Effects Of Intermolecular Forces 358 Test Bank Docx Ch8 - Chemistry Canada 4e | Complete Test Bank by John A. Olmsted. DOCX document preview.
CHAPTER 8
EFFECTS OF INTERMOLECULAR FORCES
CHAPTER STUDY OBJECTIVES
1. Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
KEY CONCEPTS: Attractive intermolecular forces are responsible for the condensation of gases and the freezing of liquids.
2. Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
SKILLS TO MASTER: Recognizing the dominant intermolecular force between two species; predicting trends in boiling points based on molecular structures
KEY CONCEPTS: All intermolecular forces are electrostatic and under most conditions are attractive. Intermolecular forces exist among all ions, dipoles, and uncharged non-polar species.
A dipole can be induced into a non-polar species by an ion or by a polar species. Hydrogen bonds exist among species having a polar bond between H and O, N, or F.
3. Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
KEY CONCEPTS: Substances with higher intermolecular forces have higher surface tensions, higher viscosities, and lower vapour pressures.
4. Explain the properties of solids in terms of the dominant intermolecular forces present.
SKILLS TO MASTER: Recognizing the dominant forces present in solids and their magnitudes
KEY CONCEPTS: Forces in solids may include dispersion, dipolar, H-bonding, metallic, covalent, and ionic.
5. Understand amorphous and crystalline solids at the molecular level.
SKILLS TO MASTER: Calculating the mass of a single unit cell; calculating the density of a crystalline solid from unit cell data; calculating the radius of an atom from unit cell data and the density of the solid
KEY CONCEPTS: Solid materials may be crystalline or amorphous. The unit cell is the building block of crystalline solids. One way to discuss ionic structures is to identify a crystal lattice for one set of ions and then describe how the other ions pack within the lattice of the first set. Crystalline defects can profoundly alter the properties of a solid.
6. Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
SKILLS TO MASTER: Calculate the total heat absorbed or evolved during a phase change; state which phases are present at any point on a pressure–temperature phase diagram; predict what happens step by step to a substance as it is heated isobarically or pressurized isothermally; construct a pressure–temperature phase diagram from physical data
KEY CONCEPTS: A phase diagram shows which phases are the most stable at any conditions of temperature and pressure. Two phases are in equilibrium on a line on a phase diagram, and three phases coexist at the triple point.
Multiple Choice QUESTIONS
1. Which of the following experience the strongest intermolecular forces?
a) F2
b) I2
c) Br2
d) Cl2
Difficulty: Easy
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
2. Which of the following is a liquid under normal atmospheric conditions of temperature and pressure?
a) F2
b) I2
c) Br2
d) Cl2
Difficulty: Easy
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
3. Which of the following experience the strongest covalent bond?
a) F2
b) I2
c) Br2
d) Cl2
Difficulty: Hard
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
Feedback: Student must distinguish between bonds and intermolecular forces. Strong covalent bonding results from good orbital overlap, typical of elements at the top of the periodic table. Note also that bond energy of F2 is lower than one would predict from trends due to small size and significant electron/electron repulsion.
Use the following equation for questions 4–5.
4. The relative size of the Van der Waals constant, α, correlates well with boiling point; that is, the larger α is, the higher the boiling point. The reason for this correlation is
a) the α constant is a measure of molecular size.
b) the boiling point is directly proportional to α.
c) the α constant varies with temperature.
d) the α constant is a measure of intermolecular force strength.
e) the α constant varies with vapour pressure.
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
Feedback: Intermolecular forces in gases are only very briefly touched on in Chapter 8.
5. The value “nb” that is used in the Van der Waals equation accounts for what INCORRECT assumption?
a) that gaseous collisions are not completely elastic
b) that gas molecules do take up space
c) that gas molecules interact with each other
d) that gas molecules do not travel in straight lines
e) that the velocity of gas molecules changes with temperature
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
Feedback: Intermolecular forces in gases are only very briefly touched on in Chapter 8.
6. Where would you expect Ne to appear in the following sequence of boiling points?
He < H2 < N2 < F2 < Ar < O2
a) lower than He
b) between He and H2
c) between H2 and N2
d) between F2 and Ar
e) between Ar and O2
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
7. Which of the following is the expected order of boiling points for H2, He, F2 and Ne?
a) H2 < He < F2 < Ne
b) H2 < F2 < Ne < He
c) Ne < H2 < He < F2
d) He < H2 < F2 < Ne
e) He < H2 < Ne < F2
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
8. Which is the most realistic picture for a container of Ar(l)?
a) 
b) 
c) 
d) 
e) 
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
9. Consider the following three molecules:
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The dominant intermolecular force acting in each is, respectively,
a) dipole–dipole; dipole–dipole; hydrogen bonding.
b) hydrogen bonding; dispersion forces; dipole–dipole.
c) hydrogen bonding; ion-ion; dipole–dipole.
d) hydrogen bonding; dipole–dipole; dispersion forces.
e) dipole–dipole; dipole–dipole; dipole–dipole.
