|
| 8.314472 J · K-1 · mol-1 |
| 0.08205746 L · atm · K-1 · mol-1 |
| 8.2057459 x 10-5 m³ · atm · K-1 · mol-1 |
| 8.314472 L · kPa · 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 |
| 10.7316 ft³ · psi · °R-1 · lb · mol-1 |
The (also known as the '''universal''' or '''ideal gas constant''', usually denoted by symbol '''''R''''') is a
Physical Constant used in
Equations Of State to relate various groups of
State Function s to one another. It is another name for the
Boltzmann Constant , but when used in the
Ideal Gas Law it is usually expressed in the more convenient units of
Energy per
Kelvin per
Mole rather than simply
Energy per
Kelvin per particle.
The gas constant occurs in the simplest equation of state, the
Ideal Gas Law , as follows:
:
where ''p'' is the
Pressure of an
Ideal Gas , ''T'' is its
Temperature , and
is its
Molar Volume . ''R'' also appears in the
Nernst Equation as well as in the
Lorentz-Lorenz formula. ''P'' = power but ''p'' = pressure.
Its value is:
:
or, removing
Avogadro's Number ,
:
The two digits in
Brackets signify the uncertainty (
Standard Deviation ) in the last two digits of the value.
The
Boltzmann Constant ''k
B'' (often abbreviated ''k'') may be used in place of the other forms of the ideal gas constant by working in pure particle count rather than number of moles of gas; this simply requires carrying a factor of
Avogadro's Number . Writing:
:
One can then express the
Ideal Gas Law in direct terms of Boltzmann's constant:
:
with ''N'' = ''nN''
A is the actual number of molecules.
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"http://physicsnistgov/cgi-bin/cuu/Valueksearch_for=boltzmann" class="copylinks" target="_blank">Boltzmann Constant CODATA Value at NIST
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