***QWhy was octanol chosen as the water partitioning standard?  Certainly there are other immiscible compounds that could have been chosen.
A. Because it has a lipophilicity about the same a fat tissue.  It is also manageable in the laboratory.  For interest, I have a “Mosquito Magnet” that has octanol as the “attractant” besides the water and CO2.

**Q. Is Pow the same as Kow?  I see the Pow listed in http://www.cdc.gov/niosh/ipcsneng/neng0250.html .  It is the same value so I think Pow may be “international or European/”
A. Pow  is the same as Kow, it means “partition.”

*Q. I understand that volatility will increase with vapor pressure and boiling point will decrease with an increase with vapor pressure.  I can compare density to water to determine if it will sink or rise.  Can I compare vapor pressure of chemical to air for a scientific assumption?  For example, volatility is low because vapor pressure is less than that of air (where chemical vapor pressure is 8.7 kPa and air is 101.3kPa).
A. No.  Vapor pressure is related to its liquid state, which for air (or nitrogen) is very cold.  Henry’s Law is more important for what we deal with.