounds are attracted (not connected) to each other ionic compounds can dissociate in water.
We can write the dissociated ions like this:
Na+ + Cl- + K+ + NO3- 
If all of the ions in a double replacement reaction STAYED aqueous, how would the products look?

4. Molecular, Ionic and Net Ionic Equations
Molecular, Ionic and Net Ionic Equations
So, in order for a change to occur, a product must become a solid, liquid, or gas.
Sodium chloride and silver nitrate
→ sodium nitrate and silver chloride
NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)
The AgCl is labeled with (s) because it is insoluble and forms a precipitate.

5. Molecular equations NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)
A molecular equation shows us all of the chemicals in a reaction, but doesn’t show how they are actually arranged.

6. Ionic Equation
Na+ + Cl- + Ag+ + NO3- → Na+ + NO3- + AgCl(s) All substance are dissociated except for the insoluble AgCl(s) --This shows how the ions are arranged in the aqueous solution

7. Net Ionic Equation
The ions not involved in forming the precipitate (Na+ and NO3-) are called "Spectator Ions" and are eliminated to form the net ionic equation.
Ag+ + Cl- → AgCl(s)

8. How do you know what elements make the precipitate?
--Use the Solubility Rules
Soluble = stay aqueous
Insoluble = become solid 
Rule 1. Most nitrate salts are soluble.
Rule 2. Most salts containing alkali metal ions and the ammonium ion are soluble.

9. Rule 3. Most chloride, bromide, and iodide salts are soluble
Rule 3. Most chloride, bromide, and iodide salts are soluble. Exceptions are salts containing Ag, Pb, and Hg
Rule 4. Most sulfate salts are soluble. Exceptions are salts containing Ba, Pb, Hg, and Ca
Rule 5. Hydroxides are generally insoluble. Exceptions include salts containing cations in Rule 2 & Ca, Ba, and Sr.
Rule 6. Most sulfide, carbonate, chromate and phosphates are insoluble, except for those with cations from rule 2.

10. Copper(II) chloride + sodium sulfide → copper(II)sulfide and sodium chloride ♦ Molecular: CuCl2 + Na2S → CuS + NaCl CuCl2 + Na2S → CuS(s) + 2NaCl ♦ Complete Ionic: Cu2+ + 2Cl- + 2Na+ + S2- → CuS(s) + 2Na+ + 2Cl- ♦ Net Ionic: Cu2+ + S2- → CuS(s) The spectator ions are Na+ and Cl-

11. Sodium bicarbonate plus hydrochloric acid yields sodium chloride plus water and carbon dioxide ♦ Molecular: NaHCO3(aq) + HCl(aq)  NaCl(aq) + H2O(l) + CO2(g) ♦ Complete Ionic: Na+ + HCO3 - + H+ + Cl -  Na + + Cl - + H2O(l) + CO2(g) ♦ Net Ionic: HCO3 - + H+  H2O(l) + CO2(g) Na+ and Cl- are spectator ions

12. 3. Calcium chloride + sodium carbonate calcium carbonate and sodium chloride CaCl2 + Na2CO3 → CaCO3(s) + 2NaCl Ca2+ + 2Cl- + 2Na+ + CO32- → CaCO3(s) + 2Na+ + 2Cl- The spectator ions are Na+ and Cl- Ca2+ + CO32- → CaCO3(s)

13. 3Ba(NO3)2 + 2Na3PO4 → Ba3(PO4)2(s) + 6NaNO3
4. Barium nitrate + sodium phosphate
→ barium phosphate and sodium nitrate
Ba(NO3)2 + Na3PO4 → Ba3(PO4)2(s) + NaNO3
3Ba(NO3)2 + 2Na3PO4 → Ba3(PO4)2(s) + 6NaNO3
3Ba2+ + 6NO3- + 6Na+ + 2PO43-
→ Ba3(PO4)2(s) + 6Na+ + 6NO3-
The spectator ions are Na+ and NO3-
3Ba2+ + 2PO43- → Ba3(PO4)2(s)

14. 5. Chromium(III) chloride + silver nitrate → chromium(III) nitrate and silver chloride CrCl3 + 3AgNO3 → Cr(NO3)3 + 3AgCl(s) Cr3+ + 3Cl- + 3Ag+ + 3NO3- → Cr3+ + 3NO3- + 3AgCl(s) 3Ag+ + 3Cl- → 3AgCl(s) Ag+ + Cl- → AgCl(s)