Download classification of matter - St. Thomas the Apostle School

CLASSIFICATION OF
MATTER
Chapter 15
Composition of matter
• Substance- either an element or a compound
• When all the atoms in a substance are alike, the substance is an
element.
• A compound is a substance with two or more elements combined in a
fixed proportion.
Two or more substances that can be easily
separated by physical means form a mixture.
1. Heterogeneous mixture- mixture of different and easily
distinguishable materials.
2. Homogeneous mixture- contains two or more gaseous,
liquid, or solid substances blended evenly; also called a
solution.
3. Colloid- heterogeneous mixture with larger particles that
never settle; colloids scatter light in the Tyndall Effect.
4. A heterogeneous mixture containing a liquid in which
visible particles settle is called a suspension.
Mixtures
HETEROGENEOUS-proportions of substance may vary
-different materials can be identified
- Particles settle in a suspension
HOMOGENEOUS- Particles are too small to be seen with a microscope.
- Particles never settle
- They remain constantly mixed
COLLOID-particles are larger than in sollutions
-Contains substances in varying proportions
-particles wil not settle
Particles scatter light
The Tyndall Effect
The Tyndall effect, also known as
Tyndall scattering, is light scattering
by particles in a colloid or else
particles in a very fine suspension.
It is named after the 19th-century
physicist John Tyndall.
On a sheet of paper give three physical
properties of yourself.
Properties of matter
•Physical Property- characteristics of a material which can
be observed without changing the identity of the substance in the
material. ; examples include color, shape, size, melting point, and
boiling point
Physical Properties:
•Appearance- physical description of a
substance
•Behavior- how a substance acts; for example
magnetism, viscosity, ductility
•Physical properties such as size and
magnetism can be used to separate
mixtures.
Physical Change- change in a substance’s size,
shape, or state of matter
• Substance does not change identity when it undergoes a physical
change
• Distillation is a process for separating a mixture by evaporating a
liquid and condensing its vapor.
CHEMICAL PROPERTY- characteristics of a
substance indicating that it can change chemically
• For example- flammability or light sensitivity of a substance
When one substance changes to another
substance, a chemical change has occurred.
• Some chemical changes are indicated by temperature change, smell,
or bubble formation.
• Other chemical changes occur very slowly such as the formation of
rust.
• Chemical changes can be used to separate substances such as metals
from their ores.
• THESE PROPERTIES of a substance NEVER CHANGE: density, specific
heat, boiling point, melting point
WEATHERING of Earth’s surface involves
both physical and chemical change.
• Physical- big rocks split into smaller ones; streams carry rock particles
from one location to another.
• Chemical- Chemical change can occur in rocks when calcium
carbonate in limestone changes to calcium hydrogen carbonate due
to acid rain.
Law of Conservation of mass- mass of all
substances present before a chemical change
equals the mass of all substances after the change.