1. Precipitation Reactions Graphic: Wikimedia Commons User Tubifex

2. Double Replacement Reactions The ions of two compounds exchange places in an aqueous solution to form two new compounds. AX + BY AY + BX One of the compounds formed is usually a precipitate (an insoluble solid), an insoluble gas that bubbles out of solution, or a molecular compound, usually water.

3. Double replacement forming a precipitate… Pb(NO 3 ) 2 (aq) + 2KI(aq) PbI 2 (s) + 2KNO 3 (aq) Pb 2+ (aq) + 2 NO 3 - (aq) + 2 K + (aq) +2 I - (aq) PbI 2 (s) + 2K + (aq) + 2 NO 3 - (aq) Pb 2+ (aq) + 2 I - (aq) PbI 2 (s) Double replacement (ionic) equation Complete ionic equation shows compounds as aqueous ions Net ionic equation eliminates the spectator ions Lead(II) nitrate + potassium iodide lead(II) iodide + potassium nitrate

4. Solubility Rules – Mostly Soluble

5. Solubility Rules – Mostly Insoluble

6. Solubility Chart: Common salts at 25 C S = Soluble I = Insoluble P = Partially Soluble X = Other