CHEM 162 COMPREHENSIVE REVIEW 2026
VERIFIED QUESTIONS AND SOLUTIONS
◉What is the role of thermal energy in determining the state of a
substance? Answer: Thermal energy determines whether IMFs are
strong enough to keep molecules in a solid, liquid, or gas state.
◉What is the relationship between boiling point and IMF strength?
Answer: Higher IMF strength correlates with higher boiling points.
◉What characterizes a polar molecule? Answer: A polar molecule
has a permanent dipole moment due to an unequal distribution of
electron density.
◉What is the equation for boiling point elevation? Answer: ΔTb = i *
m * Kb, where ΔTb is the change in boiling point, i is the Van't Hoff
factor, m is the molality, and Kb is the boiling point elevation
constant.
◉How do non-polar molecules interact with polar molecules?
Answer: Non-polar molecules primarily experience dispersion
forces and do not participate in dipole-dipole interactions.
,◉What type of intermolecular force is only present in monatomic
molecules? Answer: London forces (temporary dipoles)
◉How does the shape of molecules affect dispersion forces?
Answer: Bent, branched, or bulky molecules have less surface area,
resulting in lower dispersion forces.
◉What type of molecules exhibit dipole-dipole interactions?
Answer: Molecules with permanent dipoles (polar molecules).
◉How do polar molecules compare to non-polar molecules in terms
of boiling point? Answer: Polar molecules have higher boiling points
than non-polar molecules of similar molecular mass.
◉What is the relationship between dipole moment (μ) and boiling
point (BP)? Answer: Higher dipole moment leads to stronger
dipole-dipole interactions, resulting in a higher boiling point.
◉How is molality defined? Answer: Molality (m) is defined as the
number of moles of solute per kilogram of solvent.
◉What is vapor pressure (VP)? Answer: The pressure above a liquid
where vaporization and condensation are at dynamic equilibrium.
,◉How does temperature affect vapor pressure? Answer: As
temperature increases, vapor pressure increases due to a greater
fraction of molecules having sufficient energy to escape.
◉What is the effect of stronger intermolecular forces on vapor
pressure? Answer: Stronger intermolecular forces result in lower
vapor pressure at a given temperature.
◉What is the normal boiling point? Answer: The temperature at
which vapor pressure equals 1 atm.
◉What is heat of vaporization (ΔHvap)? Answer: The amount of
heat required to vaporize one mole of a liquid to gas; it is
endothermic.
◉How does the heat of vaporization of water compare to diethyl
ether? Answer: Water has a higher ΔHvap (40.7 kJ/mol) compared
to diethyl ether (26.5 kJ/mol) due to stronger intermolecular forces.
◉What is the Clausius-Clapeyron equation used for? Answer: It
relates vapor pressure and temperature to calculate heat of
vaporization.
◉What does the slope of the Clausius-Clapeyron plot represent?
Answer: The slope represents -ΔHvap/R.
, ◉What happens to vapor pressure as external pressure decreases?
Answer: The boiling point decreases as external pressure decreases.
◉What is the relationship between intermolecular forces and
boiling point? Answer: Stronger intermolecular forces lead to higher
boiling points.
◉What is the significance of vapor pressure curves? Answer: They
show the relationship between vapor pressure and temperature.
◉What is the effect of a non-volatile solute on the freezing point of a
solution? Answer: The freezing point is lowered compared to that of
the pure solvent.
◉What is the dynamic equilibrium in vaporization? Answer: It
occurs when the rate of evaporation equals the rate of condensation.
◉What is the minimum kinetic energy necessary for a molecule to
escape into the gas phase? Answer: It increases with stronger
intermolecular forces.
◉How can you calculate the mass of water vaporized at its boiling
point? Answer: Using the heat of vaporization and the total energy
available.
VERIFIED QUESTIONS AND SOLUTIONS
◉What is the role of thermal energy in determining the state of a
substance? Answer: Thermal energy determines whether IMFs are
strong enough to keep molecules in a solid, liquid, or gas state.
◉What is the relationship between boiling point and IMF strength?
Answer: Higher IMF strength correlates with higher boiling points.
◉What characterizes a polar molecule? Answer: A polar molecule
has a permanent dipole moment due to an unequal distribution of
electron density.
◉What is the equation for boiling point elevation? Answer: ΔTb = i *
m * Kb, where ΔTb is the change in boiling point, i is the Van't Hoff
factor, m is the molality, and Kb is the boiling point elevation
constant.
◉How do non-polar molecules interact with polar molecules?
Answer: Non-polar molecules primarily experience dispersion
forces and do not participate in dipole-dipole interactions.
,◉What type of intermolecular force is only present in monatomic
molecules? Answer: London forces (temporary dipoles)
◉How does the shape of molecules affect dispersion forces?
Answer: Bent, branched, or bulky molecules have less surface area,
resulting in lower dispersion forces.
◉What type of molecules exhibit dipole-dipole interactions?
Answer: Molecules with permanent dipoles (polar molecules).
◉How do polar molecules compare to non-polar molecules in terms
of boiling point? Answer: Polar molecules have higher boiling points
than non-polar molecules of similar molecular mass.
◉What is the relationship between dipole moment (μ) and boiling
point (BP)? Answer: Higher dipole moment leads to stronger
dipole-dipole interactions, resulting in a higher boiling point.
◉How is molality defined? Answer: Molality (m) is defined as the
number of moles of solute per kilogram of solvent.
◉What is vapor pressure (VP)? Answer: The pressure above a liquid
where vaporization and condensation are at dynamic equilibrium.
,◉How does temperature affect vapor pressure? Answer: As
temperature increases, vapor pressure increases due to a greater
fraction of molecules having sufficient energy to escape.
◉What is the effect of stronger intermolecular forces on vapor
pressure? Answer: Stronger intermolecular forces result in lower
vapor pressure at a given temperature.
◉What is the normal boiling point? Answer: The temperature at
which vapor pressure equals 1 atm.
◉What is heat of vaporization (ΔHvap)? Answer: The amount of
heat required to vaporize one mole of a liquid to gas; it is
endothermic.
◉How does the heat of vaporization of water compare to diethyl
ether? Answer: Water has a higher ΔHvap (40.7 kJ/mol) compared
to diethyl ether (26.5 kJ/mol) due to stronger intermolecular forces.
◉What is the Clausius-Clapeyron equation used for? Answer: It
relates vapor pressure and temperature to calculate heat of
vaporization.
◉What does the slope of the Clausius-Clapeyron plot represent?
Answer: The slope represents -ΔHvap/R.
, ◉What happens to vapor pressure as external pressure decreases?
Answer: The boiling point decreases as external pressure decreases.
◉What is the relationship between intermolecular forces and
boiling point? Answer: Stronger intermolecular forces lead to higher
boiling points.
◉What is the significance of vapor pressure curves? Answer: They
show the relationship between vapor pressure and temperature.
◉What is the effect of a non-volatile solute on the freezing point of a
solution? Answer: The freezing point is lowered compared to that of
the pure solvent.
◉What is the dynamic equilibrium in vaporization? Answer: It
occurs when the rate of evaporation equals the rate of condensation.
◉What is the minimum kinetic energy necessary for a molecule to
escape into the gas phase? Answer: It increases with stronger
intermolecular forces.
◉How can you calculate the mass of water vaporized at its boiling
point? Answer: Using the heat of vaporization and the total energy
available.
