The Study of Gas Laws
Gases do not have a definite shape or volume as in the case of solids and liquids.
The distance between the molecules of gases is much larger in comparison of liquids (lesser) and solids(almost negligible).
The force of attraction between the molecules of gases is negligible', more in liquids and highest in solids.
Molecules of gases move in straight line, undergo random collisions with other molecules and occupy the complete space available in the container unlike in solids and liquids.
Behaviour and Properties of Gases
Explanation on basis of Kinetic Theory
Gases occupy all available space. | Molecules of gases are far apart and force of attraction between the gases is very weak. Molecules of gases is in continuous motion and their movement is restricted by the walls of the container. |
The volume of a given mass of gas can easily be compressed. | Volume of particles is negligible to the intermolecular distance |
Gases exerts pressure in all the directions. | Impact of gas molecules with high velocity causes it to exert pressure in all the directions. |
Gases have much lower densities. | The intermolecular distance between the molecules of gases is very large. Hence, the molecules per unit volume of gas is comparatively lower than solids and liquids. |
Gases diffuse readily. | The space between the molecules of gases is very large since the intermolecular distance between the gases is very large. |
Temperature kept constant
When the temperature of fixed mass of gas is kept constant and the pressure is increased systematically its volume is decreased.
When the temperature of fixed mass of gas is kept constant and the pressure is decreased systematically its volume is increased.
Pressure kept constant
When the pressure of fixed mass of gas is kept constant and the temperature of a gas is increased systematically its volume is increased.
When the pressure of fixed mass of gas is kept constant and the temperature of a gas is decreased systematically its volume is decreased.
Boyle’s Law
States that for a fixed mass of gas at constant temperature, the volume of the gas is inversely proportional to its pressure.
When the pressure of a fixed mass of gas is increased, the volume decreases.
When the pressure is decreased, the volume increases.
Boyle's Law Formula:
The formula for Boyle's Law is represented as:
P1V1 = P2V2
Where:
P1 = Initial pressure of the gas
V1 = Initial volume of the gas
P2 = Final pressure of the gas
V2 = Final volume of the gas
This formula illustrates that when the pressure of a gas increases, its volume decreases, and vice versa, assuming constant temperature.
Charles’ Law
States that at constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute temperature.
When the temperature of a fixed mass of gas increases, its volume increases.
Conversely, when the temperature decreases, the volume decreases.
Charles' Law Formula:
The formula for Charles' Law is mathematically represented as:
V1/T1 = V2/T2
Where:
V1 = Initial volume of the gas
T1 = Initial temperature of the gas (in Kelvin)
V2 = Final volume of the gas
T2 = Final temperature of the gas (in Kelvin)
This formula shows that the volume of a gas increases with an increase in temperature, assuming constant pressure.
Gas Equation
States that at constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute temperature.
When the temperature of a fixed mass of gas increases, its volume increases.
Conversely, when the temperature decreases, the volume decreases.
Gas Equation Formula:
P1VI/T1 = P2V2/T2
Where:
P1 = Initial Pressure
V1 = Initial volume of the gas
T1 = Initial temperature of the gas (in Kelvin)
P2 = Final Pressure
V2 = Final volume of the gas
T2 = Final temperature of the gas (in Kelvin)
Standard Temperature and Pressure [S.T.P. or N.T.P.]
STANDARD TEMPERATURE: 273 K
STANDARD PRESSURE: 760 mm of Hg or 76 cm of Hg