General Chemistry 2_IMF and Properties of Liquids.pptx

This power point presentation focuses on the different intermolecular forces that binds molecules in order for solids to remain solids or liquid to remain liquids. This presentation also presents the different properties of liquid that can be explained through the concept of intermolecular forces. It also contains simple activities to test the understanding of the learners on the lesson.

1. General Chemistry 2 Presented by Kristel Joy R. Somera Subject Teacher

2. At the end of the lesson, you shall be able to: Use the kinetic molecular model to explain properties of liquids and solids STEM_GC11IMFIIIa-c-99 Describe the general types of intermolecular forces STEM_GC11IMFIIIa-c-100

3. Lesson 1: Kinetic Molecular Theory on Liquids and Solids

4. Properties of Gases: Gases have no definite shape and volume. 2. Gases diffuse rapidly. 3. Gases can be readily compressed.   4. Gases have densities much lower than solids and liquids. Review:

5. Kinetic Molecular Theory: Gases are composed of atoms or molecules which are widely separated from one another. Gas molecules move at a very high speeds, traveling in straight paths but in random directions. Gas molecules collide with one another and with the walls of its container.   The average kinetic energy of the molecules is determined by the gas temperature

6. Kinetic Molecular Theory of Solids and Liquids: Criteria Solid Liquid Particle Arrangement Movement Density Particles are not free to move Particles vibrate in fixed position Particles are able to slide pass one another Very High High

7. Kinetic Molecular Theory of Solids and Liquids: Criteria Solid Liquid Diffusibility Compressibility Volume and shape Thermal Expansibility Least Compressible Fixed volume and shape Slightly compressible Assumes the shape of the container it occupies and has a fixed volume Expands slightly when heated Expands slightly when heated Extremely slow Slow

8. Lesson 2: Intermolecular Forces

9. Force which keeps molecules together. It is the force between the atoms of a molecule or compound. Attractive force between molecules. Responsible for keeping matter in solid or liquid phase.

10. Intramolecular forces Intermolecular forces

11. Intermolecular Forces The attractions between molecules are not nearly as strong as the intramolecular attractions (bonds) that hold compounds together. Many physical properties reflect intermolecular forces, like boiling points, melting points, viscosity, surface tension, and capillary action.

12. Types of Intermolecular Force Weakest to strongest forces: dispersion forces (or London dispersion forces) dipole–dipole forces hydrogen bonding (a special dipole–dipole force) ion–dipole forces Note: The first two types are also referred to collectively as van der Waals forces .

13. These London dispersion forces are often found in the halogens (e.g., F 2 and I 2 ), the noble gases (e.g., Ne and Ar ), and in other non-polar molecules, such as carbon dioxide and methane. London dispersion forces are part of the van der Waals forces, or weak intermolecular attractions.

14. Dipole – dipole forces are formed between neighboring molecules with permanent dipoles. Polar covalent compounds usually undergo dipole – dipole forces CCl 4 , HCl , SO 2 are example of dipole – dipole.

15. H- bond is actually a dipole – dipole in nature but for molecules containing O – H, H- F and N- H 2 O, NH 3 , NH 4 and HF are examples of hydrogen bond.

16. NaCl solution, CaCl 2 solution, and KCl solution are examples of ion - dipole.

17. Activity 2 Based on the discussion, determine the intermolecular forces being described and tell its level of strength (very weak, weak, strong, very strong)

18. Description/ Nature of interaction Intermolecular Forces of Attraction (IMFA) Strength 1. Interaction of an ion with the charge end of another molecule 2. A special type of dipole – dipole formed between a partially positive hydrogen and a neighboring molecule with partially negative O, N, F 3. An interaction between molecules with temporary dipoles 4. An interaction between two polar molecules other than N- H, O-H, and H-F ion - dipole Very strong Hydrogen bond Strong Dispersion Very weak dipole – dipole Weak

19. Activity 3 Identify the type of intermolecular forces of attraction the given compound has. 1. CO 2 2. MgCl 2 Solution 3. ICl – Iodine monochloride 4. NH 3 5. HCl Dispersion Ion - dipole Dispersion Hydrogen bond Dipole - dipole

20. Arrange the following according to decreasing intermolecular force of attraction. Explain your answer Carbon tetrachloride CCl 4 Water H 2 O Sodium Chloride solution Iodine Chloride

21. Let us Review!

22. Determine the type of intermolecular forces of attraction between the given molecules HF PCl 3 CO 2 4. SO 2 5. NaCl in water

23. HF PCl 3 CO 2 4. SO 2 5 . NaCl in water H - bond Dipole - dipole London dispersion force Dipole - dipole Ion - dipole

24. Lesson 3: Properties of Liquids

25. Learning Competency: Describe the following properties of liquids, and explain the effect of intermolecular forces on these properties: surface tension, viscosity, vapor pressure, boiling point, and molar heat of vaporization

26. What are the properties of liquid according to Kinetic molecular theory? 1. Particles are not confined to a rigid position since they have sufficient kinetic energy to overcome their attractive forces. and they move but not at a far distance, they roll and slide pass each other.

27. 2. Since the molecules flow, they take the shap e of a container and diffuse moderately to occupy a fixed volume. 3. They have high density but low compressibility, and thermal expansion. 4. They are joined by intermolecular forces.

28. Special Physical Properties of Liquids and Intermolecular forces

29. Surface Tension

30. 1. Surface Tension is the force that causes the surface of a liquid to contract

31. Surface tension and Intermolecular forces The strength of surface tension depends on the intermolecular force of attraction. The stronger the IMFA, the greater the surface tension However, an increase in temperature decreases surface tension Surface tension explains why a drop of liquid is spherical in shape.

