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Difference Between Ideal Gas and Real Gas

Difference between Ideal gas and Real gas is Ideal gas has no definite volume whereas real gas has a definite volume. Explore all major differences here in the tabular form.
authorImagePraveen Kushwah27 May, 2025
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Difference Between Ideal Gas and Real Gas

Difference Between Ideal Gas and Real Gas: Matter can be present in three forms solid, liquid, or gas. Solids have a set of shapes, like ice. Liquids, like water, take the shape of their container as their particles move. Gases, such as air, have free-moving particles.

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 Gases can be real or ideal. Ideal gases are tiny with nearly no mass, like invisible points. Real gases, although small, take up space and have volume. So, in simple terms, matter can be solid, liquid, or gas, and gases can be ideal or real, each with its own special characteristics. This concept is extremely important and interesting and every NEET aspirant must understand it and excel in their NEET preparation.

Difference Between Ideal Gas and Real Gas Overview

Understanding the difference between ideal gases and real gases is like comparing a perfect theory to what happens in the real world. Ideal gases are like imaginary friends; they don't take up any space, and there are no forces between them. Real gases, like real friends, have some size and experience forces. While ideal gases follow a simple rule everywhere, real gases have to deal with more complex rules, especially when things get hot or cold or when the pressure is very high. It's like comparing a perfect idea to how things work in everyday situations.

Difference Between Ideal Gas and Real Gas

NEET aspirants can understand ideal and real gas by comparing them with real and imaginary friends. Ideal gases are those gases that have no size or push each other, while real gases are like real friends, taking up space and having some force. Real friends have more complicated rules, especially when it's very hot or cold or when they are under pressure. Having knowledge of this concept helps us understand gases in the real world.
Difference Between Ideal Gas and Real Gas
Parameters Ideal Gas Real Gas
Particle Size Negligible, considered as point particles. Has a finite size; particles occupy space.
Intermolecular Forces Assumes no intermolecular forces between particles. Experiences intermolecular forces.
Volume Occupied Occupies no volume; treated as point masses. Occupies a volume due to particle size.
Pressure-Volume Behavior Follows ideal gas law (PV = nRT) exactly. Deviates from ideal behavior at high pressures and low temperatures.
Temperature-Volume Behavior Shows infinite compressibility. Exhibits limitations on compressibility.
Equation of State Described by the ideal gas law. Described by various equations accounting for deviations.
Real-World Applications Used for theoretical calculations and conceptual understanding. Applied in practical scenarios, considering deviations from ideal behavior.

Ideal Gas Definition

An ideal gas is a theoretical concept in physics and chemistry that is characterized by the assumption that its particles have negligible volume and do not exert intermolecular forces. The behavior of an ideal gas is described accurately by the ideal gas law,

PV=nRT

where P is pressure,

V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature. Ideal gases are considered to follow this law precisely under all conditions. However, in reality, no gas perfectly adheres to these idealized assumptions.

Example of Ideal Gas

Consider a hypothetical gas that perfectly follows the ideal gas law at all pressures and temperatures. This is an idealization and does not exist in reality. 

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Real Gas Definition

A real gas is a gas that deviates from ideal behavior, accounting for factors such as the finite size of gas particles and intermolecular forces. Unlike ideal gases, real gases have measurable volumes, and their behavior is described by more complex equations of state, such as the Van der Waals equation. Real gases are encountered in everyday scenarios and exhibit deviations from ideal behavior, especially at high pressures and low temperatures.

Example of Real Gas

Consider a sample of nitrogen gas at high pressure or low temperature. Its behavior deviates from the predictions of the ideal gas law, making it an example of a real gas. Elevate your preparation with our  NEET Online Coaching and get access to expert guidance, interactive video sessions, and comprehensive study materials. Candidates can study comfortably from home, boost their confidence, and excel in the NEET exam with ease.
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Difference Between Ideal Gas and Real Gas FAQs

What is an ideal gas, and how does it behave?

An ideal gas is a theoretical concept with negligible particle volume and no inter molecular forces. It follows the ideal gas law precisely under all conditions.

How do real gases differ from ideal gases?

Real gases deviate from ideal behavior due to factors like particle size and intermolecular forces. They require more complex equations, such as the Van der Waals equation.

Can ideal gases exist in reality?

Ideal gases are a theoretical concept and don't exist in reality. They serve as a simplified model for understanding gas behavior.

What factors cause real gases to deviate from ideal behavior?

Real gases deviate at high pressures and low temperatures due to factors like the finite size of particles and intermolecular attractions.

Why is understanding the difference between ideal and real gases important?

Understanding these differences is crucial for bridging theoretical concepts with real-world applications, especially in areas where gas behavior becomes more complex.
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