Chapter 10: Liquids and Solids + Review of Gen Chem I Concepts

Question 1

What is the molar mass of carbon dioxide (CO₂)?
a) 28.01 g/mol
b) 44.01 g/mol
c) 16.00 g/mol
d) 12.01 g/mol

Answer 1

b) 44.01 g/mol

Question 2

How many moles are in 36.04 g of water (H₂O)?
a) 0.5 moles
b) 1 mole
c) 2 moles
d) 18 moles

Answer 2

c) 2 moles

• moles are the mass divided by molar mass, so calculate molar mass of water (18 g / mol)
• mass = 36.04 g
  — so: 36.04 / 18 = 2 moles

Question 3

Which element has the highest electronegativity?
a) Oxygen (O)
b) Fluorine (F)
c) Nitrogen (N)
d) Hydrogen (H)

Answer 3

b) Fluorine (F)

Question 4

Electronegativity decreases as you:
a) Move left to right across a period.
b) Move up a group.
c) Move down a group.
d) Approach the noble gases.

Answer 4

c) Move down a group

Explanation: Electronegativity decreases down a group because atoms get larger, and their outer electrons are farther from the nucleus, reducing the ability to attract shared electrons.

Question 5

Which of the following molecules is nonpolar?
a) H₂O
b) CO₂
c) NH₃
d) HF

Answer 5

b) CO₂

Explanation:

CO₂ is a linear molecule, and the dipoles of the two C=O bonds cancel out due to symmetry, making it nonpolar.
H₂O, NH₃, and HF are all polar due to their asymmetry and/or large differences in electronegativity.

Question 6

Why is water (H₂O) polar?
a) It contains a metal and a nonmetal.
b) The electronegativity difference between hydrogen and oxygen is very small.
c) It has a bent shape, leading to an unequal distribution of charge.
d) It is symmetrical

Answer 6

c) It has a bent shape, leading to an unequal distribution of charge.

Explanation:
The oxygen atom in H₂O is more electronegative than hydrogen, creating partial charges.
The bent geometry of the molecule prevents the dipoles from canceling out, resulting in a polar molecule.

Question 7

What does molar mass represent?
a) The mass of a single molecule of a substance in grams.
b) The mass of one mole of particles in a substance in grams.
c) The total mass of an atom in atomic mass units (amu).
d) The number of atoms in one mole of a substance.

Answer 7

b) The mass of one mole of particles in a substance in grams.

Question 8

How is the molar mass of a compound calculated?

a) By dividing the atomic mass by Avogadro’s number.
b) By adding the atomic masses of all atoms in the compound.
c) By multiplying the number of moles by the atomic mass.
d) By counting the number of atoms in the compound.

Answer 8

b) By adding the atomic masses of all atoms in the compound.

Question 9

What is electronegativity?

a) The ability of an atom to lose electrons.
b) The ability of an atom in a chemical bond to attract shared electrons.
c) The amount of energy required to remove an electron from an atom.
d) The total charge of an atom after forming a bond.

Answer 9

b) The ability of an atom in a chemical bond to attract shared electrons.

Question 10

Which statement about electronegativity is correct?

a) It decreases across a period from left to right.
b) It is the same for all elements in the same group.
c) It determines the polarity of a bond.
d) It increases as the atomic size increases.

Answer 10

c) It determines the polarity of a bond.

Question 11

What does polarity describe in a molecule?

a) The shape of the molecule.
b) The distribution of electrical charge within the molecule.
c) The number of bonds formed by the molecule.
d) The mass of the molecule.

Answer 11

b) The distribution of electrical charge within the molecule.

Question 12

Which of the following determines whether a molecule is polar?

a) The molecule’s molar mass and shape.
b) The number of atoms in the molecule.
c) The difference in electronegativity between atoms and the shape of the molecule.
d) The number of lone pairs on the central atom.

Answer 12

c) The difference in electronegativity between atoms and the shape of the molecule.

Question 13

How do you calculate the mass of a substance in grams?

a) Multiply the number of moles by Avogadro’s number.
b) Divide the number of moles by the molar mass.
c) Multiply the number of moles by the molar mass.
d) Add the atomic masses of all the elements in the compound.

