[hefeweizen]

I am confused about azeotropes. They are mixtures that cannot change in composition no matter how much distillation you do. A positive azeotrope is one where the boiling point is lower than that of both components in a mixture. A good example is 95.63% ethanol and 4.37% water. This happens because in a positive azeotrope containing X and Y, X and X tend to be together and Y and Y tend to be together.



If X and X tend to be together and Y and Y tend to be together, then why is it that in ethanol and water mixture, you cannot get a more pure ethanol?

[AWK]

They are mixtures that cannot change in composition no matter how much distillation you do

This statement is true only at constant pressure.

[Enthalpy]

[...] If X and X tend to be together and Y and Y tend to be together, then why [no separation...]

The ambient heat mixes molecules even in the case where, to some degree, each fits better with identical ones. For instance water and glycerine mix well but produce cold.

In the case of distillation, it's a matter of partial vapour pressure.

[hefeweizen]

[...] If X and X tend to be together and Y and Y tend to be together, then why [no separation...]

The ambient heat mixes molecules even in the case where, to some degree, each fits better with identical ones. For instance water and glycerine mix well but produce cold.

In the case of distillation, it's a matter of partial vapour pressure.

Thanks! Do you mind explaining more?  How does heat mix molecules?

[shiffdaddy]

Heat is the movement of particles right?  So wouldn't it make sense that this movement of particles causes some sort of mixing