What is the effect of pressure on chemical equilibrium

If it cannot be understood, it can be seen as a reaction in which the pressure does not change, but the volume changes, that is, under isobaric conditions, the volume changes to affect the equilibrium movement.

Effect of Pressure on Chemical Equilibrium How it works Inhale about 30 ml of nitrogen dioxide and nitrogen tetroxide mixture with a syringe (50 ml or larger) and insert the needle into the plug to close it. The nitrogen dioxide is then rapidly compressed by pushing the needle tube and the color of the gas inside the needle tube is observed. The nitrogen dioxide gas is rapidly expanded by pulling the needle and the color of the gas in the tube is observed.

Experimental phenomenon When the needle tube is rapidly compressed, it can be seen that the color of the gas in the needle tube first darkens and then slowly becomes lighter. When the gas is rapidly expanded by the needle pulling tube, the color of the gas in the needle tube first becomes lighter and then darker. Experimental conclusion There is an equilibrium in the gas in the tube, and the color of the gas in the needle pusher tube is dark and then light, because the volume of the gas in the tube decreases and the concentration increases, and then it becomes lighter because the pressure increases and the equilibrium moves in the direction of the product.

Nitrous tetroxide is a colorless gas, so the mixture becomes lighter in color. When the needle is drawn, the color of the gas is first light and then dark, because the volume of the gas in the tube expands, the pressure decreases, and the concentration decreases, and then it becomes deeper because the pressure decreases, so that the above balance shifts to the left, and more reddish-brown gas is generated. Based on the above experiments, it can be seen that under other conditions, increasing the pressure will cause the chemical equilibrium to move in the direction of the reduction of the gas volume. Decreasing the pressure shifts the equilibrium in the direction of the increase in the volume of the gas.

Experimental focus 1: The essence of pressure affecting equilibrium; 2. The similarities and differences between the effects of concentration and pressure on equilibrium.

For reversible reactions with the participation of gases, the concentration of gaseous substances can be changed by changing the pressure of the gas. If the concentration of gaseous substances is changed, it can also cause chemical equilibrium to move if the V positive and V inverses are not equal. This law of movement is for equilibrium systems with the participation of gases and the volume of gases changing before and after the reaction.

When other conditions remain constant, in the equilibrium system with gas participating in the reaction, the equilibrium is moved in the direction of decreasing gas volume by increasing the pressure. Decreasing the pressure shifts the equilibrium in the direction of increasing the volume of the gas.

Basic Information. Chemical equilibrium refers to the state in which the positive and reverse reaction rates of the chemical reaction are equal and the concentrations of the components of reactants and products no longer change in a reversible reaction under certain macroscopic conditions. It can be judged by δRGM= 0, A is the chemical potential of species A in the reaction.

According to Le Chatre's principle, if a system that has reached equilibrium is changed, the system will change accordingly to counteract the change. Chemical equilibrium is a type of dynamic equilibrium.

Generally, the change of the rate of forward reaction and the rate of reverse reaction in a reversible reaction indicates the process of establishing chemical equilibrium. The essence of chemical equilibrium: the rate of positive reaction is equal to the rate of reverse reaction.

First of all, the generation of gas pressure: a large number of molecules doing irregular thermal motion collide frequently and continuously with the wall of the device, resulting in gas pressure. The impulse of a single molecular collider wall is short-lived, but a large number of molecules frequently collide with the wall to exert continuous, uniform pressure on the wall.

Therefore, from the point of view of molecular kinetic theory, the pressure of a gas is the average force of a large number of gas molecules acting on the unit area of the vessel wall.

Therefore, the increase of pressure is the density of molecules, or the speed of motion (i.e., kinetic energy), and the number of collisions increases in a certain period of time, the molecular energy increases, and collisions are more likely to occur, resulting in the weakening of the reaction in the direction of pressure (because after the collision, it will react, and the pressure may change).

h2+i2=2hi Because the number of molecules before and after the reaction is the same, the pressure increases, even if the reaction is carried out, the speed of the pressure reduction on both sides is the same, and the equilibrium does not move, but the overall collision efficiency and reaction rate are increased.

N2+3H2=2NH3 Because the number of molecules before and after the reaction is not the same, the pressure increases, after the reaction, in order to weaken the pressure, the reaction proceeds in the forward direction, the equilibrium moves in the positive direction, and the overall collision efficiency and reaction rate are increased.

Summary. Good evening, dear<>

When the reactants and products are in a gaseous state, if the sum of the reactant coefficients is equal to the sum of the products, the pressure increases, and the equilibrium does not move, but the reaction rate increases, and if the reactant coefficients and the product coefficients are different, the equilibrium moves in the direction of the coefficient and the small. If it is not gaseous, it is hardly affected by pressure and the balance does not move. <>

Under what circumstances does changing the pressure change the chemical equilibrium?

Good evening, dear<>

When the reactants and products are in the gas attack retardation state, if the sum of the reactant coefficients is equal to the sum of the products, the pressure of the finger mold is increased, and the equilibrium does not move, but the reaction rate will increase. If it is not gaseous, it is hardly affected by pressure and the balance does not move. <>

When all reactants and all products are gases, does the pressure have anything to do with the chemical equilibrium movement?

Dear, yes oh <>

If there are multiple reactants, and only one of them is a gas, wouldn't it move if you change the pressure equilibrium?

