## definition of an ideal gas

ideal gas is a theoretical generalization, which is used by physicists to analyze the theory of probability.The ideal gas consists of molecules which repel each other and do not interact with the walls of the vessel.Inside there is no ideal gas forces of attraction or repulsion between molecules, and the energy is not lost during the collision.An ideal gas can be completely described by several parameters: volume, density and temperature.

equation of state for an ideal gas, commonly known as the ideal gas law, has the form:

PV = NkT.

Equation N - is the number of molecules, k - Boltzmann constant, which is abo
ut 14,000 Joules per Kelvin.The most important is that pressure and volume are inversely proportional to each other, and directly proportional to temperature.This means that if the pressure increases twice, and the temperature changes, the volume of gas is also doubled.If the volume of gas will be doubled and the pressure remains constant, the temperature will be doubled.In most cases, the number of molecules in the gas is constant.

Clashes between gas molecules are not perfectly elastic and some of the energy is lost.Also between the gas molecules exist, electrostatic interaction forces.But for the majority of situations the ideal gas law as close to the actual behavior of gases.The formula of the relationship between the pressure, volume and temperature can help scientist intuitively understand the behavior of gas.

## Practical application

ideal gas law is the first equation, which introduces students in the study of gases on the lessons of physics or chemistry.The equation of van der Waals forces, which includes a few minor fixes to the basic assumptions of the ideal gas law is also part of many introductory courses.In practice these differences are so small that if the ideal gas law is applicable for this particular case, the equation of van der Waals forces will not satisfy the conditions of accuracy.

As in most sections of thermodynamics, ideal gas as initially in a state of equilibrium.This assumption is not true if the pressure, volume or temperature change.When these variables are changing slowly, a condition called quasi-static equilibrium and the error in the calculations may be small.In case the parameters of the system vary chaotic way, the model of an ideal gas is not applicable.