Separation Techniques

Only available on StudyMode
  • Download(s) : 262
  • Published : February 15, 2013
Open Document
Text Preview
Main Separation Techniques
A mixture is usually an impure substance and it is necessary to separate mixtures in order to obtain its pure components. The components of a mixture are not chemically combined. Therefore, they can be separated by physical methods; the components of a mixture will still contain their properties. Methods used to separate mixtures depend on the physical differences between the components of the mixture. The main separation techniques include: Filtration

A method which is used to separate a suspension, a type of mixture produced when a solute does not dissolve in a solvent. The mixture is poured into a filter funnel containing filter paper. The paper possesses small pores which allow the solvent to pass through but does not allow the solute to pass through. The solid left in the filter paper is known as residue and the liquid which passes through is called the filtrate. Paper Chromatography

Paper chromatography is a special method used to separate inks and other pigments. The separation occurs due to different dyes travelling at different speeds up the filter paper. The speed is determined by the dyes ability to dissolve in the solvent. The faster it dissolves in the solvent, the faster and further it moves on the filter paper. Main Separation Techniques

Simple Distillation
This technique is used to obtain or separate a pure solvent from a solution. Simple distillation separates a solid or liquid solution of substances with widely different boiling points. The method is based on the fact that the solvent vaporizes at a lower temperature than the solute. The solid which remains the distillation flask is known at the residue and the distilled solvent is known as the distillate.

Solvent Extraction
A method used to separate mixtures, where one component dissolves in a solvent and another does not. These components are usually of different chemical types and solubility.

Main Separation Techniques

Sublimation
Sublimation is used to separate solid mixtures which contain one substance that is able to sublime and other which is not. Sublimation is the ability of a solid to change directly into a gas.

Fractional Distillation
Fractional distillation is used to separate miscible liquids with components of the liquid mixture having similar boiling points. The component with a higher boiling point would condense on the fractionating column and return to the solution. However, the component with the lower boiling point would pass through the column and be collected in the flask.

Main Separation Techniques

Separating Funnel
This equipment is used to separate immiscible liquids. The method is based on the fact that the liquids will not mix but will instead form two distinct layers. The less dense liquid will be on top and the more dense liquid on top.

Evaporation and Crystallization
This method is used to separate a solution of solid and liquid. The mixture is heated using an evaporating dish and the liquid will eventually boil off. The solution will then become extremely concentrated and eventually supersaturated, which will form crystals. If the solution is cooled, crystallization takes place; the crystals are then washed and dried.

Main Separation Techniques
Decantation
This method can be used to separate suspensions. A mixture if left undisturbed until all the solid particles are settled. The liquid layer is later carefully poured or decanted off, leaving the solid residue behind.

Centrifugation
When the mixture takes too long to settle, the process is able to be sped up by centrifugation. This process allows the mixture to be rotated at a high speed and the centrifugal forces cause the particles to settle out.
The Extraction of Sucrose
From Sugar Cane
What is sugar cane?
Sugar cane is a seasonal, tall and usually strong plant, which is...
tracking img