colloids definition and colloids examples
Colloidal systems (hereinafter abbreviated as "colloid") is a form of mixed system (dispersion) of two or more substances that are homogeneous the dispersed particle size but it has a fairly large (1-100 nm), and thus exposed to the effects of Tyndall. The dispersed particles of homogeneous mean are not affected by the force of gravity or other forces imposed on him; so there happen to precipitation, for example. This homogeneous properties also owned by aqueous solution, but is not owned by a mixture of regular (suspension).
Colloids are easily found everywhere: milk, agar-agar, ink, shampoo, and the clouds are examples of Colloids can be found everyday. The cytoplasm within the cell is also a colloidal system. A separate study into colloidal chemistry in the chemical industry due to its importance.
All kinds of Colloids
Colloids have varied shapes, depending on the phase of a substance pendispersi and terdispersinya substances. Some types of Colloids:
Aerosols that have substance pendispersi in the form of gas. Aerosol liquid dispersed substances that have called liquid aerosols (e.g.: fog and clouds) while having a solid dispersed substances called solid aerosols (example: smoke and dust in the air).
Sol colloid of solid particles dispersed in the liquid. (Example: the river water, sol, sol SOAP detergent and ink).
Colloid emulsion of liquid substances dispersed in the liquid, but the liquid substance that both not mutually dissolve. (Example: coconut milk, milk, mayonaise, and fish oil).
Colloidal Systems from scum gas dispersed in a liquid. (Example: the processing metal ores, fire extinguishers, cosmetics and others).
Rigid colloid Gel or half solid and half the liquid. (Example: gelatin, glue).
Properties of Colloids
Tyndall Effect
Tyndall effect is the phenomenon of scattering x-ray beam (of light) by colloidal particles. This is because the molecular size of Colloids. Tyndall effect was discovered by John Tyndall (1820-1893), a United Kingdom physicist. Therefore it is called the tyndall effect properties.
Tyndall effect is an effect that occurs when an aqueous solution exposed to sunlight. At the time of the true solution irradiated with light, then the solution will not scatter light, whereas in Kolo, the light will be dissipated. It happened because the colloidal particles have particles that are relatively large in order to scatter the light. Instead, the true solution, particles-partikelnya is relatively small so that the scattering that occurs just a little bit and it is very difficult to observe.
Brownian Motion
Brownian motion is the motion of colloidal particles are always moving straight but uncertain (random motion/irregular). If we observe the colloid under ultra microscope, then we will see that these particles will move in a zigzag form. This zigzag movement called Brownian motion. The particles of a substance are always moving. The movement can be random as in liquid and gas substances (called Brownian motion), while on the solid beroszillasi on-site only (not including Brownian motion). For colloids with medium pendispersi liquid or gaseous substances, the movement of the particles will produce collisions with colloidal particles itself. The collision took place from all directions. Because the particle size is small enough, then the collision happened is likely to be unbalanced. So there is a resultant collisions which cause changes of direction of motion of the particle motion so zigzag or Brownian motion.
The smaller the particle size of colloids, the faster the Brownian motion that occurs. Similarly, the larger size of colloidal particles, Brownian motion, the slower going. This explains why the motion hard Brown observed in solution and is not found in the heterogeneous mixture of liquid with solids (suspension). Brownian motion is also affected by temperature. The higher the temperature of the colloidal system, then the greater the kinetic energy of the particles of the medium belongs to the pendispersinya. As a result, Brownian motion of particles terdispersinya phase more quickly. And vice versa, the lower the temperature of the colloidal system, Brownian motion is getting slower.
Adsorption
Adsorption is a occasion of absorption of particles or ions or other compounds on the surface of colloidal particles caused by the surface area of the particle. (Note: Adsorption with absorption must be distinguished from the means of absorption that occurs inside a particle). Example: (i) Colloidal Fe (OH) 3 is because the surface absorbs positively charged H + ions. (ii) the negatively charged Colloidal As2S3 because their surface absorb ion S2.
The charge of Colloids
Known two kinds of colloids, which are positively charged colloidal and negatively charged colloid.
Coagulation of Colloids
Colloidal particles clotting is coagulation and form a sediment. With the onset of coagulation, the dispersed substances means no longer form a colloid. Coagulation can occur physically like heating, cooling and stirring or chemically like the addition of electrolytes, colloidal mixing of different payloads.
Protective colloid
Protective colloid colloids is having other colloids can protect nature of the process of coagulation.
Dialysis
Dialysis is the separation of Colloids from ions of a bully in this way is called the process of dialysis. That is to drain the fluid mixed with colloidal semi permeable membrane through which functions as a filter. This semi permeable membrane can be bypassed the liquid but can not be bypassed, so Colloids and colloid liquid will split up.
Electrophoresis
Elektroferesis is a colloidal particle separation events charge by using an electric current.
