## Standard conditions for temperature and pressure |

**standard conditions for temperature and pressure**are 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 thestandard (iupac) and theinternational union of pure and applied chemistry (nist), although these are not universally accepted standards. other organizations have established a variety of alternative definitions for their standard reference conditions.national institute of standards and technology in chemistry, iupac changed the definition of

**standard temperature and pressure**(**stp**) in 1982:^{[1]}- until 1982, stp was defined as a
of 273.15temperature (0 °c, 32 °f) and ank of exactly 1absolute pressure (101.325atm ).kpa - since 1982, stp is defined as a
of 273.15temperature (0 °c, 32 °f) and ank of exactly 10absolute pressure ^{5} (100 kpa, 1pa ).bar

stp should not be confused with the

commonly used in thermodynamic evaluations of thestandard state of a reaction.gibbs energy 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 callednist **normal temperature and pressure**(abbreviated as**ntp**).the international standard metric conditions for natural gas and similar fluids are 288.15 k (15.00 °c; 59.00 °f) and 101.325 kpa.

^{[2]}in

andindustry , standard conditions for temperature and pressure are often necessary to define the standard reference conditions to express the volumes of gases and liquids and related quantities such as the rate ofcommerce (the volumes of gases vary significantly with temperature and pressure):volumetric flow (standard cubic meters per second **sm**), and normal cubic meters per second (^{3}/s**nm**).^{3}/showever, many technical publications (books, journals, advertisements for equipment and machinery) simply state "standard conditions" without specifying them; often substituting the term with older "

", or "nc". in special cases this can lead to confusion and errors. good practice always incorporates the reference conditions of temperature and pressure. if not stated, some room environment conditions are supposed, close to 1 atm pressure, 293 К (20 °c), and 0% humidity.normal conditions - until 1982, stp was defined as a
- definitions
- international standard atmosphere
- standard laboratory conditions
- molar volume of a gas
- see also
- notes
- references
- external links

**Standard conditions for temperature and pressure** are

In chemistry, IUPAC changed the definition of **standard temperature and pressure** (**STP**) in 1982:^{[1]}

- Until 1982, STP was defined as a
temperature of 273.15K (0 °C, 32 °F) and anabsolute pressure of exactly 1atm (101.325kPa ). - Since 1982, STP is defined as a
temperature of 273.15K (0 °C, 32 °F) and anabsolute pressure of exactly 10^{5}Pa (100 kPa, 1bar ).

STP should not be confused with the

**normal temperature and pressure** (abbreviated as **NTP**).

The International Standard Metric Conditions for natural gas and similar fluids are 288.15 K (15.00 °C; 59.00 °F) and 101.325 kPa.^{[2]}

In **sm ^{3}/s**), and normal cubic meters per second (

However, many technical publications (books, journals, advertisements for equipment and machinery) simply state "standard conditions" without specifying them; often substituting the term with older "