V

Van der Waals Equation

(P + a/V²)(V - b) = nRT; a, b = van der Waals constants
Quick Reference
Formula / Notation(P + a/V²)(V - b) = nRT; a, b = van der Waals constants
Also Known AsVan der Waals gas law, real gas equation, modified ideal gas law

What is Van der Waals Equation?

An equation of state for real gases that modifies the ideal gas law to account for intermolecular attractions and finite molecular volume: (P + an²/V²)(V - nb) = nRT. The constants a and b are specific to each gas. It gives better predictions for non-ideal gas behavior than PV = nRT.

Formula & Notation

(P + a/V²)(V - b) = nRT; a, b = van der Waals constants

Other Names / Synonyms: Van der Waals gas law, real gas equation, modified ideal gas law

Properties & Characteristics

The van der Waals equation is a modification of the ideal gas law that accounts for real gas behaviour by incorporating corrections for intermolecular attractions (constant a) and molecular volume (constant b). At high pressures and low temperatures, real gases deviate significantly from ideal behaviour. The equation predicts gas liquefaction and critical point phenomena. The constants a and b are specific to each gas.

Uses & Applications

The van der Waals equation is used in engineering and science to model real gas behaviour under non-ideal conditions. It is used to calculate compressibility factors for process design. The equation provides qualitative understanding of the critical point and liquefaction of gases.

Safety Information

Real gas behaviour described by van der Waals equation is important in the design of high-pressure vessels and compressors. Significant deviations from ideal behaviour at high pressure affect safety margins in gas storage equipment.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Van der Waals Equation
Formula (P + a/V²)(V - b) = nRT; a, b = van der Waals constants
Synonyms Van der Waals gas law, real gas equation, modified ideal gas law

Frequently Asked Questions

An equation of state for real gases that modifies the ideal gas law to account for intermolecular attractions and finite molecular volume: (P + an²/V²)(V - nb) = nRT. The constants a and b are specific to each gas. It gives better predictions for non-ideal gas behavior than PV = nRT.

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