back

Chapter 13
Liquids, Solids, and Intermolecular Forces
 
 
 
Movie
Title
 Movie
Caption
 The effect of temperature on the vapor pressure of a liquid is illustrated.
Notes
 Vapor pressure vs temperature. A liquid in a closed container exerts a vapor pressure due to molecules that have escaped into the liquid phase. At equilibrium equal numbers of molecules leave and reenter the liquid phase. As the temperature is increased the average kinetic energy of the molecules increases. The higher kinetic energy of the liquid allows more molecules to escape, resulting in an increase in vapor pressure with increasing temperature.
Movie
Title
 Movie
Caption
 Changes of State
Notes
 Changes in state. As a solid is heated its temperature increases until its melting point is reached. At the melting point heat is used to convert the solid to a liquid at constant temperature. In the liquid state the temperatureincreases with added heat. At the boiling point the heat is used to convert the liquid to vapor at constant temperature. When the substance has vaporized, added heat causes the temperature of the vapor to increase.
Movie
Title
 Movie
Caption
 Two-dimensional representation of the close packing of spheres
Notes
 Close packing. A layer of soap bubbles on the surface of a liquid gives a two-dimensional representation of the close packing of spheres. Each soap bubble is surrounded by six other soap bubbles, illustrating a hexagonal arrangement.
Movie
Title
 Movie
Caption
 Demonstration of the reaction between sodium and chlorine to form sodium chloride
Notes
 Formation of Sodium Chloride. Molten sodium burns when it is put into a container of chlorine gas. In the reaction a sodium ion loses an electron to form a sodium cation and a chlorine atom simultaneously gains an electron to form a chloride anion. The product of the reaction is the ionic compound sodium chloride, which is the white solid observed.
Movie
Title
 Movie
Caption
 The reaction between Al and Br2 to form AlBr3 is demonstrated.
Notes
 Formation of Aluminum Bromide. When Al is placed on the surface of Br2 an exothermic reaction occurs. The Al is oxidized to Al3+ by the Br2, which is reduced to Br- ions. The ionic product, AlBr3, can be observed on the watch glass after the reaction.
13.1
Title
 13-1
Caption
 An effect of surface tension illustrated. Despite being denser than water, the needle is supported on the surface of the water. The property of surface tension accounts for this unexpected behavior.
Notes
  
13.2
Title
 13-2
Caption
 Intermolecular forces in a liquid
Notes
  
13.3
Title
 13-3
Caption
 Wetting of a surface. Water spreads into a thin film on a clean glass surface (left). If the glass is coated with oil or grease, the adhesive forces between water and the oil are not strong enough to spread the water. Drops of water stand on the surface (right).
Notes
  
13.4
Title
 13-4
Caption
 Meniscus formation. Water wets glass (left). The meniscus is concave-the bottom of the meniscus is below the level of the water/glass contact line. Mercury does not wet glass. The meniscus is convex-the top of the meniscus is above the mercury/glass contact line
Notes
  
13.5
Title
 13-5
Caption
  
Notes
 Capillary action
13.6
Title
 13-6
Caption
  
Notes
 Measuring viscosity
13.7
Title
 13-7
Caption
 Establishing liquid-vapor equilibrium. (a) A liquid is allowed to evaporate into a closed container. Initially only vaporization occurs. (b) Condensation begins. The rate at which molecules evaporate is greater than the rate at which they condense, and the number of molecules in the vapor state continues to increase. (c) The rate of condensation is equal to the rate of vaporization. The number of vapor molecules remains constant over time, as does the pressure exerted by this vapor
Notes
  
13.8
Title
 13-8
Caption
  
Notes
 Vapor pressure illustrated
13.9
Title
 13-9
Caption
  
Notes
 Vapor pressure curves of several liquids
13.10
Title
 13-10
Caption
 Boiling water in a paper cup
Notes
  
13.11
Title
 13-11
Caption
  
Notes
 Attainment of the critical point
13.12
Title
 13-12
Caption
 Predicting states of matter-Example 13-2 illustrated. For the conditions given on the left, which of the final conditions pictured on the right will result? The possibility that the sample might exist as liquid only can be ruled out because 0.132 g H2O(l) is not nearly enough to fill a 525-mL flask.
Notes
  
13.13
Title
 13-13
Caption
 Vapor pressure data plotted as ln P vs. 1/T. Pressures are in millimeters of mercury and temperatures are in kelvins. Data from Figure 13-8 have been recalculated and replotted as in the following example: For benzene at 60 °C, the vapor pressure is 400 mmHg; ln P 5 ln 400 5 5.99. T 5 60 1 273 5 333 K; 1/T 5 1/333 5 0.00300 5 3.00 3 1023; 1/T 3 103 5 3.00 3 1023 3 103 5 3.00. The point corresponding to (3.00, 5.99) is marked by the arrow (n).
Notes
  
13.14
Title
 13-14
Caption
 Cooling curve for water. The broken-line portion represents the condition of supercooling that occasionally occurs. (l) 5 liquid; (s) 5 solid.
Notes
  
