Unit 1.10 Separating Mixtures: Distillation

Flashcards covering simple and fractional distillation, when each is used, the steps involved, and key details like boiling points of ethanol and water.

What is distillation used to separate?

Distillation is used to separate mixtures, such as a liquid from a soluble solid in a solution (e.g., water from salt in saline solution).

Simple distillation: what are the four main steps?

1) Heat the solution; 2) The component with the lowest boiling point evaporates; 3) The vapour is cooled and condensed; 4) The condensed liquid is collected in a new container; the rest remains in the flask.

In simple distillation, when does it work best?

It works only when the components have very different boiling points.

When is fractional distillation required?

When the boiling points of the components are similar.

What is the purpose of fractional distillation?

To separate liquids with similar boiling points using a fractionating column.

In simple distillation, which component evaporates first?

The component with the lowest boiling point.

What happens to the evaporated vapour in simple distillation?

It is cooled and condensed to form a pure liquid, which is collected in a new container.

What happens to the remainder after simple distillation?

The rest of the solution stays in the original flask.

Give an example used to illustrate fractional distillation.

Separation of ethanol (boils at 78°C) and water (boils at 100°C).

In fractional distillation, what happens to ethanol vapour after it evaporates?

It rises up a fractionating column and is carried to a condenser where it condenses into liquid.

What is the boiling point of ethanol?

78°C.

What is the boiling point of water?

100°C.

What is produced first in fractional distillation of ethanol and water?

Pure, distillable ethanol is produced first; water is collected after raising the temperature.

In a simple distillation setup from saline solution, what is the distillate?

Pure water distills, leaving salt behind in the solution.

What equipment is used to condense vapour in distillation?

A condenser (often with a cooling water jacket) is used to condense the vapour into liquid.