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 $PV=nRT$ where $P$ is pressure, $V$ is volume, $n$ is the number of moles of gas, and $R$ is the ideal gas constant.

This constant of proportionality depends on which units are used for the other variables in the ideal gas law equation. Some common values for $R$ are:

• 8.3145 J /(mol K)
• 8.3145 (m³ Pa) / (mol K)
• 0.082057 L atm/ (mol K)

This constant is closely related to Boltzmann's constant, $k_B$ (to get the ideal gas constant from Boltzmann's constant, multiply by Avogadro's number: $R=N_A{k}_B$).

Further Reading

• Molecule and Avogadro's number
• Boltzmann's constant
• Ideal gas law
• Pressure volume diagram
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