3.9 Separation of Solutions and Mixtures; Chromatography

Can components of a liquid solution be separated by filtration?

No

How can components of a liquid solution be separated?

By processes that take advantage of differences in the intermolecular interactions of the components

Different types of chromatography:

Paper, thin=layer, and column

How does chromatography separate chemical species?

By taking advantage of the different strength of the intermolecular interactions between and among the components of the solution with the surface components of the stationary phase

How does distillation separate chemical species?

By taking advantage of the differential strength of intermolecular interactions between and among the components and the effects these interactions have on the vapor pressures of the components in the mixture

A solid that provides support for the chromatography experiment, but does not move

Stationary phase

What can the stationary phase be?

A piece of paper, a piece of metal or glass coated with a porous solid, or a glass column filled with a porous solid

A liquid or gas that moves, carrying the components of the mixture over or through the stationary phase

Mobile phase

Which substances tend to be soluble in one another?

Those with similar intermolecular interactions

What solvents do polar solutes mix well with?

Polar

What solvents do nonpolar solutes mix well with?

Nonpolar

The liquid that travels up the paper in a paper chromatography experiment:

Solvent

What is the solvent in chromatography also known as?

The mobile phase

The mark on the chromatography paper that indicates how far the solvent has moved up the paper

Solvent front

Which component of a mixture in paper chromatography will be the one that is the most soluble with the solvent?

The one that travels the farthest distance up the paper

If two substances are soluble, what are their interactions like?

Strong

What can be deduced about the component of the mixture that travels the farthest distance up the paper in paper chromatography?

It is the most soluble in the solvent and has the best interactions with the solvent

What can you calculate after a paper chromatography experiment has been completed?

Rf value for each component of the mixture

What does Rf value stand for?

Retention factor

How to calculate the Rf value?

(distance traveled by one component) / (distance traveled by the solvent)

What is the range of the Rf value?

0 to 1

How does the size of Rf value relate the distance that the component of the mixture has traveled relative to the solvent front?

Larger the Rf value, the farther up the paper it has traveled relative to the solvent front

What is distillation used for?

Separating components of a mixture that have different boiling points

What is done to the mixture during distillation?

Heated

What happens after the mixture is heated in distillation?

The component with the lowest boiling point boils

Where does the vapor in distillation travel?

Through glassware to condenser

The portion of the distillation apparatus that is surrounded by cool water

Condenser

What happens to the vapor when it reaches the condenser in distillation?

Condenses into liquid

What happens to the condensed liquid in distillation?

Collected in separate container

The liquid that is produced in a distillation experiment

Distillate

Which component in the distillate during distillation has the lowest boiling point?

The one that appears first

What is the boiling point of the component of the mixture that appears first in the distillate?

Lowest out of all the components