pVnRT

PVnRT refers to the ideal gas law, most commonly written as PV = nRT. It expresses a relation among pressure (P), volume (V), amount of substance (n), the gas constant (R), and temperature (T) for ideal gases. The law states that the product of pressure and volume is proportional to the amount of gas and its absolute temperature.

Variables and units: P can be measured in pascals (Pa) or atmospheres (atm); V in cubic meters (m^3) or liters (L); n in moles; T in kelvin. The value of R depends on the chosen units: 8.314462618 J/(mol·K) in SI units (P in Pa, V in m^3); or 0.082057 L·atm/(mol·K) when using atm and liters. Other unit systems use corresponding R values, such as 62.3637 L· Torr/(mol·K) for Torr.

Applications: The equation enables calculation of any one variable when the others are known. It is most accurate for ideal gases, which approximate real gases under low pressure and high temperature. At standard room conditions (P ≈ 1 atm, T ≈ 298 K), the molar volume V_m = RT/P is about 24.47 L per mole.

Assumptions and limitations: The ideal gas law assumes negligible intermolecular forces and negligible molecular volume. Real gases deviate from ideal behavior at high pressures or low temperatures. More accurate models include the van der Waals equation and the concept of the compressibility factor Z.

Notes: If the amount of gas is not given in moles, you can convert mass to moles using the substance’s molar mass. The relation PV = nRT remains the governing form for ideal-gas behavior.