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
10. Which is the expected order of increasing boiling point for the following molecules?
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1) | 2) | 3) |
a) 1, 2, 3
b) 1, 3, 2
c) 3, 2, 1
d) 2, 1, 3
e) 2, 3, 1
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
11. Acetone CH3COCH3 boils at a significantly higher temperature than 2-methylpropane isobutene
a) because dipole–dipole forces are always greater than dispersion forces.
b) because the molecular mass of acetone is slightly less than that of 2-methylpropane.
c) because the density of acetone is greater than that of 2-methylpropane.
d) because the attractive dispersion forces in 2-methylpropane are weaker than those in acetone.
e) because the attractive dispersion forces in 2-methylpropane are weaker than the dipole forces in acetone.
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
Feedback: a) important that student realizes that dipole–dipole forces are not always greater than dispersion forces; b) while molar mass sometimes reflects boiling points, it is the forces acting between molecules which are most significant; c) density is a reflection of the forces and not a cause; d) distinguish between forces acting in acetone and those in 2-methylpropane; e) correct answer
12. The boiling point of HCl (188 K) is lower than that for HI (238 K) because
a) HI is more polar therefore the intermolecular dipole–dipole forces are stronger in HI.
b) HCl is more polar therefore the intermolecular dipole–dipole forces are stronger in HI.
c) the molecular mass of HI is greater than that of HCl.
d) HI is more polarizable, dispersion forces compensate for the lower dipole forces in HI.
e) HI is capable of hydrogen bonding, HCl is not.
Difficulty: Hard
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
Feedback: a) student should recognize that, firstly, HCl is the more polar molecule and, secondly, dipole forces are not always the most significant; b) dipole forces are not always the most significant; c) while boiling points often follow similar trend to molar mass, molar mass is not the cause; d) correct answer; e) neither compound hydrogen bonds
13. In which of the following pure substances will hydrogen bonding be an important intermolecular force? 1) dichloromethane, CH2Cl2, 2) CH3CH2OH, 3) methylamine, (CH3NH2), 4) trimethylamine, N(CH3)3
a) 2 and 3
b) all
c) none
d) 3 and 4
d) 1 and 2
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
14. List the following three compounds in order of increasing boiling point:
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1) | 2) | 3) |
a) 1, 2, 3
b) 3, 2, 1
c) 1, 3, 2
d) 2, 1, 3
e) 2, 3, 1
Difficulty: Easy
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
15. What is the dominant intermolecular force for acetylcetone? 
a) hydrogen bonding
b) dipole interactions
c) dispersion
d) ionic
e) none of these
Difficulty: Easy
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
16. What is the dominant intermolecular force for propionic acid? 
a) hydrogen bonding
b) dipole interactions
c) dispersion
d) ionic
e) none of these
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
17. Arrange the following molecules in order of increasing viscosity:
1) CH4, 2) CH3CH2C(H)=CH2, 3) CH3CH2C(CH3)3, 4) CH3CH2CH2CH2CH2CH3
a) 4 < 3 < 2 < 1
b) 2 < 1 < 4 < 3
c) 1 < 2 < 4 < 3
d) 1 < 4 < 3 < 2
e) 3 < 1 < 2 < 4
Difficulty: Medium
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
18. Which of the following will have the lowest viscosity?
a) nonane
b) octane
c) pentane
d) heptane
e) hexane
Difficulty: Easy
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
19. Arrange the following in order of increasing vapour pressure at room temperature.
1) CH3OCH3, 2) CH3CH2OCH2CH3, 3) CH3C(O)CH3, 4) CH3CH2OH
a) 2 < 3 < 1 < 4
b) 1 < 4 < 3 < 2
c) 4 < 3 < 2 < 1
d) 3 < 4 < 1 < 2
e) 4 < 1 < 2 < 3
Difficulty: Medium
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
20. Arrange the following in order of increasing vapour pressure at room temperature:
1) H2O, 2) Hg, 3) Br2, 4) CH3CH2OH
a) 2 < 3 < 1 < 4
b) 1 < 4 < 3 < 2
c) 4 < 3 < 2 < 1
d) 4< 3< 1 < 2
e) 2 < 1 < 4 < 3
Difficulty: Medium
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
Feedback: Must recognize forces acting are hydrogen bonding, metallic bonding, strong dispersion forces, and hydrogen bonding.
