Question 1

CsCl crystallizes in a unit cell that contains a Cs⁺ion at the center of a cube and a Cl^-ion at each corner. The unit cell of CsCl is . A) amorphous B) primitive cubic C) close packed D) body- centered cubic E) face- centered cubic

Accepted Answer

B

Question 2

is the energy required to expand the surface area of a liquid by a unit amount of area.
A) Meniscus
B) Capillary action
C) Surface tension
D) Viscosity
E) Volatility

Accepted Answer

The energy required to expand the surface area of a liquid by a unit amount of area is known as surface tension. Surface tension is caused by the cohesive forces between the molecules in a liquid, which create a "skin" on the surface of the liquid. This skin makes the surface of the liquid behave like a stretched rubber membrane, resisting any attempt to break or puncture it.

Question 3

Which statements about viscosity are true?
(i) Viscosity increases as temperature decreases.
(ii) Viscosity increases as molecular weight increases.
(iii) Viscosity increases as intermolecular forces increase.
A) (i) only
B) (i) and (iii)
C) (ii) and (iii)
D) none
E) all

Accepted Answer

Viscosity generally increases as temperature decreases, molecular weight increases, and intermolecular forces increase.

Question 4

Ethanol (C₂H₅OH) melts at - 114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/g- K and 2.3 J/g- K, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at - 135°C to liquid ethanol at - 50°C? A) 207.3 B) 9.21 C) - 12.7 D) 6.91 E) 4192

Accepted Answer

The answer of Ethanol (C₂H₅OH) melts at - 114°C. The...

Question 5

Based on the figure above, the boiling point of diethyl ether under an external pressure of 1.32 atm is °C.
A) 20
B) 0
C) 10
D) 30
E) 40

Accepted Answer

According to the phase diagram, at an external pressure of 1.32 atm, the boiling point of diethyl ether is approximately 40°C.

Question 6

What fraction of the volume of each corner atom is actually within the volume of a face- centered cubic unit cell?
A) 1
B) 
C) 
D) 
E)

Accepted Answer

The answer of What fraction of the volume of each...

Question 7

CsCl crystallizes in a unit cell that contains the Cs⁺ion at the center of a cube that has a Cl^-at each corner. Each unit cell contains Cs⁺ions and Cl^-, ions, respectively. A) 1 and 8 B) 2 and 1 C) 1 and 1 D) 2 and 4 E) 2 and 2

Accepted Answer

The CsCl unit cell is a simple cubic structure with one Cs+ ion at the center and each Cl- ion at the corners shared among eight unit cells, effectively contributing one Cl- ion per unit cell.

Question 8

C₁₂H₂₆molecules are held together by . A) ion- ion interactions B) dispersion forces C) hydrogen bonding D) ion- dipole interactions E) dipole- dipole interactions

Accepted Answer

C₁₂H₂₆ is a nonpolar molecule, and nonpolar molecules are held together by dispersion forces, also known as London dispersion forces.

Question 9

The phase diagram of a substance is given above. This substance is a at 25°C and 1.0 atm.
A) supercritical fluid
B) gas
C) liquid
D) crystal
E) solid

Accepted Answer

At 25°C and 1.0 atm, the substance is within the liquid region of the phase diagram, so the best choice is C. It is not a gas because it is not above the boiling point at this pressure, and it is not a solid because it is not below the melting point at this pressure. It is also not a supercritical fluid because it is not above the critical temperature and pressure.

Question 10

Based on the figure above, the boiling point of ethyl alcohol under an external pressure of 0.0724 atm is °C.
A) 60
B) 80
C) 40
D) 70
E) 20

Accepted Answer

The answer of Based on the figure above, the boiling...

Question 11

Which statement is true about liquids but not true about solids?
A) They flow and are compressible.
B) They are highly ordered and not compressible.
C) They flow and are highly ordered.
D) They flow and are not compressible.
E) They assume both the volume and the shape of their containers.

Accepted Answer

Liquids can flow, which means they can take the shape of their container, but they are not compressible like gases. Solids, on the other hand, are highly ordered and not compressible, which makes option B incorrect. Option A is incorrect because solids are not typically compressible, and option C is also incorrect because liquids are not typically highly ordered like solids. Option E describes the behavior of both liquids and gases, but not solids.

Question 12

A substance that expands to fill its container yet has a density approaching that of a liquid, and that can behave as a solvent is called a(n) _.
A) liquid
B) supercritical fluid and gas
C) plasma
D) amorphous solid
E) gas

Accepted Answer

A supercritical fluid and gas can expand to fill its container, has a density approaching that of a liquid, and can behave as a solvent.

Question 13

What is the predominant intermolecular force in CBr₄? A) hydrogen- bonding B) ion- dipole attraction C) ionic bonding D) dipole- dipole attraction E) London- dispersion forces

Accepted Answer

CBr₄ is a non-polar molecule as it has symmetrical structure and no polar bonds. Therefore, the predominant intermolecular force in this molecule is London-dispersion forces, which are relatively weak compared to other intermolecular forces.

Question 14

Which one of the following substances will not have hydrogen bonding as one of its intermolecular forces?
A)

B)

C) 
D)

E)

Accepted Answer

The answer of Which one of the following substances will...

