# Critical Temperature, Pressure and Volume – Kinetic Theory of Gases

## Critical Temperature, Pressure and Volume – Kinetic Theory of Gases

We are giving a detailed and clear sheet on all Physics Notes that are very useful to understand the Basic Physics Concepts.

Critical Temperature, Pressure and Volume
Gases can’t be liquified above a temperature called critical temperature (TC) however large the pressure may be.

The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied.

Critical Pressure Definition:
The pressure required to liquify the gas at critical temperature is called critical pressure (pC)
The critical pressure is the vapor pressure of a fluid at the critical temperature above which distinct liquid and gas phases do not exist.

Critical Volume Physics Definition:
The volume of the gas at critical temperature and pressure is called critical volume (VC).
The volume occupied by a certain mass, usually one gram molecule of a liquid or gaseous substance at its critical point: The numerical value of the critical volume depends upon the amount of gas under experiment.

Value of critical constants in terms of van der Waals’ constants a and b are as under

VC = 3b, pC = $$\frac{a}{27 b^{2}}$$ and TC = $$\frac{8 a}{27 R b}$$

Further, $$\frac{R T_{C}}{p_{C} V_{C}}=\frac{8}{3}$$ is called critical coefficient and is same for all gases.

Kinetic Theory of Gases:
In this concept, it is assumed that the molecules of gas are very minute with respect to their distances from each other. The molecules in gases are in constant, random motion and frequently collide with each other and with the walls of any container.

In this portion, you will learn about the properties of gases, based on density, pressure, temperature and energy. Continue reading here to learn more.