Flashcards
colloids
Cards in this deck (18)
- 1what is Thomas graham's experiment?he studied the diffusion of substances in water through a semi-permeable membrane and classified substances into two categories
1) crystalloids
2)colloids - 2crystalloidssubstances whose solutions readily diffuse through the membrane
Eg salts, acids, bases, sugar, urea - 3colloidswhose solution does not diffuse easily or at all
Eg glue, gelatin albumin, starch, etc - 4what were the drawbacks of graham's experiment?substances are not crystalloids or colloids but these depend on the size of the solute particle.
Eg NaCl is crystalloid in water and colloidal in benzene
on the other hand, the soap solution is crystalloid in benzene and colloidal in water - 5what is the recent classification of substances?1) true solution
2)colloids
3)suspension - 6brief about true solutionsthey are homogenous, size is less than 1nm, pass through ordinary and animal filter paper, do not settle, particles are invisible, diffusion is very quick, appearance is clear and transparent.
- 7brief about colloids.they are heterogenous, size b/w 1to 1000 nm, they do not pass through animal filter paper, they do not settle, particles are seen by ultramicroscope, they diffuse slowly and are translucent.
- 8brief about the suspension.they are heterogenous, size more than 1000 nm, do not pass through any filter paper, settle on standing, particles are visible to the naked eye, do not diffuse and are opaque in color.
- 9how is the classification of colloids done?1)on the basis of the dispersed phase and the dispersion medium
2)nature of interaction b/w them
3)based on the size of the paarticles - 10shortcut to remembering the dispersed phase and the dispersion medium.if the dispersed phase is gas-foam
if the dispersion medium is gas- aerosol
if solid in liquid- sol
solid in solid -sol
the liquid in solid-gel - 11on the basis of interaction b/w D.P. and D.M.a)hydrophilic
b)hydrophobic - 12hydrophilic colloidsthey directly form colloids
eg. gum, gelatin, starch, rubber all are naturally occurring colloids.
they are called intrinsic since they are formed directly. are also called reversible, are stable and not easily precipitated - 13hydrophobic colloidsnot formed by simple mixing.
eg metal sol and sulphide sols
are called extrinsic colloids, not stable and easily precipitated.also called irreversible sols - 14on the basis of the size of the particle1) multimolecular
2)macromolecular
3) associated - 15multimolecular colloidsno. of particles combine to form a colloidal particle. eg gold sol
sulphur sol - 16macromolecular colloidslarge particles are broken down to form particle size of the colloidal range.
eg starch protein etc
all naturally occurring polymers - 17associated colloidsthe substance which when dissolved in a medium at low temp. behave as normal strong electrolytes but at certain higher conc. exhibit colloidal state properties
eg soap solution - 18—
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- class 12 Chemistry Flashcards on colloids, created by sakhi rathore on 28/07/2020.
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- sakhi rathore
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