PHASE CHANGE
Melting
Boiling
Deposition
Condensation
Evaporation
Freezing Sublimation
Graphic Organizer
PHASE CHANGE
Phase change happens as the temperature
changes.
All matter can move from one state to another.
It may require extreme temperatures or extreme
pressures, but it can be done.
POINTS OF CHANGE
Phase changes happen when certain points are reached.
Scientists use freezing point or melting point to measure the
temperature at which a liquid turns into a solid.
There are physical effects that can change the melting
point.
Pressure is one of those effects. When the pressure
surrounding a substance increases, the freezing point and
other special points also go up.
EXEMPTIONS! -POINTS OF CHANGE
Generally, solids are more dense than liquids because their molecules
are closer together.
The freezing process compacts the molecules into a smaller space.
There are always exceptions in science!!!!
Water is special on many levels. It has more space between its
molecules when it is frozen.
The molecules organize in a specific arrangement that takes up more
space than when they are all loosed in the liquid state. Because the
same number of molecules take up more space, solid water is less
dense than liquid water.
PHASE CHANGE
Phase change requires energy. Heat is
easiest energy that can change the
physical state of matter.
The atom in a liquid have more energy
than the atoms in a solid.
PHASE CHANGE
MELTING
Solids substance turns to Liquid.
When a solid reaches the temperature of its melting point, it can become a liquid. For water, the temperature needs to be a little over zero degrees Celsius (0oC) for it to melt.
LATENT HEAT OF FUSION
It is the change in state
resulting from heating a
given quantity of a
substance to change its
state from a solid to a liquid.
The temperature at which
this occurs is the melting
point.
PHASE CHANGE
FREEZINGLiquid to Solid
The reverse of the melting process is called freezing.
Liquid water freezes and becomes solid ice when the molecules lose energy.
Water turns to ice at 32 degrees Fahrenheit or at 0 degrees Celsius
PHASE CHANGE
BOILING
A liquid boils at a temperature at which its vapor pressure is equal to the pressure of the gas above it.
The lower the pressure of a gas above a liquid, the lower the temperature at which the liquid will boil.
LATENT HEAT OF VAPORIZATION
heat of evaporation, is
the change required to
transform a given quantity of
a substance from a liquid
into a gas at a given
pressure (often atmospheric
pressure, as in STP).
BOILING
PHASE CHANGE
CONDENSATIONthe change of water from its gaseous form
(water vapor) into liquid water.
Condensation generally occurs in the atmosphere when warm air rises, cools and looses its capacity to hold water vapor.
As a result, excess water vapor condenses to form cloud droplets.
CONDENSATION
PHASE CHANGE
SUBLIMATIONSolid become a gas.
The easiest example of sublimation is dry ice.
Dry ice is solid carbon dioxide (CO2). Amazingly, when you leave dry ice out in a room, it will not melt into liquid but it turns into a gas.
Coal is another example of a compound that will not melt at normal atmospheric pressures. It will sublimate at very high temperatures.
SUBLIMATION
PHASE CHANGE
DESUBLIMATION (Deposition)It occurs when a gas becomes a solid without
going through the liquid state of matter.
Frost on winter mornings. The frost crystals on
plants build up when water vapor from the air
becomes a solid on the leaves of plants.