Page 16 - Bruno Linder Elementary Physical Chemistry

August 18, 2010 11:35 9in x 6in b985-ch01 Elementary Physical Chemistry

Chapter 1

State of Matter. Properties of Gases

Chemistry deals with the properties of matter, the changes matter
undergoes and the energy that accompanies the changes.

Physical Chemistry is concerned with the principles that underlie
chemical behavior, the structure of matter, forms of energy and their
interrelations and interpretation of macroscopic (bulk) properties of matter
in terms of their microscopic (molecular) constituents.

Broad classification of Matter: A gas fills the container and takes on
the shape of the container. A liquid has a well-defined surface and a fixed
volume but no definite shape. A solid has a definite shape, a fixed volume,
and is independent of constraints.
The foregoing classification is a macroscopic classification. From a
microscopic (molecular) point of view — a gas consists of particles that
interact with each other weakly; a liquid consists of particles that are in
contact with each other but are able to move past each other; and a solid
consists of particles that are in contact with each other but are unable
to move past each other. For short, in a gas, particles have essentially no
restriction on motion; in a solid, particles are locked together, mostly with
fixed orientation; and in liquid, particles behave in a manner between gas
and solid.

1.1. State of Matter
The above classification is often referredto as a classificationinto states
of aggregation. In physical chemistry, the word state generally refers to
another concept. A substance is described by its properties (pressure,
volume, temperature, amount, composition, etc.). If all the properties

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