Separating Mixtures — Overview & Common Methods

What Are Mixtures?

They are the combination of two or more substances. They can be homogeneous (same throughout) or heterogeneous (not uniform). They can exist as solids, liquids, gases, or a combination of these states.

How are Mixtures Separated?

Mixtures can be separated in different ways with varying difficulty. Below are some examples used in chemistry.

Filtration is used to separate a solid from a liquid. You have probably done this in your own kitchen! When you strain water from pasta, after boiling, this is filtration. Typically is chemistry, filters are used which allow liquids to pass through.

Evaporation is similar to filtration since it separates a liquid from a solid. In this case, the liquid is turned to gas, usually through heating. The solid must be non-volatile, meaning it will not evaporate. Evaporation can be used in an outdoor setting to create safe drinking water. The evaporated water is collected on a cool surface and leaves behind impurities in the boiling vessel.

Distillation is a technique which, in the simplest terms, separates components of a mixture through heating and cooling. This technique is often used in organic chemistry to separate liquid mixtures. It is often used to create extracts, which you might find in a kitchen. Vanilla extract, which contains the chemical vanillin, is distilled from vanilla pods. A mixture is created by crushing the pods in ethanol which helps to pull out the vanillin.

(Video) How to Separate Solutions, Mixtures & Emulsions

by FuseSchool - Global Education

This video will teach you about different ways to separate mixtures. Some of these techniques include evaporation, distillation, and filtration. The technique you use depends on the physical properties of the substances you are working with.

Separating Mixtures

• Separation techniques allows for scientists to break down a mixture into simpler components

What are the different ways to separate mixtures?

There are 4 main ways of separating mixtures:

• Distillation (boiling points)
• Chromatography
• Evaporation
• Filtration/Sedimentation

Distillation:

• Distillation takes advantage of the different boiling points between liquid substances

• Distillation works by heating up a mixture to the boiling point of one of the substances (typically it is the substance that has the lowest boiling point). Once boiling, the vapor goes through a condenser so that the water vapor is turned back into a liquid, thus separating the mixture.

• Note: Distillation is only used when the mixture contains solutions with two distinct boiling points, if the boiling points of the solutions in the mixture are too similar, it may result in a poorly separated solution.

Chromatography:

• Chromatography uses a solution to put the mixture in the “mobile phase”, where the solution is able to move up a tube/sheet/plate/column until the stationary phase is reached (where the mixture is no longer moving up the medium).

• Different solutions move up the mediums (capillary tube, column, plate, etc.) at different lengths, thus it separates the mixture based on how far the solutions are able to travel through the medium.

Evaporation:

• Evaporation is used to separate a solid (insoluble solution) from a liquid (example: removing salt from salt water)

• Evaporation works by boiling the solution in a chamber until there is no liquid left, collecting the vapor, and using a condenser to condense the water vapor back into a liquid. This process leaves the solid in the first chamber, and separates the liquid into a separate chamber

Filtration

• Filtration is also referred to as sedimentation

• Filtration is another method for separating a solid (insoluble solution) from a liquid

• Filtration works by using filter paper. The mixture is slowly dripped onto the filter paper, which allows liquid to pass through, but leaves solids behind, thus separating the two from each other.