Gas constant
Values of R  Units (V·P·T^{1}·n^{1}) 

8.314472  J·K^{1}·mol^{1} 
0.0820574587  L·atm·K^{1}·mol^{1} 
8.20574587 × 10^{5}  m^{3}·atm·K^{1}·mol^{1} 
8.314472  cm^{3}·MPa·K^{1}·mol^{1} 
8.314472  L·kPa·K^{1}·mol^{1} 
8.314472  m^{3}·Pa·K^{1}·mol^{1} 
62.3637  L·mmHg·K^{1}·mol^{1} 
62.3637  L·Torr·K^{1}·mol^{1} 
83.14472  L·mbar·K^{1}·mol^{1} 
1.987  cal·K^{1}·mol^{1} 
6.132440  lbf·ft·K^{1}·g·mol^{1} 
10.7316  ft^{3}·psi· °R^{1}·lbmol^{1} 
0.7302  ft^{3}·atm·°R^{1}·lbmol^{1} 
1716 (Air only)  ft·lb·°R^{1}·slug^{1} 
286.9 (Air only)  N·m·kg^{1}·K^{1} 
286.9 (Air only)  J·kg^{1}·K^{1} 
999  ft^{3}·mmHg·K^{1}·lbmol^{1} 
WikiDoc Resources for Gas constant 
Articles 

Most recent articles on Gas constant Most cited articles on Gas constant 
Media 
Powerpoint slides on Gas constant 
Evidence Based Medicine 
Clinical Trials 
Ongoing Trials on Gas constant at Clinical Trials.gov Clinical Trials on Gas constant at Google

Guidelines / Policies / Govt 
US National Guidelines Clearinghouse on Gas constant

Books 
News 
Commentary 
Definitions 
Patient Resources / Community 
Patient resources on Gas constant Discussion groups on Gas constant Patient Handouts on Gas constant Directions to Hospitals Treating Gas constant Risk calculators and risk factors for Gas constant

Healthcare Provider Resources 
Causes & Risk Factors for Gas constant 
Continuing Medical Education (CME) 
International 

Business 
Experimental / Informatics 
Overview
The gas constant (also known as the molar, universal, or ideal gas constant, usually denoted by symbol R) is a physical constant which is featured in a large number of fundamental equations in the physical sciences, such as the ideal gas law and the Nernst equation. It is equivalent to the Boltzmann constant, but expressed in units of energy (i.e. the pressurevolume product) per kelvin per mole (rather than energy per kelvin per particle).
Its value is:
 R = 8.314472(15) J · K^{1} · mol^{1}
The two digits in parentheses are the uncertainty (standard deviation) in the last two digits of the value.
The gas constant occurs in the simplest equation of state, the ideal gas law, as follows:
where:
 is the absolute pressure
 is absolute temperature
 is the volume the gas occupies
 is the amount of gas (the number of gas molecules, usually in moles)
 is the molar volume
The gas constant has the same units as specific entropy.
Relationship with the Boltzmann constant
The Boltzmann constant k_{B} (often abbreviated k) may be used in place of the gas constant by working in pure particle count, N, rather than number of moles, n, since
 ,
where is Avogadro's number. For example, the ideal gas law in terms of Boltzmann's constant is .
Specific gas constant
The specific gas constant of a gas or a mixture of gases () is given by the universal gas constant, divided by the molar mass () of the gas/mixture.
It is common to represent the specific gas constant by the symbol . In such cases the context and/or units of should make it clear as to which gas constant is being referred to. For example, the equation for the speed of sound is usually written in terms of the specific gas constant.
The specific gas constant of dry air is
US Standard Atmosphere
The US Standard Atmosphere, 1976 (USSA1976) defines the Universal Gas Constant as:^{[1]}^{[2]}
The USSA1976 does recognize, however, that this value is not consistent with the cited values for the Avogadro constant and the Boltzmann constant.^{[2]} This disparity is not a significant departure from accuracy, and USSA1976 uses this value of R for all the calculations of the standard atmosphere. When using the ISO value of R, the calculated pressure increases by only 0.62 pascals at 11,000 meters (the equivalent of a difference of only 0.174 meters – or 6.8 inches) and an increase of 0.292 pascals at 20,000 meters (the equivalent of a difference of only 0.338 meters – or 13.2 inches).
See also
References
 ↑ "Standard Atmospheres". Retrieved 20070107.
 ↑ ^{2.0} ^{2.1} U.S. Standard Atmosphere, 1976, U.S. Government Printing Office, Washington, D.C., 1976 (Linked file is 17 MiB).
External links
 Gas Constant CODATA Value at NIST
 Boltzmann Constant CODATA Value at NIST