Ideal gas constant

The ideal gas constant is also known as the molar gas constant, the gas constant or the universal gas constant. This constant is written as R, and is a constant of proportionality (constant number that is multiplied on one side of a proportional relationship to make them equal) for the ideal gas law. The ideal gas law is simply <m>pV=nRT</m> where <m>p</m> is pressure, <m>V</m> is volume, <m>n</m> is the number of moles of gas, <m>R</m> is the ideal gas constant. This constant is closely related to Boltzmann's constant, <m>k_B</m> (to get the ideal gas constant from Boltzmann's constant, multiply by Avogadro's number: <m>R=N_A k_B </m>).

This constant of proportionality depends on which units are used, some common values are:

• 8.314 J /(mole  K)
• 0.082057 L atm/ (mole K)

For more on the ideal gas constant please see UC Davis's chem wiki.