CHAPTER 17

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CLASSIFICATION OF

MATTER

Composition of Matter

I.

Substance

A.

or a compound.

is eitheran element

When all the atoms in a substance are alike, the substance is an element.

1.

A compound is a substance with two or more elements combined in a fixed proportion. 2.

Two or more substances that can be easily separated by physical means form a mixture.

B.

Heterogeneous mixture

mixture of different & easily distinguishable materials.

1.

Homogeneous mixture•contains 2 or more gaseous, liquid, or solid substances blended evenly.

•also called a solution. 2.

Colloid -

heterogeneous mixture with larger particles that never settle. 3.

Colloids scatter light in the

3.Tyndall effect.

A heterogeneous mixture containing

a liquid in which

visible particles

settle is called a

suspension. 4.

Properties of Matter

II.

Physical property - characteristic of a material which can be observed without changing the identity of the substances in the material. Ex:

A.

Color

,

shape,

size,

melting point,

and boiling point.

- physical description of a substance.

1.

Appearance

Behavior - how a substance acts.

2.magnetis

mviscosity

ductility

as size and magnetism can be used to separate mixtures.

3.

Physical properties such

change in a substance’s size, shape,

B.

or state of matter.

Physical change

A substance does not change identity when it undergoes a physical change.

1.

Distillation is a process for separating a mixture

by evaporating a liquid and

condensing its vapor.

2.

Chemical property - characteristics of a substance indicating that it can change chemically. Ex:

C.

flammability

light sensitivity

change has occurred.

fD.

When one substance changes to another substance, a chemical

Some chemical changes are indicated by temperature change, smell, or bubble formation.

1.

Other chemical changes occur very slowly such as the formation of rust.

2.

substances such as metals from their ores.

3.

Chemical changescan be used to separate

Weathering of Earth’s surface involves

both physical

and chemical changes.

E.

Physical changes cause big rocks to split into smaller ones; streams carry rock particles from one location to another.

1.

Chemical changes can occur in rocks

when calcium carbonate

in limestone changes due

to acid rain.2.

Law of Conservation of Mass - Mass of all substances present before a chemical change equals the mass of all substances after the change. F.

THE END