The solution or true solution - this is a mixture of one or

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Solution vs Colloids

• The solution or true solution - this is a mixture
  of one or
• more substances which are dispersed in solvent
  (e.g. water or
• another solvent).
• The true solution is one phase system because it
  has dispersed particles below 1nm.
• particles can not be detected by optical means,
  like microscopes, including an ultra microscope.
• solution is homogeneous, as one-phase liquid
  (e.g. one solvent or pure water).
• does not show the Brownian movement.
• may pass throug dialitic membrane

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Solution vs Colloids

• Solution
• Transparent to ordinary light
• Stable unless solvent evaporated
• May pass through dialytic, but not true osmotic,
  membranes
• Colloids
• Typically 1000 nm or more per particle
• Not totally transparent Tyndall Effect
• May separate out
• Particles are too large to pass through most
  membranes

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COLLOIDAL SOLUTIONS
COLLOIDAL SOLUTION HETEROGENEOUS system - with
particle size of 10-9-10-7 m in diameter (1
100 nm, up to 500 nm)

10-9 m 1 nm 0.001 micron 10-7 m 100
nm 0.1 micron 10-6 m 1000 nm 1
micron
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• The colloidal system synonyms colloidal state,
  colloid, sol or colloid solution
• are heterogeneous dispersive (mostly two phase )
  configuration, in which we can distinguish two
  phases
• continues - dispersing phase (solvent(s) or
  bulk material) which is relatively very small in
  size particles (e.g. water particles are about
  0.1 by 0.2 nm)
• not continues - dispersed phase which particles
  diameter are relatively large, 1-100 nm (10-9
  107 m), and in case of biopolymers up to 500
  nm.

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• Properties of colloids
• They can be seen in ultramicroscope.
• Attention the difference between an
  ultra-microscope and ordinary one is that in the
  former the light falls laterally on the liquid
  under study, instead of from below. The ordinary
  microscope with x400 magnifications has
  limitations for particles below 1 micron, but
  still is able to show general structures of
  colloid system.
• 2. They are not dialyzed gt Colloidal particles
  will not be separated by membranes (like bladder
  or parchment paper), because will not diffuse
  through a membrane.
• 3. They show permanent Brownian motions mostly
  particles smaller than 100nm are able to make
  strong Brownian motion.
• 4. They show Tyndall effect visible scattering
  light by the colloidal particles.
• 5. They may coagulate gt colloid particles become
  agglomerated.

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Types of solutions depending of size of
disspersed phase in dispersive medium
TYPE OF SOLUTION DIAMETER OF PARTICLES OF DISPERSED PHASE
True solution (homogenieous) lt 10-9 m (lt1nm)
Colloidal (heterogeious) 10-9 - 10-7 m (1-100 nm)
Suspension gt 10-7 m (gt100 nm)
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Colloidal systems are wide spread in nature in
form organic or inorganic
All cells are some kinds of colloid system
(proteins, peptydes, hydrocarbons)
In nature collods are for example fog, volcanic
dust).
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Tyndall Effect
This is light scattering by coloidal solution
(for example by dust, fog, milk,etc.). When
light beam passes through the colloidal
dispersion it is scatter and therefore it is
visible. When light beam passes through the
solution, like water, does not scatter and
therefore it can not be seen.
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Solutions vs Colloids
The Tyndall Effect
Colloidal mixture, e.g. milk
True Solution e.g. water
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CLASSIFICATION OF COLLOIDAL SYSTEMS DEPENDING ON
I. STATE OF DISPERSSING AND DISPERSSED PHASE
Disperssed phase Disperssing phase COLLOID EXAMPLE
Gas Liquid Solid Gas Gas Gas - Aerosol liquid Aerosol solid - Fog, clouds, vapors Smoke, dust
Gas Liquid Solid Liquid Liquid Liquid Foam Emulsion Zol Foam soap, beer Creams, nail polish, milk, mayonese, butter Polymer solutions
Gas Liquid Solid Solid Solid Solid Foam Emulsion solid Zol solid Pumeks, styrofoam Gels, opal Glass rubin, colour cristals
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CLASSIFICATION OF COLLOIDAL SYSTEM DEPENDING ON
Size of colloidal particules Ø monodisspersive
(particles of disspersed phase have the same
dimensions) Ø polidysperssive (particles of
disspersed phase have the different dimensions)