21. Arrange the following in order of decreasing surface tension at room temperature:
1) H2O, 2) Hg, 3) benzene, 4) n-hexane
a) 2 < 3 < 1 < 4
b) 1 < 4 < 3 < 2
c) 2 < 1 < 3 < 4
d) 4< 3< 1 < 2
e) 2 < 1 < 4 < 3
Difficulty: Medium
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
Feedback: Must recognize forces acting are hydrogen bonding, metallic bonding, dispersion forces, and dispersion forces and that dispersion forces will be stronger in benzene than in n-hexane.
22. For the following substances determine which of the selections is arranged in order of increasing expected melting point:
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1 | 2 | 3 | 4 |
a) 1 < 3 < 2 < 4
b) 1 < 4 < 3 < 2
c) 2 < 3 < 4 < 1
d) 3 < 4 < 2 < 1
e) 3 < 2 < 4 < 1
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
23. For the following substances, choose the answer which best describes what type of solid will form, respectively, upon solidification:
Al2O3 | HCl | CaO | Sn |
a) ionic, network, ionic, metallic
b) ionic, molecular, molecular, metallic
c) network, molecular, ionic, network
d) network, molecular, ionic, metallic
e) network, ionic, ionic, metallic
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
24. For the following substances, choose the answer which best describes what type of solid will form respectively, upon solidification:
SiO2 | W | P2O5 | SrCl2 |
a) ionic, metallic, ionic, network
b) ionic, molecular, molecular, metallic
c) network, metallic, molecular, ionic
d) molecular, metallic, ionic, molecular
e) ionic, metallic, molecular, ionic
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
25. For the following substances, choose the answer which best describes what type of solid will form respectively, upon solidification:
P4 | CrO3 | P2O5 | NaCl |
a) molecular, ionic, molecular, ionic
b) metallic, molecular, molecular, ionic
c) network, metallic, molecular, ionic
d) molecular, network, ionic, ionic
e) molecular, ionic, network, ionic
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
26. Your solid is non-conductive and melts at relatively low temperature. Based on this information, one can conclude that bonding in the solid is most likely
a) metallic.
b) covalent.
c) molecular covalent.
d) ionic.
e) polar covalent.
Difficulty: Easy
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
Feedback: Low temperature melting is an indication that IMF are acting between discrete molecules.
27. You have a non-conductive solid. On melting at 30oC, it forms a conductive liquid. It is soluble in water, and when dissolved, the aqueous solution is conductive. Based on this information one can conclude that bonding in the solid is most likely
a) metallic.
b) covalent.
c) molecular covalent.
d) ionic.
e) polar covalent.
Difficulty: Hard
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
Feedback: A room temperature ionic liquid is described. a) solid is nonconductive, therefore it cannot be metallic; b) liquid form is conductive – therefore it is not covalent; c) low temperature melting, therefore not molecular covalent; d) correct response; e) liquid form is conductive – therefore it is not covalent
28. You have a solid that it characterized by high melting and boiling points, is NOT conductive, and does NOT dissolve in water. Bonding is most likely
a) metallic.
b) covalent.
c) molecular covalent.
d) ionic.
e) polar covalent.
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
Feedback: Recognition that forces acting between molecules determines observable physical properties.
29. Metals are ductile (can be drawn into wires) and malleable (forced into thin sheets by hammering) because
a) bonding is omnidirectional.
b) bonding is by directed covalent bonds.
c) they are good electrical conductors.
d) they have partially filled bonding bands.
e) they have a range of melting points.
