Deck 9: Liquids and Solids

Question 1

Which of the following statements is true for an ideal gas?

A) A plot of ln P vsersus 1/T (in Kelvin)yields a straight line with a slope equal to −ΔH_vap.
B) A plot of ln P versus T (in Kelvin)yields a straight line with a slope equal to ΔH_vap.
C) A plot of ln P versus 1/T (in Kelvin)yields a straight line with a slope equal to −ΔH_vap/R.
D) A plot of P versus 1/T (in Kelvin)yields a straight line with a slope equal to 1/−ΔH_vap.
E) A plot of P versus T (in Kelvin)yields a straight line with a slope equal to −ΔH_vap/RT.

Answer 1

A plot of ln P versus 1/T (in Kelvin)yields a straight line with a slope equal to −ΔH_vap/R.

Question 2

On the phase diagram below,which point corresponds to conditions where solid,liquid,and gas phases all exist?

A) B
B) C
C) D
D) E
E) G

Answer 2

D

Question 3

If a pure substance begins at point A on the phase diagram below and the pressure on the substance is reduced at constant temperature until point B is reached,what process occurs?

A) fusion
B) vaporization
C) condensation
D) sublimation
E) none of the above

Answer 3

sublimation

Question 4

Mount Everest rises to a height of 29,035 ft (8.850 × 10³ m)above sea level.At this height,the atmospheric pressure is 230 mm Hg.At what temperature does water boil at the summit of Mount Everest? (ΔH_vap for H₂O = 40.7 kJ/mole,R = 8.31 J/K⋅mol)

A) −17°C
B) 31°C
C) 48°C
D) 57°C
E) 69°C

Question 5

Carbon tetrachloride,an organic solvent,has a molar heat of vaporization of 29.82 kJ/mol.If CCl₄ has a normal boiling point of 3.50 × 10² K,what is its vapor pressure at 273 K? (R = 8.31 J/mol⋅K)

A) 19.3 mm Hg
B) 42.2 mm Hg
C) 59.3 mm Hg
D) 108 mm Hg
E) 359 mm Hg

Question 6

Xenon has a molar heat of vaporization of 12.6 kJ/mol and a vapor pressure of 1.00 atm at -108.0°C.What is the vapor pressure of xenon at -148.0°C? (R = 8.31 J/K⋅mol)

A) 0.053 atm
B) 0.73 atm
C) 0.93 atm
D) 0.99 atm
E) 19 atm

Question 7

All of the following statements are incorrect EXCEPT

A) gas,liquid and solid phases of a substance exist simultaneously at equilibrium at the critical pressure and temperature.
B) above the critical pressure,only the solid phase of a pure substance can exist.
C) the liquid phase of a pure substance cannot exist above its critical temperature.
D) the critical temperature and pressure cannot be produced simultaneously.
E) above the critical temperature and pressure,only the liquid phase of a substance exists.

Question 8

Methyl alcohol,CH₃OH,has a vapor pressure of 203 mm Hg at 35°C.If 5.00 g CH₃OH is sealed in a 10.0 L flask,what mass will remain in the liquid phase when equilibrium is established at 35°C? Assume any liquid remaining in the flask has a negligible volume.(760 mm Hg = 1 atm,R = 0.0821 L⋅atm/mol⋅K)

A) 0.00 g
B) 1.62 g
C) 2.08 g
D) 2.27 g
E) 4.69 g

Question 9

What process occurs when a substance is at point C on the phase diagram below,and the pressure is decreased (under constant temperature)until the substance is at point E?

A) condensation
B) vaporization
C) sublimation
D) melting
E) freezing

Question 10

Freon-113,C₂Cl₃F₃,has an enthalpy of vaporization of 27.04 kJ/mol and a normal boiling point of 48°C.At what temperature is the vapor pressure of Freon-113 equal to 76.0 mm Hg? (R = 8.31 J/K⋅mol)

A) −53.1°C
B) −23.8°C
C) −11.4°C
D) 1.44°C
E) 7.12°C

Question 11

The normal boiling point of a liquid is

A) 373 K.
B) the temperature at which a liquid's vapor pressure equals 1 atm.
C) the pressure at which the liquid boils at 373 K.
D) dependent upon the volume of the liquid.
E) dependent upon the surface area of the liquid..

