1 Ions in Aqueous Solutions and Colligative Properties Chapter 13 Modern Chemistry Sections 1 & 2 Compounds in Aqueous Solutions Colligative Properties of a Solution

Chapter 13 Section 1 Comp. in Aq. Soln p Compounds in Aqueous Solutions Section 13.1

Chapter 13 Section 1 Comp. in Aq. Soln p VOCABULARY Dissociation Equation Precipitate Net Ionic Equation Spectator Ion Ionization Hydronium Ion Strong Electrolyte Weak Electrolyte

Chapter 13 Section 1 Comp. in Aq. Soln p Concept Map 13.1 NET IONIC EQUATIONS DISSOCIATION EQUATION PRECIPITATE REACTIONS SPECTATOR IONS IONIZATION HYDRONIUM ION STRONG ELECTROLYTEWEAK ELECTROLYTE DISSOCIATION

Chapter 13 Section 1 Comp. in Aq. Soln p Dissociation Equations Dissociation is the separation of ions that occurs when an ionic compound dissolves Dissociation equations show how an ionic solid breaks into ions when it dissociates. Don’t forget to balance the equation or add state of matter symbols. NaCl (s)  Na 1+ (aq) + Cl 1- (aq) CaCl 2 (s)  Ca 2+ (aq) + 2Cl 1- (aq)

Chapter 13 Section 1 Comp. in Aq. Soln p Dissociation Equations CaCl 2 gives three ions per formula unit – one calcium and two chlorine. When one mole of CaCl 2 dissociates… One mole of calcium ions are produced Two moles of chloride ions are produced Three moles of ions – total- are produced CaCl 2 (s)  Ca 2+ (aq) + 2Cl 1- (aq)

Chapter 13 Section 1 Comp. in Aq. Soln p Write the equation for the dissolution of aluminum sulfate, Al 2 (SO 4 ) 3, in water. How many moles of aluminum ions and sulfate ions are produced by dissolving 1 mol of aluminum sulfate? What is the total number of moles of ions produced by dissolving 1 mol of aluminum sulfate? p. 436 Al 2 (SO 4 ) 3 (s)  2Al 3+ (aq) + 3SO 4 2− (aq) 2 mol aluminum ions, 3 mol sulfate ions 5 ions total Dissociation Sample Problem

Chapter 13 Section 1 Comp. in Aq. Soln p Write the equation for the dissolution of each of the following in water, and then determine the number of moles of each ion produced as well as the total number of moles of ions produced. a. 1 mol ammonium chloride b. 1 mol sodium sulfide c. 0.5 mol barium nitrate p. 436 Dissociation Practice Problems

Chapter 13 Section 1 Comp. in Aq. Soln p a.NH 4 Cl (s)  NH 4 1+ (aq) + Cl 1− (aq) 1 mol ammonium ions; 1 mol chloride ions; 2 mol total ions b. Na 2 S (s)  2Na 1+ (aq) + S 2− (aq) 2 mol sodium ions; 1 mol sulfide ions; 3 mol total ions c. Ba(NO 3 ) 2 (s)  Ba 2+ (aq) + 2NO 3 1− (aq) 1 mol barium ions; 2 mol nitrate ions; 3 mol total ions p. 436 Dissociation Practice Problems

Chapter 13 Section 1 Comp. in Aq. Soln p p. 437 Solubility of Ionic Compounds

Chapter 13 Section 1 Comp. in Aq. Soln p p. 437 General Solubility Guidelines

Chapter 13 Section 1 Comp. in Aq. Soln p General Solubility Guidelines

Chapter 13 Section 1 Comp. in Aq. Soln p General Solubility Guidelines

Chapter 13 Section 1 Comp. in Aq. Soln p p. 438 (NH 4 ) 2 S + Cd(NO 3 ) 2

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION Write the balanced equation for the reaction between ammonium sulfide and cadmium II nitrate. Be sure to include states of matter What type of reaction is it? What are the products? (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s)

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate. Write the dissociation equation for each (aq). (NH 4 ) 2 S (s)  2 (NH 4 ) 1+ (aq) + S 2- (aq) Cd(NO 3 ) 2 (s)  Cd 2+ (aq) + 2 NO 3 1- (aq) 2 NH 4 NO 3 (aq)  2 NH 4 1+ (aq) + 2 NO 3 1- (aq) (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s)

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s) (NH 4 )S ++ Cd (aq) (NO 3 ) (aq)  NH 4 NO (aq) CdS + (s) Break all (aq) into ions; not the (s) Balance and add states

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s) (NH 4 ) S ++ Cd (aq) (NO 3 ) 2+1- (aq)  NH 4 NO (aq) CdS + (s) Identify spectator ions and remove Write what’s left. + 

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s) (NH 4 ) S ++ Cd 1+ (aq) (NO 3 ) (aq)  NH 4 NO (aq) CdS + (s) This is the net ionic equation. + 

Chapter 13 Section 1 Comp. in Aq. Soln p Ag(NO 3 ) + NaCl

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION Write the balanced equation for the reaction between sodium chloride and silver nitrate. Be sure to include states of matter What type of reaction is it? What are the products? NaCl (aq) + Ag(NO 3 ) (aq)  NaNO 3 (aq) + AgCl (s)

