Colloids

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Colloids

  1. 1. Colloids
  2. 2. -To know the definition of colloids-To determine the classification ofcolloids-To distinguish the common and someexamples of colloids according to theirclassification-To know how colloids are classified.Objectives:
  3. 3. ColloidsThe word "Colloid" was derivedfrom the Greek, "kolla" for glue, assome of the original organic colloidalsolutions were glues.
  4. 4. The mixture is also called a colloidal solution,colloidal system, or colloidal dispersion. Colloidalsystems can be any combination of these states.Colloid formation can be classified in twosystems, namely reversible and irreversible. In anirreversible system, the products are so stable orremoved so well that the original reactants cannotbe reproduced.
  5. 5. Find words associated with colloids.Motivation
  6. 6. Sols Foams Emulsions GelConnect each mixture with their specific classification.Activity 1
  7. 7. A foam is a substance that is formed bytrapping pockets of gas in a liquid or solid. In mostfoams, the volume of gas is large, with thin filmsof liquid or solid separating the regions of gas.foam
  8. 8. An emulsion is a mixture of two or more liquids thatare normally immiscible (nonmixable or unblendable).Emulsions are part of a more general class of two-phasesystems of matter called colloids.emulsion
  9. 9. ______________________________________________________________________________________________________Tell whether the picture is an emulsion or not.Activity 2
  10. 10. A sol is a colloidal suspension of verysmall solid particles in a continuous liquid medium. Theyare quite stable and show the Tyndall effect. Examplesinclude blood, pigmented ink, and paint.Artificial sols may be prepared by dispersion orcondensation. Dispersion techniques include grindingsolids to colloidal dimensions byball milling and Bredigsarc method. The stability of sols may be maintained byusing dispersing agents. Sols are commonly used inpreparing sol-gels.
  11. 11. A gel (from the lat. gelu—freezing, cold, ice or gelatus—frozen, immobile) is a solid, jelly-like material that can haveproperties ranging from soft andweak to hard and tough.It is the crosslinking withinthe fluid that give a gel itsstructure (hardness) andcontribute to the adhesive stick(tack). In this way gels are adispersion of molecules of a liquidwithin a solid in which the solid isthe continuous phase and theliquid is the discontinuous phase.gel
  12. 12. 1. GSLE is a solid, jelly-like material that can haveproperties ranging from soft and weak tohard and tough.In this way gels are a dispersion of molecules of aliquid within a solid in which the solid is the____2______ and the liquid is the_____3____.2. coouinntus pahes3. dsincouintuos pshaeIt is _____4________ the within the fluidthat give a gel its structure (hardness) andcontribute to the _____5____ (tack).4.conkinsslirg5. ahvdeesi skticActivity 3
  13. 13. 1-2. The term colloid comes from the Greek words “kolla” and “oidos” .What are the meaning of KOLLA and OIDOSa. milk, acidb. glue, appearancec. glue, phase3-4.Colloidal system is composed of two phase. What are these phase?a. continuous phase and dispersed phaseb. continuous phase and dispersion mediumc. discontinuous phase and dispersed phase5-6. Colloidal system can be classified according to their _____________and_______________.a. Internal phase and dispersed phaseb. dispersion medium and continuous phasec.dispersion medium and dispersed phaseQUIZ
  14. 14. 7. what is the suspension of liquid or solid particles in gas?A. gelb. foamsc. aerosols8. these are the colloidal dispersion of gas bubbles in liquid or solids.a. gelb. foamsc. aerosols9. What is the colloidal dispersion of liquid in either a liquid or solid?A. emulsionb. solsc. aerosols10. it is a solid dispersed in either a solid or a liquid.A. emulsionb. solsc. aerosols
  15. 15. 11. What are the colloidal system in which the dispersed phase consist of fibrous,interwoven particles?A. emulsionb. solsc. gels12. what is the interwoven particles which exert marked effect on the physicalproperties of the dispersing medium?A. fiberb. fibrilsc. fibroins13. who is the father of colloid chemistry?A. Robert Brownb. Thomas Grahamc. john Tyndall14. Which of the following is NOT a colloidal system?A. marshmallowb. seawaterc. mayonnaise15. which of the following is an aerosol?A. milkB. fogC. cream
  16. 16. 1. Gel2. continuous phase3. discontinuous phase4. Crosslinking5. adhesive stick1-2.b3-4.b5-6.a7.c8.b9.a10.b11.c12.b13.b14.b15.bAnswer key:

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