Reactions in Aqueous Solution Chapter 9 Section 3

Reactions in Aqueous Solutions  Aqueous Solution – one or more substances (solutes) dissolved in water (solvent)  Types of reactions  Reactions that form precipitates  Reactions that form water  Reactions that form gases

Reactions that form Precipitates  Two aqueous solutions that when mixed together form one solid, based on solubility rules  2 NaOH (aq) + CuCl 2 (aq)  2 NaCl (aq) + Cu(OH) 2 (s)

Ionic Equations  Complete Ionic equation – an ionic equation that shows all of the particles in a solution as they exist  Spectator Ions – ions that do not participate in the reaction  Net ionic equation – ionic equations that include only the particles that participate in the reaction

Example  Aqueous solutions of potassium iodide and silver nitrate are mixed forming a precipitate of silver iodide.  Chemical Equation  KI (aq) + AgNO 3 (aq)  KNO 3 (aq) + AgI (s)  Complete Ionic Equation  K + (aq) + I - (aq) + Ag + (aq) + NO 3 - (aq)  K + (aq) + NO 3 - (aq) + AgI (s)  Net Ionic Equation  I - (aq) + Ag + (aq)  AgI (s)

Write the complete and net ionic equations for the following  LiI (aq) + AgNO 3 (aq)  AgI (s) + LiNO 3 (aq)  BaCl 2 (aq) + K 2 CO 3 (aq)  BaCO 3 (s) + 2 KCl (aq)  Aq solns of aluminum chloride and sodium hydroxide are mixed, forming the precipitate aluminum hydroxide.  Aq solns of lithium sulfate and calcium nitrite are mixed forming the precipitate calcium sulfate,

Reactions that form water  No observable evidence of a chemical reaction because water is colorless  HBr (aq) + NaOH (aq)  H 2 O (l) + NaBr (aq)

Write the complete and net ionic equations for the following  Sulfuric acid and aq potassium hydroxide produce water and aq potassium sulfate  Hydrochloric acid and aq calcium hydroxide produce water and aq calcium chloride  Hydrosulfuric acid and aq calcium hydroxide produces water and aq calcium sulfate

Reactions that form gases  When two aqueous solns combine and produce a gas  2 HI (aq) + Li 2 S (aq)  H 2 S (g) + 2 LiI (aq)

Write the complete and net ionic equations for the following  Perchloric acid reacts with aq potassium carbonate forming carbon dioxide gas and water  Sulfuric acid reacts with aq sodium cyanide forming hydrogen cyanide gas and aq sodium sulfate  Hydrochloric acid reacts with zinc metal to form hydrogen gas and aq zinc chloride

Overall Equations  When the product of one reaction is unstable and immediately reacts again to form a new product  When you combine hydrochloric acid and sodium hydrogen carbonate a double-replacement and decomposition reaction take place

Overall Reactions  Reaction 1 HCl (aq) + NaHCO 3 (aq)  H 2 CO 3 (aq) + NaCl (aq)  Reaction 2 H 2 CO 3 (aq)  H 2 O (l) + CO 2 (g)  Combined Equation HCl (aq) + NaHCO 3 (aq) + H 2 CO 3 (aq)  H 2 CO 3 (aq) + NaCl (aq) + H 2 O (l) + CO 2 (g)  Overall Equation HCl (aq) + NaHCO 3 (aq)  NaCl (aq) + H 2 O (l) + CO 2 (g)

Solubility Rules for Ionic Compounds in Water Soluble  All nitrates are soluble  Group 1 cations and NH 4 + ions form soluble salts  Most halides are soluble, except those of Pb 2+, Hg 2 2+, Ag +, and Cu +  Most sulfates are soluble, with the exceptions of those of Ba 2+, Sr 2+ and Pb 2+, Hg 2 2+, Ag +, and Ca 2+ form slightly soluble sulfates Insoluble  Hydroxides, oxides, and sulfides are usually insoluble, except for those of group 1 ions and NH 4 + are soluble and those of group 2 are slightly soluble  Chromates, phosphates, and carbonates are usually insoluble, except for those of group 1 ions and NH 4 + are soluble.