Notes

Diffusion :
It is the process Where the gas Particles moves from high concentration region to low concentration region
coefficient of diffusion of gas:
It is defined as the number of molecules per unit area second per unit concentration gradient is called coefficient of diffusion of gas
D = number of molecules crossing per second per unit / concentration gradient (dn/dt).
Conclusion :
1.The coefficient of diffusion of gas is directly proportional to the average velocity of the gas molecule.
2.The coefficient of diffusion of gas is inversely proportional to the concentration of the gas molecule.
3.The coefficient of diffusion of gas is inversely proportional to the square of the diameter of the gas molecule.

Joules kelvin effect :
When a gas under a high pressure region to low pressure region passed through a porous plug then there is a change in its temperature this effect is called joules kelvin effect or joules thomson effect .
Important Points :
1.All the gases when passes through the porous plug then there is a change in its temperature.
2.All the gases except hydrogen and helium temperature decreases this effect is called cooling effect.
3.In case the hydrogen and helium gases temperature increase . This effect is called Heating effect.
4.The change in temperature is directly proportional to the pressure on the two sides of the plug.
5.At the initial temperature of the gas raising or falling then the temperature is called "Inverse temperature denoted by T1".
Expression for joule-kelvin effect :
Consider a cylinder with A and B with non distance P and Q .Let p1v1 be the pressure and volume of the left side and p2v2 be the pressure and volume of the right side.Left side is high pressure region and right side low pressure region .