Question 12

Sulfur dioxide has a vapor pressure of 462.7 mm Hg at -21.0°C and a vapor pressure of 140.5 mm Hg at -44.0°C.What is the molar heat of vaporization of sulfur dioxide? (R = 8.31 J/K⋅mol)

A) 0.398 kJ/mol
B) 6.33 kJ/mol
C) 14.0 kJ/mol
D) 24.9 kJ/mol
E) 39.8 kJ/mol

Question 13

Which of the following equations is a correct form of the Clausius-Clapeyron equation?

A) $\ln \frac{P_{2}}{P_{1}}=-\frac{R}{\Delta H_{\mathrm{vap}}}\left[\frac{1}{T_{2}}-\frac{1}{T_{1}}\right]$
B) $\ln \frac{P_{2}}{P_{1}}=-\frac{\Delta H_{\text {vap }}}{R}\left[\frac{1}{T_{2}}-\frac{1}{T_{1}}\right]$
C) $\ln \frac{P_{2}}{P_{1}}=-\Delta H_{\text {vap }}\left[\frac{1}{T_{2}-T_{1}}\right]$
D) $\ln \frac{P_{2}}{P_{1}}=\frac{\Delta H_{\text {vap }}}{R}\left[\frac{1}{T_{2}-T_{1}}\right]$
E) $\ln \frac{P_{2}}{P_{1}}=-\frac{\Delta H_{\text {vap }}}{R}\left[\frac{1}{T_{2}-T_{1}}\right]$

Question 14

Sulfur dioxide has an enthalpy of vaporization of 24.9 kJ/mol.At 205 K,SO₂ has a vapor pressure of 30.3 mm Hg.What is the normal boiling point temperature of SO₂? (R = 8.31 J/K⋅mol)

A) 263 K
B) 278 K
C) 291 K
D) 308 K
E) 345 K

Question 15

Ethanol has a molar heat of vaporization of 42.3 kJ/mol.The compound has a vapor pressure of 1.00 atm at 78.3°C.At what temperature is the vapor pressure equal to 0.800 atm? (R = 8.31 J/K⋅mol)

A) -83.8°C
B) -24.4°C
C) 62.6°C
D) 73.0°C
E) 78.0°C

Question 16

At 75.0 °C,water has an equilibrium vapor pressure of 289.1 mm Hg.If 4.22 g H₂O is sealed in an evacuated 5.00 L flask and heated to 75.0 °C,what mass of H₂O will be found in the gas phase when liquid-vapor equilibrium is established? Assume any liquid remaining in the flask has a negligible volume.(760 mm Hg = 1 atm,R = 0.0821 L⋅atm/mol⋅K)

A) 0.240 g
B) 1.20 g
C) 2.64 g
D) 3.02 g
E) 4.22 g

Question 17

Naphthalene,a substance present in some mothballs,has a molar heat of vaporization of 49.4 kJ/mol.If the vapor pressure of naphthalene is 0.300 mm Hg at 298 K,what is the temperature at which the vapor pressure is 7.60 × 10² mm Hg? (R = 8.31 J/K⋅mol)

A) 424 K
B) 491 K
C) 501 K
D) 521 K
E) 611 K

Question 18

On the phase diagram below,which point corresponds to conditions where both liquid and gas phases exist?

A) A
B) B
C) C
D) E
E) F

Question 19

Water has an equilibrium vapor pressure of 23.8 mm Hg at 25°C.What mass of water vapor is present,at equilibrium,in a room with dimensions of 7.0 m × 8.0 m × 2.7 m? (760 mm Hg = 1 atm,R = 0.0821 L⋅atm/mol⋅K)

A) 0.0050 kg
B) 0.029 kg
C) 0.28 kg
D) 3.5 kg
E) 5.0 kg

Question 20

On the phase diagram below,which point corresponds to conditions where only the solid phase exists?

A) A
B) B
C) C
D) D
E) G

Question 21

Which of the following nonpolar molecules has the highest boiling point?

A) F₂
B) C₂H₄
C) F₂..
D) O₂
E) CS₂

Question 22

All of the following statements concerning dispersion forces are correct EXCEPT

A) the strength of dispersion forces depends on the number of electrons in a molecule.
B) dispersion forces are the primary attractive forces in metal-metal bonding.
C) dispersion forces involve the attraction between induced dipoles.
D) dispersion forces are the primary attractive force in molecular solids consisting of nonpolar molecules.
E) dispersion forces exist in all molecular solids.

