1. What is Residual Gibbs Free Energy?

Definition: Residual Gibbs Free Energy is the difference between the Gibbs energy of a real system and that of an ideal system at the same temperature, pressure, and composition.

Purpose: It quantifies the non-ideality of a system and is crucial in thermodynamic calculations for real gases and mixtures.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( G^R \) — Residual Gibbs Free Energy (J/mol)
• \( [R] \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Temperature (Kelvin)
• \( \phi \) — Fugacity coefficient (dimensionless)

Explanation: The formula calculates the deviation from ideal behavior using the natural logarithm of the fugacity coefficient.

3. Importance of Residual Gibbs Free Energy

Details: This calculation is essential in chemical engineering for designing processes involving real gases, phase equilibrium calculations, and thermodynamic modeling.

4. Using the Calculator

Tips: Enter the temperature in Kelvin and the fugacity coefficient (must be > 0). The calculator will compute the residual Gibbs free energy in J/mol.

5. Frequently Asked Questions (FAQ)

Q1: What is the fugacity coefficient?
A: The fugacity coefficient (φ) is the ratio of fugacity to pressure, measuring the deviation from ideal gas behavior (φ = 1 for ideal gases).

Q2: What does a negative residual Gibbs energy mean?
A: A negative value indicates the real system is more stable than the corresponding ideal system at the same conditions.

Q3: What's the range for fugacity coefficient?
A: Typically between 0 and 1 for most systems, but can exceed 1 for highly non-ideal systems.

Q4: How is temperature related to residual Gibbs energy?
A: Residual Gibbs energy increases linearly with temperature for a given fugacity coefficient.

Q5: What are typical applications of this calculation?
A: Used in chemical process design, vapor-liquid equilibrium calculations, and thermodynamic property estimation.