larry@kitty.UUCP (Larry Lippman) (12/03/90)
In article <14169@mcdphx.phx.mcd.mot.com>, hbg6@citek.mcdphx.mot.com writes: > > Since I don't see a sci.chemistry group, thought this might be the next > > best palce for my question regarding methyl alcohol, methanol for short. Sure, there's a chemistry group! - sci.chem > > Which is, is there any easy way to determine the amount of water mixed > > in with the methanol???? I have some methanol, but I suspect that it is > > contaminated with water. Could I simply take a small sample, say 2 oz, > > burn it and the remaining liquid is water?? Any ideas??? Thanks. Measure its specific gravity using a hydrometer, or measure its density using a specific gravity bottle or volumetric flask on an accurate balance. Calculation of the percent of water from the specific gravity is not difficult; an alternative is to find a table of methanol-water mixture constants in a chemistry or chemical engineering handbook. The above is probably the simplest method. While you could use freezing point depression or boiling point elevation, specific gravity is much more convenient. Probably the most common real world analytical laboratory method is more complicated, but is simpler to implement because it can be run on fully automated apparatus. It is called Karl Fischer titration. If *I* wanted to make this determination, I would put a sample in the Mettler KF titrator in my lab, and have an answer in a few minutes without any more than a few keystokes of data entry. > If you put it in the freezer, wouldn't the water percipitate out as ice? No, no, *NO*! Larry Lippman @ Recognition Research Corp. "Have you hugged your cat today?" VOICE: 716/688-1231 {boulder, rutgers, watmath}!ub!kitty!larry FAX: 716/741-9635 {utzoo, uunet}!/ \aerion!larry