30. What state of matter is represented by these particles? Solids

31. In order to melt this solid the forces of attraction between these particles must be overcome.

35. The forces between these liquid particles are weaker now since the particles are further apart

37. If the substance is heated further the liquid can turn into a gas

41. If the substance is cooled the gas will turn back into a liquid

43. and then into a solid

44. the energy required to overcome these forces of attraction determine the substance’s melting point.

45. the more energy required, the higher the melting point.

46. Types of Intermolecular Forces Between Molecules

49. London Dispersion Forces – very weak attractive forces between all molecules

50. nonpolar Types of Intermolecular Forces Between Molecules London Dispersion Forces – only important between non-polar molecules

51. polar Types of Intermolecular Forces Between Molecules Dipole – Dipole Forces – Stronger attractive force between polar molecules + - + + + + + + + + + + + - - - - - -- - - - -

52. Types of Intermolecular Forces Between Molecules Hydrogen Bonds – Stronger attractive force between polar molecules with O, F, N and H

53. Types of Intermolecular Forces Between Molecules Hydrogen Bonds – Stronger attractive force between polar molecules with O, F, N and H HH O   HH O   HH O   HH O   HH O   HH O   HH O   HH O   HH O   HH O   HH O   HH O  

54. Homework – pg. 88 # 9 - 11