What distillation is
Evaporation throws the vapour away and keeps what is left behind. Distillation catches the vapour instead — and that one change makes it a far more powerful technique.
Distillation
Causing a solution or a mixture to boil and subjecting the vapour obtained to condensation, so as to separate the components, is called distillation.
The apparatus that does the catching
If a mixture is heated, there has to be a way of cooling the vapour that comes off. The Liebig condenser in a school laboratory is the apparatus made for this. The vapour is made to travel through the inside of the Liebig condenser while cold water is used to cool it. There are two points on a Liebig condenser, one for water to enter and one for water to leave.
Figure to be added
The cooling water enters at the low end and leaves at the high end, so the jacket stays full and the water always flows against the direction the vapour travels. That way the vapour meets colder and colder water as it goes.
Three kinds, in the order this skill takes them
The differences between them are in the technical methods used and in the characteristics of the components being separated.
Simple distillation
For a mixture holding one volatile component and one or more that are not volatile.
Fractional distillation
For a mixture holding several volatile components, separated under controlled conditions.
Steam distillation
For substances that would be destroyed by being heated to their own boiling point.
The word for what comes out
The liquid collected after the vapour has been condensed is the distillate. Distilled water is exactly that — water that has been the distillate of a distillation.