What is the definition of standard temperature and pressure (STP)?

1 Answer
Truong-Son N.
Oct 5, 2017

Standard Temperature and Pressure is defined by IUPAC as:

  • 0^@ "C" and "1.000 bar" after 1982
  • 0^@ "C" and "1.000 atm" before 1982

The numerical difference is that one obtains a molar volume of ideal gas to be:

  • "22.414 L/mol" at 0^@ "C" and "1.000 atm".
  • "22.711 L/mol" at 0^@ "C" and "1.000 bar".

and the universal gas constant is:

  • "0.082057 L"cdot"atm/mol"cdot"K" at 0^@ "C" and "1 atm".
  • "0.083145 L"cdot"bar/mol"cdot"K" at 0^@ "C" and "1 bar".

where

  • "1.000 bar" = "100000 Pa"
  • "1.000 atm" = "101325 Pa"

As such, you should always specify which pressure your STP uses for your textbook for your course.

Note that 0^@ "C" = "273.15 K". You can always choose to use "273.15 K" instead of "273 K", and it therefore should not limit the number of significant figures you have in a calculation.

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