http://www.ck12.org Chapter 2. Matter and Change
have a greater mass. Another extensive property is volume. Thevolumeof an objectis a measure of the space that
is occupied by that object.
Anintensive propertyis a property of matter that depends only on the type of matter in a sample and not on
the amount. For example, the electrical conductivity of a pure substance is a property that depends only on the
type of substance. Silver, gold, and copper are excellent conductors of electricity, while glass and plastic are poor
conductors. A larger or smaller piece of glass will not change this property. Other intensive properties include color,
temperature, density, and solubility.
For more information on extensive and intensive properties, visit http://www.chem.tamu.edu/class/majors/tutorialnotefiles
/intext.htm.
States of Matter
Water is a very common substance that we frequently encounter in all three states of matter (Figure2.2). When
water is in the solid state, we call it ice, while water in the gaseous state is referred to as steam or water vapor. The
physical state of matter is a physical property because the identity of a pure substance does not change when it is
melted, frozen, or boiled.
FIGURE 2.2
Water is the same substance in any of
its three states. (A) A frozen waterfall in
Hungary. (B) The Nile River in Egypt. (C)
A steam powered train in Wales.Solid
Asolidis a form of matter that has a definite shape and volume. The shape of a solid does not change if it is
transferred from one container to another. The particles of a solid are packed tightly together in fixed positions,
usually in an orderly arrangement (Figure2.3). Solids are almost completely incompressible, meaning that solids
cannot be squeezed into a smaller volume. When a solid is heated, it expands only slightly.
Liquid
Aliquidis a form of matter that has a definite volume, but an indefinite shape. As water is poured from one container
into another, it adopts the shape of its new container. However, the volume of the sample does not change because
the water molecules are still relatively close to one another in the liquid state. Its ability to flow means that water is
considered a fluid. Unlike a solid, the arrangement of particles in a liquid is not rigid and orderly. Liquids are also
incompressible, and the volume of water expands slightly when heated.
Gas
Agasis a form of matter that has neither a definite shape nor a definite volume. A gas takes up the shape and
volume of its container. This is because the particles of a gas are very, very far apart from one another compared to