Practice Test Ch 10 Liquids and Solids

Chemistry Ch 10: IMFs, Liquids, and Solids PRACTICE TEST Surface tension in a liquid is due to the fact that a) surface molecules are pulled toward the interior only b) liquids tend toward lowest energy c) PE is increased for molecules at the surface d) interior molecules are attracted in all directions e) all of the above In which one of the following will dipole-dipole attractions play the most significant role as the intermolecular attraction? a) HCl b) NaCl c) Kr d) NH3 e) H2 With which type of substances do London dispersion forces play the most significant role? a) polar molecules b) metals c) ionic compounds d) non-polar molecules e) network compounds The heat of vaporization of H2S, at its boiling point (-61°C), is 18.8 kJ/mol. What mass of H2S can be vaporized (at its boiling point) with 100 kJ of energy? a) 100 x 61 / 18.8 b) 34.1 x 18.8 / 100 c) 61 x 18.8 x 100 x 34.1 d) 100 x 34.1 / 18.8 e) 18.8 kg Which one of the following substances exhibits the strongest intermolecular forces of attraction? a) CH4 b) C2H6 c) C3H8 d) CH3OH e) CCl4 For which substance would you predict the highest heat of vaporization? a) F2 b) H2O c) HF d) NaCl e) Br2 Which of the following will change the equilibrium vapor pressure of a liquid? I. Heat up or cool down the liquid II. Increase the Volume of the container III. Change the pressure above the liquid a) I only b) I and II only c) I and III only d) II and III only e) I, II, and III Which of the following statements describes a substance above its critical point? a) the substance and liquid phase become indistinguishable b) the substance experiences no intermolecular interactions c) there is a distinct phase boundary between the liquid and vapor d) all of the above At what temperature will the liquid (whose vapor pressure is shown below) boil if the air pressure is reduced to 380 mmHg = 0.5 atm? a) 30°C b) 50°C c) 70°C d) 100°C e) the liquid will not boil at this pressure Which one of the following is linked with the correct intermolecular force of attraction? a) NH3 - London dispersion forces b) AlCl3 - hydrogen bonding c) H2 - hydrogen bonding d) C2H4 - London dispersion forces e) HCl - dipole-dipole 11. The vapor pressure graph of an unknown liquid is shown below. Which of the following statements about this liquid is/are true? I. This liquid has weaker IMFs than water. YES   II. The liquid's normal boiling point is around 75°C. YES III. The liquid boils at room temperature when the pressure is dropped to about 0.25 atm. YES a) II and III only b) II only c) I and III d) I only e) I, II, and III 12. How much energy does it require to melt 25.0 g of benzene, C6H6? The heat of fusion of benzene is 2.37 kJ/mol. (molar mass = 78.0 g/mol) 25.0 g x (1 mol / 78.0 g) x (2.37 kJ / 1 mol) = 0.759 kJ 13. What type of solid(s) can contain covalent bonds? * a) metallic * b) ionic * c) molecular * d) network * e) all but "b" 14. Which type of solid generally has the highest melting point? * a) metallic * b) ionic * c) molecular * d) network * e) hydrogen 15. Which substance below exhibits the weakest IMFs? * a) IF3 * b) SO2 * c) CO2 * d) SiO2 * e) PH3 16. During the condensing of a liquid, the kinetic energy and the potential energy * a) stays the same, increases * b) increases, decreases * c) increases, increases * d) decreases, stays the same * e) stays the same, decreases   17. The phase diagram of a substance is given below. What occurs when the substance is heated from 100°C to 120°C at 3 atm pressure? a) it melts   b) it boils c) it sublimes d) it freezes e) no phase change occurs 18. A typical phase diagram for a substance is given below. At what point on the diagram do solid and liquid exist at equilibrium?   a) A b) B c) C d) D e) E 19. Which one of the following as solids has a crystal structure containing discrete (separate) molecules? * a) potassium metal * b) glass * c) quartz * d) carborundum, SiC * e) hydrogen   20. The heat of sublimation of a compound equals * a) heat of fusion plus heat of vaporization * b) heat of vaporization minus heat of fusion * c) heat of vaporization plus heat of crystallization * d) heat of fusion plus heat of crystallization * e) heat of crystallization plus heat of vaporization