The term ideal gas refers to a hypothetical gas composed of molecules which follow a few rules: Ideal gas molecules do not attract or repel each other. The only interaction between ideal gas molecules would be an elastic collision upon impact with each other or an elastic collision with the walls of the container.

As the temperature increases, the average kinetic energy increases as does the velocity of the gas particles hitting the walls of the container. The force exerted by the particles per unit of area on the container is the pressure, so as the temperature increases the pressure must also increase.

At high pressure, the ideal gas law underestimates volume. Because real molecules take up space, the molar volume of a real gas is larger than predicted by the ideal gas law at high pressures. At high temperature, the pressure of the gases is nearly identical to that of an ideal gas.

The ideal gas law is used like any other gas law, with attention paid to the units and making sure that temperature is expressed in kelvins. However, the ideal gas law does not require a change in the conditions of a gas sample.

Real gases are nonideal gases whose molecules occupy space and have interactions; consequently, they do not adhere to the ideal gas law. To understand the behaviour of real gases, the following must be taken into account: issues with molecular dissociation and elementary reactions with variable composition.

As mentioned in the previous modules of this chapter, however, the behavior of a gas is often non-ideal, meaning that the observed relationships between its pressure, volume, and temperature are not accurately described by the gas laws.

Two types of gases exist. Real gas and Ideal gas. As the particle size of an ideal gas is extremely small and the mass is almost zero and no volume Ideal gas is also considered as a point mass. The molecules of real gas occupy space though they are small particles and also have volume.

The relationship for Boyle’s Law can be expressed as follows: P1V1 = P2V2, where P1 and V1 are the initial pressure and volume values, and P2 and V2 are the values of the pressure and volume of the gas after change.

Charles’s law is best represent by the formula, V1T2= V2T1. Charles’s law state that for an ideal gas, at constant pressure, the absolute volume of a gas is directly proportional to the temperature.

Charles’ law formula V₁ / T₁ = V₂ / T₂ , where V₁ and T₁ are initial volume and temperature, respectively.