Van der Waals Equation
Van Der Waals Equation |
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| \( [ \; p + a \; (n\;/\;V\;)^2 \; ] \; ( V\;/\;n - b ) = R \; T \) | ||
| Symbol | English | Metric |
| \( p \) = pressure of gas | \(lbf\;/\;in^2\) | \(Pa\) |
| \( a \) = correction for the intermolecular forces | \(gal\;/\;mol\) | \(L\;/\;mol\) |
| \( n \) = number of moles of gas | \(dimensionless\) | \(dimensionless\) |
| \( V \) = volume of gas | \(ft^3\) | \(m^3\) |
| \( b \) = adjusts for the volume occupied by the gas particles | \(ft^3\) | \(m^3\) |
| \( R \) = specific gas constant (gas constant) | \(ft-lbf\;/\;lbm-R\) | \(J\;/\;kg-K\) |
| \( T \) = temperature of gas | \(F\) | \(K\) |
Van der Waals equation is an equation of state that describes the behavior of real gases, taking into account the finite size of gas molecules and the attractive forces between them. It represents an improvement over the deal gas law, which assumes that gas molecules are point masses with no volume and no attractive forces between them.
The Van der Waals equation provides a more accurate description of the behavior of real gases, especially at high pressures and low temperatures, where the ideal gas law deviates from experimental observations. It takes into consideration the fact that gas molecules have both attractive and repulsive interactions, and that they occupy a finite volume, unlike the idealized point masses assumed in the ideal gas law.
- See Articles - Peng-Robinson Equation of State, Peng-Robinson Equation of State, and Redlich-Kwong Equation of State, Van Der Waals Equation Constants