Question 15

Which one of the following exhibits dipole- dipole attraction between molecules? A) XeF₄ B) BCl₃ C) Cl₂ D) CO₂ E) AsH₃

Accepted Answer

AsH3 exhibits dipole-dipole attraction because it is a polar molecule with a net dipole moment due to the difference in electronegativity between arsenic and hydrogen, and its trigonal pyramidal shape.

Question 16

What portion of the volume of each atom or ion on the face of a unit cell is actually within the unit cell?
A) 3/4
B) 1/4
C) 1/2
D) all of it
E) none of it

Accepted Answer

Each face of a unit cell contains half of each atom or ion inside it. Therefore, only half of the volume of each atom or ion on a face of a unit cell is actually within the unit cell. Since there are two faces per unit cell, the total volume of each atom or ion within the unit cell is equal to (2 faces)(1/2 volume per face) = 1 unit of volume. Thus, the portion of the volume of each atom or ion on the face of a unit cell that is actually within the unit cell is 1/2 or 50%.

Question 17

Hydrogen bonding is a special case of _ .
A) ion- dipole attraction
B) London- dispersion forces
C) dipole- dipole attractions
D) none of the above
E) ion- ion interactions

Accepted Answer

Hydrogen bonding involves a dipole-dipole attraction between a hydrogen atom bonded to a highly electronegative atom (such as oxygen, nitrogen, or fluorine) and a lone pair of electrons on another highly electronegative atom. Therefore, this type of bonding is a specific type of dipole-dipole attraction. It is not ion-dipole, London-dispersion, or ion-ion interactions.

Question 18

A gas is _ and assumes of its container whereas a liquid is and assumes of its container.
A) compressible, the shape, not compressible, the volume and shape
B) condensed, the volume and shape, condensed, the volume and shape
C) compressible, the volume and shape, compressible, the volume
D) condensed, the shape, compressible, the volume and shape
E) compressible, the volume and shape, not compressible, the shape of a portion

Accepted Answer

Gases are compressible and take the volume and shape of their container, while liquids are not compressible and take the shape of the portion of the container they occupy.

Question 19

The vapor pressure of a liquid _.
A) decreases linearly with increasing temperature
B) decreases nonlinearly with increasing temperature
C) increases linearly with increasing temperature
D) increases nonlinearly with increasing temperature
E) is totally unrelated to its molecular structure

Accepted Answer

The vapor pressure of a liquid increases nonlinearly with increasing temperature due to the exponential nature of the Clausius-Clapeyron equation, which describes the relationship between vapor pressure and temperature.

Question 20

The predominant intermolecular force in CaBr₂is _ . A) dipole- dipole forces B) London- dispersion forces C) ion- dipole forces D) hydrogen bonding E) ionic bonding

Accepted Answer

CaBr2 is an ionic compound, and the predominant intermolecular force is ionic bonding, which occurs between the positively charged calcium ions and the negatively charged bromide ions.

Quiz 11: Intermolecular Forces, Liquids, and Solids

CsCl crystallizes in a unit cell that contains a Cs+ ion at the center of a cube and a Cl- ion at each corner. The unit cell of CsCl is .

is the energy required to expand the surface area of a liquid by a unit amount of area.

Which statements about viscosity are true? (i) Viscosity increases as temperature decreases. (ii) Viscosity increases as molecular weight increases. (iii) Viscosity increases as intermolecular forces increase.

Ethanol (C2H5OH) melts at - 114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/g- K and 2.3 J/g- K, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at - 135°C to liquid ethanol at - 50°C?

Based on the figure above, the boiling point of diethyl ether under an external pressure of 1.32 atm is °C.

What fraction of the volume of each corner atom is actually within the volume of a face- centered cubic unit cell?

CsCl crystallizes in a unit cell that contains the Cs+ ion at the center of a cube that has a Cl- at each corner. Each unit cell contains Cs+ ions and Cl- , ions, respectively.

C12 H26 molecules are held together by .

The phase diagram of a substance is given above. This substance is a at 25°C and 1.0 atm.

Based on the figure above, the boiling point of ethyl alcohol under an external pressure of 0.0724 atm is °C.

Which statement is true about liquids but not true about solids?

A substance that expands to fill its container yet has a density approaching that of a liquid, and that can behave as a solvent is called a(n) _.

What is the predominant intermolecular force in CBr4?

Which one of the following substances will not have hydrogen bonding as one of its intermolecular forces?

Which one of the following exhibits dipole- dipole attraction between molecules?

What portion of the volume of each atom or ion on the face of a unit cell is actually within the unit cell?

Hydrogen bonding is a special case of _ .

A gas is _ and assumes of its container whereas a liquid is and assumes of its container.

The vapor pressure of a liquid _.

The predominant intermolecular force in CaBr2 is _ .

CsCl crystallizes in a unit cell that contains a Cs⁺ion at the center of a cube and a Cl^-ion at each corner. The unit cell of CsCl is .

Ethanol (C₂H₅OH) melts at - 114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/g- K and 2.3 J/g- K, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at - 135°C to liquid ethanol at - 50°C?

CsCl crystallizes in a unit cell that contains the Cs⁺ion at the center of a cube that has a Cl^-at each corner. Each unit cell contains Cs⁺ions and Cl^-, ions, respectively.

C₁₂H₂₆molecules are held together by .

What is the predominant intermolecular force in CBr₄?

The predominant intermolecular force in CaBr₂is _ .