Ideal gases
An ideal gas is one which follows the ideal gas equation of state, namely
PV = (m/M) (MR) T = n Ru T
The universal gas constant has a value of 8.314 J/mol K or kJ/kmol K and is related to the specific gas constant by the relation Ru = (R /M)
The internal energy of an ideal gas is a function of temperature only and is independent of pressure and volume. That is,
u= u(T)
(∂u/∂P)T =0, (∂u /∂v)T = 0
Real gases:
The ideal gas law is only an approximation to the actual behavior of gases.
At high densities, that is at high pressures and low temperatures, the behavior of actual or real gases deviate from that predicted by the ideal gas law. In general, at sufficiently low pressures or at low densities all gases behave like ideal gases.
Hope this helps.
What is internal energy ? & how is internal energy of a real gas differs from that of ideal gas?
2 answers
Thanks Awesome, but it a little more complicated.
What is internal energy, and how does that differ in ideal and real gases?
Internal energy is the sum of all the energys in the particles. In ideal gases, it exists as Kinetic energy only, there are no potential energies to consider. In real gases, there are attractions between molecules, so we have rotational energy, and vibration energy, as well as kinetic energy. In those molecules which are vibrating, and rotating, consider it like little springs, which have potential enrgy and moving energy oscillating.
That may be a function of temperature we measure, but it is not the same as what we consider in single moving particles, it is more complicated, and we have to use statistical approaches in deriving relationships. those vibrational and rotational motions may be a function of density (particle proxmity) also, which is altered by pressure, In an idealized gas, this is not so.
What is internal energy, and how does that differ in ideal and real gases?
Internal energy is the sum of all the energys in the particles. In ideal gases, it exists as Kinetic energy only, there are no potential energies to consider. In real gases, there are attractions between molecules, so we have rotational energy, and vibration energy, as well as kinetic energy. In those molecules which are vibrating, and rotating, consider it like little springs, which have potential enrgy and moving energy oscillating.
That may be a function of temperature we measure, but it is not the same as what we consider in single moving particles, it is more complicated, and we have to use statistical approaches in deriving relationships. those vibrational and rotational motions may be a function of density (particle proxmity) also, which is altered by pressure, In an idealized gas, this is not so.
1 answer