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

What’s a mixture? A mixture consists of two or more pure substances combined physically A mixture has variable composition – As opposed to pure substances, which always have the same composition (elements or compounds)

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 Maybe even DIRT 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 Purifying gases

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 re- crystallization

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

Almost any difference in physical properties can be used to separate mixtures physically Differences in chemical properties can also be used to separate mixtures chemically. Identify the physical property and the chemical property that are being used to clean up this oil spill

Single stream recycling: How do they sort this mess out? Lots of ingenuity…and knowledge of physical and chemical properties!

Separation challenges Frack water cleanup Fracking Water Recycling Fracking Water Recycling Articles from 2013 and 2014 about cleaning up water used for hydraulic fracturing to get natural gas…fracking

SEPARATION TECHNIQUES are limited only by people’s ingenuity and imagination!