The constant used in the ideal gas law equation:
PV = nRT
where P is pressure; V is volume; n is number of moles; and T is temperature.
The gas constant is also known as the ideal gas constant. The value of the gas constant (R) depends on the units used for pressure, volume, and temperature.
Here are R values for various systems of units:
R = 0.0821 L∙atm/mol∙K
R = 8.3145 J/mol∙K
R = 8.2057 m3∙atm/mol∙K
R = 62.3637 L∙Torr/mol∙K or L∙mmHg/mol∙K