Standard conditions (English: standard temperature and pressure, STP, standard temperature and standard pressure), referred to as "standard conditions" or "STP", is one of the ideal states of physics and chemistry. In physics and chemistry, it represents the situation when the temperature is 0°C and the pressure is 101.325 kPa.
Because many definitions of standard temperature and pressure vary widely from standard laboratory temperatures (e.g., 0°C to ?25°C), reference is often made to "standard laboratory conditions" (chosen intentionally as distinct from the term "standard conditions of temperature and pressure", although its semantic approximate identity when interpreted literally).
However, "standard" temperatures and pressures for laboratories are unavoidable given the varying climates, altitudes, and use of heat/cold in the workplace in different parts of the world. For example, schools in New South Wales, Australia use 25°C at 100 kPa for standard laboratory conditions.
ASTM International has published the standard ASTM E41 - Terminology for Conditioning and hundreds of special conditions for specific materials and test methods. Other standards organizations also have specialized standard test conditions.
Standard state of gas
1. The standard state agreed by the 10th International Conference on Weights and Measures (CGPM) in 1954 is: temperature 273.15K (0℃), pressure 101.325KPa. This standard is widely used in the scientific and technological fields around the world.
2. The International Organization for Standardization and the American National Standard stipulate that the temperature of 288.15K (15℃) and the pressure of 101.325KPa are used as the standard state for measuring gas volume flow.
3. my country's "Standard Orifice Plate Calculation Method for Natural Gas Flow" stipulates that the temperature of 293.15K (20℃) and the pressure of 101.325KPa are the standard conditions for measuring gas volume flow.
4. A pure gas state that exhibits ideal gas properties at any temperature T and standard pressure Pθ=100 kPa. Note: my country stipulated the standard pressure Pθ=101.325kPa before 1993, and then adopted the current regulation of Pθ=100kPa according to GB 3102.8-93.
5. In chemistry, standard temperature and pressure (STP) was once defined as 0°C (273.15K) and 101.325kPa (1atm). However, since 1982, IUPAC redefined "standard pressure" as 100 kPa.