GASES
As studied in States of Matter a gas has no bounding surface and
thus has no definite volume or shape.
In this chapter, we examine and learn to use the laws governing the behavior
of gases. These laws, combined with the other properties of gases, form the
basis for the Kinetic molecular theory of gases.
Properties of Gaseous State
Following are the five properties of gases which can be measured
experimentally.
| 1. |
Gases are easily
compressible. |
The molecules in a
gas are very far apart due to very low intermolecular forces. By
external pressure they can be brought closer, thereby compressing the
gas. |
| 2. |
Gases do not have
definite volume. |
Molecules move easily
and occupy the entire volume of the container and take the shape of the
container. |
| 3. |
Gases exert pressure
in all directions. |
Molecules are always
in a state of rapid zig zag motion, colliding with each other and with
the walls of the container. Collisions account for pressure. As the same
number of molecules strike a given surface in unit time, gases exert
pressure uniformly in all directions. |
| 4. |
Gases diffuse easily.
|
Molecules of other
substances can fill a large space between gaseous molecules. This is
nothing but diffusion. |
| 5. |
Gases
have low density. |
Due to
large space, the number of units of molecules per unit volume of gas is
very low compared to solids or liquids. |
Gas Laws :
The quantitative relationship between volume, pressure, temperature and the
rate of diffusion for a given quantity of gas are termed as �Gas Laws�.
These Laws are
* Boyle�s law
* Charles� law
* Pressure-temperature law
* Avogadro�s law
* Graham�s law of diffusion
|
