Wohl Parameter (a) of Real Gas using Wohl Equation Calculator

Wohl Parameter (a) Formula:

\[ a = \left( \frac{[R] \times T_{rg}}{V'_m - b} + \frac{c}{T_{rg}^2 \times V'_m^3} - P_{rg} \right) \times T_{rg} \times V'_m \times (V'_m - b) \]

Temperature of Real Gas:

Molar Volume of Real Gas:

m³

Wohl Parameter b:

Wohl Parameter c:

Pressure of Gas:

Wohl Parameter a:

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1. What is Wohl Parameter (a)?

Definition: Wohl parameter a is an empirical parameter characteristic to equation obtained from Wohl model of real gas.

Purpose: It helps in describing the behavior of real gases by accounting for intermolecular forces in the Wohl equation of state.

2. How Does the Calculator Work?

The calculator uses the Wohl equation:

\[ a = \left( \frac{[R] \times T_{rg}}{V'_m - b} + \frac{c}{T_{rg}^2 \times V'_m^3} - P_{rg} \right) \times T_{rg} \times V'_m \times (V'_m - b) \]

Where:

\( a \) — Wohl parameter a (empirical parameter)
\( [R] \) — Universal gas constant (8.314 J/mol·K)
\( T_{rg} \) — Temperature of real gas (K)
\( V'_m \) — Molar volume of real gas (m³)
\( b \) — Wohl parameter b (empirical parameter)
\( c \) — Wohl parameter c (empirical parameter)
\( P_{rg} \) — Pressure of gas (Pa)

3. Importance of Wohl Parameter Calculation

Details: The Wohl equation provides a more accurate description of real gas behavior compared to the ideal gas law, especially at high pressures and low temperatures.

4. Using the Calculator

Tips: Enter the temperature in Kelvin, molar volume in cubic meters, Wohl parameters b and c, and gas pressure in Pascals. All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for Wohl parameters?
A: Parameters vary by gas. For example, for CO₂: a ≈ 0.365 Pa·m⁶/mol², b ≈ 4.28×10⁻⁵ m³/mol, c ≈ 0.0427 m³·K³/mol.

Q2: How does temperature affect the Wohl parameter a?
A: The parameter a generally decreases with increasing temperature as intermolecular forces become less significant.

Q3: When is the Wohl equation most accurate?
A: The Wohl equation works best for moderately non-ideal gases at intermediate pressures.

Q4: How do I determine Wohl parameters experimentally?
A: Parameters are typically determined by fitting experimental P-V-T data to the Wohl equation.

Q5: What's the difference between Wohl parameters and van der Waals constants?
A: Both account for non-ideal behavior, but Wohl's equation includes an additional parameter (c) for better accuracy.