1. Precipitation Reactions

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) 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 for Chemistry All sodium, potassium, ammonium, and nitrate salts are soluble in water. Memorisation of other “solubility rules” is beyond the scope of this course, you will always be given a solubility table for your Chemistry test & exam.

5. Solubility Rules – Mostly Soluble

6. Solubility Rules – Mostly Insoluble

7. Solubility Chart: Common salts at 25  C S = Soluble I = Insoluble P = Partially Soluble