TO use this program install all files onto your TI-89.
then in the main window type:
					
chemie() 
  Interpolate
  Enthalpy
  Peng-Robinson EoS
  Peng-Robinson Mix
  Peng-Robinson Fugacity
  Virial EoS
  Virial Mix
  Redlich Kwong Soave EoS
  Redlich Kwong EoS
  Van der Walls Eos
  Antoine

activity()
  Van Laar
  Wilson
  Margules

to execute the functions of the programs. 

This version for the TI-89 of chemie was fixed by 

Eric DiStefano, ej2x@hotmail.com

This version of chemie is based on the one for TI-92
plus and is modified to fit correctly the screen of the 
TI-89, the basics of the program have not been changed.
I don't know who did the original one, but it was not me.
You can contact me at the e-mail above.

I also fixed a lot of bugs.