MATTER: INTRODUCTION
“Matter is anything that occupies space and has mass.”
Matter is composed of small building units like atoms,
molecules etc which are packed or arranged in various ways to give matter
various states, physical and chemical properties etc. These molecules have
forces of interaction between them which are responsible to keep matter bound
or else the molecules would have been free. These intermolecular forces depend
on the distance between the molecules. In case of gases the molecules are far
apart from each other and that’s why the forces are very weak and gases are
most loosely bound state of matter. They don’t have fixed shape or volume of
their own. They take the shape and volume of the container they are kept in. In
case of liquids the intermolecular distances are lesser than gases and that’s
why forces are stronger and empty spaces are also less. That is why liquids
have a fixed volume if not shape of their own. The molecules are closely packed
in case of solids reducing the empty spaces drastically and increasing the
intermolecular forces. This gives solids a fixed shape and dimensions and also
a volume.
IDEAL GAS:
Ideal Gas is a hypothetical state of matter in which there
are no interactions between the molecules. All other states of matter are
studied comparatively to an ideal gas. There are some assumptions taken in case
of Ideal Gas which are:
1.
The intermolecular distances are very large and that’s why forces are
negligible.
2.
The volume occupied by the molecules is negligible as compared to the volume of
the container that is most of the space in an ideal gas is occupied by “voids”.
3.
The molecules of the gas are in a continuous and random motion.
4.
The molecules keep colliding among themselves and with the walls of the
container, these collisions are elastic, and due to the momentum change
associated with them there is a force applied on the walls which appears as the
pressure of the gas.
5.
Laws of classical mechanics (Newton’s Laws) are applicable on the molecular
motion of the Gas.
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