Difference Between Ideal and Real Gases

Explanation of the concept of gases

Ideal and real gases are important in various fields and have different applications. Gases are one of the three states of matter, along with solids and liquids. A gas is a substance that fills its container completely and uniformly, regardless of the size and shape of the container. Gases are composed of atoms, molecules, or ions that move freely in all directions, colliding with each other and the walls of the container.

The behavior of gases is described by a set of physical properties, such as pressure, volume, temperature, and the amount of substance present. These properties are interdependent and can be related mathematically through laws and equations, which help to predict and understand the behavior of gases in different conditions.

Gases have many applications in various fields, including chemistry, physics, engineering, and industry. Some examples include fuel gases for heating and combustion, refrigerants for cooling and air conditioning, and gases used in chemical synthesis and processing. Understanding the properties and behavior of gases is essential for designing and optimizing processes and systems that involve gases.

Brief overview of the two types of gases

The two types of gases are ideal gases and real gases.

An ideal gas is a theoretical gas that follows a set of assumptions about the behavior of its particles, such as having no volume, no intermolecular forces, and obeying the laws of thermodynamics perfectly. Ideal gases are used in mathematical models to simplify the analysis of gas behavior and are often used as a reference point for real gases.

Real gases, on the other hand, are gases that do not obey all the assumptions of ideal gases due to the presence of intermolecular forces and non-zero particle volume. Real gases have complex and variable behavior, and their properties are affected by factors such as temperature, pressure, and the type of gas present. Real gases deviate from the ideal gas behavior, and the extent of this deviation depends on the specific conditions under which the gas is present.

Ideal Gases

Ideal gases are theoretical gases that follow a set of assumptions about the behavior of their particles. The assumptions of ideal gases include:

1. Particle size: The particles of an ideal gas are assumed to be infinitely small, with no volume.
2. Intermolecular forces: The particles of an ideal gas are assumed to have no intermolecular forces between them, meaning that they do not attract or repel each other.
3. Kinetic energy: The particles of an ideal gas are assumed to have random motion and to collide elastically with each other and with the walls of the container. The kinetic energy of the particles is proportional to the temperature of the gas.

The behavior of ideal gases is described by the Ideal Gas Law, which is given by the equation:

PV = nRT

where P is the pressure of the gas, V is the volume of the gas, n is the number of moles of gas present, R is the universal gas constant, and T is the temperature of the gas in kelvin. The Ideal Gas Law assumes that the gas is at low pressure and high temperature, where the particles have enough kinetic energy to overcome intermolecular forces.

The assumptions of ideal gases are not perfectly met in real gases, but the behavior of real gases can be approximated as ideal under certain conditions, such as at low pressure and high temperature. Ideal gases are used in mathematical models to simplify the analysis of gas behavior, and they are often used as a reference point for real gases.

Real Gases

Real gases are gases that do not obey all the assumptions of ideal gases. Real gases have complex behavior that is affected by factors such as temperature, pressure, and the type of gas present. The deviations from ideal gas behavior are caused by two primary factors: the finite volume of the gas molecules and intermolecular forces between the gas molecules.

At high pressures, the finite volume of gas molecules becomes significant, causing the gas to occupy a larger volume than predicted by the ideal gas law. At low temperatures, the intermolecular forces between the gas molecules become significant, causing the gas to condense into a liquid or solid at a certain pressure, called the gas’s critical pressure.

To account for these deviations from ideal gas behavior, the Van der Waals equation is often used as a more accurate description of real gas behavior. The Van der Waals equation is given by the equation:

(P + a(n/V)^2) (V – nb) = nRT

where P is the pressure of the gas, V is the volume of the gas, n is the number of moles of gas present, R is the universal gas constant, T is the temperature of the gas in kelvin, a is a constant that accounts for the intermolecular forces between the gas molecules, and b is a constant that accounts for the finite volume of the gas molecules.

The deviations from ideal gas behavior are most significant for gases at low temperatures and high pressures. Real gases are important in many applications, including chemical synthesis and processing, and understanding their behavior is essential for designing and optimizing processes and systems that involve gases.