Answer 13

c) Multiply the number of moles by the molar mass.

Question 14

If you have 2 moles of NaCl (molar mass = 58.44 g/mol), what is the mass in grams?

a) 29.22 g
b) 58.44 g
c) 116.88 g
d) 120.00 g

Answer 14

c) 116.88 g

Mass=2moles×58.44g/mol=116.88g

Question 15

How many moles are in 90.12 g of H₂O (molar mass = 18.02 g/mol)?

a) 2 moles
b) 3 moles
c) 4 moles
d) 5 moles

Answer 15

c) 4 moles

90.12 g / 18.02 g = 5 moles

Question 16

What does Avogadro’s number represent?
a) The mass of one mole of a substance.
b) The number of particles in one mole of a substance.
c) The number of molecules in one gram of a substance.
d) The molar mass of an element.

Answer 16

b) The number of particles in one mole of a substance.

Question 17

How many molecules are in 3 moles of CO2

a. 1.80610^23
b. 6.02210^23
c. 1.80610^24
d. 3.00010^23

Answer 17

c. 1.806*10^24

particles = 3 moles * 6.02210^23 = 1.80610^24

Question 18

How many moles are in 1.204*10^24 atoms of O2?

a) 1 mole
b) 2 moles
c) 3 moles
d) 4 moles

Answer 18

b) 2 moles

1.20410^24/6.02210^23 = 2 moles

Question 19

Which of the following is true about gases?
a) They have a definite shape and volume.
b) They have a definite volume but take the shape of their container.
c) They have no definite shape or volume.
d) They are incompressible.

Answer 19

c) They have no definite shape or volume.

Question 20

What is a characteristic property of liquids?
a) They have a fixed shape and fixed volume.
b) They have no fixed shape but a fixed volume.
c) They expand to fill the entire container.
d) They are highly compressible.

Answer 20

b) They have no fixed shape but a fixed volume.

Question 21

Which of the following is true about solids?
a) They have no fixed shape but a fixed volume.
b) They have a fixed shape and fixed volume.
c) They take the shape of their container.
d) They are highly compressible.

Answer 21

b) They have a fixed shape and fixed volume.

Question 22

Which of the following correctly matches the states of matter to their compressibility?
a) Gases > Liquids > Solids
b) Solids > Liquids > Gases
c) Liquids > Gases > Solids
d) Gases > Solids > Liquids

Answer 22

a) Gases > Liquids > Solids

Question 23

What is the difference between intermolecular and intramolecular forces?

a) Intermolecular forces occur within a molecule, while intramolecular forces occur between molecules.

b) Intramolecular forces occur within a molecule, while intermolecular forces occur between molecules.

c) Intermolecular forces only occur in solids, while intramolecular forces only occur in gases.

d) There is no difference between the two; they are the same.

Answer 23

b) Intramolecular forces occur within a molecule, while intermolecular forces occur between molecules.

Question 24

Which of the following is an example of an intermolecular force?
a) Covalent bond
b) Ionic bond
c) Hydrogen bond
d) Metallic bond

Answer 24

c) Hydrogen bond

Question 25

Which of the following is an example of an intramolecular force? a) Dipole-dipole interactions b) London dispersion forces c) Covalent bond d) Van der Waals forces

Answer 25

c) Covalent bond

Question 26

Why are intermolecular forces generally weaker than intramolecular forces? a) They occur within the molecule, making them stronger. b) They involve the sharing of electrons, which is less stable. c) They are based on weaker attractions, such as dipole interactions or dispersion forces, rather than direct bonding. d) They occur only in certain states of matter, making them less significant.

Answer 26

c) They are based on weaker attractions, such as dipole interactions or dispersion forces, rather than direct bonding.

Question 27

What are dispersion forces? a) Permanent dipole-dipole interactions between polar molecules. b) Weak intermolecular forces caused by temporary dipoles in molecules or atoms. c) Strong intramolecular forces that hold atoms together in a molecule. d) Hydrogen bonding between molecules containing hydrogen and highly electronegative atoms.

