What is the cause of osmosis?

There are two conditions for osmosis to occur: semi-permeable membranes.

The amount of concentration of the substance on both sides of the semi-permeable membrane.

Difference. The vacuole-filled aqueous solution of plant cells is called cell sap, and we can call the vacuolar membrane, cytoplasm and cell membrane the protoplasmic layer, which is equivalent to a semi-permeable membrane. Osmosis occurs between cells, or when cells are immersed in solution or water, whenever there is a difference in concentration between the two sides of the protoplasm layer.

In fact, biofilms are not ideal semi-permeable membranes, they are selectively permeable membranes, which allow both water molecules.

Passage also allows the passage of certain solutes but usually allows the solvent molecules to pass through much more than the solute molecules, so osmosis can occur.

Plant cells due to the cell wall.

The cell wall has a protective and supportive effect, which can generate pressure and gradually equalize the water potential inside and outside the cell, and the cell satisfies the dynamic equilibrium. So plant cells generally do not break when placed in water. Animal cells, such as red blood cells, will rupture when they are put into water.

There are two main points in the formation of osmosis:1There is a semi-permeable membrane.

2.There should be osmotic pressure on both sides of the semi-permeable membrane.

The main reason is not the concentration difference, but osmotic pressure.

Concentration differences are a common cause of osmolality.

What kind of substance is the cause of the phenomenon of osmosis is an analogy below.

Take the salt water that we usually see.

Osmosis is a physical phenomenon, when two kinds of water containing different concentrations of salts, such as separated by a semi-permeable thin membrane, it will be found that the water on the side with less salt content will penetrate through the membrane into the water with high salt content, and the salt content contained in it does not permeate, so that the salt concentration on both sides is gradually melted to equal. However, it takes a long time to complete this process, which is also known as natural osmosis.

But if on the side of the water with high salt content, try to add a pressure, and the result can also stop the above-mentioned osmosis, and the pressure at this time is called osmotic pressure. If the pressure is increased further, the water can penetrate in the opposite direction, leaving the salt behind.

1.The first question answered:

The cause of osmosis is osmotic pressure" is strictly the cart before the horse, wrong, it is just the opposite of cause and effect.

What do you think is osmotic pressure? It is defined as a specific value of static pressure that, in the case of a worthwhile situation, is just the amount of pressure applied to prevent the osmosis from proceeding macroscopically.

Okay, isn't the concept particularly easy to understand? Well, I'll give you a life example to talk about what osmotic pressure is.

Insert a thin glass tube on top of a radish and add sugar water to the tube until you see the surface of the sugar water

Then put the carrot into the water, and then find that the water surface of the thin tube rises, slowly until it no longer rises, the phenomenon mechanism is: the water level of the glass tube rises, increasing the static pressure of the water, and after the static pressure increases to a certain extent, the internal and external permeation rate of the water is equal and the liquid level does not rise (good!). I make the value of this static pressure fa).

So! This static pressure fa is the osmotic pressure of this sugar water.

Okay, so let's look back at the definition, preventing the permeation from being carried out macroscopically = the glass tube level is no longer raised.

PS: Why do you say that it prevents the macroscopic progress, pay attention to the note: it seems to stop after the penetration to a certain extent, but in fact it is not, but because the permeation rate of water molecules on both sides of the semi-permeable membrane gradually equalizes from the beginning, it reaches a dynamic equilibrium, and the microscopic is still dynamic. ）

The main cause of osmosis is the concentration difference between the two ends of the semi-permeable membrane, which causes the solvent to move towards a place with a small ionic concentration (without external force).

So! The osmotic pressure of the solution is the result of the osmotic action of the solvent molecules! And not the reason.

2.The second question answered: ...There is no such thing as osmotic pressure is the attraction or thrust of the world, or that sentence: osmotic pressure is the result of the penetration of solvent molecules, and his mechanism is determined.

osmotic pressure) = c*r*t see it? It is determined by c (the particle concentration of the solution), t (absolute temperature) and the constant r, and is the result of these three factors. , which is a microscopic expression. Right, it's not a macro thrust or attraction

There are two main points in the formation of osmosis:1There is a semi-permeable membrane 2There should be osmotic pressure on both sides of the semi-permeable membrane.

The main reason is not the concentration difference, but osmotic pressure.

Concentration differences are a common cause of osmolality.

When the static pressure on both sides is equal, the solvent will flow through the membrane from the dilute solution side to the concentrated solution side due to the unequal concentration of the solution and the osmotic pressure of the solution, which is called osmotic phenomenon.

