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kelter_ch11

  1. 1. 일반화학 2 (09 여름 ) <ul><li>교수정보 : 이 동 수 ( 화학과 ) </li></ul><ul><li>2123-2641 </li></ul><ul><li>[email_address] </li></ul><ul><li>과 442 </li></ul><ul><li>조교정보 : </li></ul><ul><li>엄지원 , 채경수 </li></ul><ul><li>연습문제 풀이 조교 : TBA </li></ul>
  2. 2. 일반화학 2 (09 여름 ) <ul><li>주교재 1. Chemistry: The Practical Science(1st ed) 저자 : Kelter, Mosher & </li></ul><ul><li>Scott 번역서 자유아카데미 , 2008 년 % </li></ul>
  3. 3. 일반화학 2 (09 여름 ) 11 장 액체의 성질과 물의 화학 12 장 탄소 ( 유기화학 ) 14 장 열역학 1 15 장 화학반응속도론 16 장 화학평형 16 장 화학평형 중간시험 17 장 산과 염기 18 장 수용액의 평형 19 장 전기화학 20 장 배위화학 22 장 생명화학 기말시험
  4. 4. 일반화학 2 (09 여름 ) <ul><li>중간 기말 50% ( 각 25%) </li></ul><ul><li>실험 : 20% </li></ul><ul><li>수업참여도 10% </li></ul><ul><li>퀴즈 , 연습문제 : 20% </li></ul>
  5. 5. The Chemistry of Water and the Nature of Liquids Chapter 11
  6. 6. CHAPTER OUTLINE <ul><li>I. The Structure of Water: An Introduction to Intermolecular Forces </li></ul><ul><li>II. A Closer Look at Intermolecular Forces </li></ul><ul><ul><li>A. London Dispersion Forces : Induced Dipoles, B. Permanent Dipole : Dipole Forces, C. Hydrogen Bonds </li></ul></ul><ul><li>III. Impact of Intermolecular Forces on the Physical Properties of Water, I </li></ul><ul><li>IV. Phase Diagrams </li></ul><ul><li>V. Impact of Intermolecular Forces on the Physical Properties of Water, II </li></ul><ul><ul><li>A. Viscosity, B. Surface Tension, C. Capillary Action </li></ul></ul><ul><li>VI. Water: The Universal Solvent </li></ul><ul><ul><li>A. Why Do So Many Substances Dissolve in Water? </li></ul></ul><ul><li>VII. Measures of Solution Concentration </li></ul><ul><ul><li>A. Measures Based on Moles, B. Measures Based on Mass </li></ul></ul><ul><li>VIII. The Effect of Temperature and Pressure on Solubility </li></ul><ul><ul><li>A. Temperature Effects, B. Pressure Effects </li></ul></ul><ul><li>IX. Colligative Properties </li></ul><ul><ul><li>A. Vapor Pressure Lowering, B. Boiling Point Elevation, C. Freezing Point Depression, D. Osmosis, E. Reverse Osmosis, F. Back to the Future </li></ul></ul>
  7. 7. Water Consumption (UNESCO )
  8. 8. 11.1 Structure of Water <ul><li>1. 2 Pipe line at home : Water & Methane ( 도시가스 ) </li></ul><ul><li>One is liquid, the other gas!!!!!! </li></ul><ul><li>(Molecular mass 18g/mol vs 16g/mol) </li></ul><ul><li>Chemical structure determines properties!!!!!!! </li></ul><ul><li>Because of different IF </li></ul>An Introduction to Intermolecular forces BP Mp H2O 100 0 CH4 -164
  9. 9. 11.1 Structure of Water <ul><li>Bent molecule (See next or text) </li></ul><ul><li>H-O-H bond angle of 104.5 o </li></ul><ul><li>Polar molecule – permanent dipole </li></ul><ul><li>(Methane – Non-polar molecule) </li></ul><ul><li>In the liquid state, intermolecular forces cause between 3 and 6 molecules to aggregate. </li></ul><ul><li>Water vs Methane </li></ul><ul><li>Intramolecular attrcn>>> intermolecular attrcn </li></ul><ul><ul><li>O-H (BE 940kJ/mol) C-H (BE 1650kJ/mol) </li></ul></ul><ul><ul><li>∆ H vap =44kJ/mol ∆H vap =9kJ/mol </li></ul></ul>An Introduction to Intermolecular forces
  10. 10. Structure of Water Methane???
