The number of elementary entities contained in one mole of a substance. It provides the bridge between microscopic particle counts and macroscopic thermodynamic quantities.
Molecular-scale calculations, ideal-gas relations
The average molar mass of dry air, based on its standard composition. This value is commonly used when modeling air as an ideal gas in thermodynamic cycles.
Gas turbines, compressors, turbines, HVAC systems
The specific gas constant for dry air, obtained by dividing the universal gas constant by the molar mass of air. It is widely used in energy and flow calculations.
Air-standard Otto, Diesel, Brayton cycles