Chemistry Reference
In-Depth Information
CHEMISTRY
S
S
UBSTANCE
TATES
Solid state
The state (or phase) in which a substance has a definite
volume and shape
Liquid state
The state in which a substance has a definite volume, but
can change shape
Gaseous state
A state in which a substance has no definite volume or shape
Melting
The change of state from solid to liquid
Vaporization
A change of state from liquid to gaseous
Condensation
A change of state from gaseous to liquid
Sublimation
The change of state from solid to gaseous without going
through the liquid state
A change of state is a physical change that does not alter chemical properties.
It usually takes place by increasing or decreasing the temperature of a
substance. The ability to change the state of substances is important in the
synthesis and purification of chemicals.
Water from a tap is an example of a chemical in the liquid state, whereas
ice is water in a solid state. When liquid water boils, it turns to steam, which
is water in the gaseous state. A dripping icicle on a warm winter day is an
example of melting, whereby the solid phase of water (ice) is converted back
to the liquid state. Droplets of water forming on a cool surface is the result
of condensation of gaseous water (steam) back to liquid water. Carbon dioxide,
the gas in carbonated beverages, is known as dry ice when it is in the solid
state. When dry ice is heated, it goes directly to a gas without first becoming
liquid. This is sublimation.
