Chapter 17: Change of Phase Study Questions

When warm, moist air blows over the Pacific Ocean and meets the cold waters off the coast of San Francisco, the result is: a. fog b. cloud cover c. updrafts over the land d. lowered humidity

a. fog

The dew that forms on a cold soda can when taken from a refrigerator is due to: a. evaporation b. condensation c. sublimation d. regelation

b. condensation

Steam burns are much more damaging than burns from boiling water because steam: a. has a higher temperature b. contains more internal energy c. is hotter d. is gaseous

b. contains more internal energy

The process of boiling water tends to: a. warm the water b. cool the water c. both warm and cool the water at the same time d. have no effect on water's temperature

b. cool the water

Boiling and freezing can occur at the same time when water is subjected to: a. decreased temperatures b. decreased atmospheric pressure c. increased temperature d. increased atmospheric pressure

b. decreased atmospheric pressure

When gas changes phase to become a solid, energy is: a. absorbed b. given off c. unchanged d. in effect multiplied

b. given off (this occurs when snowflakes form in the air)

When salt is introduced to water, the temperature at which freezing takes place is: a. quite unaffected b. lowered c. increased d. dependent on the shape of slat and ice crystals

b. lowered

Regelation occurs due to water's: a. high specific heat b. open-structured ice crystals c. high rate of expansion d. slight tendency to freeze when temperature is lowered

b. open-structured ice crystals

When water turns to ice, water molecules: a. absorb energy b. release energy c. retain their energy d. lose the quality of wetness

b. release energy

When steam condenses to water, energy is: a. absorbed by the steam b. released by the steam c. conserved as the phase change occurs d. changed to a different form

b. released by the steam

When snow forms in clouds, the surrounding air is: a. cooled b. warmed c. both d. none of the above

b. warmed

When a gas changes phase to become, energy is: a. absorbed b. given off c. unchanged d. in effect multiplied

a. absorbed

When ice changes phase to become water, energy is: a. absorbed b. given off c. unchanged d. in effect multiplied

a. absorbed

Put a saucer of water on your table. A process that then occurs is: a. evaporation b. condensation c. both of these d. none of these

c. both of these (both evaporation and condensation occur simultaneously, which rate is greater, if any, produces the net effect)

We feel uncomfortable on a muggy day because water molecules are: a. evaporating from our moist bodies b. condensing from our moist bodies c. condensing from the atmosphere onto our bodies d. preventing evaporation

c. condensing from the atmosphere onto our bodies

When relatively slow-moving molecules condense from the air, the temperature of the remaining air tends to: a. remain unchanged b. decrease c. increase d. spread out uniformly

c. increase (removal of slow molecules results in a greater proportion of fast ones in the air)

When matter changes phase directly from solid to gas, we call the process: a. evaporation b. condensation c. sublimation d. regelation

c. sublimation

The melting point of a substance such as water is normally: a. higher than the freezing point b. lower than the freezing point c. the same as the freezing point d. unrelated to the freezing point

c. the same as the freezing point (water freezes at 0 C and ice melts at 0 C. Likewise for the melting and freezing points of other substances.)

A common device that transfers heat from one location to another is: a. a refrigerator b. a heat pump c. an air conditioner d. all of the above

d. all of the above (both a refrigerator and an air conditioner are heat pumps)

When evaporation occurs in a dish of water, the molecules left behind in the water: a. are less energetic b. have decreased average speeds c. result in lowered temperature d. all of these

d. all of these