Answer 27

b) Weak intermolecular forces caused by temporary dipoles in molecules or atoms.

Question 28

What causes dispersion forces? a) Permanent dipoles in polar molecules. b) Instantaneous dipoles inducing dipoles in nearby atoms or molecules. c) The sharing of electrons between atoms. d) The attraction between ions and polar molecules.

Answer 28

b) Instantaneous dipoles inducing dipoles in nearby atoms or molecules.

Question 29

Which type of molecule or atom will have stronger dispersion forces? a) Smaller molecules with lower molar mass. b) Larger molecules with greater molar mass. c) Nonpolar molecules only. d) Molecules with permanent dipoles.

Answer 29

b) Larger molecules with greater molar mass.

Question 30

Which of the following increases dispersion forces? a) Decreasing the molecular weight of a molecule. b) Decreasing the surface area of a molecule. c) Increasing the molecular weight and surface area of a molecule. d) Having a molecule with hydrogen bonds.

Answer 30

c) Increasing the molecular weight and surface area of a molecule.

Question 31

What is an instantaneous dipole? a) A temporary uneven distribution of electrons in a molecule or atom. b) A permanent dipole that occurs in polar molecules. c) A dipole that results from hydrogen bonding. d) An ionic charge in a molecule.

Answer 31

a) A temporary uneven distribution of electrons in a molecule or atom.

Question 32

What is an induced dipole? a) A permanent dipole in a polar molecule. b) A temporary dipole created when an instantaneous dipole causes electron displacement in a nearby atom or molecule. c) A dipole caused by the sharing of electrons in a covalent bond. d) A type of intramolecular force.

Answer 32

b) A temporary dipole created when an instantaneous dipole causes electron displacement in a nearby atom or molecule.

Question 33

How do instantaneous and induced dipoles contribute to dispersion forces? a) Instantaneous dipoles repel molecules, weakening dispersion forces. b) Instantaneous dipoles create temporary attractions with nearby molecules, and induced dipoles enhance these attractions. c) Induced dipoles form hydrogen bonds, which are a type of dispersion force. d) Dispersion forces arise only from induced dipoles, not instantaneous dipoles.

Answer 33

b) Instantaneous dipoles create temporary attractions with nearby molecules, and induced dipoles enhance these attractions.

Question 34

How does molecular size affect boiling points? a) Larger molecules with more electrons have stronger dispersion forces and higher boiling points. b) Smaller molecules with fewer electrons have stronger dispersion forces and higher boiling points. c) Molecular size has no effect on boiling points. d) Larger molecules have weaker dispersion forces and lower boiling points.

Answer 34

a) Larger molecules with more electrons have stronger dispersion forces and higher boiling points.

Question 35

How does surface area influence dispersion forces and boiling points? a) Molecules with smaller surface areas have stronger dispersion forces and higher boiling points. b) Molecules with larger surface areas have stronger dispersion forces and higher boiling points. c) Surface area only affects polar molecules, not nonpolar ones. d) Surface area has no effect on boiling points.

Answer 35

b) Molecules with larger surface areas have stronger dispersion forces and higher boiling points.

Question 36

Which of the following substances will likely have the highest boiling point? a) CH₄ (Methane) b) C₂H₆ (Ethane) c) C₄H₁₀ (Butane) d) C₆H₁₄ (Hexane)

Answer 36

d) C₆H₁₄ (Hexane)

Question 37

What are dipole-dipole attractions? a) Weak intermolecular forces caused by temporary dipoles. b) Strong intramolecular forces that hold atoms together in a molecule. c) Intermolecular forces between permanent dipoles in polar molecules. d) The attraction between ions and nonpolar molecules.

Answer 37

c) Intermolecular forces between permanent dipoles in polar molecules.

Question 38

Dipole-dipole attractions occur in which type of molecules? a) Nonpolar molecules only. b) Polar molecules with permanent dipoles. c) Nonpolar molecules with temporary dipoles. d) Ionic compounds dissolved in water.

Answer 38

b) Polar molecules with permanent dipoles.

