[vmelkon]

Anyone know what this graph means?
http://en.wikipedia.org/wiki/File:Vapor-Liquid_Equilibrium_Mixture_of_Ethanol_and_Water.png

I have some ethanol with a boiling point of 358 K. Does this mean it is 50% molar water and 50% molar ethanol?

[Borek]

Anyone know what this graph means?
http://en.wikipedia.org/wiki/File:Vapor-Liquid_Equilibrium_Mixture_of_Ethanol_and_Water.png

I have some ethanol with a boiling point of 358 K. Does this mean it is 50% molar water and 50% molar ethanol?

More like molar fraction slightly above 0.1. 50/50 mixture will boil at 353 K.

Unless I had too much ethanol (in the form of Tokaji Furmint bought last week while driving back home ).

[vmelkon]

If what you are saying is true, then if the boiling point is 85 C, then there is more water than ethanol.
I am having a hard time accepting that. I would expect for there to be more ethanol than water. The graph is . extremely non linear between the bp of water and the bp of ethanol.

[Borek]

If what you are saying is true, then if the boiling point is 85 C, then there is more water than ethanol. I am having a hard time accepting that. I would expect for there to be more ethanol than water.

Why? Ethanol left the solution much earlier, at lower temperatures, it is - after all - much more volatile.

[vmelkon]

Ok, I guess it is what it is.
When I distilled my liquid, the temp went from 78 to 85 C and I stopped the distillation process. Can I measure the density of the liquid and know the concentration of ethanol? (I prefer mol/L but whatever data is available is fine).
I don't have a hygrowhatever to measure the concentration.

[Borek]

Either hydrometer to measure density, or refractometer to measure refractive index should do the trick. But if you have neither you can't measure neither.

[vmelkon]

I found this. http://www.separationprocesses.com/CourseWare/Experiments/Property01.htm
Perry says so. He knows things.