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Ions in Aqueous Solutions and Colligative Properties Chapter 13 Modern Chemistry

Ions in Aqueous Solutions and Colligative Properties Chapter 13 Modern Chemistry. Sections 1 & 2 Compounds in Aqueous Solutions Colligative Properties of a Solution. Section 13.1. Compounds in Aqueous Solutions. VOCABULARY. Dissociation Equation Precipitate Net Ionic Equation

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Ions in Aqueous Solutions and Colligative Properties Chapter 13 Modern Chemistry

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

  2. Section 13.1 Compounds in Aqueous Solutions Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  3. 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. 434-445

  4. Concept Map 13.1 DISSOCIATION EQUATION PRECIPITATE REACTIONS SPECTATOR IONS NET IONIC EQUATIONS DISSOCIATION IONIZATION HYDRONIUM ION STRONG ELECTROLYTE WEAK ELECTROLYTE Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  5. 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) Na1+(aq)+ Cl1-(aq) CaCl2(s) Ca2+(aq)+ 2Cl1-(aq) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  6. Dissociation Equations CaCl2(s) Ca2+(aq)+ 2Cl1-(aq) • CaCl2 gives three ions per formula unit – one calcium and two chlorine. • When one mole of CaCl2 dissociates… • One mole of calcium ions are produced • Two moles of chloride ions are produced • Three moles of ions – total- are produced Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  7. Dissociation Sample Problem • Write the equation for the dissolution of aluminum sulfate, Al2(SO4)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 Al2(SO4)3 (s) 2Al3+(aq) + 3SO42−(aq) 2 mol aluminum ions, 3 mol sulfate ions 5 ions total Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  8. Dissociation Practice Problems 1. 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 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  9. Dissociation Practice Problems • NH4Cl (s) NH4 1+(aq) + Cl 1−(aq) 1 mol ammonium ions; 1 mol chloride ions; 2 mol total ions b. Na2S (s) 2Na1+(aq) + S 2−(aq)2 mol sodium ions; 1 mol sulfide ions; 3 mol total ions c. Ba(NO3)2 (s) Ba2+(aq) + 2NO31−(aq) 1 mol barium ions; 2 mol nitrate ions; 3 mol total ions p. 436 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  10. Solubility of Ionic Compounds p. 437 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  11. General Solubility Guidelines p. 437 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  12. General Solubility Guidelines Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  13. General Solubility Guidelines Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  14. (NH4)2S + Cd(NO3)2 p. 438 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  15. 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? (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  16. NET IONIC EQUATION (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate. Write the dissociation equation for each (aq). (NH4)2S (s)  2 (NH4)1+ (aq) +S2-(aq) Cd(NO3)2 (s)  Cd2+(aq) + 2 NO31- (aq) 2 NH4NO3(aq)  2 NH41+ (aq) + 2 NO31-(aq) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  17. NET IONIC EQUATION Cd NH4 (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) (NH4) S (NO3) NO3 CdS 1+ 1+ 2- 1- 1- 2+ 2 2 + + + 2  + + 2 (s) (aq) (aq) (aq) (aq) (aq) (aq) Break all (aq) into ions; not the (s) Balance and add states Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  18. NET IONIC EQUATION (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) 1+ 1+ 2- 2+ 1- 1- 2 (NH4) 2 NO3 + + + 2 (NO3)  + + CdS Cd 2 NH4 S (aq) (aq) (aq) (aq) (aq) (s) (aq) +  Identify spectator ions and remove Write what’s left. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  19. NET IONIC EQUATION (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) 1+ 1+ 1- 1- 2 (NH4) 2 NO3 + + + 2 (NO3)  + + 2 NH4 (aq) (aq) (aq) (aq) +  Cd 2+ 2- CdS S (aq) (aq) (s) This is the net ionic equation. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  20. Ag(NO3) + NaCl Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  21. 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(NO3) (aq)  NaNO3(aq)+ AgCl (s) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  22. NET IONIC EQUATION NaCl (aq) + AgNO3 (aq)  NaNO3(aq) + AgCl (s) Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate. Write the dissociation equation for each (aq). NaCl (s)  Na1+ (aq) +Cl1-(aq) Ag(NO3) (s)  Ag1+(aq) + NO31- (aq) NaNO3(aq)  Na1+ (aq) + NO31-(aq) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  23. NET IONIC EQUATION Na Cl NO3 Na NO3 AgCl NaCl (aq) + AgNO3 (aq)  NaNO3(aq) + AgCl (s) Ag 1+ 1+ 1- 1+ 1- 1- + + +  + + (s) (aq) (aq) (aq) (aq) (aq) (aq) Break all (aq) into ions; not the (s) Balance and add states Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  24. NET IONIC EQUATION NaCl (aq) + AgNO3 (aq)  NaNO3(aq) + AgCl (s) 1- 1- 1+ 1+ 1- 1+ + + +  + + Na Ag Na NO3 Cl NO3 AgCl (s) (aq) (aq) (aq) (aq) (aq) (aq)  + Identify spectator ions and remove Write what’s left. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  25. NET IONIC EQUATION NaCl (aq) + AgNO3 (aq)  NaNO3(aq) + AgCl (s) 1- 1+ 1- 1+ + + +  + + Na Na NO3 NO3 (aq) (aq) (aq) (aq) 1- 1+  AgCl + Cl Ag (s) (aq) (aq) This is the net ionic equation. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  26. NET IONIC EQUATION (NH4)2S (aq) + Cd(NO3)2 (aq)  2 NH4NO3(aq) + CdS (s) 1+ 1+ 1- 1- 2 (NH4) 2 NO3 + + + 2 (NO3)  + + 2 NH4 (aq) (aq) (aq) (aq) 2+ 2- +  Cd CdS S (aq) (aq) (s) This is the net ionic equation. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  27. Sample Problem p. 440 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. Zn 2+(aq)+ S 2−(aq)→ ZnS (s) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445 p. 440

  28. Practice Problems p. 440 • Will a precipitate form if solutions of potassium sulfate and barium nitrate are combined? If so, write the net ionic equation for the reaction. • Will a precipitate form if solutions of potassium nitrate and magnesium sulfate are combined? If so, write the net ionic equation for the reaction. 1. Yes; Ba 2+(aq)+ SO42−(aq)→BaSO4(s) 2. No Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445 p. 440

  29. Practice Problems p. 440 • 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. • Write the net ionic equation for the precipitation of nickel(II) sulfide. 3. Yes; Na+ and Cl−; Ba 2+(aq)+ SO4 2−(aq)→ BaSO4(s) 4. Ni 2+(aq)+ S 2−(aq)→ NiS (s) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445 p. 440

  30. Ionization vs. Dissociation • Ionic compounds • Ions are already present – the ions are separated by the water molecules. • Covalent compounds • Ions are formed from solute molecules when they dissolve. Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  31. Dissociation & Ionization Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  32. 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) H1+(aq)+ Cl1-(aq) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  33. Hydronium ion, H3O+ • H+ ion does not exist by itself. • H+ ion bonds to a water molecule to form H3O+, a hydronium ion. • Better described as a reaction. H2O (l) + HCl (g) H3O+(aq) + Cl-(aq) Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  34. Strong Electrolytes • A solution which contains all (or most) of the solute in the form of ions. • The solute is completely dissociated. CaCl2(s)1 mole Ca2+(aq)+ 2Cl1-(aq)1 mole 2 moles -1 +2 -1 Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  35. Weak Electrolytes • 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. HF (aq) + H2O (l)1 mole H3O+(aq)+ F1-(aq)0.05 mol 0.05mol Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

  36. Electrolytes p. 442* Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445

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