Chapter 3
Solids, Liquids, and Gases
8th Grade Science
States of Matter
• Solids, liquids, and gases can be _________,
elements
__________,
or ___________.
compounds
mixtures
• _________
- a definite shape and volume
Solid
– Solids will keep their shape in any position and in any
container
– Particles of a solid are packed _________together
Closely
vibrate slightly – they are in
– Particles of a solid ______
constant motion.
– Particles stay in the same position - ________
in place
vibrate
Types of Solids
• _____________
Crystalline solids - particles in a regular, repeating
pattern. Examples: sugar, salt, and snow.
– Cyrstalline solids will melt
_____ at a specific temperature.
Amorphous solids
• _______________
- particles are not arranged in
a particular pattern. Examples: plastics, rubber,
and glass.
– Amorphous Solids will _________
not melt at a specific
temperature – they may become softer and softer
until they change into other substances. Example:
butter.
Liquids
Liquids - a definite volume and takes the
• ______
shape of its container.
- particles of a liquid are packed almost as
closely as a solid.
freely than in a
-particles move around more _____
solid.
- no definite _____
shape but a definite ________.
volume
Fluid
______
- freely moving particles.
Properties of Liquids
• ____________
- the result of an inward pull
Surface Tension
among the particles of a liquid that brings the
particles on the surface closer together.
– Water particles pull together and bead up on
surfaces or form a skin – water striders walk on
water due to surface tension
viscosity
• ___________
- a liquids resistance to flowing.
– Depends on the size and shape of the particles
and the attractions between the particles.
– Liquids with ______
viscosity flow ______
high
Slowly (honey)
Gases
• ______
- can change volume , particles are
Gas
spread out and free to move, no definite
shape.
– Particles of gas move in all directions.
– As gas particles move, they fill the space around
them
– Particles of gas can be squeezed into a container.
When the container is open, the particles will
move freely and spread out.
Changes Between Solid and Liquid
• Particles of a liquid have more ________
thermal
energy than particles of the same substance in
solid form.
• Particles of the same substance as a gas has
even more _________
energy than the liquid
thermal
or solid form.
• A substance changes state when its thermal
increases or __________
decreases
energy either _______
sufficiently.
Melting
• A change in state from a solid to a liquid involves
the ________
in thermal energy.
increase
• ___________
is the change in state from a solid
Melting
to a liquid.
Melting point - specific temperature at which the
• ___________
melting occurs.
• At a substances ____________,
the particles that
Melting point
are bound together begin to vibrate so rapidly
that they break free from their fixed positions.
Freezing
• __________
- the change of state from a liquid
Freezing
to a solid.
• _________
of melting
Reverse
• ____________
- the particles begin to move
Freezing Point
so slowly that they begin to form a regular
pattern.
• Example: water loses energy – water
molecules move slowly because they lose
energy until freezing is complete
Changes between Liquid and Gas
• ____________
- the change from a liquid to a
Vaporization
gas.
energy
• Particles gain enough _______
to form a gas.
evaporation
• ___________
- vaporization that takes place
only on the surface of a substance.
boiling
• ________
- vaporization that occurs when a
liquid changes to a gas below the surface as
well as at the surface of the liquid.
Boiling Point / Condensation
Boiling point
• The __________
of a substance depends on
the __________
of the air above.
pressure
lower
less energy
• The _______
the pressure, the ___
needed for the particles to escape into the air.
Condensation
• ___________
- opposite of vaporization.
Particles in a ___
Gas lose enough energy to form
liquid
a _____.
Changes between a Solid and a Gas
• ____________
- surface particles of a solid
Sublimation
gain enough energy that they form a gas
without passing through the liquid phase.
• Example: dry ice (aka