Several conditions are specified for the standard state:
- The standard state temperature is 25 degrees C (298 K). Note that temperature is not specified for standard state conditions, but most tables are compiled for this temperature.
- All gases are at 1 atm pressure.
- All liquids and gases are pure.
- All solutions are at 1M concentration.
- The energy of formation of an element in its normal state is defined as zero.
Know the Standard State Conditions
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Standard State Conditions
Certain assumptions apply to standard state conditions. Standard temperature and pressure commonly is abbreviated as STP .
What temperature is SATP?
SATP may be used, which means Standard Ambient Temperature and Pressure. SATP is at 25 degrees C (298.15 K) and 101 kPa (essentially 1 atmosphere, 0.997 atm).
What is STP in science?
Both STP and standard state conditions are commonly used for scientific calculations. STP stands for Standard Temperature and Pressure. It is defined to be 273 K (0 degrees Celsius) and 1 atm pressure (or 105 Pa). The definition of standard state conditions specifies 1 atm of pressure, that liquids and gases be pure, ...
What is STP in math?
STP is used for calculations involving gases that approximate ideal gases. Standard conditions are used for any thermodynamic calculation. Values cited for STP and standard conditions are based on ideal conditions, so they may deviate slightly from experimental values. STP is short for Standard Temperature and Pressure, ...
What is standard state condition?
The definition of standard state conditions specifies 1 atm of pressure, that liquids and gases be pure, and that solutions be at 1 M concentration. Temperature is not specified, although most tables compile data at 25 degrees C (298 K).
What is the standard for air temperature?
Another standard is NTP, which stands for Normal Temperature and Pressure. This is defined for air at 20 degrees C (293.15 K, 68 degrees F) and 1 atm.
What is the energy of formation of an element in its normal state?
The energy of formation of an element in its normal state is defined as zero.
Is standard condition the same as STP?
Both STP and standard state specify a gas pressure of 1 atmosphere. However, the standard state isn't usually at the same temperature as STP. The standard state also includes several additional restrictions.
What is the standard gas volume reference?
Natural gas companies in Europe, Australia, and South America have adopted 15 °C (59 °F) and 101.325 kPa (14.696 psi) as their standard gas volume reference conditions, used as the base values for defining the standard cubic meter. Also, the International Organization for Standardization (ISO), the United States Environmental Protection Agency (EPA) and National Institute of Standards and Technology (NIST) each have more than one definition of standard reference conditions in their various standards and regulations.
What was the standard reference temperature for gas?
Before 1918, many professionals and scientists using the metric system of units defined the standard reference conditions of temperature and pressure for expressing gas volumes as being 15 °C (288.15 K; 59.00 °F) and 101.325 kPa (1.00 atm; 760 Torr ). During those same years, the most commonly used standard reference conditions for people using the imperial or U.S. customary systems was 60 °F (15.56 °C; 288.71 K) and 14.696 psi (1 atm) because it was almost universally used by the oil and gas industries worldwide. The above definitions are no longer the most commonly used in either system of units.
What is the NIST temperature?
NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa). This standard is also called normal temperature and pressure (abbreviated as NTP ). However, a common temperature and pressure in use by NIST for thermodynamic experiments is 298.15 K (25° C, 77° F) and 1 bar (14.5038 psi, 100 kPa). NIST also uses "15 °C (60 °F)" for the temperature compensation of refined petroleum products, despite noting that these two values are not exactly consistent with each other.
What is the absolute pressure of STP?
Since 1982, STP is defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 10 5 Pa (100 kPa, 1 bar ).
What is STP in science?
Not to be confused with Standard sea-level conditions or Standard state. Standard temperature and pressure ( STP) are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry ...
What is the relationship between the gas constants?
The relationship between the two constants is Rs = R / m, where m is the molecular mass of the gas.
What is the value of R in the US?
The US Standard Atmosphere (USSA) uses 8.31432 m 3 ·Pa/ (mol·K) as the value of R. However, the USSA,1976 does recognize that this value is not consistent with the values of the Avogadro constant and the Boltzmann constant.
STP - Standard Temperature and Pressure
STP is commonly used to define standard conditions for temperature and pressure which is important for the measurements and documentation of chemical and physical processes:
NTP - Normal Temperature and Pressure
NTP is commonly used as a standard condition for testing and documentation of fan capacities:
SATP - Standard Ambient Temperature and Pressure
SATP - Standard Ambient Temperature and Pressure is also used in chemistry as a reference:
ISA - International Standard Atmosphere
ISA - International Standard Atmosphere is used as a reference to aircraft performance:
ICAO Standard Atmosphere
Standard model of the atmosphere adopted by the International Civil Aviation Organization (ICAO):
