SOLUTIONS – Very small particles, too small to be seen By the unaided eye • homogeneous dispersion of two or more substances in an ionic or molecular scale Na + OH CHO H CH OH - Cl H O H CH2OH O H H Kinds of Mixture suspension colloid solution Particle Size 10-4 cm. in diameter 10-5 – 10-6 cm. in diameter 10-7 cm. in diameter Settles upon standing Always suspended in the medium (too small to be pulled down by gravity) Shows Tyndall Effect : reflect light to produce a visible beam of light Always suspended in the medium ( too small to be pulled down by gravity) EXAMPLES OF COLLOIDS Aerosols Foams Solid Foams Emulsions fog insecticide spray clouds smoke dust whipped cream shaving cream marshmallows Styrofoam milk gelatin mayonnais butter e jelly lotion Solid Sols pearl gemstones some colored glass some alloys Gels Sols ink rubber liquid detergent shampoo Parts of a Solution Dissolved substance solute is solution solvent is Dissolving medium Parts of a solution Physical state amount Solute Dissolved substance Solid, gas Less Solvent Dissolving medium liquid more Nature of the Dissolving Process Na+1 Cl-1 Na+1 H2O H2O H2O Cl-1 Na+1 Na+1 Cl-1 Cl-1 Dissolving rate Cl-1 H2O Na+1 Crystallizing rate salt Solvated ion Nature of Dissolving Process: • The nature of the dissolving process is • a 2 way process 1. Process of dissolution 2. Process of crystallization Which, at one point in time the 2 processes will attain equilibrium • At equilibrium • Rate of dissolution == rate of crystallization • Solution is called saturated solution • Concentration of the solution is constant • corresponds to the solubility of the solute in question . • How Water Dissolves Salt
