Homework Help: Chemistry - Please help!!

Posted by Laura on Tuesday, October 5, 2010 at 11:41pm.

I did a lab for Organic Chemistry

We did a simple distillation of an unknown alcohol to determine the boiling point, which was found to be 74*C

The four possibilities for the unknown were methanol, ethanol, 1-propanol and 2-propanol. So from the boiling point the unkown must be ethanol...

We then did a fractional distillation of this alcohol mixed with water. The alcohol was distilled off after 4.0 mL (25.0 mL of mixture was used).

To find:
1.
beginning percent composition of unknown/H20

would this be :

4.0/25.0*100%

2.

Does it form any azeotrops, list them:

does this mean binary with water etc., ternary...? or am I supposed to write some other description?

3.
If it did form an azeotrops Calculate the beginning % composition of the mixture

confused about this...

Any help would be greatly appreciated!

Chemistry - Please help!! - DrBob222, Tuesday, October 5, 2010 at 11:52pm
I skipped your earlier post. I don't understand the question. For example, "The alcohol was distilled off after 4 mL." Does that mean that all of the alcohol was gone after 4 mL or does it mean that 4 mL of the mixture was distilled BEFORE any alcohol began to appear? I'm confused by that and the question then asks about the beginning percent composition.
With regard to azeotropes, yes, ethanol/water form an azeotrope. It is very close to 95%alcohol/5% water.(see
http://en.wikipedia.org/wiki/Azeotropic_distillation)

Answer this Question

Related Questions

Chemistry - I did a lab for Organic Chemistry We did a simple distillation of an...
chemistry - If im trying to separate alcohol from water by distillation, is it ...
organic chemistry - Why is steam distillation rather than a simple distillation ...
Chemistry - I did a lab for Organic Chemistry I did a simple distillation for an...
Chem. - Why is it not possible to achieve a complete separation of the ethanol ...
org. chem. - Why is it not possible to achieve a complete separation of the ...
Org. Chem. - Why is it not possible to achieve a complete separation of the ...
Organic Chemistry Lab - They are asking me to predict the boiling point at ...
OChem - 1. if and when boiling points can be used to determine the purity of ...
B.P. - Why does the boiling point of a two-component mixture rise slowly ...

For Further Reading

First Name:
School Subject:
Answer: