Critical Temperature
| Also Known As | T_c, gas critical temperature, liquefaction temperature limit |
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What is Critical Temperature?
Critical temperature is the temperature above which a gas cannot be liquefied by applying pressure alone, regardless of how high the pressure is. Below the critical temperature, sufficient pressure will cause liquefaction. For practical gas liquefaction, gases must be cooled below their critical temperatures. For oxygen Tc = −118.6°C, for nitrogen Tc = −147°C.
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
Critical temperature is the temperature above which a gas cannot be liquefied by applying pressure alone, regardless of how high the pressure is. Below the critical temperature, sufficient pressure will cause liquefaction. For practical gas liquefaction, gases must be cooled below their critical temperatures. For oxygen Tc = −118.6°C, for nitrogen Tc = −147°C.
Critical temperature governs whether a gas can be stored as a liquid at ambient temperatures (CO₂, propane, ammonia can be liquefied; O₂, N₂, H₂ require cryogenic cooling). This determines storage and transport requirements for industrial gases.
Gases with T_c below room temperature (O₂, N₂, H₂, He) must be stored in cryogenic vessels or high-pressure cylinders. Liquid oxygen stored in cryogenic tanks is a powerful oxidiser hazard. Knowledge of T_c is essential for correct gas storage system design.