Separation Techniques

This class we learned about separating mixtures.

Since components keep their identities, you can devise a process that discriminates between components with different properties. There properties include:

-Density                                     -Reactiveness
-Volatility                                   -Magnetic/non-magnetic
-Solubility                                  -Polarity

Here are some basic separation techniques:

Filtration: select components by particle size through a filter

Floatation: by density

Distillation: by boiling points

Chromatography: by attraction for a stationary phase

Hand Separation: (solids and solids): A mechanical mixture/heterogenous misture can be separated by a magnet or a sieve(sifter)

Evaporation: (solid dissolved in a liquid solution): boils away the liquid and leaves the solid behind.

Here is how each process works:

Filtration:(undissolved solids and liquid): Passes a mixture that contains solid particles through a porous filter. If the pores are smaller than the particles, then the solid particles stay on the filter.

Crystallization: (solid and liquid) A saturated solution of a desired solid is used. Which is then turned into a precipitate through chemical or physical change. The solids are then separated by floatation or by filtration. The liquid is then evaporated or cooled and the solids come out as pure crystals.

Gravity Separation:(solids based on density) A centrifuge whirls a test tube at high speeds forcing denser materials to the bottom. This works best with small quantities.

Solvent Extraction: A component movies into a solvent shaken with the mixture. Works best with one component that dissolves.

          Mechanical Mixture: (solid and solid): liquid to dissolve one solid but not the other, so the desired solid is lieft behind or dissolved
 
         Solution: solvent is insoluble with solvent already present. The solvent dissolves one or more substances and leaves the unwanted behind.

Distillations(liquid in liquid solution): Distillation is collecting and condensing volatilized components. Heating a mixture can cause low-boiling components to vapourize. The component that boils evaporates and enters a condenster; the gas the ncools and condenses back into liquid dropping as a purified liquid.

exmaple of distillation

Chromatography: There are many different types of chromatography and they include both the mobile and stationary phase. It is highly accurate and precise with its analyses and it is used to separate very complex mixtures (for eg. drugs, plastics, foods, pesticides). Then the separated components can be collected individually.

Sheet Chromatography: Paper Chromatography (PC) involves a strip of paper. The solvent is applied on the strip of paper and then the components appear as separate spots spread out on the paper.

Now for an example of paper chromatography: