Ideal Gas Equation, Introduction, Equation of Ideal Gas Law (For CBSE, ICSE, IAS, NET, NRA 2022)

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Ideal Gas Equation


  • When dealing with gas, a famous equation was used to relate all-of the factors needed in order to solve a gas problem. This equation is known as the Ideal Gas Equation.
  • Anything ideal does not exist in real world.
  • Here, two well-known assumptions should have been made beforehand:
    • The particles have no forces acting among them
    • These particles do not take up any space, meaning their atomic volume is completely ignored.
  • An ideal gas is a hypothetical gas dreamed by chemists and students because it would be much easier if things like intermolecular forces do not exist to complicate the simple Ideal Gas Law.
  • Ideal gases are point masses moving in constant, random, straight-line motion. Its behavior is described by the assumptions listed in the Kinetic-Molecular Theory of Gases.
  • This definition of an ideal gas contrasts with the Non-Ideal Gas definition, because this equation represents how gas actually behaves in reality.

About Ideal Gas Equation

Ideal gas law is a well-defined approximation of the behaviour of many gases under diverse conditions in thermodynamics.

Ideal Gad Law

Ideal Gad Law
  • Ideal Gas Equation is the combination of empirical laws like
    • Charle՚s law,
    • Boyle՚s law,
    • Gay-Lussac՚s law
    • 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.
  • Definition: ‘The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation of the behaviour of many gases under many conditions, although it has several limitations’

Equation of Ideal Gas Law

  • State of an ideal gas is determined by the macroscopic and microscopic parameters like pressure, volume, temperature.
  • So, the ideal gas equation is often written as:


  • 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.

The Ideal Gas Equation Units, Terms, and Corresponding Definitions

The Ideal Gas Equation Units, Terms, and Corresponding Definitions
PressurePForce per unit՚s areaPa or N/
VolumeVThree-dimensional space enclosed by the closed surface
Amount of substances/number of molesnThe ratio of the mass of the gas (m) to its molar mass (M) .Mole
Ideal gas constantRPhysical constant relating the average kinetic energy of an ideal gas with temperature. It is expressed in units of energy per temperature increment per mole8.3144598 (48)
TemperatureTMeasure of heatK or

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