91Ó°ÊÓ

Solid ice is less dense than liquid water. What does this say about how many water molecules there are per unit volume of ice relative to how many water molecules there are per unit volume of liquid water?

Which of the following best describes a liquid: (a) The phase of matter in which particles are typically separated by the least distance (b) The phase of matter in which particles are in a fixed, rigid arrangement (c) The phase of matter in which particles completely fill the volume of their container (d) The phase of matter in which particles are in a loose, changeable arrangement but do not completely fill the volume of their container

At \(25^{\circ} \mathrm{C}\), fluorine, \(\mathrm{F}_{2}\), and chlorine, \(\mathrm{Cl}_{2}\), are gases but bromine, \(\mathrm{Br}_{2}\), is a liquid. What does this say about the intermolecular forces in bromine relative to those in fluorine and chlorine?

Which of the following does not form hydrogen bonds? Justify your choice. (a) Methyl alcohol, \(\mathrm{CH}_{3} \mathrm{OH}\) (b) Hydrofluoric acid, HF (c) Ammonia, \(\mathrm{NH}_{3}\) (d) Methane, \(\mathrm{CH}_{4}\)

(a) Name the strongest intermolecular force in \(\mathrm{CH}_{3} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{Cl}, \mathrm{CH}_{3} \mathrm{CH}_{3}\), and \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}\) (b) Rank these molecules from lowest to highest boiling point.

Name the strongest intermolecular force expected in (a) Boron trifluoride, \(\mathrm{BF}_{3}\) (b) 1-Propanol, \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\) (c) Xenon, Xe (d) Hydrogen fluoride, HF (e) Hydrogen iodide, HI

\(\mathrm{SiO}_{2}\), the main component of glass, is a solid at room temperature, and \(\mathrm{CO}_{2}\) is a gas at room temperature. How do the structures of these compounds explain this fact?

Arrange these substances in order of increasing melting point: \(\mathrm{CH}_{3} \mathrm{OH}, \mathrm{SiO}_{2}, \mathrm{C}_{2} \mathrm{H}_{6}, \mathrm{NaCl}\).

Ethylene glycol, \(\mathrm{CH}_{2} \mathrm{OHCH}_{2} \mathrm{OH}\), and pentane, \(\mathrm{C}_{5} \mathrm{H}_{12}\), have approximately the same molar mass. Nevertheless, one of these compounds boils at \(198{ }^{\circ} \mathrm{C}\), and the other boils at \(36{ }^{\circ} \mathrm{C}\). Which compound boils at which temperature? Use an argument based on intermolecular forces to justify your choice.

Sketch the hydrogen bonds present in the liquid 1-propanol, \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{OH}\).