Why do liquids sometimes flow from high concentrations to bottoms of concentration? Sometimes it s t

Let's first explain osmolality, see.

We know according to osmotic pressure.

In general, liquids flow from high concentrations to low concentrations. However, under special conditions, in the case of cells, the solution may flow from a low concentration to a high concentration. This is due to the presence of special channels on the cell membrane. Such as sodium ion channel, potassium ion channel.

So when talking about the direction of the flow of a liquid, it is important to grasp the environment in which it is located.

That is further illustrating the following.

Dilute solutions have a property, that is, --- dependence. As the name suggests, this property has nothing to do with the nature of the solute (whether it is male or female, sodium or potassium), but only the number of molecules of the solute (how much it is).

The dependency is quantitatively described by Raoult's law, boiling point increase, freezing point decrease and osmotic pressure formula.

As mentioned earlier, the membrane used in the experiment is semi-permeable (the solvent can pass back and forth, but the solute cannot), and the solvent from the low concentration solution will flow to the high concentration solution. The highly concentrated solution is diluted to a certain extent.

When there is no semipermeable membrane in the middle, the high-concentration solution flows to the low-concentration solution through --free diffusion (the energy is provided by the chemical potential energy).

In the case of cell membranes in the middle, it has now been confirmed that there are sodium and potassium channels (sodium pump and potassium pump, energy provided by electrochemical energy) on the membrane, which allows the flow of low-concentration solutions to high-concentration solutions.

The concentration is relative to the composition, it is possible that the concentration of solute A in the two solutions is greater than 1, and the concentration of solute B is greater than 1, so it is difficult to say who is thicker than whom, so the solute must be referred to must be certain in order to discuss the concentration size.

Ion exchange adsorption will be reversed.

Generally, it depends on the level of the water.

The osmotic pressure of the high-concentration solution is high, so the water flows to the high-concentration solution.

A solution is made up of at least two substances.

1. A stable mixture in which the dispersed substance (solute) is dispersed in molecules or smaller particles in another substance (solvent). Substances have three states at room temperature: solid, liquid, and gas. Therefore, the solution also has three states, the atmosphere itself is a gas solution, and the mixture of solid solution is often called a solid solution, such as alloy.

General solution simply refers specifically to liquid solution. There are two types of liquid solutions, namely electrolyte solutions that can conduct electricity and non-electrolyte solutions that cannot conduct electricity. The so-called colloidal solution should be more precisely called a sol.

Among them, the solute is equivalent to the dispersion, and the solvent is equivalent to the dispersant.

A common solution in life is sucrose.

Solution, iodine wine, clarified lime water.

Dilute hydrochloric acid, salt water, air, etc.

Because the solute is in the solvent, the molecules of the solute will have a diffusion motion, so that the solvent will move in the opposite direction of the solute, and water is a solvent, so the water moves from the place where the concentration is low to the place where the concentration is high. Soybean oil, on the other hand, does not diffuse in water because it is not a solute, so it does not move from a place with a low concentration to a place with a high concentration.

Purpose: To make the concentration of the inside and outside equal.

Flowing to a place with a high concentration is equivalent to diluting the high concentration, so that it may be equal to the low concentration.

I think it's the easiest way to understand.

There is only one way to flow from a high concentration to a low concentration, and that is through the action of a semi-permeable membrane.

A semi-permeable membrane is a kind of film that only diffuses a certain molecule or ion in and out, and is selective for the passage of different particles. For example, cell membranes, bladder membranes, parchment paper, and artificial cotton films. The semi-permeable membrane made of polymer materials through a special process only allows water molecules to pass through, but does not allow solutes to pass through.

When the pressure of the raw water on one side of the semi-permeable membrane exceeds the osmotic pressure with a high-pressure pump, the water molecules in the raw water can enter the other side through the semi-permeable membrane to obtain pure water. The dissolved and insoluble inorganic salts, heavy metal ions, organic matter, bacteria, colloids and other substances in the raw water cannot pass through the semi-permeable membrane and can only be discharged in the concentrated water.