Methods of Colloid Preparation

Download Methods of Colloid Preparation

Post on 26-May-2015

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Images on dialysis, methods of preparation of colloids, association/ amphiphilic colloids to give students a visual concept and empty slides to be used as cue cards

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<ul><li> 1. COLLOIDS </li></ul> <p> 2. colloids 3. Buchner funnel used in ultra filtration 4. Dialysis 5. Colloidal gold how color changes with increasing particle size 6. Methods of preparing colloids 7. For lyophillic 8. 1. SOLVATION 9. For lyophobic 10. Methods for preparing lyophobic colloids Dispersion Methods Condensation or Aggregation Methods 11. Dispersion Methods Electrical dispersion Bredigs Arc Method Bredigs Arc Method Mechanical Dispersion Colloid mill Ultrasonic dispersion High Intensity Ultra sonic generators 12. Bredigs Arc Method 13. High Intensity Ultra sonic generators 14. Ultrasonic generators 15. How? 16. Colloid mill 17. Colloid mill 18. Peptisation 19. Peptisation Similarly a precipitate of AgCl on shaking with dilute solution of AgNO3, adsorbs Ag+ ion and gets peptised to colloidal particles of type AgCl / Ag+ 20. Similarly a precipitate of AgCl on shaking with dilute solution of AgNO3, adsorbs Ag+ ion and gets peptised to colloidal particles of type AgCl / Ag+ Cellulose nitrate is peptised by ethanol. The colloidal solution so obtained is known as Colloidion. 21. condensation Supersaturation Chemical reaction 22. Superaturation By decreasing temperature By changing solvent 23. Process of crystal growth 24. By change in solvent Alcohol + sulphur Supersat urated solution Excess of water Nuclei of crystal Crystal growth Sulphur colloidal sol 25. Chemical reaction 26. Reduction 27. Oxidation Sulphur 28. Hydrolysis Ferric chloride Chromium and Almunium Salts 29. Double decomposition 30. This causes Au3+ ions to be reduced to neutral gold atoms. As more and more of these gold atoms form, the solution becomes supersaturated, and gold gradually starts to precipitate in the form of sub-nanometer particles. The rest of the gold atoms that form stick to the existing particles, and, if the solution is stirred vigorously enough, the particles will be fairly uniform in size. 31. Association Colloids Or amphiphilic colloids 32. amphiphiles 33. Amphiphilic molecule? Is it colloidal? 34. Phenomenon of micelle formation 35. phenomenon 36. CMC 37. Aggregation number 38. In water and in oil 39. Some shapes 40. When spherical? When laminar? 41. Effect on (surface tension) 42. Are micelles solid? 43. In lyophillic sols? 44. Types of association colloids? 45. gegenions 46. Types of Amphiphiles </p>