Gas Constatn
Gas Constatn
a universal physical constant R in the equation of state for 1 mole of an ideal gas: pv = RT, where p is the pressure, v is the volume, and T is the absolute temperature. From the physical point of view, the gas constant is the expansion work of 1 mole of an ideal gas under constant pressure when it is heated 1° C. On the other hand, it is the difference between the molar heat capacities for constant pressure and constant volume cp — cv = R (for all extremely rarefied gases). It is usually expressed numerically in the following units:
| J/(mole·°K) | 8.31434 ± 0.0035 (1972) |
| erg/(mole·°K) | 8.314 × 107 |
| cal/(mole·°K) | 1.986 |
| l·atm/(mole·°K) | 82.05 × 10-3 |
The universal gas constant, which is used with regard to a single molecule rather than 1 mole, is called the Boltzmann constant. [6-19-1; updated]