States of Matter
States of Matter
There are 4 forms or phases of matter:
•
•
•
•
Solid
Liquid
Gas
Plasma
The states of matter are physical states.
This means that matter can go from one
state to another without changing any of its
chemical properties.
Anything that has mass and takes up space
is called matter.
Most common substances exist as solids,
liquids, and gases, which have diverse
chemical and physical properties.
Solids, liquids, and gases are the the
physical forms in which all matter naturally
exists on Earth.
Matter can also exist as plasma, but this
state is not common on Earth.
Solids
A solid is a form of matter that has its own
definite shape and volume.
A solid does not take the shape of a
container it is placed in.
Wood, iron, paper, and sugar are examples
of solids.
Particles in a solid are tightly packed.
Liquid
A liquid is a form of matter that flows, has
constant volume, but has no definite shape.
A liquid takes the shape of its container.
Common examples of liquids include water,
blood, and mercury.
Particles in a liquid are not held in place
rigidly, so are able to flow past one another.
Gas
A gas is a form of matter that has no
definite shape and no definite volume.
A gas takes the shape of its container and
also fills the whole container, unlike a
liquid.
Some examples are helium and oxygen.
Particles in a gas are very far apart.
Particles in a solid and a liquid are close
enough together that they are not able to be
compressed into a smaller volume.
The particles of a gas, however, are far
enough apart that they are able to be
compressed into a smaller volume.
Vapor
What is the difference between a gas and
vapor?
Gas refers to a substance that is naturally in
the gaseous state at room temperature.
Vapor refers to the gaseous state of a
substance that is a solid or a liquid at room
temperature.
Oxygen, hydrogen, and helium are all gases
at room temperature.
Water is a liquid at room temperature and
turns to a gas when it has been sufficiently
heated. Then it becomes water vapor
(steam).
Changes of State
Matter changes form or state all the time.
Ice melts, water freezes or vaporizes.
Ice melting is an example of water changing
state from solid to liquid.
Matter changes state by the addition or
removal of heat or energy.
Solid ø Liquid ø Gas
Melting point is the temperature at which a
substance changes from the solid state to the
liquid state.
Freezing point is the temperature at which
a substance changes from the liquid state to
the solid state. It is the opposite of melting
point and are the exact same temperature.
Boiling point is the temperature at which a
substance changes from the liquid states to
the gaseous state.
Condensation point is the temperature
which a substance changes from the
gaseous state to the liquid state. It is the
opposite of boiling point and is the same
temperature.
Sublimation is the process by which a
substance changes from the solid state
directly to the gaseous state without ever
entering the liquid state.
Dry ice (frozen CO2) sublimates when it is
exposed to room temperature.
Change of State Diagram
Lets take a look at the change of state
diagram.
(a) Solid & liquid present. Solid is melting
when energy is added or liquid is freezing
when energy is being taken away.
During this time, the temperature does not
change. All the energy is going into
changing state.
(b) Liquid and vapor present. Liquid is
vaporizing when energy is added or gas is
condensing when energy is being taken
away.
During this time, the temperature also does
not change. All the energy is going into
changing state.