Question

A hydrogen atom must be directly bonded to F, N, or O in a molecule in order to participate in a hydrogen bonding.

Select one:

True

False

Question 2

As the strength of temporary (induced) dipoles decreases within a substance, the boiling point increases.

Select one:

True

False

Question 3

The lines in a phase diagram of a given substance represent the co-existence curves where two phases of the same substance are present at equilibrium for a well-defined set of temperature and pressure (P, T).

Select one:

True

False

Question 4

Nonpolar molecules can slightly dissolve in polar solvents due to induced dipole moment.

Select one:

True

False

Question 5

When a negatively charged ion dissolves in water, the water molecules will orient themselves such that their oxygen atoms point toward the anion in solution to form a hydration sphere.

Select one:

True

False

Question 6

Ethanol (CH₃CH₂OH) is more soluble in carbon tetrachloride (CCl₄) than dimethyl ether (CH₃OCH₃), which is also known as methoxymethane.

Select one:

True

False

Question 7

Based on the phase diagram (P versus T) of water, sublimation (i.e., the direct phase change from the solid phase to the gas phase) is not possible.

Select one:

True

False

Question 8

Bromine (Br₂) is more soluble in carbon tetrachloride (CCl₄) than sodium bromide (NaBr).

Select one:

True

False

Question 9

At the triple point in the phase diagram (P versus T) of water, water molecules coexist at equilibrium in three phases: solid (ice), liquid, and gas phases.

Select one:

True

False

Question 10

Water forms a concave meniscus (e.g., U) in a glass tube because the cohesive (or intermolecular) forces among water molecules is much larger than the adhesive forces between water molecules and the glass wall.

In contrast, mercury forms a convex meniscus (e.g., ∩) in a glass tube because the adhesive forces between mercury molecules and the glass wall is much larger than the cohesive (or intermolecular) forces among mercury molecules."

Select one:

True

False

Question 11

Which type of intermolecular force (or interaction) that exists for all kinds of compounds?

Select one:

a. Ion–ion.

b. Dipole–dipole.

c. London dispersion.

d. Hydrogen bonding.

e. Dipole–induced dipole.

Question 12

Polarizability refers to ___________________________________________ (choose one).

Select one:

a. The ease with which the electron cloud of an atom or molecule can be distorted.

b. The magnitude of the dipole moment of a molecule.

c. The ease with which a hydrogen bond can form.

d. The perturbation in electron density because of hydrogen bonding.

e. The ability to transmit polarized light.

Question 13

Which one of the following molecules exhibits the greatest dispersion (London) forces?

Select one:

a. CH₃CH₃            

b. CH₃CH₂CH₃        

c. C₂H₂

d. CH₃CH₂CH₂CH₃

e. CH₄

Question 14

Which one of the following straight-chain alkanes has the highest boiling point?

Select one:

a. CH₄

b. C₆H₁₂

c. C₈H₁₈

d. C₂H₆

e. C₄H₁₀

Question 15

As the intermolecular forces among molecules in the liquid state increase, ↑, (i.e., IMF become stronger), ___________________________ will decrease (↓).

Select one:

a. Viscosity

b. Boiling Point

c. Surface Tension

d. Vapor Pressure

e. Solubility (regardless the solvent-solvent or solvent-solute interaction forces)

Question 16

Which one of the following compounds will exhibit hydrogen bonding with itself in the liquid state?

Select one:

a. CH₃OCH₃

b. CH₃CH₂NH₂

c. CH₃COCH₃

d. H₂CO

e. CH₃F

Question 17

Which one of the following compounds that is likely to have the highest boiling point?

Select one:

a. CH₃CF₃      

b. CH₃CN      

c. (CH₃)₂CO

d. CH₃CH₂SH

e. CH₃CH₂OH

Question 18

When two liquids mix completely in all proportions, they are __________________________________.

Select one:

a. Soluble.      

b. Miscible.    

c. Immiscible.

d. Solvated.

e. Ubiquitous.

Question 19

Hydrophilic substances ____________________________________.

Select one:

a. Are immiscible in water.

b. Are insoluble in water.

c. Are soluble in water.

d. Generally do not form a hydrogen bond.

e. Are soluble in lipids.

Question 20

Which one of the following compounds would be most soluble in benzene, C₆H₆?

Select one:

a. H₂O

b. H₂C(OH)₂

c. PCl₃

d. CCl₄

e. CH₃CH₂OH

Answer 1

1. A hydrogen bond is formed between a X-H group and a X atom where X = N, O and F. The X atom must be highly electronegative to polarize the X-H bond significantly so that the H atom bears a partial positive charge and can easily accept electron density from the X atom. The X atom must not only be highly electronegative, but must have non-bonding or lone electron pairs to donate to the positively polarized H atom of the X-H group. Hence, the given statement is true.

2. The boiling point of a substance depends on the strength of the intermolecular forces present in the substance. As the strength of the intermolecular forces, the molecules or ions in the substance are tightly bound to each other and thus, higher energy is required to separate the molecules in the substance and hence, the boiling point increases. Thus, the strength of the induced dipole forces in the substance must directly be related to the boiling point. Hence, the given statement is false.

3. The lines on a phase diagram indeed represent two phases existing together under a given condition of temperature of pressure. The regions on either sides of the phase diagram indicate pure phases and every point on the line indicates an equilibrium state where both the phases exist together. Thus, the given statement is true.

4. Non-polar molecules do not usually dissolve in polar solvents since there are no polarizable groups in non-polar molecules. However, polar solvent molecules can induce temporary dipole moment in non-polar groups and thus, there is partial dissolution of non-polar molecules in polar molecules.