1. What is Critical Pressure?

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

Purpose: This calculator determines the critical pressure without using Van der Waals constants, based on critical temperature and volume.

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)
• \( T_c \) — Critical Temperature (Kelvin)
• \( V_{cr} \) — Critical Volume (m³)

Explanation: The formula relates critical pressure to critical temperature and volume through the universal gas constant.

3. Importance of Critical Pressure Calculation

Details: Critical pressure is essential for understanding phase behavior of substances and designing industrial processes involving supercritical fluids.

4. Using the Calculator

Tips: Enter the critical temperature in Kelvin and critical volume in cubic meters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is critical temperature?
A: Critical Temperature is the highest temperature at which the substance can exist as a liquid. At this point, phase boundaries vanish.

Q2: What is critical volume?
A: The Critical Volume is the volume occupied by the unit mass of gas at critical temperature and pressure.

Q3: Why is the universal gas constant used?
A: The universal gas constant relates the energy scale to the temperature scale in the kinetic theory of gases.

Q4: How accurate is this calculation?
A: This provides a theoretical estimate. For real gases, Van der Waals corrections might be needed for higher precision.

Q5: What are typical units for critical pressure?
A: The calculator outputs Pascals, but atmospheres or bars are also commonly used (1 atm ≈ 101325 Pa).