Part 1 of 2 • Which of the following compounds exhibits the weakest intermolecular forces? Select the single best answer. Part 2 of 2 OH H x 5 Which of the following compounds exhibits the strongest intermolecular forces? Select the single best answer. OH H

What are intermolecular forces? How do they differ from intramolecular forces? What are dipole-dipole forces? How do typical dipole-dipole forces differ from hydrogen bonding interactions? In what ways are they similar? What are London dispersion forces? How do typical London dispersion forces differ from dipole-dipole forces? In what ways are they similar? Describe the relationship between molecular size and strength of London dispersion forces. Place the major types of intermolecular forces in order of increasing strength. Is there some overlap? That is, can the strongest London dispersion forces be greater than some dipole-dipole forces? Give an example of such an instance.

Classify each of the following statements as true or false. a Intermolecular attractions are stronger in liquids than in gases. b Substances with weak intermolecular attractions generally have low vapor pressures. c Liquids with high molar heats of vaporization usually are more viscous than liquids with low molar heats of vaporization. d A substance with a relatively high surface tension usually has a very low boiling point. e All other things being equal, hydrogen bonds are weaker than induced dipole or dipole forces. f Induced dipole forces become very strong between large molecules. g Other things being equal, nonpolar molecules have stronger intermolecular attractions than polar molecules. h The essential feature of a dynamic equilibrium is that the rates of opposing changes are equal. i Equilibrium vapor pressure depends on the concentration of a vapor above its own liquid. j The heat of vaporization is equal to the heat of fusion, but with opposite sign. k The boiling point of a liquid is a fixed property of the liquid. l If you break shatter an amorphous solid, it will break in straight lines, but if you break a crystalline solid, it will break in curved lines. m Ionic crystals are seldom soluble in water. n Molecular crystals are nearly always soluble in water. o The numerical value of heat of vaporization is always larger than the numerical value of heat of condensation. p The units of heat of fusion are kJ/gC. q The temperature of water drops while it is freezing. r Specific heat is conerned with a change in temperature.

For liquid-state samples of the following diatomic molecules, indicate the type or types of intermolecular forces (dipoledipole interactions, hydrogen bonding, London forces) present. There may be more than one correct answer in a given situation. a. H2 b. HF c. CO d. F2