13.15
Title
 13-15
Caption
  
Notes
 Heating cureve for water
13.16
Title
 13-16
Caption
 Sublimation of iodine. Even at temperatures well below its melting point of 114 °C, solid iodine exhibits an appreciable sublimation pressure. Here, purple iodine vapor is produced at about 70 °C. Deposition of the vapor to solid iodine occurs on the colder walls of the flask.
Notes
  
13.17
Title
 13-17
Caption
 Temperatures, pressures, and states of matter. The outline of a phase diagram is suggested by the distribution of dots. (See also Figures 13-17 and 13-18.)
Notes
  
13.18
Title
 13-18
Caption
 Phase diagram for iodine. Note that the melting-point and triple-point temperatures for iodine are essentially the same. Generally, large pressure increases are required to produce even small changes in solid-liquid equilibrium temperatures. The pressure and temperature axes on a phase diagram are generally not drawn to scale so that the significant features of the diagram can be more readily emphasized.
Notes
  
13.19
Title
 13-19
Caption
 Phase diagram for carbon dioxide
Notes
  
13.20
Title
 13-20
Caption
  
Notes
 Critical point and critical isotherm
13.21
Title
 13-21
Caption
 Phase diagram for water. Point O, the triple point, is at 10.0098 ¼C and 4.58 mmHg. The critical point, C, is at 374.1 ¼C and 218.2 atm. The negative slope of the fusion curve OD is exaggerated in this diagram. The significance of the broken straight lines is described in Example 13-4.
Notes
  
13.22
Title
 13-22
Caption
  
Notes
 Example 13-4 illustrated
13.23
Title
 13-23
Caption
 The phenomenon of induction
Notes
  
13.24
Title
 13-24
Caption
 Instantaneous and induced dipoles. (a) Normal condition. A nonpolar molecule has a symmetrical charge distribution. (b) Instantaneous condition. A displacement of the electronic charge produces an instantaneous dipole with a charge separation represented as d1 and d2. (c) Induced dipole. The instantaneous dipole on the left induces a charge separation in the molecule on the right. The result is a dipole-dipole attraction.
Notes
  
13.25
Title
 13-25
Caption
 Molecular shapes and polarizability. The elongated pentane molecule is more easily polarized than the compact neopentane molecule. Intermolecular forces are stronger in pentane than in neopentane. Pentane boils at a higher temperature than neopentane.
Notes
  
13.26
Title
 13-26
Caption
 Dipole-dipole interactions. Dipoles tend to arrange themselves with the positive end of one dipole pointed toward the negative end of a neighboring dipole. Ordinarily, thermal motion upsets this orderly array. Nevertheless, this tendency for dipoles to align themselves can affect physical properties, such as the melting points of solids and the boiling points of liquids.
Notes
  
13.26.1UN-1
Title
 AABYHSC0
Caption
 Ball and stick model of butane
Notes
  
13.27
Title
 13-27
Caption
 Comparison of boiling points of some hydrides of the elements of Groups 4A, 5A, 6A, and 7A. The values for NH3, H2O, and HF are unusually high compared with those of other members of their groups.
Notes
  
13.28
Title
 13-28
Caption
 Hydrogen bonding in gaseous hydrogen fluoride. In gaseous hydrogen fluoride many of the HF molecules are associated into cyclic (HF)6 structures of the type pictured here. Each H atom is bonded to one F atom by a single covalent bond (O) and to another F atom through a hydrogen bond (****).
Notes
  
13.29
Title
 13-29
Caption
 Hydrogen bonding in water. (a) Each water molecule is linked to four others through hydrogen bonds. The arrangement is tetrahedral. Each H atom is situated along a line joining two O atoms, but closer to one O atom (100 pm) than to the other (180 pm). (b) The crystal structure of ice. H atoms lie between pairs of O atoms, again closer to one O atom than to the other. Molecules behind the plane of the page are shaded light blue. O atoms are arranged in bent hexagonal rings arranged in layers. This characteristic pattern is revealed in the hexagonal shapes of snowflakes. (c) In the liquid, water molecules have hydrogen bonds to only some of their neighbors. This allows the water molecules to pack more densely in the liquid than in the solid.
Notes
  
13.30
Title
 13-30
Caption
 Solid and liquid densities compared. The sight of ice cubes floating on liquid water (left) is a familiar one. Ice is less dense than liquid water. The more common situation, however, is that of paraffin wax (right). Solid paraffin is denser than the liquid and sinks to the bottom of the beaker.
Notes
  
13.31
Title
 13-31
Caption
 EPM slice for acetic acid dimer
Notes
 an acetic acid dimer
13.31.2UN
Title
 P 503
Caption
 EPM slice of salicylic acid
Notes
 Intramolecular hydrogen bonding in salicylic acid
13.32a-b
Title
 13-32
Caption
 The diamond structure. (a) A portion of the Lewis structure. (b) Crystal structure. Each carbon atom is bonded to four others in a tetrahedral fashion. The segment of the entire crystal shown here is called a unit cell.
Notes
  
