Download FREEZING – is the change of a liquid to a solid. Freezing occurs

Unit II: Matter
Chapter 3: Physical
and
Chemical Changes
Phases of Matter
Phase of matter is an important physical
property of matter.
 Matter can exists in four phases:
1) Solid

2) Liquid
3) Gases
4) Plasma
Solids
 Solids
have a definite shape
and a definite volume.
 The tiny particles that make up
a solid are packed very close
together.
 The particles are only able to
vibrate.
Crystalline solid
 In
most solids the particles are
arranged in regular, repeating
patterns called a crystal.
Amorphous solids
Some solids are not arranged in regular,
repeating patterns.
 These solids do not keep their definite
shape permanently.
 These amorphous solids lose their shape
under certain conditions.
 They act like a slow moving liquid.

Amorphous solids
 Examples:
candle
wax, window glass
and tar.
Liquids
 Liquids
have no definite shape, but
do have a definite volume.
 The tiny particles within a liquid are
free to flow around on another.
Liquid Viscosity
 Some
liquids will flow more easily
than others. The resistance of a
liquid to flow is called viscosity.
 High viscosity liquids include:
automotive oil, honey
Gases
Gases have no definite shape,no definite
volume.
 Gases particles tend to spread far out
from one another; they can be pushed
together.

Solids, Liquids, and Gases
Gas Laws (Boyle’s Law)
At constant temperature… A volume of
gas varies inversely with the pressure.
 Volume UP…Pressure DOWN
 Volume DOWN…Pressure UP

Gas Laws (Charles’ Law)
At constant pressure… The volume of
gas varies directly with the temperature.
 Volume UP… Temperature UP
 Volume DOWN… Temperature DOWN

Plasma
 Is
quite rare on Earth.
 Actually quite common
state of matter in the
universe, stars and our
Sun contain plasma.
 Plasma phase occurs at
extremely high energy.
Phase Change

Because energy content is responsible
for the different phases of matter,
substances can be made to change
phase by adding or taking energy.
Solid – Liquid phase change
– is the change
of a solid to a liquid.
 During melting energy is
absorbed.
 The temperature at which a
solid changes to liquid is
called the melting point.
 MELTING
Solid – Liquid phase change
FREEZING – is the change of
a liquid to a solid.
 Freezing occurs when a
substance loses energy.
 The temperature at which a
liquid changes to solid is
called the freezing point.

Liquid –Gas phase changes
– is the change of a
substance from a liquid to a gas.
 Energy is absorbed in this process.
 The process is called evaporation when
it takes place at the surface.
 If energy is supplied until the liquidgas
occurs, then the process is called
boiling.
 VAPORIZATION
Liquid –Gas phase changes
 CONDENSATION
– is the change of
a gas to a liquid.
 Energy is released during this
process.
Solid-Gas phase change
– when solid surface
particles escape directly into gas phase.
 Example: Dry Ice
 SUBLIMATION
Phases of Matter
Phase change diagram
Chemical Properties
 The
properties that
describe how a substance
changes into another
NEW substance.
 Flammability is a chemical
property. It describes the
ability to burn.
Flammabilty
Chemical Change
 Is
the process by which the
substance changes.
 Another name for a chemical
change is a chemical reaction.