Physical Chemistry 103 ABC Solutions, Colloids, and Suspensions PDF

Solutions, colloids and suspension (Physical chemistry 103ABC 1st term 2024) Physical Chemistry 103 ABC (Second term 2020, Second part) Dr...

Solutions, colloids and suspension (Physical chemistry 103ABC 1st term 2024) Physical Chemistry 103 ABC (Second term 2020, Second part) Dr. Yasser Saeed, Cairo Uni.  Properties of solutions, colloids and suspensions Mixtures between solute and solvent Solute and solvent can be gas, liquid or solid state Can be homogenous or heterogenous Homogenous (true solution): evenly distributed, can not distinguish between solute and solvent by normal physical means Heterogenous (colloids and suspensions): can distinguish between solute and solvent by visible means (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni.  Properties of solutions, colloids and suspensions True Solution Colloids Suspension solute particles Below 10 angstrom 10-1000 visible to naked eye, Angstroms Not visible settle down with time Heterogeneous at (precipitated) Homogeneous microscopic level visible by ultra microscope pass through ordinary filter paper but retained by parchment membrane (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni. Properties of solutions, colloids and suspensions True Solution Colloids Suspension osmotic pressure high very low non Light scattering do not reflect light light beam visible particle visible light is dispersed by colloidal particles (Tyndall effect) surface non remarkable much less phenomenon property of adsorption electrical properties non electroosmosis, non cataphoresis and coagulation (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni. Properties of solutions, colloids and suspensions (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni.  Classification of colloids Based on the physical state of Dispersed Phase (solute) and Dispersion medium (solvent) solute solvent name examples Solid Solid Solid sol Colored glass, Solid Liquid Sol Paints, inks, white of egg, Solid Gas Aerosol Smoke, dust, Liquid Gas Aerosol Mist, fog, clouds, Liquid Solid Gel Curds, Cheese, Jelly, Liquid Liquid Emulsion Milk, butter, oil in water Gas Liquid Foam Soap lather, aerated water, Gas Solid Solid foam Cake, bread, pumice stone, (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni.  Classification of colloids Based on affinity between dispersed phase and dispersion medium (Lyophobic OR Lyophilic) (Solvent hating) (solvent loving) or Hydrophobic (solvent is water) or Hydrophilic (solvent is water) Prepared by special techniques, Easily prepared, less stable, irreversible stable, reversible small quantities of the electrolytes Small quantities of electrolytes do can cause precipitation not effect precipitation Charged particles migrate to one Little or no charged particles may direction in electric field or may not migrate in electric field ferric hydroxide in water sols gelatin, gum, starch and protein (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni.  Classification of colloids Based on nature of dispersed phase ❑ Multimolecular aggregates of atoms or molecules forming particle of colloidal size range (gold sol, sulphur sol). ❑ Macromolecular or molecular colloids Synthetic polymers such as polyethylene, polypropylene ❑ Association colloids (micelles formation in soap solutions) behave like true solution at low concentrations but shows colloidal properties at higher concentrations due to the formation of aggregated particles. (Physical chemistry 103ABC 1st term 2024) Dr. Yasser Saeed, Cairo Uni.  critical micellization concentration (CMC) = 10-3 mol / L (Physical chemistry 103ABC 1st term 2024) https://www.askiitians.com/iit-jee-chemistry/physical-chemistry/classification-of-colloids-based-on-physical-state.aspx Dr. Yasser Saeed, Cairo Uni.