Chem 202 Exam 1 Prep with Questions and
Answers
For a given compound, its liquid phase has less entropy than its solid phase. ANSWER False.
Entropy is Gas > Liquid > Solid.
Of the three common phases, intermolecular forces are the strongest in the solid phase.
ANSWER True. Intermolecular forces are Gas < Liquid < Solid.
An ideal gas has no intermolecular forces. ANSWER True.
Deposition is favored by entropy. ANSWER False. Sublimation is favored by entropy.
Ice cubes left in a freezer will shrink over time. ANSWER True. This is due to sublimation.
For any given substance, Delta S (sublimation) is greater (more positive) than Delta S
(vaporization). ANSWER True.
Freezing is exothermic. ANSWER True.
Condensation is endothermic. ANSWER False. Vaporization is endothermic.
Of the three common phases, the gas phase has the most entropy. ANSWER True.
Liquid and solid phases can exist when intermolecular forces are strong enough to overcome
the natural tendency to maximize entropy. ANSWER True.
, Air at 80% RH is unsaturated. ANSWER True. Any time the RH is below 100%, the air is
unsaturated.
EVP increases as temperature increases. ANSWER True. Pressure and temperature are
directly related. As one goes up, the other must do so as well.
Evaporation involves vaporization from the surface of a liquid. ANSWER True. Evaporation
involves vaporization from the surface while boiling involves vaporization from below the
surface of a liquid.
Stronger intermolecular forces tend to give a greater (more positive) delta H (vaporization).
ANSWER True. Stronger intermolecular forces have to be overcome in order for
vaporization to occur which means that the delta h (vaporization) will be more positive.
Boiling cannot occur until a liquid's vapor pressure equals the surrounding pressure.
ANSWER True. In order for a liquid to boil, the liquid's vapor pressure does have to equal
the pressure of the surroundings. When the temperature goes up, so does the pressure.
Sweating cools you down because vaporization is exothermic. ANSWER False. Sweating
cools you down because vaporization is endothermic. (endothermic uses joules from your
skin which therefore, cools you down)
At higher temperatures, more molecules can escape a liquid phase and go to the gas phase.
ANSWER True. At higher temperatures, there is more energy which allows more molecules
to go from the liquid phase to the gas phase.
Strong intermolecular forces give a higher boiling point. ANSWER True. Stronger
intermolecular forces give rise to a higher boiling points because of the raise in the barrier of
energy needed to go from liquid to gas.
Answers
For a given compound, its liquid phase has less entropy than its solid phase. ANSWER False.
Entropy is Gas > Liquid > Solid.
Of the three common phases, intermolecular forces are the strongest in the solid phase.
ANSWER True. Intermolecular forces are Gas < Liquid < Solid.
An ideal gas has no intermolecular forces. ANSWER True.
Deposition is favored by entropy. ANSWER False. Sublimation is favored by entropy.
Ice cubes left in a freezer will shrink over time. ANSWER True. This is due to sublimation.
For any given substance, Delta S (sublimation) is greater (more positive) than Delta S
(vaporization). ANSWER True.
Freezing is exothermic. ANSWER True.
Condensation is endothermic. ANSWER False. Vaporization is endothermic.
Of the three common phases, the gas phase has the most entropy. ANSWER True.
Liquid and solid phases can exist when intermolecular forces are strong enough to overcome
the natural tendency to maximize entropy. ANSWER True.
, Air at 80% RH is unsaturated. ANSWER True. Any time the RH is below 100%, the air is
unsaturated.
EVP increases as temperature increases. ANSWER True. Pressure and temperature are
directly related. As one goes up, the other must do so as well.
Evaporation involves vaporization from the surface of a liquid. ANSWER True. Evaporation
involves vaporization from the surface while boiling involves vaporization from below the
surface of a liquid.
Stronger intermolecular forces tend to give a greater (more positive) delta H (vaporization).
ANSWER True. Stronger intermolecular forces have to be overcome in order for
vaporization to occur which means that the delta h (vaporization) will be more positive.
Boiling cannot occur until a liquid's vapor pressure equals the surrounding pressure.
ANSWER True. In order for a liquid to boil, the liquid's vapor pressure does have to equal
the pressure of the surroundings. When the temperature goes up, so does the pressure.
Sweating cools you down because vaporization is exothermic. ANSWER False. Sweating
cools you down because vaporization is endothermic. (endothermic uses joules from your
skin which therefore, cools you down)
At higher temperatures, more molecules can escape a liquid phase and go to the gas phase.
ANSWER True. At higher temperatures, there is more energy which allows more molecules
to go from the liquid phase to the gas phase.
Strong intermolecular forces give a higher boiling point. ANSWER True. Stronger
intermolecular forces give rise to a higher boiling points because of the raise in the barrier of
energy needed to go from liquid to gas.
