(HOCH2CH2OH) is less viscous than glycerine
(HOCH2CHOHCH2OH), but more viscous than ethyl alcohol (CH3CH2OH).
20. Consider the following substances: sodium fl uoride
(NaF), chlorine monofl uoride (ClF), hydrogen fl uoride
(HF), and fluorine (F2 ). (a) What type of particles does each substance have? (b) What type of intermolecular attractive forces hold the particles together in each substance? The table below lists the melting point (mp), boiling point (bp), density (D), and solubility in water of each of these substances. mp, °C bp, °C D, g/L Solubility
NaF 993 1700 2558 (s) 4.13 g/100 g
ClF 2156 2100 2.43 (g) violent reaction
HF 284 20 0.922 (g) miscible
F2 2220 2188 1.69 (g) mild reaction
(c) Based on this information, determine the relative strengths of the forces holding the particles together.
(d) List the intermolecular attractive forces in order of increasing strength.
25. Within each group, assign each of the boiling points to the respective substances on the basis of intermolecular forces. (a) N2, HCN, C2H6: 2196°C, 289°C, 26°C;
(b) H2, HCl, Cl2: 235°C, 2259°C, 285°C.
26. ■ What type of intermolecular forces must be overcome in converting each of the following from a liquid to a gas? (a) CO2; (b) NH3; (c) CHCl3; (d) CCl4.
57. Toluene, C6H5CH3, is a liquid used in the manufacture of
TNT. Its normal boiling point is 111.0°C, and its molar heat of vaporization is 35.9 kJ/mol. What would be the vapor pressure (torr) of toluene at 75.00°C?
73. ▲ ■ (a) How many triple points are there for sulfur?
(b) Indicate the approximate pressure and temperature at each triple point. (c) Which phases are in equilibrium at each triple point?
81. ■ Based only on their formulas, classify each of the following in the solid state as a molecular, ionic, covalent
(network), or metallic solid: (a) Au, (b) NO2, (c) CaF2,
(d) SF4, (e) Cdiamond.
93. A certain metal has a specifi c