  11. 11. Interaction vs. states
  12. 12. 11.2 Intermolecular Forces <ul><li>1) London dispersion forces : Induced dipole </li></ul><ul><li>2) Permanent Dipole-Dipole Forces </li></ul><ul><li>3) Hydrogen Bonds </li></ul><ul><li>분자간 힘 (* 이온간 힘 ) </li></ul><ul><li>분자내 원자간 힘 ??? </li></ul>
  13. 13. Type-I : London Dispersion Forces <ul><li>Induced dipoles ( 유도 ) </li></ul><ul><li>The result of temporary dipoles ( 순간 ). </li></ul><ul><li>Explain bp of nonpolar ones </li></ul>Fritz London 1929
  14. 14. London Dispersion Forces
  15. 15. Polarizability vs Distance (length) <ul><li>중요도 </li></ul><ul><li>Molecular mass </li></ul><ul><li>Shapes </li></ul><ul><li>Longer is stronger. </li></ul><ul><li>Cyclic is strongest. </li></ul>
  16. 16. Type-II Permanent Dipole-Dipole Forces <ul><li>The result of the dipole in polar covalent molecules </li></ul><ul><li>Approximately 1% as strong as a covalent bond Still weak) </li></ul><ul><li>HCl : -85 C ( 염산 ?) </li></ul><ul><li>H2S : -61 C </li></ul>
  17. 17. Dipole-Dipole Forces
  18. 18. Type-III Hydrogen Bonds <ul><li>The attraction between a hydrogen, bonded to F, O, or N in a molecule, and the lone electrons of F, O, or N in another molecule. </li></ul><ul><li>The strongest of all intermolecular forces, about 10% of a covalent bond. </li></ul>
  19. 19. Hydrogen Bonds
  20. 21. 11.3 Phase Change <ul><li>Evaporation </li></ul><ul><ul><li>the process of molecules leaving the surface of the liquid phase and entering the vapor phase. </li></ul></ul><ul><li>Condensation </li></ul><ul><ul><li>the process of molecules leaving the vapor phase and entering the liquid phase. </li></ul></ul><ul><li>Sublimation-Deposition </li></ul><ul><ul><li>the escape of molecules from the solid phase directly to the vapor phase. </li></ul></ul>(Impact of IF on physical properties of H2O)
  21. 23. Vapor Pressure ( 증기압 )
  22. 24. Vapor Pressure <ul><li>The pressure of a vapor over a liquid. </li></ul><ul><li>Vapor pressure increases with temperature. </li></ul><ul><li>Heavier molecules have lower vapor pressures than lighter molecules. </li></ul><ul><li>Molecules with the strongest intermolecular forces will have the lowest vapor pressure. </li></ul>
  23. 25. Vapor Pressure
  24. 26. Vapor Pressure
  25. 27. Heating Curves
  26. 28. Changes of State <ul><li>Boiling point </li></ul><ul><ul><li>the pressure of a liquid’s vapor is equal to the surrounding pressure. </li></ul></ul><ul><li>Normal boiling point </li></ul><ul><ul><li>the boiling point of a liquid if the surrounding pressure is 1 atm. </li></ul></ul><ul><li>Melting point </li></ul><ul><ul><li>the temperature at which a solid changes to a liquid. </li></ul></ul>
  27. 29. Changes of State <ul><li>Heat of Fusion </li></ul><ul><ul><li>the amount of heat necessary to convert a solid to a liquid at its melting point and constant pressure. </li></ul></ul><ul><li>Heat of Vaporization </li></ul><ul><ul><li>the amount of heat needed to convert a liquid to a vapor at it normal boiling point. </li></ul></ul>
  28. 30. Sample Problem <ul><li>How much heat is necessary to bring 10.0 g of ice at –10.0 o C to a temperature of 50.0 o C? The specific heat of ice is 2.05 J/g o C, the heat of fusion of water is 334 J/g, the specific heat of water is 4.184 J/g o C. </li></ul><ul><li>There are three steps: 1. warming the ice; 2. melting the ice; and 3. warming the water. </li></ul>
  29. 31. Sample Problem (cont)
  30. 32. 11.4 Phase Diagram (4.6torr) Phase diagram of CO 2
