The Vapor Density comparisons are only valid when the gas escaping is at a similar temperature as being the surrounding air by itself. If your chemical is escaping from a container where it was pressurized or refrigerated, it may very first escape and behave for a heavy fuel and sink https://potassium-cyanide49132.livebloggs.com/36317304/little-known-facts-about-potassium-cyanide-what-type-of-bonds