Atmosphere
| Formula / Notation | 1 atm = 101325 Pa = 760 mmHg |
|---|---|
| Also Known As | Atm, standard atmosphere, atmospheric pressure unit, 1 atm |
What is Atmosphere?
In chemistry, the atmosphere (atm) is a unit of pressure equal to 101,325 pascals (101.325 kPa), representing the average air pressure at sea level. The term also refers to the layer of gases surrounding the Earth, primarily nitrogen (78%) and oxygen (21%), which plays a vital role in chemical cycles including the carbon cycle, nitrogen cycle, and the greenhouse effect.
Formula & Notation
Other Names / Synonyms: Atm, standard atmosphere, atmospheric pressure unit, 1 atm
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
In chemistry, the atmosphere (atm) is a unit of pressure equal to 101,325 pascals (101.325 kPa), representing the average air pressure at sea level. The term also refers to the layer of gases surrounding the Earth, primarily nitrogen (78%) and oxygen (21%), which plays a vital role in chemical cycles including the carbon cycle, nitrogen cycle, and the greenhouse effect.
Atmosphere units are used in gas law calculations, phase diagrams, and reporting equilibrium constants (Kp) involving gases. Industrial processes such as the Haber process (ammonia synthesis, ~200 atm) and autoclave sterilisation operate at pressures measured in atmospheres.
Systems operating under high pressure (many atmospheres) require pressure-rated vessels and safety relief valves. Rapid decompression can cause mechanical failure or personnel injury. Compressed gas cylinders must be secured and handled according to OSHA/ISO regulations.
The formula or notation for Atmosphere is: 1 atm = 101325 Pa = 760 mmHg