There are two conditions for osmosis to occur:

First, there is a semi-permeable membrane.

Second, there is a difference in the amount and concentration of substances on both sides of the semi-permeable membrane.

The phenomenon of diffusion of a solution from a low concentration to a high concentration is called the phenomenon of osmosis Condition: Concentration difference Semi-permeable membrane.

The broad bean seed coat (or animal bladder membrane) is tightly tied to the funnel, the sucrose solution is injected, and then the whole device is immersed in a beaker filled with clean water, and the liquid level inside and outside the funnel is equal. Since the fava bean seed coat is a semipermeable membrane (i.e., a membrane that allows water molecules to pass through but sucrose molecules cannot pass through), the whole device becomes an osmosis system.

In an osmotic system, the direction of water movement is determined by the water potential of the solution on both sides of the semi-permeable membrane. Water from a solution with a high water potential, flowing to a solution with a low water potential.

In essence, the water molecules on both sides of the semi-permeable membrane can pass freely, but the water potential of the clear water is high, the water potential of the sucrose solution is low, and the water molecules from the clear water to the sucrose solution are more than the water molecules from the sucrose solution to the clear water, so in terms of appearance, the water in the beaker flows into the funnel, and the liquid level in the glass tube in the funnel rises, and the hydrostatic pressure also begins to increase.

As the water gradually enters the glass tube, the higher the liquid level rises, the greater the hydrostatic pressure, the faster the pressure of the water moves from the glass tube to the beaker, and the speed of moisture inside and outside the membrane is getting closer and closer.

Finally, the liquid level no longer rises and does not move, essentially the speed of water entering and exiting is equal, showing a dynamic equilibrium.

What are the conditions for the occurrence of osmosis are described below:

There are two major conditions that must be met for the phenomenon of osmosis to occur:

There is a semi-permeable membrane. There is a concentration difference between the two sides of the membrane.

When the static pressure on both sides is equal, the solvent will flow through the membrane from the dilute solution side to the concentrated solution side due to the unequal concentration of the solution and the osmotic pressure is not equal, which is called the osmotic phenomenon.

Osmosis is the way in which mature plant cells with vacuoles absorb water, and the principle is that the protoplasm layer is selectively permeable, and there is a concentration difference between the solution inside and outside the protople, so that water molecules can diffuse from the side with low solution concentration through the protopplasm layer to the early side with high solution concentration.

Precautions for osmosis:

Experiments show that the aqueous solution of crystals such as sugar and salt has the permeability effect of passing through the semi-permeable membrane, but does not have the permeability effect of those pasty and gelatinous amorphous substances. There are many osmotic phenomena that can be seen in daily life, such as the expansion of cereal seeds when exposed to water, the absorption of nutrients by plant roots, and the entry of nutrients into the blood through the membrane in the animal's body.

The pressure produced by osmosis is known as osmotic pressure. If a semi-permeable membrane that only allows solvents in the solution to pass through but not solutes is used as a fixed barrier, and the solution and solvent are placed on both sides of the barrier, a part of the solvent will enter the solution until equilibrium is reached. At this time, the temperature of the two sides is equal, but the pressure acting on both sides of the semi-continental cavity is not equal, and the pressure difference is called the osmotic pressure of the solution.

There is a semi-permeable membrane. There is a difference in the amount and concentration of the substance on both sides of the semipermeable membrane. Osmosis refers to the phenomenon that two solutions of different concentrations are separated by a semi-permeable membrane (a membrane that allows solvent molecules to pass through but does not allow solute molecules to pass through), and water molecules or other solvent molecules enter a high-concentration solution from a low-concentration solution through a semi-permeable membrane.

When the static pressure on both sides is equal, the solvent will flow through the membrane from the dilute solution side to the concentrated solution side due to the unequal concentration of the solution and the osmotic pressure is not equal, which is called osmosis phenomenon.

There are two conditions for osmosis to occur:

1.There is a semi-permeable membrane.

2.There is a difference in the amount and concentration of the substance on both sides of the semipermeable membrane.

OsmosisOsmosis refers to the phenomenon that two solutions of different concentrations are separated by a semi-permeable membrane (a membrane that allows solvent molecules to pass through but does not allow solute molecules to pass through), and water molecules or other solvent molecules enter a high-concentration solution from a low-concentration solution through a semi-permeable membrane. or the phenomenon of water molecules moving from the side with high water potential through a semi-permeable membrane to the side with low water potential.