Precipitation PDF

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A. Define(a) digestion - the complex process of turning the food you eat into nutrients, which the body uses for energy, growth and cell repair needed to survive.(b) adsorption - the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface.(c) reprecipitation - after r...

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A. Define (a) digestion - the complex process of turning the food you eat into nutrients, which the body uses for energy, growth and cell repair needed to survive. (b) adsorption - the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. (c) reprecipitation - after returning a precipitate to a dissolved state, the process of precipitating it again. (d) precipitation from homogeneous solution - if a precipitating agent is produced over a long period of time in a homogeneous solution the level of supersaturation remains low and compact crystal precipitates usually result instead of coagulated colloids. (e) counter-ion layer - contains sufficient excess of negative ions (principally nitrate) to just balance the charge on the surface of the particle. (f) mother liquor - the solution remaining after a component has been removed by some process such as filtration or more commonly, crystallization. (g) supersaturation - occurs with a chemical solution when the concentration of a solute exceeds the concentration specified by the value equilibrium solubility.

B. Explain the difference between (a) a colloidal and a crystalline precipitate - colloidal precipitates do not form easily and are difficult to be obtained via filtering whereas crystalline precipitates are easily formed and are easily obtained via filtering. (b) peptization and coagulation of a colloid - peptization is the formation of a colloidal dispersion from a precipitation while coagulation is the formation of aggregates from oppositely charged particles which are then settled down under gravity. (c) occlusion and mixed-crystal formation - mixed-crystal formation may occur in both colloidal and crystalline precipitates, but occlusion and mechanical entrapment are confined to crystalline precipitates. (d) nucleation and particle growth - nucleation is the formation of a new structure whereas particle growth is the process of increasing the size of a pre-existing structure....