3 Oil and Water Don’t Mix Oil is nonpolar Water is polar “Like dissolves like”Lycopodium Powder demonstration.Lycopodium powder is a nonpolar hydrocarbon that doesn’t mix with water. It is dry to the touch and not oily feeling. Sprinkle lycopodium powder on top of a beaker of water. Slowly, push your finger through the surface of the lycopodium powder into the water. Slowly withdraw your finger, it remains dry the entire time. Why?Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 470
4 Hydrogenation + H2 shortening stick margarine tub (soft) margarine vegetable oils+ H2FOOD SUBSTITUTES“Chemistry is widely used in the food industry to manufacture new convenient foodstuffs and to check for impurities. Butter is known as a saturated fat, whereas most vegetable oils, which are normally liquid, are polyunsaturated fats. They can be changed to solids, such as margarine, by a chemical process called hydrogenation – the addition of hydrogen to the oils using a catalyst. Hydrogenation makes the oil more like butter and easier to spread. Margarine was first developed in the 1860’s in France as a cheap butter substitute.”Eyewitness Science “Chemistry” , Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 7heat, nickelcatalystTimberlake, Chemistry 7th Edition, page 570
5 Molecular Polarity H nonpolar molecules: -- e– are shared equally H–C–HHnonpolar molecules: -- e– are shared equally-- tend to be symmetrice.g., fats and oilsHOpolar molecules: -- e– NOT shared equallye.g., water“Like dissolves like.”polar + polar = solutionnonpolar + nonpolar = solutionpolar + nonpolar = suspension (won’t mix evenly)
6 Using Solubility Principles Chemicals used by body obey solubility principles.-- water-soluble vitamins: e.g., vit. C-- fat-soluble vitamins: e.g., vits. A, DDry cleaning employs nonpolar liquids.-- polar liquids damage wool, silk-- also, dry clean for stubborn stains (ink, rust, grease)-- (tetra) perchloroethylene is in common useC=CCl
7 One unit washes and dries Dry Cleaning Unit-One unit washes and driesWashing ProcessDrying ProcessProcess used forWash and dryPressingDirtyClothesAir toAtmosphereWarm VaporFrom DryerDirtyPercFilterCondenserPercUsed,FilteredPercSeparatorNewPerchloro-ethylene(PERC)CondensedLiquid PercFinishedClothesPerc Storage/CollectionCleanPercCollectedUsedPercWater DischargeHazardousWaste*Distiller*Soil, dirt, unrecovered Perc
8 MODEL OF A SOAP MOLECULE emulsifying agent (emulsifier):-- molecules w/both a polar AND a nonpolar end-- allows polar and nonpolar substances to mixe.g., soapdetergentlecithineggsMODEL OF A SOAP MOLECULENa1+NONPOLARHYDROCARBONTAILPOLARHEAD
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