(a) Which kind of intermolecular attractive force is shown in each case here? (b) Predict which of the four interactions is the weakest. [Section 11.2]

a. Which of the molecules shown here can form dipole–dipole interactions with other molecules of the same type?

b. Which are capable of forming hydrogen bonds with other molecules of the same type? [Section 11.2]

If 42.0 kJ of heat is added to a 32.0-g sample of liquid meth-ane under 1 atm of pressure at a temperature of -170°C, what are the final state and temperature of the methane once the system equilibrates? Assume no heat is lost to the surroundings. The normal boiling point of methane is -161.5 °C. The specific heats of liquid and gaseous methane are 3.48 and 2.22 J/g-K, respectively. [Section 11.4]

Using this graph of CS2 data, determine (a) the approximate vapor pressure of CS2 at 30°C,

The molecules

have the same molecular formula (C3H8O) but different chemical structures. (b) Which molecule do you expect to have a larger dipole moment? [Sections 11.2 and 11.5]

The phase diagram of a hypothetical substance is

(b) What is the physical state of the substance under the following conditions? (i) T = 150 K, P = 0.2 atm; (ii) T = 100 K, P = 0.8 atm; (iii) T = 300K, P = 1.0atm. [Section 11.6]

At three different temperatures, T1, T2, and T3, the molecules in a liquid crystal align in these ways:

(a) At which temperature or temperatures is the substance in a liquid crystalline state? At those temperatures, which type of liquid crystalline phase is depicted?

At three different temperatures, T1, T2, and T3, the molecules in a liquid crystal align in these ways:

(b) Which is the highest of these three temperatures? [Section 11.7]

List the three states of matter in order of (a) increasing molecular disorder

List the three states of matter in order of (b) increasing intermolecular attraction.

(a) How does the average kinetic energy of molecules com- pare with the average energy of attraction between mole- cules in solids, liquids, and gases?

(c) What happens to a gas if you put it under extremely high pressure?

At room temperature, Si is a solid, CCl₄ is a liquid, and Ar is a gas. List these substances in order of (a) increasing intermolecular energy of attraction

At standard temperature and pressure, the molar volumes of Cl₂ and NH₃ gases are 22.06 and 22.40 L, respectively (b) On cooling to 160 K, both substances form crystalline solids. Do you expect the molar volumes to decrease or increase on cooling the gases to 160 K?

At standard temperature and pressure, the molar volumes of Cl₂ and NH₃ gases are 22.06 and 22.40 L, respectively. (c) The densities of crystalline Cl₂ and NH₃ at 160 K are 2.02 and 0.84 g/cm³, respectively. Calculate their molar volumes.

At standard temperature and pressure, the molar volumes of Cl2 and NH3 gases are 22.06 and 22.40 L, respectively. (d) Are the molar volumes in the solid state as similar as they are in the gaseous state?

Benzoic acid, C₆H₅COOH, melts at 122 °C. The density in the liquid state at 130 °C is 1.08 g/cm³. The density of solid benzoic acid at 15 °C is 1.266 g/cm³. (b) If you converted a cubic centimeter of liquid benzoic acid into a solid, would the solid take up more, or less, volume than the original cubic centimeter of liquid?

(a) Which type of intermolecular attractive force operates between all molecules?

(b) Which type of intermolecular attractive force operates only between polar molecules?

(c) Which type of intermolecular attractive force operates only between the hydrogen atom of a polar bond and a nearby small electronegative atom?

(b) Which of these kinds of interactions are broken when a liquid is converted to a gas?

Describe the intermolecular forces that must be overcome to convert these substances from a liquid to a gas: (a) SO₂, (b) CH₃COOH, (c) H₂S.

Which type of intermolecular force accounts for each of these differences? (a) CH₃OH boils at 65 °C; CH₃SH boils at 6 °C. (d) Acetone boils at 56 °C, whereas 2-methylpropane boils at -12 °C.

Which type of intermolecular force accounts for each of these differences? (b) Xe is a liquid at atmospheric pressure and 120 K, whereas Ar is a gas under the same conditions. (c) Kr, atomic weight 84 amu, boils at 120.9 K, whereas Cl₂, molecular weight about 71 amu, boils at 238 K.

(a) List the following molecules in order of increasing polar- izability: GeCl4, CH4, SiCl4, SiH4, and GeBr4. (b) Predict the order of boiling points of the substances in part (a).

True or false: (b) For the noble gases the dispersion forces decrease while the boiling points increase as you go down the column in the periodic table.

True or false: (e) The larger the atom, the more polarizable it is.

Which member in each pair has the greater dispersion forces? (a) H₂O or H₂S,

Which member in each pair has the greater dispersion forces? (b) CO₂ or CO, (c) SiH₄ or GeH₄.