Differences Between Ideal and Real Gases

The main differences between ideal and real gases are:

1. Assumptions: Ideal gases follow a set of assumptions about the behavior of their particles, such as having no volume and no intermolecular forces. Real gases do not meet all these assumptions, and their behavior is affected by factors such as the finite volume of gas molecules and intermolecular forces between the gas molecules.
2. Pressure-Volume-Temperature (PVT) Behavior: Ideal gases follow the Ideal Gas Law, which describes the relationship between pressure, volume, temperature, and the number of moles of gas present. Real gases do not follow this law precisely, and their behavior is better described by the Van der Waals equation, which accounts for the deviations from ideal gas behavior.
3. Predictability: Ideal gases are easier to predict and analyze mathematically because they follow simple and predictable behavior. Real gases are more complex and variable, and their behavior depends on various factors such as temperature, pressure, and the type of gas present.
4. Applications: Ideal gases are often used as a reference point for real gases and are used in mathematical models to simplify the analysis of gas behavior. Real gases are important in many applications, including chemical synthesis and processing, and understanding their behavior is essential for designing and optimizing processes and systems that involve gases.

The main difference between ideal and real gases is that ideal gases are theoretical gases that follow a set of assumptions, while real gases are actual gases that do not meet all these assumptions and exhibit more complex behavior.

Applications and Importance of Ideal and Real Gases

Ideal and real gases are important in various fields and have different applications.

Here are some of the applications and importance of ideal and real gases:

Applications of Ideal Gases:

1. Thermodynamics: Ideal gases are used in thermodynamics to simplify the analysis of gas behavior, as they follow predictable behavior and are easier to analyze mathematically.
2. Gas Law: The Ideal Gas Law is used to calculate the properties of gases, such as pressure, volume, and temperature.
3. Engineering: Ideal gases are used in the design and analysis of various engineering systems, such as gas turbines and internal combustion engines.

Applications of Real Gases:

1. Chemical Engineering: Real gases are important in chemical engineering for designing and optimizing processes that involve gases, such as chemical synthesis and processing.
2. Physical Chemistry: Real gases are used in physical chemistry to study the behavior of gases under different conditions and to understand the behavior of real gases in various systems.
3. Atmospheric Science: Real gases are important in atmospheric science for understanding the composition and behavior of the Earth’s atmosphere and for predicting climate change.

Ideal gases are used to simplify the analysis of gas behavior, while real gases are important for understanding the behavior of actual gases in various systems and processes. Understanding the behavior of both ideal and real gases is essential for designing and optimizing various engineering systems and processes.

Conclusion

Gases are an important component of our everyday lives, and understanding their behavior is essential for many applications, from engineering and manufacturing to environmental science and weather prediction. While ideal gases are a theoretical construct that follows a set of assumptions about the behavior of gas particles, real gases are actual gases that exhibit more complex behavior and do not meet all the assumptions of ideal gases.

The behavior of real gases is affected by factors such as temperature, pressure, and the type of gas present, and deviations from ideal gas behavior are described by the Van der Waals equation. Both ideal and real gases have important applications in various fields, and understanding their behavior is crucial for designing and optimizing systems and processes that involve gases.

Reference website

Here are some websites that can provide more information about the difference between ideal and real gases:

1. Khan Academy: Ideal Gas Law and Kinetic Theory – https://www.khanacademy.org/science/chemistry/gases-and-kinetic-molecular-theory/ideal-gas-laws/v/introduction-to-the-ideal-gas-law
2. Chem LibreTexts: Deviation from Ideal Gas Law – https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/States_of_Matter/Gases/Real_Gases_and_Deviations_from_Ideal_Behavior/Deviation_from_Ideal_Gas_Law
3. Engineering ToolBox: Real Gases – https://www.engineeringtoolbox.com/real-gases-d_976.html
4. MIT OpenCourseWare: Ideal Gas Law and Real Gases – https://ocw.mit.edu/courses/chemistry/5-60-thermodynamics-kinetics-spring-2008/lecture-notes/chap_01.pdf
5. University of Waterloo: Real Gases and the van der Waals Equation – https://uwaterloo.ca/chemistry/sites/ca.chemistry/files/uploads/files/Real_Gases_van_der_Waals.pdf