Question 39

Are dipole-dipole attractions temporary or permanent? a) Temporary, caused by instantaneous dipoles. b) Permanent, caused by the alignment of polar molecules. c) Temporary, caused by induced dipoles in nonpolar molecules. d) Permanent, caused by ionic bonding.

Answer 39

b) Permanent, caused by the alignment of polar molecules.

Question 40

How do dipole-dipole attractions compare in strength to dispersion forces? a) Dipole-dipole attractions are generally weaker than dispersion forces. b) Dipole-dipole attractions are generally stronger than dispersion forces. c) Dipole-dipole attractions and dispersion forces are the same strength. d) Dipole-dipole attractions only occur in nonpolar molecules, so they can’t be compared.

Answer 40

b) Dipole-dipole attractions are generally stronger than dispersion forces.

Question 41

Which of the following has the strongest intermolecular forces? a) A polar molecule with dipole-dipole interactions. b) A nonpolar molecule with only dispersion forces. c) A polar molecule with hydrogen bonding. d) A molecule with induced dipoles only.

Answer 41

c) A polar molecule with hydrogen bonding.

Question 41

Which of the following is required for dipole-dipole attractions? a) The molecule must be nonpolar. b) The molecule must contain hydrogen atoms bonded to oxygen, nitrogen, or fluorine. c) The molecule must be polar with a permanent dipole. d) The molecule must have a high molar mass.

Answer 41

c) The molecule must be polar with a permanent dipole.

Question 42

Which type of molecule will exhibit dipole-dipole attractions? a) Nonpolar molecules like CH₄. b) Polar molecules like HCl. c) Noble gases like Argon. d) Ionic compounds like NaCl.

Answer 42

b) Polar molecules like HCl.

Question 43

Which of the following correctly describes dipole-dipole attractions? a) They arise from interactions between temporary dipoles in nonpolar molecules. b) They are stronger in molecules with greater molecular mass, regardless of polarity. c) They occur between the positive end of one polar molecule and the negative end of another polar molecule. d) They are the weakest type of intermolecular force.

Answer 43

c) They occur between the positive end of one polar molecule and the negative end of another polar molecule.

Question 44

What is hydrogen bonding? a) A bond between hydrogen atoms in the same molecule. b) A strong intermolecular force involving hydrogen and a highly electronegative atom. c) A weak force caused by temporary dipoles. d) A type of covalent bond within molecules.

Answer 44

b) A strong intermolecular force involving hydrogen and a highly electronegative atom.

Question 45

Which elements must be present for hydrogen bonding to occur? a) Nitrogen (N), Oxygen (O), and Fluorine (F). b) Hydrogen (H) and any other nonmetal. c) Hydrogen (H) and any halogen. d) Carbon (C), Hydrogen (H), and Oxygen (O).

Answer 45

a) Nitrogen (N), Oxygen (O), and Fluorine (F).

Question 46

Why does hydrogen bonding occur with N, O, or F? a) These atoms are small and highly electronegative, creating a strong partial charge. b) They are the only elements capable of forming polar bonds. c) They have high atomic masses, making them more polarizable. d) They are always found in ionic compounds.

Answer 46

a) These atoms are small and highly electronegative, creating a strong partial charge.

Question 47

How does hydrogen bonding affect boiling points? a) It lowers boiling points by weakening intermolecular forces. b) It raises boiling points by strengthening intermolecular forces. c) It has no effect on boiling points. d) It decreases boiling points in polar molecules but increases them in nonpolar molecules.

Answer 47

b) It raises boiling points by strengthening intermolecular forces.

Question 48

Which of the following has the highest boiling point due to hydrogen bonding? a) CH₄ (Methane) b) NH₃ (Ammonia) c) H₂ (Hydrogen gas) d) CO₂ (Carbon dioxide)

Answer 48

b) NH₃ (Ammonia) Explanation: NH₃ exhibits hydrogen bonding because nitrogen is highly electronegative and directly bonded to hydrogen.

Question 49

Why does water (H₂O) have an unusually high boiling point? a) It has strong ionic bonds within its molecules. b) It has multiple hydrogen bonds between molecules. c) It is a nonpolar molecule with strong dispersion forces. d) It contains heavy atoms, which increase boiling point.

