Gas Critical Temperature Pressure
Reference data and engineering information about gas critical temperature pressure for thermodynamics applications.
Overview
Engineering reference data for Gas Critical Temperature Pressure in thermodynamics.
Key Formulas
First Law
Energy is conserved — heat added minus work done.
Ideal Gas Law
Relates pressure, volume, and temperature of an ideal gas.
Heat Transfer
Sensible heat transfer.
Carnot Efficiency
Maximum efficiency between two temperatures.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Internal energy | J | |
| Heat | J | |
| Work | J | |
| Pressure | Pa | |
| Volume | m³ | |
| Temperature | K |
Critical Properties Data
Substance | Critical Temperature (°F) | Critical Temperature (°C) | Critical Pressure (psi) | Critical Pressure (bar) | Boiling Temperature (°F) | Boiling Temperature (°C) |
|---|---|---|---|---|---|---|
| Air | -220.94 | -140.52 | 549.08 | 37.858 | — | — |
| Ammonia (NH₃) | 270 | 132.4 | 1636 | 112.8 | -27.4 | -33 |
| Argon | -188 | -122 | 705.6 | 48.7 | -302.5 | -185.8 |
| Butane | 305.6 | 152 | 550.4 | 38 | 32 | 0 |
| Carbon dioxide (CO₂) | 87.8 | 31.2 | 1071.6 | 73.8 | -110 | -79 |
| Carbon monoxide (CO) | -220.5 | -140.3 | 507.5 | 35 | -310 | -190 |
| Chlorine | 291 | 144 | 1118.7 | 77.1 | -29.3 | -34 |
| Ethane | 90 | 32.2 | 708 | 48.9 | -127.4 | -88.5 |
| Ethanol | 467 | 242 | 914 | 63 | 173 | 78.4 |
| Helium | -456 | -268 | 33.2 | 2.3 | -452 | -269 |
| Hydrogen (H₂) | -400 | -240 | 188.2 | 13 | -423 | -253 |
| Methane | -117 | -82.6 | 673.3 | 46.5 | -259 | -162 |
| Nitrogen (N₂) | -232.6 | -147 | 492.4 | 34 | -321 | -195 |
| Oxygen (O₂) | -181.5 | -118.6 | 732 | 50.5 | -297 | -183 |
| Propane | 206.1 | 96.7 | 617.4 | 42.6 | -44 | -42 |
| Water | 705 | 374 | 3206.2 | 220.5 | 212 | 100 |
Source: Engineering Toolbox
Phase Transition Concepts
Critical Point Behavior: At the critical point (, ), the distinction between liquid and gas phases disappears. The liquid-vapor coexistence curve terminates, creating a single supercritical phase.
Practical Implications:
- Below : Can liquefy gas by increasing pressure above
- Above : Supercritical fluids exhibit hybrid liquid/gas properties
- Useful for extraction processes, enhanced oil recovery, and supercritical fluid chromatography
Critical Ratio: The critical compressibility factor is approximately 0.27 for many simple fluids, providing a consistency check for equations of state.