Molar gas constant: Difference between revisions
imported>Milton Beychok (Added a section on relation between universal gas constant and the gas-specific constant) |
imported>Milton Beychok (→= Notation for the gas constant: Fixed typos of mine) |
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where ''p'' is the pressure, ''V''<sub>''m''</sub> the molar volume, and ''T'' the absolute temperature of the ideal gas. | where ''p'' is the pressure, ''V''<sub>''m''</sub> the molar volume, and ''T'' the absolute temperature of the ideal gas. | ||
== Notation for the gas constant == | |||
The gas constant defined in this article is the universal gas constant, <math>R</math>, that applies to any gas. There is also a gas-specific version of the gas constant, which can be denoted as <math>R_s</math>. The gas-specific constant is defined as <math>R_s = R/M</math> where <math>M</math> is the [[molecular weight]]. | The gas constant defined in this article is the universal gas constant, <math>R</math>, that applies to any gas. There is also a gas-specific version of the gas constant, which can be denoted as <math>R_s</math>. The gas-specific constant is defined as <math>R_s = R/M</math> where <math>M</math> is the [[molecular weight]]. | ||
Unfortunately, many authors in the technical literature sometimes use <math>R</math> as the gas-specific constant without denoting it as such or stating that it is the gas-specific constant. This can and does lead to confusion. | Unfortunately, many authors in the technical literature sometimes use <math>R</math> as the gas-specific constant without denoting it as such or stating that it is the gas-specific constant. This can and does lead to confusion. | ||
==Reference== | ==Reference== | ||
<references /> | <references /> | ||
Revision as of 22:34, 1 April 2008
In chemistry and physics, the molar gas constant R is a physical constant with the value:[1] 8.314 472 J mol−1K−1.
The constant R is equal to the Boltzmann constant times Avogadro's constant: R = kBNA.
The constant arises in equations of state, most notably in the ideal gas law
where p is the pressure, Vm the molar volume, and T the absolute temperature of the ideal gas.
Notation for the gas constant
The gas constant defined in this article is the universal gas constant, , that applies to any gas. There is also a gas-specific version of the gas constant, which can be denoted as . The gas-specific constant is defined as where is the molecular weight.
Unfortunately, many authors in the technical literature sometimes use as the gas-specific constant without denoting it as such or stating that it is the gas-specific constant. This can and does lead to confusion.