Wohl Equation Formula:
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Definition: The Wohl equation is a thermodynamic equation of state used to calculate the pressure of real gases, accounting for molecular size and intermolecular forces.
Purpose: It provides more accurate pressure calculations than the ideal gas law for real gases under various conditions.
The calculator uses the Wohl equation:
Where:
Details: The Wohl equation provides more accurate results than ideal gas law for real gases, especially near critical points where intermolecular forces become significant.
Tips: Enter all required parameters including reduced temperature, critical temperature, reduced molar volume, critical molar volume, and the three Wohl parameters (a, b, c).
Q1: What are typical values for Wohl parameters?
A: Wohl parameters vary by gas. For example, for CO₂: a ≈ 3.59, b ≈ 0.0427, c ≈ 0.00263 (units depend on the equation form).
Q2: How do I get reduced temperature and volume?
A: Reduced temperature = T/Tc, Reduced volume = V/Vc, where T and V are actual conditions.
Q3: When is the Wohl equation most accurate?
A: For moderate pressures, not too close to the critical point or at extremely high pressures.
Q4: How does this compare to van der Waals equation?
A: Wohl equation includes an additional term (c parameter) for better accuracy with polar gases.
Q5: What are common applications?
A: Chemical engineering calculations, gas processing, and thermodynamic analysis of real gases.