Answer 49

b) It has multiple hydrogen bonds between molecules.

Question 50

Rank the types of intermolecular forces from weakest to strongest. a) Dispersion forces < Dipole-dipole attractions < Hydrogen bonding. b) Dipole-dipole attractions < Dispersion forces < Hydrogen bonding. c) Hydrogen bonding < Dispersion forces < Dipole-dipole attractions. d) Dispersion forces < Hydrogen bonding < Dipole-dipole attractions.

Answer 50

a) Dispersion forces < Dipole-dipole attractions < Hydrogen bonding.

Question 51

Which statement about intermolecular forces is correct? a) Hydrogen bonding only occurs in nonpolar molecules. b) Dispersion forces are the only intermolecular forces present in nonpolar molecules. c) Dipole-dipole attractions are stronger than hydrogen bonding. d) Dispersion forces are stronger than dipole-dipole attractions.

Answer 51

b) Dispersion forces are the only intermolecular forces present in nonpolar molecules.

Question 52

Do dispersion forces occur in polar molecules? a) No, dispersion forces only occur in nonpolar molecules. b) Yes, but they are weaker than dipole-dipole attractions and hydrogen bonding in polar molecules. c) Yes, and they are the dominant intermolecular force in polar molecules. d) No, polar molecules only exhibit dipole-dipole interactions.

Answer 52

b) Yes, but they are weaker than dipole-dipole attractions and hydrogen bonding in polar molecules.

Question 53

What are cohesive forces? a) Forces between molecules of the same type. b) Forces between molecules of different types. c) Forces that break surface tension. d) Forces that increase boiling points in nonpolar substances.

Answer 53

a) Forces between molecules of the same type.

Question 54

How do cohesive forces relate to viscosity? a) Higher cohesive forces lead to lower viscosity. b) Higher cohesive forces lead to higher viscosity. c) Viscosity is not affected by cohesive forces. d) Viscosity only depends on the size of the molecule.

Answer 54

b) Higher cohesive forces lead to higher viscosity.

Question 55

What does higher surface tension indicate about a liquid's droplets? a) They form more irregular shapes. b) They form larger, flat drops. c) They form more spherical droplets. d) They evaporate faster.

Answer 55

c) They form more spherical droplets.

Question 56

What are adhesive forces? a) Intermolecular forces within the same type of molecules. b) Intermolecular forces between different molecules. c) Forces that reduce boiling points. d) Forces that prevent evaporation.

Answer 56

b) Intermolecular forces between different molecules.

Question 57

What does vaporization involve? a) Forming hydrogen bonds between molecules. b) Breaking intramolecular forces. c) Separating intermolecular forces. d) Increasing cohesive forces.

Answer 57

c) Separating intermolecular forces.

Question 58

How can molecules vaporize? a) By decreasing kinetic energy and temperature. b) By increasing kinetic energy and temperature. c) By strengthening hydrogen bonds. d) By reducing adhesive forces.

Answer 58

b) By increasing kinetic energy and temperature.

Question 59

Why does water have a higher boiling point? a) It has strong dispersion forces. b) It contains hydrogen bonds that require more energy to break. c) It has weak cohesive forces. d) It has high adhesive forces with nonpolar molecules.

Answer 59

b) It contains hydrogen bonds that require more energy to break.

Question 60

What happens to molecules that evaporate? a) They break intramolecular forces. b) They move fast enough to break the liquid’s surface tension. c) They form new hydrogen bonds with the air. d) They decrease the temperature of the liquid.

Answer 60

b) They move fast enough to break the liquid’s surface tension.

Question 61

What does the Clausius-Clapeyron equation relate? a) The boiling point of a liquid and its cohesive forces. b) The change in heat of vaporization and vapor pressures at two temperatures. c) The viscosity of a liquid and its temperature. d) The surface tension and cohesive forces of a liquid.

Answer 61

b) The change in heat of vaporization and vapor pressures at two temperatures.