If only one substance is a gas, the increase or decrease of pressure has an effect on the chemical equilibrium. Increasing the pressure will shift the equilibrium in the direction of decreasing the number of gas molecules, i.e., to the side without gas. <>

The effect of changing the total pressure of the system on the chemical equilibrium is as follows:

The process of establishing chemical equilibrium. When the reaction does not start, V positive and particles, V inverse are equal to zero, when the reaction does not reach equilibrium, the positive reaction rate is greater than the reverse reaction rate, after a period of positive reaction, we will find that the positive reaction rate and the reverse reaction rate are equal, we consider it to have reached the state of chemical equilibrium, thus establishing chemical equilibrium.

When the external conditions change, we will measure that the rate of the forward reaction and the rate of the reverse reaction also change, but the degree of change is different, that is, the rate of the forward reaction and the rate of the reverse reaction are no longer equal, so the reaction will be in the forward or reverse direction.

After a certain period of time, it re-reaches the state of equality between the positive reaction rate and the reverse reaction rate, that is, a new chemical equilibrium state is established.

This process of establishing a state of chemical equilibrium from the old state of chemical equilibrium to the new state of chemical equilibrium is called the chemical equilibrium shift. That is to say, from the initial state of disequilibrium in which the rate of forward reaction and the rate of reverse reaction are not equal, the dynamic state of chemical equilibrium with equal rates of both is gradually reached.

Neither pressurization nor decompression will make the chemical equilibrium equation move. It should be noted here that the body base deficit of solid or pure liquid substances is negligible due to the effect of pressure.

Hello, yes, simply because of the change in volume and thus in terms of concentration and, in turn, the equilibrium!!

The problem depends on how you pressurize him, by filling the system with non-reactive gases, the reaction volume does not change, the concentration of the components related to the reaction in the system does not change, so the equilibrium does not move.

By pressurizing the system by reducing the volume of the reaction vessel, the concentration of each component related to the reaction in the system changes, so that the equilibrium moves.

By pressurizing the system by filling the reaction gas, the concentration of each component related to the reaction in the system is changed, which is very complicated, and the concentration of the reversible side is changed separately and the concentration of each component related to the reaction in the system is changed at the same time, which is not required to be mastered! Embarrassment!

And many more!

Therefore, I should say: in fact, the effect of pressure on equilibrium should not be directly added to the book at all, but it should be written: "When the pressure is changed only by changing the volume of the reaction vessel, so that the concentration of all components related to the reaction in the system changes at the same time, the concentration of the side with the largest amount of gas in the equation changes relatively greater, so the rate of the side with the largest amount of gas also changes relatively large—that is, it increases much when pressurized and decreases more when depressurized." ”

For example: 2a+2b = (reversible) 3c

When the pressure is changed only by changing the volume of the reaction vessel, so that the concentration of all components related to the reaction in the system changes at the same time.

The concentration change (increase) on the left side is large, and the concentration change (increase) on the right side is small;

Therefore, the rate change (increase) on the left side is large, and the rate change (increase) on the right side is small;

Therefore: the balance moves in the positive direction!

Typing word by word, my hard work, you know!

Tonggang No. 1 Middle School, two years, seventeen classes, a handsome guy submitted.

Effect of pressure on chemical equilibrium: under other conditions, increasing pressure will cause the chemical equilibrium to move in the direction of decreasing the number of gas molecules. Decreasing the pressure shifts the equilibrium in the direction of an increase in the number of gas molecules. If the number of gas molecules is equal before and after the reaction, the pressure has no effect on the movement of the equilibrium.

The change in pressure has little effect on the equilibrium of the liquid-solid reaction. For chemical reactions involving gases, the effect of pressure changes on equilibrium is discussed in several cases.

Changes in partial pressure of some species under constant temperature and constant volume.

1. Increase the partial pressure of the reactant or decrease the partial pressure of the product, and the balance moves to the positive direction. 2. Reduce the partial pressure of the reactant or increase the partial pressure of the product, and move the equilibrium in the opposite direction. 3. The total number of gas molecules before and after the reaction remains unchanged, and the equilibrium will not change with the change of the total pressure of the system.

Increasing the pressure shifts the equilibrium in the direction of decreasing the number of molecules, e.g.

If the sum of the number of molecules of the reactants on the left side of the equation is 1, and the number of molecules of the gaseous product on the right side of the equation is 2, if the conditions are suddenly changed in a certain equilibrium state: the pressure increases, then the equilibrium will move to the left of the decreasing number of molecules to slow down the effect of increasing the pressure, but the slowdown is weakened rather than eliminated, which is called Le Chatletre's principle.

The essence of chemical reactions is caused by probabilistic collisions between molecules, and the increase of pressure has a significant impact on the equilibrium of gas and liquid reaction systems, mainly due to the following reasons:

1. The pressure difference between the left and right sides of the reaction, for example, 2 molecules of hydrogen and 1 molecule of oxygen to produce 1 molecule of water, without considering the condensation of water, the total pressure of the gas is reduced by one-third, so increasing the pressure in the reaction will push the equilibrium to move in the direction of decreasing pressure.

2. The pressure increases the potential energy of the reactants, increases their collision probability, and affects the reaction balance. A specific example is the increase in the conductivity of some semiconductors under pressure conditions, which is actually due to the increase in energy and the change in the electron layer.

3. According to the ideal gas model, the gas in the adiabatic system is compressed, and its internal energy increases.

The principle of natural nitrogen fixation.

N2 + O2 = Lightning = 2NO

2no+o2=2no2

3no2+h2o=2hno3+no

Lightning converts nitrogen in the air into nitric acid, the nitrogen fertilizer that plants need to grow.

Laboratories require high temperatures and pressures.