Water (polar molecule) forms beaded droplets on waxy surface (nonpolar molecule) because the attraction between the water molecules and the waxy surface is lesser than the attraction between the water molecules. The most prominent intermolecular force/s of attraction between water and the waxy surface is/are: I. London dispersion forces II. Dipole-dipole force III. Hydrogen bond   A. I only B. II only C. III only D. I, II, and III

If a piece of filter paper (an absorbent paper used in laboratories) is suspended above a beaker of water and just touching the surface, water will slowly move up the paper. What is the name given to this phenomenon, and how is this behavior explained?

Of the four general types of solids, which one(s) (a) are generally insoluble in water? (b) have very high melting points? (c) conduct electricity as solids?

Intermolecular Forces The following picture represents atoms of hypothetical, nonmetallic, monatomic elements A, B, and C in a container at a temperature of 4 K (the piston maintains the pressure at 1 atm). None of these elements reacts with the others. a What is the state (solid, liquid, or gas) of each of the elements represented in the container? b Rank the elements in the container from greatest to least, in terms of intermolecular interactions. Explain your answer. c What type(s) of intermolecular attractions are present in each of these elements? d Explain which element has the greatest atomic mass. e One of the elements in the container has a normal boiling point of 2 K. Which element would that be (A, B, or C)? How do you know? f One of the elements has a melting point of 50 K. Which element would that be (A, B, or C)? Why? g The remaining element (the one you have yet to choose) has a normal boiling point of 25 K. Identify the element. Could this element have a freezing point of 7 K? Explain. h If you started heating the sample to 20 K, explain what you would observe with regard to the container and its contents during the heating. i Describe the container and its contents at 20 K. Describe (include a drawing) how the container and its contents look at 20 K. j Now you increase the temperature of the container to 30 K. Describe (include a drawing) how the container and its contents look at 30 K. Be sure to note any changes in going from 20 K to 30 K. k Finally, you heat the container to 60 K. Describe (include a drawing) how the container and its contents look at this temperature. Be sure to note any changes in going from 30K to 60k

Explain why evaporation leads to cooling of the liquid.

When wet laundry is hung on a clothesline on a cold winter day, it will freeze but eventually dry. Explain.

The following data are the equilibrium vapor pressure of limonene, C10H16, at various temperatures. (Limonene is used as a scent in commercial products.) (a) Plot these data as ln P versus 1/T so that you have a graph resembling the one in Figure 11.13. (b) At what temperature does the liquid have an equilibrium vapor pressure of 250 mm Hg? At what temperature is it 650 mm Hg? (c) What is the normal boiling point of limonene? (d) Calculate the molar enthalpy of vaporization for limonene using the Clausius-Clapeyron equation.

A solution is made by adding 50.0 mL of ethanol (C2H5OH, d = 0.789 g/mL) to 50.0 mL of water (d = 0.998 g/mL). What is the total vapor pressure over the solution at 20 C? (See Study Question 75.) The vapor pressure of ethanol at 20 C is 43.6 mm Hg.

8.87 Use the vapor pressure curves illustrated here to answer the questions that follow. (a) What is the vapor pressure of ethanol (C2H5OH) at 60°C? (b) Considering only carbon disulfide (CS2) and ethanol, which has the stranger intermolecular forces in the liquid state? (c) At what temperature does heptane (C7H16) have a vapor pressure of 500 mm Hg? (d) What are the approximate normal boiling pains of each of the three substances? (e) At a pressure of 400 mm Hg and a temperature of 70°C, is each substance a liquid, a gas, or a mixture of liquid and gas?