gázállandó

The ideal gas constant, symbolized by R, is a fundamental physical constant that appears in many basic equations of physics and chemistry, most notably the ideal gas law. It relates the energy scale to the temperature scale and the amount of substance. The ideal gas law, PV = nRT, describes the relationship between pressure (P), volume (V), the amount of substance (n), the ideal gas constant (R), and temperature (T) for an ideal gas.

The value of the ideal gas constant depends on the units used for pressure, volume, and temperature. Common values include 8.314 joules per mole-kelvin (J/mol·K) when using SI units of pressure (pascals), volume (cubic meters), and temperature (kelvin). Another frequently used value is 0.08206 liter-atmospheres per mole-kelvin (L·atm/mol·K), which is useful when working with pressures in atmospheres and volumes in liters.

The ideal gas constant is also known as the molar gas constant or the universal gas constant. It can be derived from fundamental constants like the Boltzmann constant (k_B) and Avogadro's number (N_A) through the relationship R = k_B * N_A. This connection highlights its role in bridging macroscopic thermodynamic properties with microscopic molecular behavior. While the ideal gas law is an approximation, the ideal gas constant remains a crucial parameter in many calculations involving gases.