The Molar gas constant reference article from the English Wikipedia on 24-Apr-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Molar gas constant

Values of R
8.314570 (J)(K-1)(mol-1)
0.0820578 (L)(atm)(K-1)(mol-1)
62.3639 (L)(torr)(K-1)(mol-1)
1.987 (cal)(K-1)(mol-1)

Molar gas constant (also known as universal gas constant, usually denoted by symbol R) is the constant occurring in the universal gas equation, i.e. the equation of state of an ideal gas:

Here p is the pressure of gas, V the volume it ocupies, n the number of moles of gas, and T its temperature.

It can be shown that R is an universal constant, equal for all gases. Real gases obey this equation only in an approximation of very diluted gases.

R also appears in the Nernst equation.

Its value is:

R = 8.314570[70] J K^-1 mol^-1

The two digits in brackets signify the uncertainty (standard deviation) in the last two digits of the value.

The Boltzmann constant k_B is defined as a ratio of molar gas constant and the Avogadro's number:

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