Chapter No. 3 The Three states of Mater (Gases) (Gas Laws (Boyle's…
Chapter No. 3
The Three states of Mater
Gas is a substance, which under normal conditions have
neither a fixed volume and nor a fixed shape.
The kinetic molecular theory of Gasses
the physical behavior of gases described by a theory 'kinetic molecular theory'
1- All gases consist of
atoms or discrete particles
2- The size of molecule is very small as compared to the distance between them.
3-Constant random motion
4- no attractive forces between the molecules
5- Pressure: result of the collision of molecules with container.
6- collision between molecules is perfectly elastic.
Average speed and average kinetic energy of gas molecules are directly proportional to the Kelvin temperature
fore per unit area* P = F/A
Compressibility and Expansion
Gases can be compressed by increasing pressure, expand by decreasing pressure.
Effect of Tempreture and Pressure
Gases expand on heating, and contract on cooling.
Boyle's Law/ Pressure-volume-law
If temperature is constant, volume of a gas is inversely proportional to the temperature.
Charle's Law / The Temperature-volume-law
If pressure is constant, volume of a gas is directly proportional to its absolute tempreture.
Gay-Lussac's Law: The Pressure Temperature Law
If volume is constant, Pressure is directly proportional to the temperature. P/T = C
when temperature and pressure are constant, If the amount of gas in a container is increased, the volume increases. If the amount of gas in a container is decreased, the volume decreases. V/n =C
Dalton's Law of partial pressure
if two or more gases are enclosed in a container, and they don't chemically react. Then the total pressure exerted by the gaseous mixture is equal to the sum of the partial pressure of individual gases.
P = p1 + p2 + p3 +....
Ideal gas is one whose behavior can be predicted on the basis of kinetic molecular theory.
- on High-pressure and low-temperature gases deviates from their behavior.
- Molar Volume
: one mole of any gas at S.T.P occupies 22.4 cm3.
The volume of gases compared under
N.T.P(Natural conditions for Temp and Pressure)
S.T.P ( Standard Condition of temp & pressure)