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate. Write the dissociation equation for each (aq). NaCl (s)  Na 1+ (aq) + Cl 1- (aq) Ag(NO 3 ) (s)  Ag 1+ (aq) + NO 3 1- (aq) NaNO 3 (aq)  Na 1+ (aq) + NO 3 1- (aq) NaCl (aq) + AgNO 3 (aq)  NaNO 3 (aq) + AgCl (s)

Chapter 13 Section 1 Comp. in Aq. Soln p NaCl (aq) + AgNO 3 (aq)  NaNO 3 (aq) + AgCl (s) NET IONIC EQUATION NaCl ++ Ag (aq) NO (aq)  NaNO (aq) AgCl + (s) Break all (aq) into ions; not the (s) Balance and add states

Chapter 13 Section 1 Comp. in Aq. Soln p NaCl (aq) + AgNO 3 (aq)  NaNO 3 (aq) + AgCl (s) NET IONIC EQUATION Na Cl ++ Ag (aq) NO (aq)  NaNO (aq) AgCl + (s) Identify spectator ions and remove Write what’s left. + 

Chapter 13 Section 1 Comp. in Aq. Soln p This is the net ionic equation. + NaCl (aq) + AgNO 3 (aq)  NaNO 3 (aq) + AgCl (s) NET IONIC EQUATION Na Cl ++ Ag (aq) NO (aq)  NaNO (aq) AgCl + (s) + 

Chapter 13 Section 1 Comp. in Aq. Soln p NET IONIC EQUATION (NH 4 ) 2 S (aq) + Cd(NO 3 ) 2 (aq)  2 NH 4 NO 3 (aq) + CdS (s) (NH 4 ) S ++ Cd 1+ (aq) (NO 3 ) (aq)  NH 4 NO (aq) CdS + (s) This is the net ionic equation. + 

Chapter 13 Section 1 Comp. in Aq. Soln p Identify the precipitate that forms when aqueous solutions of zinc nitrate and ammonium sulfide are combined. Write the equation for the possible double- displacement reaction. Then write the formula equation, overall ionic equation, and net ionic equation for the reaction. p. 440 Zn 2   (aq)  S 2−  (aq) →  ZnS (s) Sample Problem p. 440

Chapter 13 Section 1 Comp. in Aq. Soln p Will a precipitate form if solutions of potassium sulfate and barium nitrate are combined? If so, write the net ionic equation for the reaction. 2.Will a precipitate form if solutions of potassium nitrate and magnesium sulfate are combined? If so, write the net ionic equation for the reaction. p No Practice Problems p Yes; Ba 2   (aq)  SO 4 2−  (aq) →BaSO 4 (s)

Chapter 13 Section 1 Comp. in Aq. Soln p Will a precipitate form if solutions of barium chloride and sodium sulfate are combined? If so, identify the spectator ions and write the net ionic equation. 4.Write the net ionic equation for the precipitation of nickel(II) sulfide. p Ni 2   (aq)  S 2−  (aq) →  NiS (s) Practice Problems p Yes; Na  and Cl−; Ba 2   (aq)  SO4 2−  (aq) →  BaSO 4 (s)

Chapter 13 Section 1 Comp. in Aq. Soln p Ionization vs. Dissociation Covalent compounds Ions are formed from solute molecules when they dissolve. Ionic compounds Ions are already present – the ions are separated by the water molecules.

Chapter 13 Section 1 Comp. in Aq. Soln p Dissociation & Ionization

Chapter 13 Section 1 Comp. in Aq. Soln p Ionization Usually occurs with polar molecules If the strength of a bond within the solute molecule is weaker than the attractive forces of the solvent molecules, then the covalent bond of the solute breaks and the molecule is separated into ions. The ions are hydrated – just like ions from dissociation. HCl (g)  H 1+ (aq) + Cl 1- (aq)

Chapter 13 Section 1 Comp. in Aq. Soln p Hydronium ion, H 3 O + H + ion does not exist by itself. H + ion bonds to a water molecule to form H 3 O +, a hydronium ion. Better described as a reaction. H 2 O (l) + HCl (g)  H 3 O + (aq) + Cl - (aq)

Chapter 13 Section 1 Comp. in Aq. Soln p A solution which contains all (or most) of the solute in the form of ions. The solute is completely dissociated. Strong Electrolytes CaCl 2 (s)  1 mole Ca 2+ (aq) + 2Cl 1- (aq) 1 mole 2 moles +2

Chapter 13 Section 1 Comp. in Aq. Soln p A solution which contains some of the solute in the form of ions, but most of the molecules stay intact. The solute is slightly ionized. Weak Electrolytes HF (aq) + H 2 O (l)  1 mole H 3 O + (aq) + F 1- (aq) 0.05 mol 0.05mol

Chapter 13 Section 1 Comp. in Aq. Soln p p. 442* Electrolytes

Chapter 13 Section 1 Comp. in Aq. Soln p Strong & Weak Electrolytes Insert Holt Disc 2

Chapter 13 Section 1 Comp. in Aq. Soln p Glowing Pickle Insert Houghton Mifflin Chemistry DVD

Chapter 13 Section 1 Comp. in Aq. Soln p Ch 13 Sec 1 Homework Page 443 # 1-5