II.
III.

• Ratio of disperssed phase to dispersing medium
• liophilic colloids they have large affinity to
  solvent particules colloidal particulues are
  serrundes by solvents particules
• liophobic colloids they have small affinity to
  solvent and absorb on the particules surface
  large quantities of one type of ions

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CLASSIFICATION OF COLLOIDAL SYSTEM DEPENDING ON
(cont.)
IV. Quality of disperssive phase

• Emulssions the dispersed phase solutions of
  nonpolar substances (e.g. lipids) which do not
  have affinity with dispersing phase (e.g. water).
  Emulsions have hydrophobic character and are also
  called suspenssions or not-reverse colloids.
• In living organisms example of emulssions are
  lipids.
• Small particles of lipids can be dispersed in
  water thanks to the compounds called emulsifiers.

• Emulsifier this is compund which can be
  dissolved in both liquids- dispersed and
  dispersing.
  For example consumed fats
  are emusified by bile acids included in bile.
  
  
  
• They have ability to decrease surface tension,
  like soap in water.

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How detergent works...
Head ( polar, hydrophilic)
Tail ( nonpolar, hydrophobic)
Dirt
H2O
H2O
H2O
H2O
H2O
Micell
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Coagulation (1)
COAGULATION it is ability of colloid particles
to combine and form larger structures called
agregates. After reaching appropriate size they
loose ability to flow and they sediment on the
bottom.
Coagulation can be caused by
  1. radioactivity beta ray 2.
heating coagulation of protein (egg) 3.
evaporationor freezing of dispersive medium
4. dehydration , for example by using acetone,
alcohol 5. addition of electrolite to colloid
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Coagulation (2)
Peptization process reverse to coagulation
breaking coagulate and return from coagulate to
colloid.
    SOL coagulation GEL
peptization      
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Donnans equlibrium (1)
A Membrane B
At the begining
solvent solvent
Na Pr- Na Cl-
c1 c1 c2 c2
During diffusion
solvent solvent
Na Pr- Na Cl-
After established equilibrium
solvent solvent
Cl- Na Pr- Na Cl-
x c1 x c1 c2 - x
c2 x
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Donnans equlibrium (2)
After established equilibrium
A Membrane B
solvent solvent
Cl- Na Pr- Na Cl-
x c1 x c1 c2 - x
c2 x
mNa RT ln aNa mCl- RT ln aCl- mNa
RT ln aNa mCl- RT ln aCl-
aNaA aCl-A aNaB a Cl-B
dla f1 ca
cNaA cCl-A cNaB c C l-B
Na A Cl- A Na BCl-B in A Cl-
Pr- Na In B Na
Cl-
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Donnans equlibrium (3)
Na A Cl-A Na BCl-B in A Cl-
Pr- Na in B Na Cl-

• Product of diffuse ion concentration on one side
  of the semipermeable membrane is equal to the
  product of diffuse ions concentration on the
  other side of the membrane.
• On both sides of the membrane sum of cations and
  anions must be the same.

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Donnans equlibrium (4)
From the side where ions are not able to diffuse,
diffusing ions concentration of the same charge
as protein is always smaller and concentration
of ions with oposite charge is always larger when
compared to side with no-diffusing ion (protein).
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Example 1 protein with anionic character A
Membrane B Na Pr - Na Cl Cl- NaA
gt NaB Cl A lt Cl B
Amount of ions on let side is compensate by
anions of protein
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Example 2 protein with cationic character A
Membrane B Cl- Pr Na Cl
Na NaA lt NaB Cl A gt Cl B
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THE END