In the equation PV nRT R is the universal gas constant. Write the formula for an ideal gas equation. How Do I Know Which R Value To Use In Pv Nrt R Apchemistry The ideal gas law is. . The gas constant value is given by R 8314459848 Jmol1K1. The ideal gas equation is given by PVnRT. The ideal gas law is. Thevalue of R depends on the units involved but isusually stated with SI. V is the volume of the gas measured in m³. R has for value 8314 JmolK 1989 2 calmolK or 00821 LatmmolK. Units as R 8314. You may think of it as a unit conversion factor because the product PV on the left does not have the same units as. The ideal gas law is pV nRT where n isthe number of moles and R is universal gas constant. N is the amount of substance measured in moles. R P V n T displaystyle Rfrac PVnT where P is pressure V is volume n is number of moles of a given substance and T is temperature. The value of R de