AbstractThe derived thermodynamic properties of acetylene have been determined over a temperature range of 32 to 500°F. and up to pressures of 2,000 lb./sq. in. abs. The data were calculated from vapor pressure, volumetric, and heat‐capacity data by the use of rigorous thermodynamic relationships. The calculated data were found to be internally consistent. The enthalpy values are believed to be accurate within ±1.0 B.t.u./lb. and the entropy values to ±0.001 B.t.u./(lb.)(