13.33
Title
 13-33
Caption
 The graphite structure.
Notes
  
13.33.1UN
Title
 P 506
Caption
 Graphite conducts electricity
Notes
 Graphite conducts electricity
13.34d
Title
 13-34
Caption
 Computer-generated molecular model of fullerene, C60.
Notes
  
13-35
Title
 13-35
Caption
  
Notes
 nanotubes
13.36
Title
 13-36
Caption
 Interionic forces of attraction. Because of the higher charges on the ions and the closer proximity of their centers, the interionic attractive force between Mg21 and O22 is about seven times as great as between Na1 and Cl2.
Notes
  
13.37
Title
 13-37
Caption
 The cubic space lattice. A typical parallelepiped formed by the intersection of mutually perpendicular planes is shaded in green. It is a cube. An endless lattice can be generated by simple displacements of the green cube in the three perpendicular directions (that is, left and right, up and down, and forward and backward).
Notes
  
13.38T
Title
 13-38
Caption
 Unit cells in the cubic crystal system. In the line-and-ball drawings in the top row only the centers of spheres (atoms) are shown at their respective positions in the unit cells. The space-filling models in the bottom row show contacts between spheres (atoms). In the simple cubic cell, spheres come into contact along each edge. In the body-centered cubic (bcc) cell, contact of the spheres is along the cube diagonal. In the face-centered cubic (fcc) cell, contact is along the diagonal of each face.
Notes
  
13.39a-L
Title
 13-39
Caption
 Closest packed structures
Notes
  
13.41.1UN
Title
 P 512
Caption
 cannon balls
Notes
  
13.40
Title
 13-40
Caption
 A face-centered cubic unit cell for the cubic closest packing of spheres
Notes
  
13.41a
Title
 13-41
Caption
 The hexagonal closest packed (hcp) crystal structure
Notes
  
13.42
Title
 13-42
Caption
  
Notes
 Apportioning atoms among unit cells
13.43
Title
 13-43
Caption
 Diffraction of X-rays by a crystal.
Notes
  
13.44
Title
 13-44
Caption
 Determination of crystal structure by X-ray diffraction. The two triangles outlined by dotted lines are identical. The hypotenuse of each triangle is equal to the interatomic distance, d. The side opposite the angle u thus has a length of d sin u. Wave b travels farther than wave a by the distance 2d sin u.
Notes
  
13.45
Title
 13-45
Caption
 Determination of the atomic radius of iron-Example 13-8 illustrated. The right triangle must conform to the Pythagorean formula a2 1 b2 5 c2. That is, with l an edge of the cube, (l)2 1 (lÏ2w)2 5 (l Ï3w)2, or l2 1 2(l2) 5 3(l2).
Notes
  
13.46
Title
 13-46
Caption
  
Notes
 holes in a face-centered cubic unit cell
13.47
Title
 13-47
Caption
  
Notes
 Cross section of an octahedral hole
13.48
Title
 13-48
Caption
 The sodium chloride unit cell
Notes
  
13.49
Title
 13-49
Caption
 The cesium chloride unit cell
Notes
  
13.50 1
Title
 13-50
Caption
 Some unit cells of greater complexity.
Notes
  
13.50.1UN
Title
 P 520
Caption
 A face-centered array of methane spheres
Notes
  
13.51
Title
 13-51
Caption
 Enthalpy diagram for the formation of an ionic crystal. Shown here is a five-step sequence for the formation of one mole of NaCl(s) from its elements in their standard states. The sum of the five enthalpy changes gives DH¼f[NaCl(s)]. The equivalent one-step reaction for the formation of NaCl(s) directly from Na(s) and Cl2(g) is shown in color. (DH values are not to scale.)
Notes
  
13.52L
Title
 13-52
Caption
 The liquid crystalline state.
Notes
  
P 485
Title
 P 485
Caption
  
Notes
 A liquid boils at low pressure
P 499
Title
 P 499
Caption
  
Notes
 Butane and acetone
P 502
Title
 P 502
Caption
  
Notes
  
P 512
Title
 P 512
Caption
  
Notes
 Illustrating the coordination number for the hcp and ccp structures
P 512
Title
 P 512
Caption
  
Notes
 Illustrating the coordination number for the hcp andccp structures
P 513
Title
 P513
Caption
  
Notes
 How spheres are shared between or among unit cells
Table 13.1
Title
 Table 13.1
Caption
  
Notes
 Some Enthalpies of vaporization at 298 K
Table 13.2
Title
 Table 13.2
Caption
  
Notes
 vapor pressure of water at various temperatures
Table 13.3
Title
 Table 13.3
Caption
  
Notes
 Some critical temperatures, Tc and Critical pressures, Pc.
Table 13.5
Title
 Table 13.5
Caption
  
Notes
 Intermolecular Forces and Properties of Selected Substances
Table 13-6
Title
 Table 13-6
Caption
  
Notes
 Some features of close-packed structures in metals.
Table 13.7
Title
 Table 13.7
Caption
  
Notes
 Characteristics of crystalline solids