Volume number of moles and

A eonstant (symbolized by R) and used throughout the diseiplines of kinetics and thermodynamics, equal to 8.314510 J-mol-i-K-i or 1.987216 cabmol- -K k [The term was originally developed as the proportionality constant for the ideal gas law (PV = nRT where P, U, n, and T are pressure, volume, number of moles, and absolute temperature of the ideal gas, respectively), hence the appearance of gas in its name.] See Boltzmann Constant... 

The ideal gas law relates (at least approximately) the pressure, volume, number of moles, and temperature of any sample of any gas under any conditions PV = nRT. The value of the constant R usually used is 0.0821 L atm/mol K. If any three of the four variables are given, the fourth may be calculated. The ideal gas law is often useful for finding the number of moles of a gas. Because R is given in atmospheres and liters, these same units should be used for the pressure and volume, respectively. As always, the temperature must be in kelvins (Section 12.5). 

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