1. What is Critical Pressure of Real Gas?

Definition: Critical pressure is the minimum pressure required to liquify a substance at its critical temperature.

Purpose: This calculator determines the critical pressure using the Wohl equation parameters, which is essential for understanding gas behavior under extreme conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_c \) — Critical pressure (Pascal)
• \( [R] \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Temperature of real gas (Kelvin)
• \( T_r \) — Reduced temperature (dimensionless)
• \( b \) — Wohl parameter b (empirical constant)

Explanation: The formula relates the critical pressure to temperature and Wohl parameter through fundamental thermodynamic relationships.

3. Importance of Critical Pressure Calculation

Details: Critical pressure is crucial for designing high-pressure systems, understanding phase behavior, and modeling gas properties in chemical engineering applications.

4. Using the Calculator

Tips: Enter the gas temperature in Kelvin, reduced temperature (dimensionless), and Wohl parameter b. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is reduced temperature?
A: Reduced temperature is the ratio of the actual temperature to the critical temperature of the substance (T/Tc).

Q2: How do I obtain Wohl parameter b?
A: Wohl parameter b is typically determined experimentally or from critical property data for specific substances.

Q3: What units does this calculator use?
A: Temperature must be in Kelvin, and the result is in Pascals (Pa).

Q4: Can I use this for any gas?
A: This calculation is specific to gases that follow the Wohl equation of state.

Q5: Why is critical pressure important?
A: It defines the conditions needed to liquefy a gas and is essential for phase equilibrium calculations.