How do I identify solutions and colloids? How do I separate a solution from a colloid?

How do I identify solutions and colloids?

Answer: The Tyndall effect (the use of a beam of light to irradiate a liquid in the dark, and a light path is formed by colloids) because colloidal particles are large and easy to reflect light.

Whereas, the solution produces refraction.

How do I separate a solution from a colloid?

A: Using a semi-permeable membrane (generally using an egg membrane is also acceptable) is to operate like filtration, but be careful not to penetrate the semi-permeable membrane! Particles with a diameter of between 1,100 nanometers are colloids, and particles below 1 nanometer are solutions.

Irradiated with a beam of light, if a bright path of light is produced (Tyndall effect), it is colloidal, otherwise it is a solution.

The Tyndall phenomenon is formed by the scattering of visible light (wavelength 400 700 nm) by dispersed particles in the colloid.

When a beam of light passes through the colloid, a bright "pathway" can be observed in the colloid from the vertical direction of the incident light, which is called the Tyndall phenomenon, also known as the Tyndall effect. And the solution will not have a "pathway".

Does separation mean separation? Generally, semi-permeable membranes are used.

A semi-permeable membrane is a synthetic membrane that has a gap between its molecules and allows substances with a diameter smaller than the gap to pass through.

Take advantage of the Tyndall effect. When two liquids are irradiated with a beam of light, a bright pathway is formed by colloids.

1. It can pass the Tyndall effect.

to distinguish between solutions and colloids.

2. The difference between colloids and solutions is that colloids have a Tyndall effect, while solutions do not, and the two can be identified accordingly.

3. Tyndall effect: When a beam of light passes through the colloid, a bright path will appear in the colloid, which is formed by the scattering of light by colloidal particles.

Here's how to distinguish between a solution and a colloid:

Apply the Tyndall effect. If a laser is used to irradiate the liquid in the glass, if it can form a light path, it is a colloid, otherwise it is a solution. Colloidal solutions are not solutions, they are just used to being called so.

The essential difference is, of course, the diameter of the particles in the dispersion system: the diameter of the solution particles < 1 nm, and the diameter of the colloidal particles is between 1 nm and 100 nm. The solution is more stable than the colloid.

What are the properties of colloids: Tyndall phenomenon: When a parallel ray of light passes through the colloid, a bright "pathway" is seen from the side.

This is formed by the scattering of light by 1653 particles of glue in the colloid. In the case of a solution, the dispersed (solute) particles are too small, and when the light is irradiated, the light can be diffracted and bypass the solute, making it impossible to observe the "pathway" of light from the side.

Therefore, this method can be used to distinguish between true solutions and colloids. Suspension and emulsion, because of the large diameter of the dispersion, only reflect the incident light without scattering, and the suspension and emulsion themselves do not penetrate, and it is impossible to observe the path of light.

Brownian motion: The colloids in the colloid are constantly moving irregularly. The direction and rate of movement of the colloids can change at any time, making it difficult for colloidal particles to aggregate, which is one reason for the stability of colloids.

Brownian motion is a phenomenon of thermal motion of particles. This phenomenon is not unique to colloids.

Electrophoresis phenomenon: Under the action of an external electric field, the colloidal particles can move directionally to the anode or cathode in the dispersant, which is called electrophoresis. The electrophoresis phenomenon indicates that the colloids are charged.

The charge of colloids is due to the fact that they have a large total surface area and have excess adsorption force, which adsorbs ions. In general, colloidal particles of metal hydroxides and metal oxides adsorb cations and have a positive charge, such as colloids and colloidal particles.

Non-metal oxides, metal sulfide colloidal particles adsorb anions and have a negative charge. Such as colloids, colloidal particles. Of course, the type of charge of the gel band in the colloid may be related to the amount used during the reaction.

Colloidal particles have a negative charge when there is an excess and a positive charge when there is an excess. The colloids are charged, but the entire colloid is still electrically neutral.

The colloidal particles of the same solution have the same charge, have electrostatic repulsion, and when the colloidal particles are close to each other, they will produce repulsive force, so the colloidal is stable, which is the main and direct reason for the colloidal stability.

The radius of the imitation trapped colloid molecule is outside 100 nanometers, while the radius of the particles in the solution is generally between 1 and 100 nanometers, so the semi-permeable membrane is used to filter the mixed solution so that the colloid will remain on top of the semi-permeable membrane, and the solution can pass through the semi-permeable membrane.

Colloid, also known as colloidal dispersion, is a relatively homogeneous mixture, which contains two different states of substances in the colloid, one dispersed phase and the other continuous backup phase. A part of the dispersed matter is composed of tiny particles or droplets, and the dispersion system of the dispersed particles between 1 and 100 nanometers in diameter is colloidal; Colloids are a kind of dispersion system with a diameter of dispersed particles between the coarse dispersion system and the solution, which is a highly dispersed multi-type trace heterogeneous system.

