Adiabatic process : 1. An adiabatic process is one in which pressure, volume and temperature of the system change but there is no exchange of heat between the system and the surroundings.
2. An adiabatic process may be achieve
a) If the gas is enclosed in a vessel whose walls are made of a highly insulating material and
b) The gas is compressed or allowed to expend very quickly.
3. When the gas expands, cooling will take place. Because the process takes place very quickly and the walls are made of insulating material, hence no heat cans either the system from surroundings. On the other hand, when the gas is compressed quickly, heat cannot escape to surroundings through the insulating walls and temperature of gas gets increased.
4. In case of an adiabatic process taking place in an ideal gas, internal energy of the system always changes.
5. As ΔQ = 0 in this process, hence the molar heat capacity in such a process is
C adiabatic = ΔQ/μΔT = zero
6. Adiabatic process takes place according to Poisson’s Law
PVϒ = constant