Difficulty: Easy
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
30. In the simple cubic crystal structure at right, the unit cell is outlined in heavy lines which intersect to form the corners at the center of the spheres. If the corners of the unit cells are at the center of the spheres, how many atoms are in one unit cell?
a) 1
b) 2
c) 3
d) 4
e) 6
Difficulty: Easy
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
31. The face-centered cubic unit cell to the right has been shaded to add clarity; the balls in the corners are black: those in the faces are gray. If the corners of the unit cells are at the center of the corner spheres, how many atoms are in one unit cell?
a) 1
b) 2
c) 3
d) 4
e) 6
Difficulty: Medium
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
32. Ruby is a crystalline compound that contains aluminum, oxygen and chromium. The structure of ruby is best described as having
a) amorphous structure.
b) interstitial defects.
c) substitutional defects.
d) a and c
e) a and b
Difficulty: Easy
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
33. Which type of solid is the most densely packed?
a) simple cubic
b) face-centered cubic
c) body-centered cubic
d) amorphous solid
e) density is the same for all
Difficulty: Easy
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
34. Below is the structure for zinc sulphide. If the zinc atoms (zinc) are contained within the unit cell and the sulphur atoms (clear) form a face-centered cubic structure, how many sulphur atoms must be contained within the unit cell to balance the charge?
a) 1
b) 2
c) 3
d) 4
e) 5
Difficulty: Medium
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
35. Polonium metal crystallizes in a simple cubic structure. If the atomic radius of polonium is 160 pm, what is the volume of a unit cell?
a) 3.28x10-23 cm3
b) 4.10 x 10-29 m3
c) 4.10 x106 pm3
d) 3.28 x 10-6 m3
e) 3.28 x 10-23 m3
Difficulty: Hard
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
36. Na+ has an ionic radius of 116 pm and Cl- an ionic radius of 167 pm. Estimate the volume of a NaCl unit cell.
a) 1.81 x 10-4 m3
b) 2.27 x 10-29 m3
c) 1.81x10‑28 m3
d) 3.73 x10-29 m3
e) 2.27 x 107 pm3
Difficulty: Hard
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
37. Use the phase diagram of oxygen to determine the phases oxygen passes through starting at 0.001 atm and 100oK, cooling and increasing the pressure steadily to 25 K at 1 atm.
a) gas, liquid
b) liquid, solid
c) gas, liquid, solid
d) liquid, solid, gas
e) gas, solid
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
38. What feature makes the phase diagram of water unusual?
a) The boiling point is high.
b) The positive slope of the liquid-gas equilibrium line.
c) The positive slope of the solid-liquid equilibrium line.
d) The negative slope of the liquid-gas equilibrium line.
e) The negative slope of the solid-liquid equilibrium line.
Difficulty: Easy
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
ESSAY QUESTIONS
39. The order of increasing melting point for several simple molecular compounds is: H2, F2, O2, N2, Ar, while for these same compounds boiling point increases as H2, N2, F2, Ar, O2. Explain why the trends for boiling point and melting point are different.
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
40. A sample of 1.5 moles of CO2 (a = 3.59 atm•L2/mol2; b = 0.0427 L/mol) is contained in a cylinder of 100 mL volume at a temperature of 350oK. What is the percent deviation from ideal behaviour?
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
Feedback: Intermolecular forces in gases are only very briefly touched on in Chapter 8.
41. A tank of nitrogen in a lab contains about 125 moles of N2 (a = 1.39 atm•L2/mol2; b = 0.0391 L/mol) in a volume of 20 L. Calculate the percent deviation from ideal behaviour at 298oK.
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
Feedback: Intermolecular forces in gases are only very briefly touched on in Chapter 8.
42. Some believe that differences between boiling points are truer indicators of relative intermolecular forces than melting points. Why?
Difficulty: Medium
Learning Objective: Understand the effects of intermolecular forces on condensation, vapourization, and melting and boiling points.
Section Reference: 8.1 Effects of Intermolecular Forces
43. Draw molecular pictures that illustrate and explain the different polarizabilities of CH2Cl2 and CHCl3.
Difficulty: Medium
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
44. Of the following pairs, select the pair that undergoes hydrogen bonding and draw a molecular picture of the hydrogen bond interaction.
- NaCl and acetone, (CH3)2CO
- CH3OCH3 and CF3Cl
- NH3 and CCl4
- NF3 and CF4
- CH3NH2 and CH3OCH3
Difficulty: Hard
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
45. Draw how water can hydrogen bond with itself.
Difficulty: Easy
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
46. For the three molecules whose structures and boiling points are shown below, explain the trend in boiling points in terms of the strength and types of intermolecular forces acting between the molecules in the pure liquids.
structure formula, name normal boiling point |
C2H6O, methyl ether –24.8°C |
C3H8, propane –42.1°C |
C2H6S, methylsulfide 38°C |
compound | propane | methyl ether | methyl sulphide |
intermolecular forces present | dispersion forces no polar bonds; therefore no dipolar forces | dispersion forces, also the molecule has a permanent dipole moment; therefore dipolar forces are present | dispersion forces, also the molecule has a permanent dipole moment; therefore dipolar forces are present |
Difficulty: Hard
Learning Objective: Predict the relative magnitudes of intermolecular forces and their effects on physical properties of substances.
