[StarBurns]

So I have a mixture of ethanol (27%) and tricholoroethylene (73%) that forms an azeotrope. The boiling points are as follows:

ethanol: 78.5 C

trichloroethylene: 87.1 C

azeotrope: 70.9 C

1) If this mixture goes through simple distillation, what is the approximate composition of the first drop of distillate?

2) How does the composition of the initial solution change as the mixture is distilled?

Please, any help? I'm lost, and don't know where to start.

[CrimpJiggler]

First you need to know the mixtures azeotropic composition. Alcohol and water form an azeotrope but only when the alcohol reaches 95%. This is the solutions azeotropic composition. I found it for you here:
http://www.chemeng.ed.ac.uk/people/jack/azeotrope/TT.html#trichloro
so the azeotropic composition is 27% ethanol and 73% trichloroethylene. The solution you have is at its azeotropic composition. This is a pretty silly question. An azeotrope is a solution which doesn't change composition by simple distillation. So the sum it up:
1.) 27% ethanol and 73% trichloroethylene
2.) The mixture is an azeotrope therefore its composition cannot be changed by simple distillation

I might be missing something there but thats my understanding of azeotropes. I did a lab dealing with a toluene/ethanol azeotrope I think it was and each distillation changed the composition until the azeotropic composition was finally reached.

[vmelkon]

I think the question isn't saying that "the azeotropic composition is 27% ethanol and 73% trichloroethylene".
The question is badly worded.
It should say : ethanol and tricholoroethylene is known to form a azeotrope.
Your initial % are 27 and 73.
And I guess you need to get the graph for the azeotropic composition from somewhere.

1) If you distill it, the vapor is likely to contain the vapors of the thing that has the lower bp the most. As for the composition, I have no idea.

2) As time passes, the vapor composition would have more tricholoroethylene.

I found this http://www.chemeng.ed.ac.uk/people/jack/azeotrope/TT.html
and also, your initial question says "% are 27 and 73" but is that in weight percentage, mol percentage, volume percentage?