2. Separation Techniques

3. Methods of Separating Mixtures Magnet Filter Decant Evaporation Centrifuge Chromatography Distillation

4. A magnet Can be used to separate a magnetic substance from a non-magnetic substance

5. Filtration separates a liquid from a solid Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 40 Mixture of solid and liquid Stirring rod Filtrate (liquid component of the mixture) Filter paper traps solid Funnel

7. evaporation

8. 1. Pour some distilled water into the mixture to dissolve the soluble substance. 2. Filter the mixture. 3. Wash the residue with a little distilled water to remove all the salt solution from it. The residue is sand. 4. Evaporate the filtrate to dryness. Salt is recovered. Procedure:

10. Distillation Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

12. Setup to heat a solution Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 42 Ring stand Beaker Wire gauze Ring Bunsen burner

13. long spout helps vapors to condense mixture for distillation placed in here Furnace Glass retort A Hero’s Fountain Eyewitness Science “Chemistry”, Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 13

14. A Distillation Apparatus liquid with a solid dissolved in it thermometer condenser tube distilling flask pure liquid receiving flask hose connected to cold water faucet Dorin, Demmin, Gabel, Chemistry The Study of Matter, 3 rd Edition, 1990, page 282

15. Water, water, everywhere, And all the boards did shrink; Water, water, everywhere, Nor any drop to drink.” “

16. The solution is boiled and steam is driven off. Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 39

17. Salt remains after all water is boiled off. Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 39

18. Chromatography Tie-dye t-shirt Black pen ink DNA testing –Tomb of Unknown Soldiers –Crime scene –Paternity testing

19. Time to remove your chromatography paper

20. Paper Chromatography

21. No chemical change occurs when salt water is distilled. Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 40 Saltwater solution (homogeneous mixture) Distillation (physical method) Salt Pure water

22. Separation of a sand-saltwater mixture. Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 40

23. Separation of Sand from Salt 1.Gently break up your salt-crusted sand with a plastic spoon. Follow this flowchart to make a complete separation. Salt- crusted sand. Dry sand. Wet sand. Weigh the mixture. Decant clear liquid. Evaporate to dryness. Pour into heat-resistant container. Fill with water. Stir and let settle 1 minute. Weigh sand. Calculate weight of salt. Repeat 3 times? Yes No 2.How does this flow chart insure a complete separation?

24. Centrifugation

25. Spin sample very rapidly: denser materials go to bottom (outside) Separate blood into serum and plasma –Serum (clear) –Plasma (contains red blood cells ‘RBCs’)

26. Physical properties exploited for identification Most common boiling point Most substances have different boiling points Even solutions often have different boiling points Wavelength of emitted / absorbed light Density Solubility

27. Physical properties exploited for identification Chromatography Advanced techniques for another day Mass spectroscopy Nuclear magnetic spectra HPLC For now if in doubt boil it and measure the boiling point.. See if there is any solute left