32. Viscosity

33. 2. Viscosity is the resistance of fluid to flow. This is cause by the intermolecular attraction between the molecules of liquids.

34. Viscosity and Intermolecular forces A liquid with low intermolecular forces allows molecules of liquid to move freely, therefore, low viscosity A liquid with strong intermolecular forces have high viscosity

35. Viscosity and Intermolecular forces Increasing the temperature causes the kinetic energy of the molecules of liquid to increase. Heat breaks the intermolecular forces causing the molecules to move faster. Therefore, increase in temperature will decrease the viscosity.

36. Let us compare the viscosity and intermolecular forces of the given liquids. Arrange them according to increasing viscosity and IMF. Water Toothpaste Honey Cooking Oil

37. Water Toothpaste Honey Cooking Oil increasing viscosity and IMF.

38. Vapor pressure and boiling point

39. 3. Vapor Pressure and Boiling Point Vapor pressure of a liquid is the pressure of the vapor resulting from evaporation of a liquid.

40. Let us determine which of the following samples of liquid has high vapor pressure Water

41. samples of liquid in increasing vapor pressure Water

42. 3. Vapor Pressure and IMF If a liquid has a weak IMF, the escaping tendency of the molecules is high (molecules easily breaks apart/ turn into its gaseous state) Weak IMF means high vapor pressure and strong IMF means low vapor pressure Liquids have different vapor pressure at different temperature.

43. 3. Vapor Pressure and Boiling Point Boiling Point of a liquid is the temperature at which the vapor pressure of the liquid is equal to the atmospheric pressure. At this temperature, the amount of heat added to the system by heating the liquid is equal to the amount of heat escaping through evaporation. This is why the temperature remains constant at boiling point.

44. Boiling Point= temperature where vapor pressure = Atmospheri c pressure

45. Boiling Point and Vapor pressure and IMF The lower atmospheric pressure, the faster it is to equalize the vapor pressure of the liquid and the atmospheric pressure, the lower the boiling point. A liquid that has weak intermolecular forces has high vapor pressure evaporates easily, therefore it has a low boiling point. A liquid with strong IMF has low vapor pressure, does not evaporate easily and with high boiling point

46. Let us study and compare the different Boiling Point of some liquids. Let us arrange the liquids into increasing boiling point, IMFA and increasing vapor pressure Liquid Boiling Point Water 100 ºC Isopropyl Alcohol 82.5 ºC Soy bean Cooking Oil 300ºC acetone 56 ºC

47. Arrangement of the sample liquids into increasing boiling point and IMFA Liquid Boiling Point Acetone 56ºC Isopropyl Alcohol 82.5 ºC Water 100ºC Soy bean Cooking Oil 300 ºC

48. Arrangement of the sample liquids into increasing vapor pressure Liquid Boiling Point Soy bean cooking oil 300ºC Water 100 ºC Isopropyl Alcohol 82.5ºC Acetone Soy bean Cooking Oil 56 ºC

49. The amount of heat needed to vaporize a given amount of liquid at its boiling point . 4. Molar heat of Vaporization

50. What is the most abundant liquid on Earth? WATER!

51. Common Uses of Water

52. WATER AND ITS PROPERTIES

53. Properties of Water

54. 1. Water has high boiling point (100ºC) Reason Consequence

55. 2. Water has high specific heat Reason Consequence

56. 3. Water has high density in its liquid form Reason Consequence

57. 4. Water has high surface tension Reason Consequence

58. 5. Water has high heat of vaporization Reason Consequence

59. Water has: high boiling point 2. high specific heat 3. high density in its liquid form 4. high surface tension; and 5. high heat of vaporization

60. Test your mastery!

61. Water plays a vital role in our life. Determine the property/ ies of water where the given situation or illustration can be attributed.

62. 1. Answer

63. Water moves from roots of a tree to the top of very tall trees. 2. Answer

64. Perspiration lowers body temperature. 3. Answer

65. preventions of temperature variations that are outside the range suitable for life 4. Answer

66. Water is liquid at room temperature. 5. Answer

67. Water resist sharp changes in temperature so earth would not experience great temperature variations. 6. Answer Back

68. The high boiling point of water is due to its strong intermolecular forces of attraction caused by the formation of the H - bond

69. The high specific heat of water is due to its strong intermolecular forces of attraction caused by the formation of the H - bond

70. The high surface tension of water is due to the formation of the h – bond on the surface of the water molecules

71. The high heat of vaporization of water is due to its strong intermolecular forces of attraction caused by the formation of the H – bond.

72. Water is not easily vaporize or turn into its gaseous state

73. Water can absorb or release large quantities of heat without change in temperature.

74. Ice floats in water.

75. Water can be able to move against gravity or flow into fibers

76. Large amount of heat is needed to vaporize a given amount of water.

77. 1. Water has high density in its liquid form Back to mastery

78. Water moves from roots of a tree to the top of very tall trees. 2. Water has high surface tension Back to mastery

79. Water has high molar heat of vaporization/ high specific heat Perspiration lowers body temperature. 3. Back to mastery

80. preventions of temperature variations that are outside the range suitable for life 4. Water has high molar heat of vaporization/ high specific heat Back to mastery

81. Water is liquid at room temperature. 5. Water has high boiling point Back to mastery

82. Water resist sharp changes in temperature so earth would not experience great temperature variations. 6. Water has high molar heat of vaporization/ high specific heat Back to mastery

83. Connecting to real – life

84. How does the molecular structure and intermolecular forces affect the properties of water?

85. Evaluation!

86. Assignment: Follow- up 1. Search for more applications of the properties of water in daily life not mentioned during the lesson.   Advance 1. What are the processes involving phase change? 2. Draw/plot the phase diagram of water and interpret.