Ideal Gas Law Formula – Equation and Problem Solved with Example

Practically, there is no such thing like ideal gas but based on the behavior of gases and its properties, names could be given. If gases start behaving ideal at a particular temperature or pressure then it is named as the ideal gas. Here, are the few assumptions for the concept –

  • Gases are made up of molecules that are in random motion constantly and arranged on straight lines only.
  • Gases are made up of molecules that further acts like rigid spheres.
  • When two molecules collide with the each other, it will create the pressure on the walls of container too.
  • The collision between molecules or across walls of container is generally elastic. There is no loss of kinetic energy at all.
  • The temperature of gas is further proportional to the average kinetic energy of molecules ahead.

Finally, we will highlight two more assumptions that are necessary to discuss here to differentiate the real gases from the ideal ones –

  • There are no intermolecular forces between the molecules of gas,
  • There is only negligible space occupied by the molecules related to the volume of the container.

Let us see ahead how to represent the ideal gas equation formula in Chemistry –

ideal gas equation formula

pV = nRT

P = Pressure (atm)
V = Volume (Liters – L)
n = Number of moles (mol)
R = The Ideal Gas Constant (0.08206 L-atm/mol-K)
T = Temperature (Kelvin)

This is a most common equation in Chemistry and easy to remember as well. Here, p is pressure and it is measures in Pascals. If it is given in other units then first convert the same into pascals before it could be used for the ideal gas equation.

The next popular term associated with the equation is Volume V and it is measure in cubic meters. Further, n is the number of moles in a chemical reaction, R is the Constant and the SI value for R is 8.31441 J K-1 mol-1, and T is the temperature under which the ideal gas equation takes place.