The exact boiling point (BP) of nitrogen is -195.8 °C.
Understanding Nitrogen's Boiling Point
The boiling point of a substance is the temperature at which it changes from a liquid to a gas at a given pressure, typically standard atmospheric pressure. For nitrogen, this transition occurs at an extremely low temperature, making it a cryogenic liquid.
Here is the precise boiling point of nitrogen:
| Substance | Property | Value |
|---|---|---|
| Nitrogen | Boiling Point | -195.8 °C |
For broader context, this temperature is equivalent to approximately -320.4 °F.
Why is Nitrogen's Boiling Point So Low?
Nitrogen ($\text{N}_2$) exists as a diatomic molecule. The extremely low boiling point of nitrogen is primarily due to the weak intermolecular forces between its molecules. Specifically, it exhibits only weak van der Waals forces (London dispersion forces). These forces are relatively easy to overcome, requiring very little energy (and thus very low temperatures) for the molecules to break free from the liquid phase and enter the gaseous phase.
In contrast, substances with strong intermolecular forces, like hydrogen bonding or strong dipole-dipole interactions, have significantly higher boiling points.
Practical Applications of Liquid Nitrogen
Because of its incredibly low boiling point, nitrogen in its liquid state (liquid nitrogen or LN2) has numerous crucial applications across various industries:
- Cryogenic Freezing: Its low temperature makes it ideal for flash-freezing food products, preserving biological samples (e.g., blood, tissue, sperm, eggs), and in cryotherapy for medical treatments.
- Cooling Agent: Used as a cooling agent for superconductors, vacuum pumps, and in some computer systems to achieve very low operating temperatures.
- Industrial Processes: Employed in inerting operations, purging pipelines, and in the manufacturing of electronics to prevent oxidation.
- Research and Development: Indispensable in scientific laboratories for cooling equipment and performing low-temperature experiments.
The ability to produce and maintain nitrogen at such a low temperature has revolutionized fields from medicine to manufacturing, highlighting its significance as an industrial gas.