Question 23

Which of the following substances will exhibit dipole forces?

A) SO₃
B) H₂S
C) CH₄
D) SF₆
E) N₂

Question 24

All of the following substances will exhibit dipole forces EXCEPT

A) SO₃.
B) SF₂.
C) H₂Se.
D) NO₂.
E) NO.

Question 25

Arrange N₂,O₂,He,and Cl₂ in order from lowest to highest melting point.

A) O₂ < N₂ < Cl₂ < He
B) N₂ < O₂ < He < Cl₂
C) He < Cl₂ < N₂ < O₂
D) He < O₂ < N₂ < Cl₂
E) He < N₂ < O₂ < Cl₂

Question 26

Which of the following pure substances will have hydrogen bonds? (Lone electron pairs have been omitted from these structures. )

A) Acetone
B) Dimethyl ether
C) Methanol
D) Acetone and methanol
E) Dimethyl ether and methanol

Question 27

All of the following statements concerning hydrogen bonding are correct EXCEPT

A) water is less dense in the solid phase than the liquid phase due to hydrogen bonding.
B) hydrogen bonding occurs in molecules with N−H,O−H,and F−H bonds.
C) hydrogen bonding in water results in lower than expected melting points.
D) the unusually high boiling points of water,ammonia,and hydrogen fluoride are the result of hydrogen bonding.
E) hydrogen bonding is an unusually strong dipole force.

Question 28

Arrange Cl₂,ICl,and Br₂ in order from lowest to highest melting point.

A) Br₂ < ICl < Cl₂
B) Br₂ < Cl₂ < ICl
C) Cl₂ < ICl < Br₂
D) Cl₂ < Br₂ < ICl
E) ICl < Br₂ < Cl₂

Question 29

What is the correct method for determining the number of atoms in a face-centered cubic cell?

A) $\# \text { atoms }=\frac{1}{8}(8)$
B) $\# \text { atoms }=\frac{1}{8}(8)+1$
C) $\# \text { atoms }=\frac{1}{8}(8)+\frac{1}{4}(4)$
D) $\# \text { atoms }=\frac{1}{8}(8)+\frac{1}{2}(6)$
E) $\# \text { atoms }=\frac{1}{8}(8)+\frac{1}{2}(4)$

Question 30

What is a correct method for determining the number of atoms in a body-centered cubic cell?

A) $\# \text { atoms }=\frac{1}{8}(8)+1$
B) $\# \text { atoms }=\frac{1}{8}(8)+\frac{1}{2}(4)$
C) $\# \text { atoms }=\frac{1}{8}(8)+\frac{1}{2}(6)$
D) $\# \text { atoms }=\frac{1}{4}(8)+\frac{1}{2}(6)$
E) $\# \text { atoms }=\frac{1}{4}(8)+\frac{1}{2}(4)$

Question 31

What is the dominant intermolecular force in HF(l)?

A) Dispersion forces
B) Hydrogen bonding
C) Ionic bonding
D) Dipole forces
E) Induced dipole forces

Question 32

Arrange the noble gases in order from weakest to strongest interatomic forces.

A) Kr < Ar < Ne < He
B) Ne < He C) He < Ar < Ne < Kr
D) He < Ne < Ar < Kr
E) Ar < Kr < He < Ne

Question 33

All of the following statements are correct EXCEPT

A) network covalent solids are usually good electrical conductors.
B) network covalent solids often have high melting points.
C) network covalent solids are insoluble in common solvents.
D) ionic solids typically have high melting points.
E) ionic solids are often hard and brittle.

Question 34

How many unit cells share an atom which is located at a corner (or lattice point)of a simple cubic unit cell?

A) 1
B) 2
C) 4
D) 6
E) 8

Question 35

Which one of the following molecules has the lowest boiling point?

A) CH₄
B) CHCl₃
C) CH₂Cl₂
D) CH₃Cl
E) CCl₄

Question 36

Arrange NH₃,CH₄,and PH₃ in order from lowest to highest boiling points.

