Separation of Mixtures Mixtures may be separated by many different techniques based on differing physical and/or chemical properties

Sorting Simply picking apart the different components This can be easy and obvious… Sort the laundry into colored and whites! Or it can be challenging… An organic chemist who used a microscope to sort out mirror image crystals of a compound

Sieving Using screens to sort by size Sifting flour or sugar… or gold nuggets or soil

Filtration Particles separated form liquid or gas Coffee, Furnace, Lab filter setup with funnel

Decantation Pouring liquid off of settled mixture Or remove a layer of liquid Wine from sediment Cleaner water in water treatment plant

Magnetism Iron from aluminum, plastic, and paper at recycling plant Cow magnets!

Density Different types of plastic at recycling plant Oil on water

Dissolving If one substance dissolves and another doesn’t Salt and sand…salt dissolves in water…sand doesn’t…sand settles Tea flavor from tea leaves…flavor and color dissolves…tea leaves don’t…the bag acts as a filter

Centrifugation Spinning to pull heavier part of mixture to bottom Blood cells are separated from serum The spin cycle in the washer removes water from clothes

Distillation Differences in boiling points can be used to separate liquids (differences in freezing and sublimation points may also be used ) Alcohol in stills Oil refineries

Chromatography From “chroma” meaning color because this technique was first used for dyes A mobile phase carries sample along over or through a stationary phase. Components are separated because they have different attractions for the phases. Paper chromatography to separate pigments in ink is one example There are many variations for many different mixtures

Evaporation Remove a liquid from a solid Sea salt isolated by evaporating sea water in shallow ponds Solids may also be purified by recrystallization

Shaking Motion… a dog shaking to remove water Gravity/density… gentle shaking causes dense items to sink and less dense to rise

As you can see, almost any difference in physical properties can be used to separate mixtures physically Differences in chemical properties can also be used to separate mixtures chemicallt. For example, oil floats on water (physical difference in density) and burns, but water does not (chemical property of flammability) This picture shows an oil spill being contained and burned.

SEPARATION TECHNIQUES are limited only by people’s ingenuity!