Drill What type of chemical reaction uses the activity series? What is the activity series used for?

Objective The student will be able to: Observe, identify, and write balanced equations for precipitation reactions.

SAT/HSA Enrichment Food will stay fresh longer when enzyme activity is slowed. Which of the following conditions would most likely slow enzyme activity? Reducing pH from 8 to 7 by adding a weak acid Increasing pH from 5 to 6 by adding a weak base Reducing temperature from 30C to 20C by refrigeration Increasing temperature from 30C to 40C by heating

Reactions in Aqueous Solution How do elements react in water?

Reactions in Aqueous Solution Structures in limestone caverns are formed when carbon dioxide converts calcium hydrogen carbonate into calcium carbonate. The calcium carbonate precipitates and forms dramatic stalactites and stalagmites. You will learn to predict the formation of precipitates and write equations to describe the reactions that produce them. Illustration from page 342

Net Ionic Equations A complete ionic equation is an equation that shows dissolved ionic compounds as dissociated free ions. A precipitate of silver chloride forms when aqueous solutions of silver nitrate and sodium chloride are mixed. Inferring Which ions do not participate in the reaction?

Net Ionic Equations An ion that appears on both sides of an equation and is not directly involved in the reaction is called a spectator ion. The net ionic equation is an equation for a reaction in solution that shows only those particles that are directly involved in the chemical change.

Net Ionic Equations A net ionic equation shows only those particles involved in the reaction and is balanced with respect to both mass and charge.

Net Ionic Equations Sodium ions and nitrate ions are not changed during the chemical reaction of silver nitrate and sodium chloride so the net ionic equation is Equation from text page 343

Predicting the Formation of a Precipitate You can predict the formation of a precipitate by using the general rules for solubility of ionic compounds.

Predicting the Formation of a Precipitate

Predicting the Formation of a Precipitate Will a precipitate form when a sodium carbonate solution is mixed with a barium nitrate solution? Equation from text page 344

Predicting the Formation of a Precipitate Sodium nitrate is soluble but barium carbonate is insoluble. The net ionic equation is

Section Quiz 1. Identify the correct net ionic equation for the following reaction and the spectator ion, if there is one. FeO(s) + 2HClO4(aq)  H2O(l) + Fe(ClO4)2(aq) FeO(s) + 2H+(aq) + 2ClO4-(aq)  H2O(l) + Fe2+(aq) + 2ClO4-(aq); no spectator ion FeO(s) + 2H+(aq) + 2ClO4-(aq)  H2O(l) + Fe2+(aq) + 2ClO4-(aq); ClO4- is a spectator ion FeO(s) + 2H+(aq)  H2O(l) + Fe2+(aq); ClO4- FeO(s) + 2HClO4(aq)  H2O(l) + Fe(ClO4)2(aq); no spectator ion

Section Quiz 2. Which one of the following products of double-replacement reactions would NOT form a precipitate? AgCl PbSO4 Mg(OH)2 Mo(NO3)2

Section Quiz 3. Which reaction will NOT produce a precipitate from aqueous solution? Hg2(NO3)2 + KCl FeSO4 + Ba(OH)2 Pb(NO3)2 + Na2CO3 NaBr + Al2(SO4)2

Small-Scale Lab 45 min Precipitation Reactions: Formation of Solids Purpose Students observe, identify, and write balanced equations for precipitation reactions. 45 min

Summary Did we accomplish the objective? Explain. What is a net ionic equation? What type of reactions did you work with today? How can you predict the formation of a precipitate in a double-replacement reaction? What is a precipitate?

Homework Net Ionic Equation worksheet Read Identification of Anions and Cations in Solutions Lab