A solution is made up of at least two substances.

1. Stability.

The answer is the Tyndall effect. The British physicist John Tyndall was the first to discover and study the above phenomena in colloids. This bright pathway is formed by the scattering of light by colloidal particles.

When a beam of light passes through the colloid, a bright path in the colloid can be observed from the vertical direction of the incident light, which is called the Tyndall phenomenon, also known as the Tyndall effect, the Tynzel phenomenon, the Tinzel effect, and the Tyndear effect. Practical application: for the identification of colloids and solutions.

Therefore, colloids can have Tyndall phenomenon, and the solution is almost none, you can use Tyndall phenomenon to distinguish colloids and solutions, note: when there is light passing through the suspension, sometimes there will be an optical path, but because the particles in the suspension obstruct the light too much, the resulting optical path is very short.

It refers to the solution formed by the dispersion of solid particle drugs or polymer compounds in a solvent of a certain size. The particle point of the dispersed system is generally between 1 100 nm, and most of the dispersed medium is water, and a few are non-aqueous solvent. Solid particles are dispersed in the solvent as multimolecular aggregates (colloidal particles) to form a multiphase inhomogeneous dispersion system (hydrophobic gel) Polymer compounds are dispersed in the solvent in the form of single molecules to form a single-phase uniform dispersion system (hydrophilic gel).

For example: protein solution, starch solution, plasma substitute, protein solution, etc.

Characteristics of colloidal solution: particle size; Between the true solution and the crude dispersion system, it has a certain viscosity, the diffusion speed of its colloids is small, it can pass through the filter paper but cannot penetrate the semi-permeable membrane, and it has little impact on the boiling point, freezing point reduction, vapor pressure drop and osmotic pressure of the solution. Brownian motion:

Therefore, the colloidal solution can be maintained for a long time without precipitation. However, in addition to the strong Brownian motion in the colloidal system, due to the high dispersion, the specific surface dust and surface energy of the colloidal particles are larger, and there is a spontaneous tendency of the colloidal particles to merge and reduce the surface energy. scattering; When the bright light passes through the solution, countless flashes of light can be seen in the darkroom observation on the side where the light passes.

It's like sunlight shining through a window hole into a dusty dark room. This phenomenon is called the Tyndall effect. Charged particles; The charge of the rubber particles can be proved by the electrokinetic phenomenon in which the dispersed phase particles (the rubber particles) swim towards the electrode with opposite signs and the medium swims towards the other electrode under the action of an electric field.

Methods for separating colloids and solutions such as slag down:The diameter of dispersed particles in colloids is greater than 100 nm, and the diameter of dispersed particles in solution is between 1 and 100 nm. The latter can pass through semi-permeable membranes, while the former cannot pass through semi-permeable membranes, so they can be separated by dialysis.

Put the semi-permeable membrane bag into the beaker, put the mixture to be separated into the semi-permeable membrane bag, tie the bag mouth with a thin wire rope, and tie the other end to the middle of the glass rod, and the glass rod is on the beaker mouth, so that the semi-permeable membrane bag is suspended in the beaker.

Fill the beaker with an appropriate amount of distilled water and submerge the semi-permeable membrane bag. Change the water in half an hour. If you want to have a good effect, you can change the water several times.

That's a different definition! ok?

The solute in the solution is very small, and the colloids are much larger, I checked the details for you, then

Honey, please look.

Colloidal definition; Dispersion particle size in 1 nm to 100 nm dispersion system.

The fundamental reason for the significant difference in the properties of colloids, solutions and turbidity is the difference in the size of dispersed particles.

Common colloids: Fe(OH)3 colloid, Al(OH)3 colloid, silicate colloid, starch colloid, protein, blood, soybean milk, ink, paint, soapy water, AG2S, AS2S3

Classification: According to the state of the dispersant, it is divided into:

Aerosols – dispersions, dispersants are gaseous substances: such as fog, clouds, smoke.

Liquid sols - dispersions and dispersants are liquid substances: such as Fe(OH)3 colloids.

Solid sols - dispersions and dispersants are solid substances: such as colored glass and alloys.

3. A common physical method to distinguish colloids from solutions - using the Tyndall effect.

The phenomenon of colloidal particles scattering light to form a bright coarse "pathway" is called Tyndall phenomenon.

The colloidal pellets are electrically charged.

The colloidal particles have a large specific surface area (specific surface area = surface area particle volume), so they have a strong adsorption capacity, so that the surface of the colloids adsorbs ions in the solution. In this way, the gel particles have an electric charge. Different colloids adsorb ions with different charges.

Generally speaking, the colloidal particles of metal hydroxides and metal oxides adsorb cations, and the colloidal particles are positively charged, while the colloidal particles of non-metallic oxides and metal sulfides attract anions, and the colloidal particles are negatively charged.