20 Examples of Ideal Gas and Real Gas

The chemistry is the science that studies the composition and the transformations that can occur to matter, in any of its forms. One of the most important areas of study in chemistry is that of gases.

The gas concept It was established by the Belgian chemist Jan van Helmont. To explain the behavior of gases, different mathematical equations were developed using statistical tools. However, it was necessary to simplify and modify these equations because they did not work for all types of gases, so different gas models were defined (ideal gas Y real gas, among other intermediate approaches). For example: nitrogen, helium, methane.

In this sense, three laws were established to relate in a general way the volume, the temperature and the pressure of the gases:

Where P₁, V₁ Y T₁are the initial pressure, volume and temperature of the gas respectively, and P₂, V₂ Y T₂ are the finals.

Thus, relating the three laws, we obtain the General Gas Law,

PV / T = C where C is a constant that depends on the amount of gas.

Ideal gas examples

The ideal gas it is a theoretical model that represents a gas that does not really exist. It is a tool to facilitate a large number of mathematical calculations, since it greatly simplifies the complex behavior of a gas. This gas is considered to be made up of particles that neither attract nor repel each other and whose collisions are absolutely elastic. It is a model that fails if the gas is subjected to high pressures and low temperatures.

The general equation ideal gas results from the combination of the laws of Boyle-Mariotte, Charles and Gay Lussac with Avogadro's law. Avogadro's law states that if different gaseous substances are contained in equal volumes and subjected to the same pressure and temperature, then they have the same number of particles. Thus, the ideal gas equation of state is:

Where n is the number of moles of the gas and R is the gas constant equal to 8.314 J / Kmol.

It is not possible to make a specific list of ideal gases since it is a hypothetical gas. e can list a group of gases (including noble gases) whose treatment can be approximated to that of gases ideal, because the characteristics are similar, as long as the pressure and temperature conditions are the normal.

1. Nitrogen (N₂)
2. Oxygen (O₂)
3. Hydrogen (H₂)
4. Carbon dioxide (CO₂)
5. Helium (He)
6. Neon (Ne)
7. Argon (Ar)
8. Krypton (Kr)
9. Xenon (Xe)
10. Radon (Rn)

Examples of real gases

The real gases They are those that have a thermodynamic behavior and that is why they do not follow the same equation of state as ideal gases. In high pressure and low temperature, gases must inevitably be considered as real, since in that case the interactions between their particles increase.

The substantial difference between the ideal gas and the real gas is that the latter cannot be compressed indefinitely but its compression capacity is relative to the pressure and temperature levels.

Different equations have been developed to explain the behavior of real gases. One of the most important is the one provided by Van der Waals in 1873, which must be applied under high pressure conditions. The Van der Waals equation is represented as:

Where toY bthey are constants referred to the nature of each gas.

The following list shows some examples of real gases, although you can also add those that already have been listed as ideal gases, but this time in a context of high pressure and / or low temperature.

1. Ammonia (NH₃)
2. Methane (CH₄)
3. Ethane (CH₃CH₃)
4. Ethene (CH₂CH₂)
5. Propane (CH₃CH₂CH₃)
6. Butane (CH₃CH₂CH₂CH₃)

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