Question 62

When using the Clausius-Clapeyron equation, which conversions must you remember? a) Convert Kelvin to Celsius and Joules to kilojoules. b) Convert Celsius to Kelvin and kilojoules to Joules. c) Convert Kelvin to Celsius and kilojoules to calories. d) Convert Celsius to Kelvin and Joules to calories.

Answer 62

b) Convert Celsius to Kelvin and kilojoules to Joules.

Question 63

Using the Clausius-Clapeyron equation, if the temperature of water increases from 25°C to 58°C (ΔHvap = 44.01 kJ/mol), what is the new vapor pressure at 58°C if the initial pressure at 25°C is 1 atm? a) 3.50 atm b) 4.72 atm c) 5.89 atm d) 6.20 atm

Answer 63

c) 5.89 atm

Question 64

Adhesive forces are responsible for which of the following phenomena? a) The formation of spherical droplets. b) Liquids sticking to the walls of a container. c) Increased viscosity in a liquid. d) Increased boiling points due to hydrogen bonding.

Answer 64

b) Liquids sticking to the walls of a container.

Question 65

What is required for molecules to vaporize? a) Decreased cohesive forces. b) Increased adhesive forces. c) Increased kinetic energy through heating. d) Formation of new intramolecular bonds.

Answer 65

c) Increased kinetic energy through heating.

Question 66

Why does water evaporate slower than alcohol at the same temperature? a) Alcohol has weaker hydrogen bonding than water. b) Water has stronger adhesive forces with air. c) Alcohol has a higher surface tension. d) Water has a lower boiling point.

Answer 66

a) Alcohol has weaker hydrogen bonding than water.

Question 67

The predominant intermolecular force found in Na⁺(aq) is _____ ionic bonds dipole-dipole interactions ion-dipole interactions dispersion forces covalent bonds

Answer 67

ion-dipole interactions For Na+(aq)(an aqueous solution of sodium cations), the two species that are present are Na⁺ ions and water molecules. Since Na+ is an ion, and since water has a dipole, this system will exhibit ion-dipole interactions.

Question 68

Which is predicted to have the lowest vapor pressure? CH4 SiH4 NH3 PH3 H2O

Answer 68

H2O Vapor pressure describes the amount of a liquid that can escape into the gas phase, so compounds with stronger intermolecular forces will have lower vapor pressures. Two of these options exhibit hydrogen bonding (NH3 and H2O). The dipole created by the more electronegative O atom makes the intermolecular forces stronger in H2O, meaning it will have the lower vapor pressure.

Question 69

Which of the following substances is a liquid at room temperature? CH3CH3 CH3OH CH4 HCl CF4

Answer 69

CH3OH The phase of a chemical compound depends on the strength of its intermolecular forces, with strong intermolecular forces resulting in greater attractions and a greater tendency to be in the liquid or solid phase. All of these options exhibit dispersion forces, and some exhibit dipole-dipole forces, but CH3OH is the only compound that exhibits hydrogen bonding (due to its internal O-H bond), meaning it has the strongest intermolecular forces and is most likely to be a liquid.

Question 70

As a pure substance, which of the following could experience dipole-dipole interactions? I. CO2 II. HCl III. CCl4 I only II only III only II and III only I, II, and III

Answer 70

II only All polar molecules experience dipole-dipole interactions. CO2 is a linear symmetrical molecule and is nonpolar. HCl is a linear asymmetrical molecule and is polar. CCl4 is a symmetrical tetrahedral molecule and is nonpolar. Therefore, only HCl (II only) experiences dipole-dipole interactions.

Question 71

As a pure substance? which of the following could experience hydrogen bonding? I. H2Se II. H2O III. H2 II only III only I and II II and III I, II, and III

Answer 71

II only For hydrogen bonding to be present, a hydrogen atom needs to be bonded to N, O, or F. H2O is the only option that meets that criteria and can form hydrogen bonds.

Question 72

Which of the following represents the intermolecular forces present in CO2? dispersion only dipole-dipole only hydrogen bonding only dispersion and dipole-dipole dispersion and hydrogen bonding

Answer 72

dispersion only CO2 has no H atoms. While CO2 has two internal dipoles, they are of equal magnitude and point in opposite directions, meaning they cancel each other out and the molecule has no net dipole moment, so it cannot exhibit dipole-dipole forces.

