hi, i don't see this as a chemical reaction. i see it as a physical change in state. assuming temperature and pressure remain constant, the rate of change of solid into gas would remain constant and thus a '0' order operation. phil -----Original Message----- From: Bev Christian [mailto:[log in to unmask]] Sent: Wednesday, December 17, 2003 10:57 AM To: [log in to unmask] Subject: [TN] Need a chemist or chemical engineer to answer Technetters, It has been almost 30 years since I took kinetics. I have dug out my old text books, but they only help so much. I'm a preparative inorganic chemist by training. My question is the following: If a single compound sublimes, without decomposition, would you expect the kinetics to be zero or first order? Thanks. Bev Christian Research in Motion --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------