  31. 33. Phase Diagram <ul><li>Triple point </li></ul><ul><ul><li>the point representing the temperature and pressure at which the three phases coexist in equilibrium. </li></ul></ul><ul><li>Critical temperature </li></ul><ul><ul><li>the temperature above which the liquid state can no longer exist at any pressure. </li></ul></ul><ul><li>Critical pressure </li></ul><ul><ul><li>the vapor pressure at the critical temperature. </li></ul></ul><ul><li>Critical point </li></ul><ul><ul><li>the point defined by the critical temperature and the critical pressure. </li></ul></ul>강의
  32. 34. 11.5 Properties of Water <ul><li>Viscosity </li></ul><ul><ul><li>the resistance of a liquid to flow. </li></ul></ul><ul><ul><li>Water : 0.890 mPa.s(25°C) ->0.378 mPa.s(75°C) </li></ul></ul><ul><ul><li>C 5 H 12 : 0.224 mPa.s, C 8 H 18 : 0.508 mPa.s </li></ul></ul><ul><ul><li>intermolecular force, temperature (average kinetic energy) </li></ul></ul><ul><li>Surface tension </li></ul><ul><ul><li>a measure of the energy per area on the surface of a liquid </li></ul></ul><ul><ul><li>To maximize the # of hydrogen bond (minimum energy) </li></ul></ul><ul><li>Capillary action </li></ul><ul><ul><li>the upward rise of a liquid is a small diameter tube caused by the adhesion of molecules to the surface of the tube. </li></ul></ul><ul><ul><li>H water interact with the O glass : adhesion </li></ul></ul><ul><ul><li>Cohesive force </li></ul></ul>
  33. 35. Cohesive force & Adhesion meniscus
  34. 36. 11.6 Water : The Universal Solvent <ul><li>Solution </li></ul><ul><ul><li>solvent, solute </li></ul></ul><ul><ul><li>aqueous solution </li></ul></ul><ul><ul><li>universal solvent </li></ul></ul><ul><li>Process of Dissolving </li></ul><ul><ul><li>Dissolving can be described as occurring in three steps: </li></ul></ul><ul><ul><ul><li>Solute separation. </li></ul></ul></ul><ul><ul><ul><li>Solvent separation. </li></ul></ul></ul><ul><ul><ul><li>Electrostatic interaction between solvent and solute. </li></ul></ul></ul>
  35. 37. Solution Process
  36. 38. Solution Process Ion-dipole interaction cf) solvation, hydration
  37. 39. <ul><li>Solution formation can be exothermic or endothermic. </li></ul><ul><li>Heat of solution is: </li></ul><ul><li> H sol =  H solute +  H solvent +  H solvation </li></ul><ul><li>Like dissolves like </li></ul><ul><ul><li>polar molecules dissolve in polar liquids. </li></ul></ul><ul><ul><li>nonpolar molecules dissolve in nonpolar liquids. </li></ul></ul>Solution Process
  38. 40. Solution Process
  39. 41. Sample Problem <ul><li>Which of the following substances are soluble in water? </li></ul><ul><li>KBr, ethanol (CH 3 CH 2 OH), hexane (C 6 H 12 ) </li></ul><ul><li>KBr is an ionic compound it will dissolve in water. </li></ul><ul><li>ethanol is polar it will dissolve in polar water. </li></ul><ul><li>hexane is nonpolar, it will not dissolve in water. </li></ul>
  40. 42. Solubility
  41. 43. 10.7 Molarity <ul><li>Molarity ( M ) is the number of moles of solutes per volume of solution in liters. </li></ul>
  42. 44. Sample Problem <ul><li>Calculate the molarity of a solution of 24.0g of HCl made up to a volume of 500. mL. </li></ul>
  43. 45. <ul><li>Molality ( m ) is the number of moles of solute per kilogram of solvent. </li></ul>Molality
  44. 46. Sample Problem <ul><li>Calculate the molality of a solution of 13.5g of KF dissolved in 250. g of water. </li></ul>
  45. 47. Mole Fraction <ul><li>Mole fraction ( χ ) is the ratio of the number of moles of a substance over the total number of moles of substances in solution. </li></ul>
  46. 48. Sample Problem - Conversions between units- <ul><li>ex) What is the molality of a 0.200 M aluminum nitrate solution (d = 1.012g/mL)? </li></ul><ul><ul><li>Work with 1 liter of solution. mass = 1012 g </li></ul></ul><ul><ul><li>mass Al(NO 3 ) 3 = 0.200 mol × 213.01 g/mol = 42.6 g ; </li></ul></ul><ul><ul><li>mass water = 1012 g -43 g = 969 g </li></ul></ul>