A) CH₄ < PH₃ < NH₃
B) CH₄ < NH₃ < PH₃
C) PH₃ < NH₃ < CH₄
D) NH₃ < CH₄ < PH₃
E) PH₃ < CH₄ < NH₃

Question 37

Which one of the following molecules will exhibit dipole forces as a pure liquid or solid?

A) CS₂
B) C₂H₂
C) CCl₄
D) Br₂
E) PH₃

Question 38

Elemental phosphorus is a molecular solid consisting of P₄ molecules.It melts at 44°C.What is the principal force present in P₄(s)?

A) Dipole forces
B) Hydrogen bonding
C) Dispersion forces
D) Metallic bonding
E) Ionic bonding

Question 39

In the phase diagram below,which phase is most dense?

A) solid
B) liquid
C) gas
D) supercritical fluid
E) none of the above

Question 40

In which of the following pure solids is it necessary to break covalent bonds in order to make a liquid or gas?

A) SO₂
B) NaCl
C) H₂SO₄
D) I₂
E) SiO₂

Question 41

For a simple cubic unit cell,what percentage of the space in the cell is occupied by the atoms at the corners of the cell?

A) 47.6%
B) 52.4%
C) 57.4%
D) 62.3%
E) 71.2%

Question 42

What type of solid is conductive when melted but not as a solid?

A) Metallic
B) Ionic
C) Molecular
D) Crystalline
E) Covalent

Question 43

Arrange the three common unit cells in order from least dense to most dense packing.

A) simple cubic < body-centered cubic < face-centered cubic
B) simple cubic < face-centered cubic < body-centered cubic
C) body-centered cubic < face-centered cubic < simple cubic
D) body-centered cubic < simple cubic < face-centered cubic
E) face-centered cubic < body-centered cubic < simple cubic

Question 44

Iron packs in a body-centered cubic structure.If an iron atom has a radius of 126 pm,what is the distance between lattice points at two opposite corners of the unit cell? (Note: a line drawn between the points would go through the center of the unit cell)

A) $\sqrt{2}(126 \mathrm{pm})=178 \mathrm{pm}$
B) 2(126 pm)= 252 pm
C) $\frac{\sqrt{3}}{2}(126 \mathrm{pm})=109 \mathrm{pm}$
D) 4(126 pm)= 504 pm
E) $\sqrt{3}(126 \mathrm{pm})=218 \mathrm{pm}$

Question 45

Dorothy Crowfoot Hodgkin was famous for what?

A) The discovery of x-rays
B) The invention of x-ray diffraction
C) The discovery of supercritical fluids
D) The determination of the structure of insulin
E) All of the above

Question 46

Niobium crystallizes in a body-centered cubic unit cell.If the radius of a niobium atom is 0.145 nm,what is the length of an edge of the unit cell?

A) 0.251 nm
B) 0.290 nm
C) 0.335 nm
D) 0.410 nm
E) 0.502 nm

Question 47

What is the distance,in atomic radii,along any edge of a face-centered unit cell?

A) $\frac{4 \times r}{\sqrt{3}}$
B) 2 × r
C) 4 × r
D) $2 \sqrt{2} \times r$
E) r

Question 48

Rhodium (atomic mass 102.9 g/mol)crystallizes in a face-centered cubic unit cell.In addition,rhodium has an atomic radius of 135 pm.What is the density (in g/cm³)of rhodium?

A) 1.53 g/cm³
B) 6.14 g/cm³
C) 17.4 g/cm³
D) 12.3 g/cm³
E) 27.8 g/cm³

Question 49

What type of solid is generally soluble in nonpolar solvents?

A) Metallic
B) Ionic
C) Molecular
D) Crystalline
E) Covalent

Question 50

Potassium crystallizes in a body-centered cubic unit cell.If the length of an edge of the unit cell is 524 pm,what is the atomic radius (in pm)of a potassium atom?

A) 151 pm
B) 185 pm
C) 227 pm
D) 262 pm
E) 371 pm

Question 51

Nickel has a face-centered cubic cell,and its density is 8.90 g/cm³.What is the radius (in pm)of a nickel atom? (The molar mass of nickel is 58.69 g/mol)

A) 62.3 pm
B) 88.1 pm
C) 125 pm
D) 249 pm
E) 535 pm

Question 52

What type of solid is malleable?

A) Metallic
B) Ionic
C) Molecular
D) Crystalline
E) Covalent