A chemical compound is called a gas when its particles or molecules are free to move anywhere inside a container. There are two kinds of gases – Real and ideal gases. The primary difference between ideal gas and real gas is that real gas molecules contain intermolecular forces, whereas ideal gas molecules do not. In the following article, we will learn more about the difference between real gas and ideal gas.
Real Gas
A real gas is one that does not obey gas laws under all conventional pressure and temperature conditions. Real gases obey gas laws only at high temperatures and low pressures. These real gases are made up of distinct atoms or molecules known as particles. Real gases have mass, volume, and velocity. The volume of a gas is defined as the volume of the container in which it is stored.
Additionally, real gas molecules possess intermolecular interactions. Van Der Waal interactions are the names given to these attraction forces. When two real gas particles collide, there is a transition in the energy of the particle as well as a change in the direction of its travel.
Ideal Gas
Ideal gases are gases that obey the ideal gas law at all temperature and pressure circumstances. An ideal gas is a theoretical gas that does not exist in reality. Because an ideal gas has no interparticle connections, numerous minute particles flow randomly in all directions. Ideal gases are gaseous compositions made up of extremely small molecules with zero volume and mass.
At high pressures and low temperatures, however, ideal gases can become real gases because the gas particles come close to one other with low kinetic energy, resulting in the development of intermolecular forces.
Why is an Ideal gas considered hypothetical?
Every molecule in the universe has some sort of intermolecular attraction with each other. In the case of an ideal gas, however, the molecules do not attract or repel each other. The sole interaction between ideal gas molecules would be an elastic collision when they collided or an elastic collision with the container’s walls. As a result, ideal gas does not exist in reality. It is a hypothetical gas created to simplify computations.
Properties of Real Gases
- The coefficient of thermal expansion (α) of a gaseous molecule is determined by its composition.
- The coefficient of compressibility (β) was also discovered to be gas-specific.
- A temperature below the critical temperature (Tc) allows the molecule to liquefy after a given pressure, which varies with temperature.
- Inter-molecular attraction exists in real gases, and when expanded, the molecules must expend more kinetic energy to overcome inter-molecular attraction. As a result, the temperature drops.
Properties of Ideal Gases
- Because the gaseous molecule has no intermolecular attraction, an ideal gas cannot be liquefied.
- The coefficient of thermal expansion (α) is determined by the temperature of the gases and is not affected by nature.
- The coefficient of compressibility (β) is also pressure-dependent and will be the same for all gases.
- There will be no change in the specific heat or temperature if the ideal gas flows through a porous plug from higher pressure to lower pressure within the insulated enclosure. This demonstrates that there is no intermolecular attraction in ideal gases.
Difference between Ideal Gas and Real Gas
| Ideal Gas | Real Gas |
| Ideal gases obey the ideal gas law at all temperature and pressure conditions. | Real gas does not obey gas laws under all standard pressure and temperature conditions. |
| Elastic collisions occur between the molecules. | The molecules collide in an inelastic manner. |
| There are no intermolecular forces of attraction in a perfect/ideal gas. | The forces in a real gas are either attracting or repulsive. |
| An ideal gas’s particles lack a fixed volume and mass. | A real gas’s particles have a defined volume and mass. |
| Ideal gas particles have constant kinetic energy. | Collisions change the kinetic energy of real gas particles. |
| At high pressure and low temperature, an ideal gas can act like a real gas. | At low pressure and high temperature, a real gas can behave like an ideal gas. |
| Ideal gases do not exist | Gases that exist in nature such as H2, O2, CO2, N2, He, etc. are real gases |
| It obeys gas law, PV = nRT | It obeys (P + (an2)/V2)(V – nb) = nRT |
Frequently Asked Questions
Q1. What exactly is an ideal gas?
Answer. Ideal gases are gases that obey the ideal gas law at all temperature and pressure circumstances. An ideal gas is a theoretical gas that does not exist in reality. Ideal gases are gaseous compositions made up of extremely small molecules with zero volume and mass.
Q2. What are real gases?
Answer. A real gas is one that does not obey gas laws under all conventional pressure and temperature conditions. Real gases obey gas laws only at high temperatures and low pressures.
Leave a Reply