Recommend two useful free websites to whoever need them:

1. Steam/water properties calculation website, which calculate steam and water's thermodynamic properties such as enthalpy, entropy, density etc. using IF97 equation.

http://steam.dreamworld.ltd2. Air, oxygen, nitrogen and argon properties calculation website, which calculate air, oxygen, nitrogen, argon's thermodynamic properties such as enthalpy, entropy, density etc. using Bender equation. Bender equation is the most accurate equation used in air separation area.

http://air.dreamworld.ltd