Thermodynamics

A property depends only on the current state, not the path taken to reach it (its cyclic integral is zero).

Intensive properties are independent of mass (e.g., temperature, pressure); extensive properties scale with mass (e.g., volume, total energy).

Two independent intensive properties completely fix the equilibrium state of a simple compressible substance.

Pv = RT, or equivalently PV = mRT, where R is the specific gas constant (kJ/kg·K).

R = R_u / M, where R_u = 8.314 kJ/kmol·K is the universal gas constant and M is the molar mass.