SOLUBILITY AND PRECIPITATION RULES Solubility The ability to

SOLUBILITY AND PRECIPITATION RULES

Solubility � The ability to dissolve or break down into its component ions in a liquid � Example: � Na. Cl is soluble Completely dissolves in water � Ag. Cl is insoluble Stays a solid in water

Solubility Rules � Li, Na, K, NH 4, NO 3 are all soluble � Therefore, soluble anything that contains these ions are � Cl, Br, and I are soluble except when paired with Ag, Hg 2, and Pb � SO 4 is soluble except with Sr, Ba, Pb, or Ca � OH, S, CO 3, PO 4 are insoluble except when paired with Li, Na, K, NH 4

Let’s Try � Determine whether each of the follow compounds is soluble or insoluble: � Ag. Br Insoluble – Br is normally soluble but not when its with Ag � Ca. Cl 2 Soluble � Pb(NO 3)2 Soluble – NO 3 is always soluble � NH 4 Cl Soluble - NH 4 and Cl are both soluble

Precipitation Reactions � � A reaction in which a solid is formed upon mixing two aqueous solutions Example: � Potassium Iodide + Lead Nitrate 2 KI (aq) + Pb(NO 3)2 (aq) -> 2 KNO 3 (aq) + Pb. I 2 (s)

Your Turn � Write an equation for the precipitation reaction that occurs (if any) when solutions of sodium carbonate and copper (II) chloride are mixed. Na 2 CO 3 (aq) + Cu. Cl 2 (aq) -> � Write an equation for the precipitation reaction that occurs (if any) when solutions of lithium nitrate and sodium sulfate are mixed. Li 2 NO 3 (aq) + Na 2 SO 4 (aq) ->

Writing Chemical Equations � Molecular Formula � An equation that shows the complete neutral formula for every compound Ag. NO 3 (aq) + Na. Cl (aq) -> Ag. Cl (s) + Na. NO 3 (aq) � Complete Ionic Equation � An equation that shows the reactants and products as they are present in solution Ag+ (aq) + NO 3 - (aq) + Na+ (aq) + Cl- (aq) -> Ag. Cl (s) + Na+ (aq) + NO 3 - (aq)

Writing Chemical Equations cont. � Spectator Ions � Ions that are present on both the reactant and product side. � They do not participate in the reaction Ag+ (aq) + NO 3 - (aq) + Na+ (aq) + Cl- (aq) -> Ag. Cl (s) + Na+ (aq) + NO 3 - (aq) � Net Ionic Equation � An equation that eliminates the spectator ions and shows only the elements or compounds that are participating Ag+ (aq) + Cl- (aq) -> Ag. Cl (s)

You Try � Consider the following reaction: HCl (aq) + Na. OH (aq) -> H 2 O (l) + Na. Cl (aq) � � � What is the complete ionic equation? Which ions are the spectators? What is the net ionic equation?