Matter is anything that occupies space and has weight. If you look around you,
you will see matter. The table, books, walls, and your body are all composed of matter.
Obviously, the matter around you is not all the same.
a. Physical States of Matter. In general, we can group all matter into three
groups called states of matter.
(1) Solids. Solids have a definite shape and volume. Examples of solids
are books, rocks, pieces of steel, and sand.
(2) Liquids. Liquids have a definite volume but indefinite shape. That is,
they take the shape of their container. Water, mercury, alcohol, and oils are liquids.
(3) Gases. Gases have neither a definite shape nor a definite volume.
They assume not only the shape of their container, but also the volume of their
container. Gases may be expanded or compressed to fit the container in which they are
being placed. Therefore, the air in an automobile tire would, if released, expand to fill a
large weather balloon.
b. Properties of Matter. Matter possesses two types of properties, physical
and chemical. Characteristics such as smell, color, shape, freezing point, boiling point,
and solubility are said to be physical properties of matter. Energy content, reactions
with other substances, and chemical reactions due to light, heat, and electricity are said
to be chemical properties of matter. From the physical and chemical properties
exhibited by a substance, it is possible to isolate, identify, and classify the particular
c. Classification of Pure Matter. Matter that cannot be separated into two or
more types of matter by physical means is called pure matter. Pure matter consists of
two types, elements and compounds.
(1) Elements. Elements are substances that cannot be separated into two
or more types of matter by physical or chemical methods. Another way to say this is
that elements consist of only one type of atom. An atom is a chemical building block
and can be defined as the smallest part of an element that remains unchanged during
any chemical reaction and exhibits or displays the chemical properties of that element.
Examples of common elements are oxygen, gold, iron, mercury, hydrogen, and carbon.
Table 1-1 lists the elements with their symbols, atomic numbers, and atomic weights.
(2) Compounds. Compounds are composed of two or more elements
chemically combined. Compounds are substances that have been purified by physical
means, but not by chemical methods. They can be separated into two or more types of
matter by chemical methods because their basic unit, the molecule, is a combination of