  47. 49. Sample Problem <ul><li>Calculate the mole fraction of 10.0g of NaCl dissolved in 100. g of water. </li></ul>
  48. 50. Conc. Based on mass
  49. 51. ppm, ppb, ppt in dilute aqueous solution
  50. 52. 11.8 Effect of Temperature on Solubility <ul><li>The solubility of a gas decreases with temperature. </li></ul>
  51. 53. Solubility of O 2
  52. 54. Effect of Temperature on Solubility <ul><li>The solubility of an ionic solid generally increases with temperature. </li></ul>
  53. 55. Effect of Pressure on Solubility <ul><li>Henry’s Law </li></ul><ul><li>P gas = k gas C gas </li></ul><ul><ul><li>P gas = pressure of the gas above the solution </li></ul></ul><ul><ul><li>C gas = concentration of the gas </li></ul></ul><ul><ul><li>k gas = Henry’s law constant </li></ul></ul><ul><ul><li>Henry’s law holds best for gases O 2 and N 2 , does not hold HCl </li></ul></ul>
  54. 56. Sample Problem <ul><li>A liter of water dissolves 0.0404 g of oxygen at 25 o C at a pressure of 760. torr. What would be the concentration of oxygen (in g/L) if the pressure were increased to 1880 torr at the same temperature? </li></ul>
  55. 57. 11.9 Colligative Properties <ul><li>Vapor pressure lowering – the vapor pressure of a solvent is lowered by the addition of a nonvolatile solute . </li></ul>cf) volatile solute
  56. 59. Raoult’s Law P o solvent = vapor pressure of the pure solvent
  57. 60. Sample Problem <ul><li>What will be the vapor pressure of a solution made by dissolving 6.25g of glucose, C 6 H 12 O 6 , in 50.0g of water at 25 o C? How much was the vapor pressure of the pure water lowered? The vapor pressure of water at 25 o C is 23.8 torr </li></ul>
  58. 61. Colligative Properties <ul><li>Boiling point elevation – the change in the boiling point is: </li></ul><ul><li> T b = i K b m </li></ul><ul><ul><ul><li>i = sum of the coefficients of the ions ( i = 1 for molecular compounds) </li></ul></ul></ul><ul><ul><ul><li>K b = boiling point elevation constant </li></ul></ul></ul><ul><ul><ul><li>m = molality </li></ul></ul></ul>
  59. 62. Colligative Properties <ul><li>Freezing point depression – the change in the freezing point is: </li></ul><ul><li> T f = i K f m </li></ul><ul><ul><ul><li>i = sum of the coefficients of the ions ( i = 1 for molecular compounds) </li></ul></ul></ul><ul><ul><ul><li>K f = freezing point depression constant </li></ul></ul></ul><ul><ul><ul><li>m = molality </li></ul></ul></ul>
  60. 63. Colligative Properties
  61. 64. Antifreeze solution
  62. 65. Sample Problem <ul><li>Calculate the boiling point elevation and the freezing point depression of a solution made by dissolving 12.2g of KCl in 45.0g of water. K b = 0.512 o C/m and K f = 1.86 o C/m </li></ul><ul><li>i = 2 for KCl  K + + Cl  </li></ul>
  63. 66. Colligative Properties <ul><li>Osmotic pressure </li></ul><ul><li>П = i M RT </li></ul><ul><ul><ul><li>i = sum of the coefficients of the ions ( i = 1 for molecular compounds) </li></ul></ul></ul><ul><ul><ul><li>M = molarity </li></ul></ul></ul><ul><ul><ul><li>R = gas constant (0.0821 L • atm/mol • K) </li></ul></ul></ul><ul><ul><ul><li>T = temperature in Kelvin </li></ul></ul></ul>
  64. 67. Osmosis
  65. 68. Osmosis
  66. 69. Osmosis
  67. 71. Sample Problem <ul><li>What is the osmotic pressure of a 100. mL solution containing 9.50 g of glucose, C 6 H 12 O 6 , at 20.0 o C? </li></ul>
  68. 72. Problems <ul><li>4, 22, 34, 47-48, 60, 74, 78, 82, 100, 112 </li></ul>

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