Section Reference: 8.2 Types of Intermolecular Forces
47. Which of the following molecules will have the greatest surface tension and why?
1) methanol, CH3OH
2) gasoline, ~C8H18
3) diethyl ether, CH3CH2OCH2CH3.
Difficulty: Easy
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
48. Describe how trees are able to transport water from their roots to the leaves on their branches high in the air.
Difficulty: Easy
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
49. The leaves of the lotus plant are extremely hydrophobic. That is, water does not stick to the leaves. In 2004, scientists were able to replicate this phenomenon on a film. Sketch what you think the meniscus of water would look like in a tube made of this material? What would the meniscus look like for oil?
Difficulty: Hard
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
50. Explain why water “beads” up on waxed surfaces, but oil spreads out on the same surface?
Difficulty: Easy
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
51. Which will have the highest vapour pressure at standard condition and explain why.
1. 1-hexanol, C6H13OH
2. benzene, C6H6
3. hexane, C6H14
Difficulty: Medium
Learning Objective: Explain trends in surface tension, capillary action, viscosity, and vapour pressure in terms of intermolecular forces.
Section Reference: 8.3 Liquids
52. What are the differences in interparticle forces for network and metallic solids?
Difficulty: Medium
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
53. List at least two different physical properties between network and molecular solids.
Difficulty: Easy
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
54. What are the differences in interparticle forces for metallic and ionic?
Difficulty: Easy
Learning Objective: Explain the properties of solids in terms of the dominant intermolecular forces present.
Section Reference: 8.4 Forces in Solids
55. The figure shows the unit cell of a compound containing A (open spheres) and X (shaded spheres). What is the empirical formula of this compound if the shaded spheres form a face-centered cubic arrangement and the open spheres are contained within the unit cell?
Difficulty: Medium
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
56. What is the main difference between an amorphous solid and a crystalline solid?
Difficulty: Easy
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
57. Cesium chloride forms a body-centered cubic solid. One of the elements is in the middle; the other is on each corner of the cube. Which element is in each location and why?
Difficulty: Easy
Learning Objective: Understand amorphous and crystalline solids at the molecular level.
Section Reference: 8.5 Order in Solids
58. Oxygen is an important component of the atmosphere. Draw the phase diagram for O2 given the normal melting point (–218°C), the normal boiling point (–183°C) and the triple point (–219°C and 1.10 mm Hg.
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
59. Use the phase diagram of oxygen to estimate the temperature at which liquid oxygen will boil under 0.5 atm external pressure and compare that to the normal boiling point.
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
60. Sketch a phase diagram for hydrazine locating all points given: normal melting point (1.4˚C), normal boiling point (113.5˚C), critical point (380˚C, 145 atm), triple point (2.0˚C, 3.4 mm Hg)
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
61. Sketch the phase diagram for benzene identifying the solid, liquid, and gas phases given the following: normal boiling point (80.1˚C), triple point (5.5˚C, 35.8 mm Hg), critical point (288.5˚C and 47.7 atm)
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
62. Define supercritical fluid and how to make such a fluid.
Difficulty: Easy
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
63. To melt or vapourize a substance, a certain amount of energy needs to be supplied. These are referred to as the heat of fusion and heat of vapourization. Which is typically a lot larger and why?
Difficulty: Medium
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
64. How much energy is required when 23 grams of ethanol at 30˚C are vapourized from a “flaming” desert? ΔH˚vap = 39.3 kJ/mol, Tvap = 351 K, ΔH˚fus = 7.61 kJ/mol, Tfus = 156 K, Cethanol = 112 J/mol˚C
Difficulty: Hard
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
65. How much energy is required when 23 grams of ice at –4˚C are melted in a 240 ml glass of pop? ΔH˚vap = 40.7 kJ/mol, ΔH˚fus = 6.0 kJ/mol, Cice = 37.8 J/mol˚C, Cwater = 75.3 J/mol˚C
Difficulty: Hard
Learning Objective: Explain enthalpies of phase changes in terms of intermolecular forces and interpret a pressure–temperature phase diagram of a pure substance.
Section Reference: 8.6 Phase Changes
Feedback: Includes energy to warm ice to 0oC and energy to melt ice; ΔH˚vap and Cwater as well as volume of pop are all distractors.
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