What is Ideal Gas Law?

Ideal gas law is a well-defined approximation of the behavior of many gases under diverse conditions. It is the combination of empirical laws like Charle’s law, Boyle’s law, Gay-Lussac’s law, and Avogadro’s law. Ideal Gas Equation is the equation defining the states of the hypothetical gases expressed mathematically by the combinations of empirical and physical constants. It is also called the general gas equation.

Equation of Ideal Gas Law

The state of an ideal gas is determined by the macroscopic and microscopic parameters like pressure, volume, temperature. Thus, the ideal gas equation is often written as:

PV = nRT

Ideal Gas Law-Equation

  • P is the pressure of the ideal gas.
  • V is the volume of the ideal gas.
  • n is the amount of ideal gas measured in terms of moles.
  • R is the gas constant.
  • T is the temperature.

The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation of state, and is amenable to analysis under statistical mechanics. It can be derived from basic principles but was originally deduced from experimental measurements of Charles’ law (that volume occupied by a gas is proportional to temperature at a fixed pressure) and from Boyle’s law (that for a fixed temperature, the product PV is a constant). In the ideal gas model, the volume occupied by its atoms and molecules is a negligible fraction of V. The ideal gas law describes the behavior of real gases under most conditions. (Note, for example, that N is the total number of atoms and molecules, independent of the type of gas.)


Although, It has some limitations.

  • This equation holds well as long as the density is kept low.
  • This equation is applicable for single gas or even a mixture of multiple gasses where ‘n’ will stand for the total moles of gas particles in the given mixture.

The Equation of States of an ideal gas explains the simple relation between the parameters or properties that are very generic and accurate. In general, an equation relating the relation between P, V, T of an ideal gas is called Equation of States. Sometimes the relation involving other parameters of a substance at equilibrium state is also referred to as the Equation of States.

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