satp

SATP stands for Standard Ambient Temperature and Pressure. It is a reference condition used in chemistry and physics to describe the behavior of gases independent of a specific container. In the SATP convention, the temperature is defined as 25°C (298.15 K) and the pressure as 100 kPa (1 bar). These values are widely used in thermodynamics and gas-volume calculations when a convenient ambient reference state is needed.

Under SATP, the molar volume of an ideal gas is about 24.79 liters per mole (Vm = RT/P with R = 8.314 J/mol·K, T = 298.15 K, P = 100,000 Pa). This reference volume facilitates comparisons and calculations in laboratory data, stoichiometry, and material property tables.

SATP is distinct from other standard-state conventions, such as STP (Standard Temperature and Pressure). Historically, STP has varied in definition, with early versions using 0°C and 1 atm, while more recent formulations may use 0°C with 100 kPa, or 25°C with 1 atm depending on the standard-setting body. Because definitions can differ between sources, it is important to note the exact conditions used when interpreting gas-volume data or performing calculations.

In practice, SATP is employed to report gas volumes and to perform calculations under a fixed, conveniently achievable environment, especially in laboratory contexts and chemical data compilations. The acronym SATP may also appear in other domains to denote different concepts, but the standard ambient condition remains the most common scientific reference associated with the term.