If the general gas equation is applied to V = m/s, the gas equation assumes the following enlarged form:

Formula 2.3.2.1
It simplifies calculation with the gas equation if one operates with the specific volumes v, where v = V/m. If one substitutes V = v x m in equation 2.3.2.1, the physical state equation of gases related to 1 kg becomes:

Formula 2.3.2.2