Phase Changes
Which statements describe phase changes? Particles in a liquid need to move more slowly in order to freeze. Attractive forces overcome the motion of particles when a solid sublimes. Attractive forces between the particles in a liquid are broken when a liquid boils. Particles in gas move fast enough to make more attractive forces when the gas condenses.
1, 3
Use kinetic-molecular theory to describe what happens when an ice cube or icicle melts. Include how energy is involved and what happens to the motion of the water molecules
The particles in a solid move faster as the solid absorbs heat. The particles in a solid overcome the attractions that hold them together as the solid melts. The particles slide past one another, but are still close together during the liquid phase.
describe how phase changes can be diagrammed as a substance is heated?
The temperature is on the y-axis and the time is on the x-axis.
What are the 5 steps during Temperature and Phase Changes?
The temperature of solid increases The solid melts. The temperature of the liquid increases. The liquid boils. The temperature of the gas increases.
What is sublimation?
a transition directly from solid phase to vapor phase
What is deposition?
a transition directly from vapor phase to solid phase
What is freezing?
a transition from liquid phase to solid phase
What is boiling?
a transition from liquid phase to vapor phase
What is melting?
a transition from solid phase to liquid phase
What is condensing?
a transition from vapor phase to liquid phase
Identify each of the phase changes described below. Liquid nitrogen becomes a gas when it is poured out of its container. The nitrogen is...
boiling
If you have enough energy for all the particles in that liquid to change phase at the same time, then you achieve __________.
boiling
The ____________ point is the y-value of the upper horizontal line.
boiling
Energy is absorbed during which phase changes?
boiling melting subliming
Identify each of the phase changes described below. Water vapor in the air becomes tiny liquid droplets that form fog. The water is...
condensing
Energy is released during which phase changes?
condensing depositing freezing
Temperature is ________ during phase changes.
constant
Horizontal lines where the temperature is _________ during phase changes connect upward-sloping lines where the temperature _________.
constant increases
Identify each of the phase changes described below. In a very cold cryogenic freezer, solid oxygen forms on the walls from the oxygen gas in the air. The oxygen is...
depositing
When a particle has enough energy at the surface of a liquid, it can _______, or launch from the liquid phase up to the gas phase.
evaporate
The higher the vapor pressure, the more readily the liquid __________.
evaporates
Identify each of the phase changes described below. Liquid gold is poured into molds and cools to become solid bars. The gold is...
freezing
Evaporation takes place at(in terms of vapor pressure)
higher vapor pressure
Both evaporation and boiling are phase changes from...
liquid to gas
Boiling takes place at(in terms of vapor pressure)
lower vapor pressure
Identify each of the phase changes described below. Solid iron is heated to high temperatures so that it becomes a liquid. The iron is...
melting
The ______________ point or __________ point is the y-value of the lower horizontal line.
melting/freezing
Is this part of kinetic-molecular theory? The particles in a solid are far apart.
no
Is this part of kinetic-molecular theory? The particles in a solid do not move.
no
During equilibrium between liquid & gas, _____ move between liquid and gas phase.
particles
During equilibrium between liquid & gas, gas particles exert __________.
pressure
Phase transitions happen at _________ temperatures.
specific
Identify each of the phase changes described below. In the high desert, snow changes to water vapor without becoming liquid water. The snow is...
subliming
The ____________ increases when there is only solid, liquid, or gas.
temperature
Vapor pressure is directly related to...
temperature
What is vapor pressure?
the pressure exerted by the gas in equilibrium with a pure liquid at a given temperature
evaporation and boiling are phase changes; it all depends on the __________________.
vapor pressure
Is this part of kinetic-molecular theory? The particles in a gas have few attractions between them.
yes
Is this part of kinetic-molecular theory? The particles in a liquid are moving past one another constantly.
yes
Is this part of kinetic-molecular theory? The particles in a solid vibrate in a fixed position.
yes
Is this part of kinetic-molecular theory? The particles in all states of matter are always moving.
yes
Is this part of kinetic-molecular theory? The particles in gas move freely in all directions.
yes
