Chemistry Chapter 11 States of Matter Liquids & Solids Part 2

1. The intermolecular forces that are most significant in accounting for the high boiling point of liquid water relative to other substances of similar molecular weight are the: a) ion-ion attractions b) London dispersion forces c) hydrogen bonding forces d) dipole-dipole attractions 2. Which of the following substances will have the highest boiling point? a) methane (MW=16) b) butane (MW=58) c) ethyl alcohol (MW=46) d) methyl alcohol (MW=32) 3. Which of the following substances will have the lowest boiling point? a) neon b) water c) ammonia d) helium 4. Identify the INCORRECT statement below: a) When the vapor pressure of a liquid equals the surrounding pressure, the liquid boils. b) The boiling point is the temperature at which the vapor pressure of the liquid equals the surrounding pressure. c) The normal boiling point is the temperature at which the vapor pressure of the liquid equals 1 atm. d) The vapor pressure of a liquid increases as the temperature of the liquid increases. e) Easily vaporized liquids are called volatile liquids, having low vapor pressures. 5. Calculate the heat required in Joules to convert 18.0 grams of water ice at a temperature of -20° C to liquid water at the normal boiling point of water. Given: -specific heat of ice = 2.09 J/g°C -specific heat of liquid water = 4.184 J/g°C -specific heat of water vapor = 2.03 J/g°C -molar heat of fusion of water = 6.02 kJ/mol -molar heat of vaporization of water = 40.7 kJ/mol a) 757 J b) 13626 J c) 943 J d) 108360 J 6. Based on Coulomb's law of interaction strength between ions, which of the following compounds has the highest melting point? a) CaCl2 b) NaCl c) NaF d) MgO 7. Rank the following liquids in order of increasing boiling points, from lowest to highest: He / NH3 / Ar / N2 a) He < N2 < Ar < NH3 b) He < Ar < N2 < NH3 c) NH3 < Ar < N2 < He d) NH3 < N2 < Ar < He 8. The interaction responsible for the cohesive intermolecular forces of liquid nitrogen is: a) hydrogen bonding b) the London dispersion force c) dipole-dipole interaction d) covalent bonding 9. Identify the INCORRECT statement below: a) The vapor pressure of liquid water at 100°C is 760 Torr (1 atm). b) The normal boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals 1 atm. c) The boiling point of a liquid increases as the surrounding pressure decreases. d) Vapor pressure of a liquid increases as the temperature increases. e) A liquid boils when its vapor pressure equals the surrounding pressure. 10. Calculate the energy in joules required to convert a mole of ice at -10°C to steam at 120°C. Given: ΔHvap of H2O = 40.7 kJ/mol ΔHfus of H2O = 6.02 kJ/mol Cm (ice) = 37.6 J/mol°C Cm (liquid H2O) = 75.3 J/mol°C Cm (steam) = 36.5 J/mol°C a) 8680 J b) 356 J c) 55,356 J d) 196 J 11. The smallest repeat unit of a crystalline solid is called: a) a point group b) a lattice point c) a unit cell d) a crystalline element 12. The type of solid which is characterized as positive ions embedded in a sea of delocalized electrons is called: a) a metallic solid b) a ionic solid c) a molecular solid d) a covalent (network) solid 13. Diamond (pure carbon) would be classified as which type of solid: a) a metallic solid b) a ionic solid c) a molecular solid d) a covalent (network) solid 14. Which of the following intermolecular forces is INCORRECTLY assigned as the principal force in the compound given? a) CCl4, London b) NH3, London c) HF, H-bonding d) CH3OH, H-bonding e) H-Br, dipole 15. According to the following phase diagram for a substance X, which of the following statements is FALSE? a) The normal boiling point of X is 184°C. b) At 25°C, X will boil if the pressure is lowered enough. c) X is liquid at 120°C and 1 atm. d) The melting point of X varies little with pressure. 16. Which of the following is NOT true of covalent (network) solids? a) The units which occupy the lattice points are atoms. b) The inter-unit forces are covalent bonds. c) They typically exhibit low melting points. d) They are usually very hard. e) They are usually poor electrical conductors. 17. Chlorine has a critical temperature of 144°C and a critical pressure of 77 atm. Under which of the following conditions would Cl2 most likely be a liquid? a) 125°C, 70 atm b) 125°C, 30 atm c) 150°C, 70 atm d) 150°C, 30 atm 18. The normal boiling point of ether is 35°C. Comparing ether and water, at the same temperature, which statement below is TRUE? a) The vapor pressure of both liquids are the same. b) The vapor pressure of ether is greater than that of water. c) The vapor pressure of water is greater than that of ether. d) The vapor pressure of both liquids are equal to the temperature. 19. The term used to describe resistance to flow of a liquid is: a) surface tension b) capillary action c) viscosity d) vapor pressure e) vaporization 20. How many atoms are considered to belong to the face-centered cubic unit cell? a) 1 b) 2 c) 4 d) 6 e) 8 21. Which of the following descriptions of solid type is INCORRECT? a) Cu ; metallic b) SiO2(quartz) ; molecular c) CaCl2 ; ionic d) H2O ; molecular e) C(diamond); covalent 22. Which response lists interparticle forces (between molecules of comparable size) in order of increasing strength? a) London < ionic < H-bonds < dipole b) dipole < London < H-bond < ionic c) H-bond < ionic < dipole < London d) ionic < H-bond < London < dipole e) London < dipole < H-bond < ionic 23. The molar heat of fusion for nitrogen is 710 J/mole. How many grams of N2, at its melting point, can be melted by 1080 joules of heat? a) 43 g b) 1.5 g c) 21 g d) .065 g e) 18 g 24. On the following typical phase diagram, which statement is INCORRECT? a) Point A corresponds to sublimation/deposition. b) Point B corresponds to the critical point, where all three phases coexist. c) Point C corresponds to the liquid phase of the substance. d) At a higher temperature and pressure than point D, the substance exists as a supercritical fluid. e) Raising the pressure from point E to point C causes the substance to condense. 25. Arrange these substances in order of INCREASING boiling point: Xe, H2, H2O, LiCl, H2S. a) Xe < H2 < H2O < LiCl < H2S b) Xe < H2 < H2S < H2O < LiCl c) H2 < Xe < H2S < H2O < LiCl d) H2 < Xe < H2O < H2S < LiCl 26. Which of the following is NOT a molecular solid? a) solid CO2 b) solid water c) white phosphorus (solid P4) d) S8 e) diamond 27. Which is the weakest intermolecular force among a group of molecules of comparable molecular weight (molar mass)? a) dipole-dipole b) London c) ionic bonding d) hydrogen bonding 28. Which of the following best describes the properties of a metallic solid? a) soft, very low melting point, poor electrical conductor b) an amorphous solid with no unit cell, conducts electricity, doesn't conduct heat well c) very hard, very high melting point, poor electrical conductor d) variable hardness, variable melting point, excellent thermal conductor 29. Which of the following pure substances exhibits hydrogen bonding? a) NH3 b) H2S c) HCl d) CH4 e) all of these do KEY 1)c 2)c 3)d 4)e 5)b 6)d 7)a 8)b 9)c 10)c 11)c 12)a 13)d 14)b 15)b 16)c 17)a 18)b 19)c 20)c 21)b 22)e 23)a 24)b 25)c 26)e 27)b 28)d 29)a