N 10 pg

13.List major types of intermolecular forces in order of increasing strength. Is there some overlap in strength from one type of force to the next. Give examples of each Weakest dispersion forces (also called van der Waal’s forces or London forces) dipole—dipole forces Strongest hydrogen bonding Yes there is overlap

13. Dipole—dipole forces

13. Hydrogen Bonding

13. Dispersion Forces Induced dipole

15. How do these physical properties depend on the strength of intermolecular forces? a.Surface tension Increases with increasing intermolecular force

Measuring surface tension

15. How do these physical properties depend on the strength of intermolecular forces? b. viscosity Increases with increasing intermolecular force

15. How do these physical properties depend on the strength of intermolecular forces? c. Melting point temperature Increases with increasing intermolecular force

15. How do these physical properties depend on the strength of intermolecular forces? d. Boiling point temperature Increases with increasing intermolecular force

15. How do these physical properties depend on the strength of intermolecular forces? e. Vapor pressure decreases with increasing intermolecular force

17. Distinguish between a)Polarizability—ease of distorting the electron cloud—to make it polar polarity—presence of a permanent dipole

17. Distinguish between b) London dispersion forces— present in all substances, “accidental” (induced dipoles) Dipole—dipole forces— attraction between molecules with permanent dipoles

17. Distinguish between c) Intermolecular forces— inter—between. intramolecular forces— intra—within. Chemical Bonds

20. Critical temperature— above this temperature a substance cannot be liquified. Critical pressure—the pressure that must be used to liquefy a gas at its critical temperature At critical temp. all gas particles have sufficient KE so there are no intermolecular attractive forces

Critical temperature and pressure of methane -82°C 45.8 atm

22. Molecules with the greatest KE overcome the attractive forces and escape the surface of the liquid. The average kinetic energy of the remaining molecules is lower.

23. Distinguish between items in the following pairs. A ) crystalline solid Regular repeating structure amorphous solid Irregular arrangement of atoms or molecules

23. Distinguish between items in the following pairs. B) ionic solid Made up of ions held together by ionic bonding molecular solid Made up of covalently bonded molecules held together by intermolecular forces *dispersion, hydrogen bonding, dipole-dipole )

23. Distinguish between items in the following pairs. C) molecular solid Made up of covalently bonded molecules held together by intermolecular forces Covalent network solid No discrete molecules one large molecule the intermolecular forces are the covalent bonds between atoms

23. Distinguish between items in the following pairs. D) metallic solid Completely delocalized electrons conductor of electricity (ions in a sea of electrons) network solid Localized electrons, insulator or semiconductor

35. Identify the most important interparticle forces present in each of the following substances. a) Ar b) HCl c) HF Non polar— dispersion forces Hydrogen Bonding and Dispersion

35. Identify the most important interparticle forces present in each of the following substances. d) CaCl 2 e) CH 4 f) CO Ionic Dispersion forces (no dipole) Dipole

35. Identify the most important interparticle forces present in each of the following substances. g) NaNO 3 Ionic

36. Identify the most important interparticle forces present in each of the following substances. a) NH 4 Cl b) CF 3 (CF 2 CF 2 ) n CF 3 c) CH 3 (CH 2 CH 2 ) n CH 3 Ionic Mostly Dispersion Dispersion

36. Identify the most important interparticle forces present in each of the following substances. d) CHCl 3 e) NH 3 f) NO Dipole and dispersion H-bonding and Dispersion Dipole and dispersion

36. Identify the most important interparticle forces present in each of the following substances. BF 3 Dispersion

43. A meniscus happens because there are characteristic surface tensions, and adhesive and cohesive forces at work in liquids. If water is in a tube, for example, the adhesive forces between the glass and the water is stronger than the cohesive forces among the water molecules themselves. Thus, one sees a concave or downward curving meniscus.

43. With mercury, the cohesive forces are much greater than the adhesive forces toward the glass wall, and it has an upward curving or convex meniscus.

85. From the information given construct a heating curve.

86. Describe how a phase diagram can be constructed from heating curve information

87. How much energy does it take to convert 0.5 kg -20 °C to steam at 250 °C

88. What is the final temperature when kJ of energy is added to 10.0 g of ice at 0 °C

91. Consssider the phase diagram below. What phases are present at the points A through H? A D C B E F G,,,,

1 atm 91. Consssider the phase diagram below. Identify triple point normal boiling point normal freezing point

91. Consssider the phase diagram below. WHICH IS MORE DENSE, the liquid or the solid? First let us consider water If pressure was one atm and Temp was normal melting point Would increasing the pressure raise or lower the melting point? If pressure was one atm and Temp was normal melting point Would increasing the pressure raise or lower the melting point? Placing pressure on the substance forces the particles toward their maximum density---in this case the liquid state Therefore the liquid state of water is the most dense Placing pressure on the substance forces the particles toward their maximum density---in this case the liquid state Therefore the liquid state of water is the most dense Note that in problem 91 the slope of the solid / liquid line is positive---The solid phase is more dense than the liquid phase.

91. Consssider the phase diagram below. WHICH IS MORE DENSE, the liquid or the solid? Is there any place along the liquid vapor line where the slope is negative? Which has the greater density the liquid or the gas? Is there any place along the liquid vapor line where the slope is negative? Which has the greater density the liquid or the gas?