1. What is Fugacity?

Definition: Fugacity is a thermodynamic property of a real gas which if substituted for the pressure or partial pressure in the equations for an ideal gas gives equations applicable to the real gas.

Purpose: It helps in the study of real gases by providing a corrected pressure that accounts for non-ideal behavior.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( f \) — Fugacity (Pa)
• \( P \) — Pressure (Pa)
• \( G \) — Gibbs Free Energy (J)
• \( G^{ig} \) — Ideal Gas Gibbs Free Energy (J)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Temperature (K)

Explanation: The formula relates the fugacity of a real gas to its pressure, Gibbs free energy, and temperature.

3. Importance of Fugacity Calculation

Details: Fugacity is crucial in chemical engineering and thermodynamics for accurate modeling of real gas behavior, especially in phase equilibrium calculations.

4. Using the Calculator

Tips: Enter the pressure in Pascals, Gibbs free energies in Joules, and temperature in Kelvin. Temperature must be > 0K.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between Gibbs free energy and ideal gas Gibbs free energy?
A: Gibbs free energy (G) is for the real system, while ideal gas Gibbs free energy (G^ig) is what the system would have if it behaved ideally.

Q2: Why does fugacity differ from pressure?
A: Fugacity accounts for non-ideal interactions between gas molecules that aren't considered in ideal gas law.

Q3: What units should I use for input values?
A: Use Pascals for pressure, Joules for energy, and Kelvin for temperature.

Q4: When is fugacity equal to pressure?
A: For an ideal gas or at very low pressures where real gases behave ideally, fugacity equals pressure.

Q5: Can I use this for liquids or solids?
A: The concept of fugacity applies to all phases, but this specific formula is most commonly used for gases.