Chapter 3 Notes | Chemistry 1st Year

“Gases”

Index:

1. States of Matter
2. Gas Laws
3. General Gas Equation
4. Avogadro’s Law
5. Dalton’s Law of Partial Pressures
6. Diffusion And Effusion
7. Kinetic Molecular Theory of Gases
8. Kinetic Interpretation of Temperature
9. Liquefaction of Gases
10. Non-Ideal Behavior of Gases
11. Plasma State

Key Points:

1. The behavior of gas is described through 4 variables i.e. pressure, volume, temperature and its number of moles. The relationships b/w gas variables are know as the simple gas laws. Boyle’s law relates pressure of a gas with its volume, while Charles’s law relates gas volume with temperature. Avogadro’s law is concerned with volume and amount of gas.
2. By combining the above mentioned three laws, a more general equation about the behavior of gas is obtained PV=nRT.  This equation can be solved for any one of the variables when values of others are known.
3. Dalton’s law of partial pressure can be used to calculate the partial pressure of gases.
4. The process of diffusion and effusion are best understood by Graham’s law of diffusion.
5. Kinetic molecular theory of gases provides a theoretical basis for various gas laws. With the help of this theory a relationship is established b/w average molecular kinetic enegrgy and kelvin temperature.
6. The real gases show ideal behavior under specific conditions. They become non-ideal at high pressure and low temperature.
7. Gases can be liquified applying sufficient pressure but temperature should either be critical one or below it.
8. To calculate the pressure of volume of a real gas under the non-ideal conditions, alternative kinetic equation has been developed. This is known as the van der Waal’s equation.
9. The plasma, a forth state of mater, consist of neutral particles, positive ions and negative electron, 99% of the known universe is in the plasma state.