91Ó°ÊÓ

The density of liquid sulfur dioxide is \(1.43 \mathrm{~g} / \mathrm{mL},\) and that of the gas is \(0.00293 \mathrm{~g} / \mathrm{mL}\) at standard temperature and pressure. Account for the large difference betwecn these two densities.

For any particular substance, the types of intermolecular forces in the solid, liquid, and gas phases are the same. What determincs which of these phases is stable at a given temperature?

For most substances, the liquid state is less dense than the solid state. How does density affect the energy of the intermolecular attractions?

Why does water have a lower vapor pressure at \(25^{\circ} \mathrm{C}\) than dimethyl ether \(\left(\mathrm{CH}_{3} \mathrm{OCH}_{3}\right) ?\) Which of these two liquids has the greater enthalpy of vaporization?

"A liquid stops evaporating when the equilibrium vapor pressure is reached." What is wrong with this statement?

Why does a perspiring body achieve greater cooling when the wind is blowing than in calm air?

How does humidity affect the efficiency of cooling by perspiration? Explain.

The enthalpy of vaporization of water (boiling point = \(\left.100{ }^{\circ} \mathrm{C}\right)\) is greater than that of diethyl ether (boiling point \(\left.=35^{\circ} \mathrm{C}\right)\). Despite its smaller enthalpy of vaporization, liquid diethyl ether feels colder than water does when it evaporates from a person's skin. Explain.

Each of two glasses contains \(200 \mathrm{~g}\) of an ice-water mixture. In one glass, \(10 \mathrm{~g}\) is ice, and in the other glass, \(90 \mathrm{~g}\) is ice. Assuming both samples are at equilibrium, which is colder?

For a typical substance, arrange the enthalpies of sublimation, fusion, and vaporization in order of increasing value.