Question 73

molecules with ____ forces have the lowest freezing points lowest highest

Answer 73

lowest

Question 74

what term is the measure of energy required to increase the surface tension area of a liquid? adhesion capillary action cohesion viscosity surface tension

Answer 74

surface tension

Question 75

which best explains why the meniscus of mercury in a glass tube is convex? the greater attraction of mercury to the lass than to itself the lower attraction of mercury to the glass than to itself the low surface tension of mercury the high density of mercury compared to water the repulsion between mercury and the glass

Answer 75

the lower attraction of mercury to the glass than to itself

Question 76

What does a phase diagram represent? a) The chemical composition of a substance. b) The relationship between pressure, temperature, and state of matter. c) The rate of vaporization of a liquid. d) The boiling point of water at standard pressure.

Answer 76

b) The relationship between pressure, temperature, and state of matter.

Question 77

What occurs at the triple point of a substance? a) The substance exists only as a gas. b) The substance exists only as a liquid. c) All three phases (solid, liquid, gas) coexist in equilibrium. d) The substance becomes a supercritical fluid.

Answer 77

c) All three phases (solid, liquid, gas) coexist in equilibrium.

Question 78

What is the significance of the critical point on a phase diagram? a) The point where all three phases exist in equilibrium. b) The temperature and pressure at which the substance can no longer exist as a liquid or gas but becomes a supercritical fluid. c) The boiling point of the substance at standard pressure. d) The freezing point of the substance at standard pressure.

Answer 78

b) The temperature and pressure at which the substance can no longer exist as a liquid or gas but becomes a supercritical fluid.

Question 79

What effect does increasing pressure have on the boiling point of a liquid? a) Decreases the boiling point. b) Increases the boiling point. c) Has no effect on the boiling point. d) Causes the liquid to immediately freeze.

Answer 79

b) Increases the boiling point.

Question 80

What type of solid is characterized by a highly organized, repeating structure? a) Crystalline solid b) Polycrystalline solid c) Amorphous solid d) Molecular solid

Answer 80

a) Crystalline solid

Question 81

What distinguishes polycrystalline solids from crystalline solids? a) Polycrystalline solids lack any organized structure. b) Polycrystalline solids consist of multiple small crystalline regions with different orientations. c) Polycrystalline solids are always metallic. d) Polycrystalline solids are better conductors of electricity than crystalline solids.

Answer 81

b) Polycrystalline solids consist of multiple small crystalline regions with different orientations.

Question 82

Which of the following is true about amorphous solids? a) They have a well-defined, repeating structure. b) They lack long-range order and have no crystalline structure. c) They are primarily ionic compounds. d) They are excellent conductors of electricity.

Answer 82

b) They lack long-range order and have no crystalline structure.

Question 83

Why are ionic compounds poor conductors of electricity in solid form? a) Their electrons are delocalized. b) Their ions are free to move in the lattice. c) Their ions are held in fixed positions within the lattice. d) Their intermolecular forces are weak.

Answer 83

c) Their ions are held in fixed positions within the lattice.

Question 84

Which type of crystalline solid is composed of metal cations in a sea of delocalized electrons? a) Covalent crystalline solid b) Molecular solid c) Ionic crystalline solid d) Metallic crystalline solid

Answer 84

d) Metallic crystalline solid

Question 85

Which type of crystalline solid is formed by a network of covalent bonds? a) Ionic crystalline solid b) Covalent crystalline solid c) Metallic crystalline solid d) Molecular solid

Answer 85

b) Covalent crystalline solid

Question 86

Which of the following is an example of a molecular crystalline solid? a) Sodium chloride b) Ice crystals c) Diamond d) Iron

Answer 86

b) Ice crystals

Question 87

What intermolecular forces hold molecular solids together? a) Covalent bonds b) Ionic bonds c) Metallic bonds d) Intermolecular forces such as hydrogen bonding or dispersion forces

Answer 87

d) Intermolecular forces such as hydrogen bonding or dispersion forces