Judgment that the reversible reaction has reached an equilibrium state?

It is necessary to consider which of the two has the greatest influence before determining the direction of the equilibrium movement.

How to take the high school exam.

1) The physical change is greater than the chemical change, for example: a+b=c+d The equilibrium of the flushing into A decreases in the positive direction of the positive movement A, but the flushing A is more than the transformed A, and the A increases.

A+B=2C+D Impulse into A equilibrium moves in the positive direction, pressure increases equilibrium and moves in the opposite direction, but impulses into A more than transformed A (the physical change is greater than the chemical change), A increases. BCD, on the other hand, needs to consider which of the two has a greater impact before determining the direction of equilibrium movement.

2) The overall thinking method is as follows: two identical equilibrium containers 1 2 are 1L, there is a + B = 2C + D, mixed in a volume of 1L container, at this time, it can be assumed that 1 and 2 overlap together for 2L, and then compress to 1L equilibrium on the direction of strong volume reduction that is reversed, ignoring the change of concentration.

I say in layman's terms, when m+n=p+q, no matter who becomes on both sides, it is a 1 to 1 relationship, there is no change in volume, so the pressure will not change, what changes is only matter, so there will be no change in volume from beginning to end, of course, there is no change in pressure, that is, the pressure is certain, so there is no characteristic (unless you look at the color of the gas), and it is impossible to judge whether it is equilibrium or not. When m+n does not =p+q, the difference from the above is that the process from left to right or the opposite is accompanied by a quantitative change (of course, there is also a qualitative change), because the ratio of the coefficient of the two sides is not equal and not 1 to 1, so the quantitative change, that is, the volume change, as long as it is not an ideal container, will definitely cause a change in p. So in your fixed-volume vessel, the pressure doesn't change, which means that the reaction is in (dynamic) equilibrium.

Because the four substances of ABCD are all gases, when M+N is not equal to P+Q, the total volume will change when the reaction does not reach equilibrium, which is reflected as a change in pressure in a certain volume of container.

If m+n is equal to p+q, there will be no change in the volume before and after the reaction, and there will be no change in pressure in a certain volume of container.

1.The concentration of the reactant does not change from the concentration of the product.

2.The quantity, concentration or volume fraction of each component of the substance in the system, and the quantity fraction of the substance remain unchanged.

The characteristics are as follows:

1) Rate v positive = v inverse (v is not 0).

The amount of each substance.

The percentage content remains the same.

The concentration of each substance does not change over time.

The amount of matter of each substance does not change with time.

3) In the case of a reaction with gases, the total pressure of the gas mixture or the amount of total substances does not change with time. (when the sum of the gas dosing coefficients at both ends of the reaction is unequal).

4) If it is a reaction of gases, the average mass of the gas mixture does not change.

5) For reversible reactions in which colored substances participate.

If the color of the system does not change, the reaction reaches equilibrium.

6) Due to any chemical reaction.

are accompanied by changes in energy, so when the temperature of the total system is constant, the reaction reaches equilibrium when the temperature of the total system is constant.

AboutEquilibrium constantCalculation & Image Analysis:

Example: A reversible reaction z(?) occurs in a constant temperature closed container)w(?

Reversible) x(g)+y(?H, the reaction reached equilibrium at time T1, the volume of the container was reduced at time T2, and the conditions were not changed after the equilibrium state was reached again at time T3. The following statement is incorrect (b).

and w must not be gaseous under these conditions.

After the time period and the t3 moment, the average molar mass of the gas in the reaction system of the two time periods cannot be equal.

c.If at this temperature, this reaction equilibrium constant is expressed.

is k=c(x), then the time period of t1 t2 is equal to the concentration of x after time t3.

d.If the reaction only occurs spontaneously above a certain temperature t0, the equilibrium constant k of the reaction increases with the increase of temperature.

The non-equilibrium reaction isReversible reaction

Reversible reaction, also known as confrontation reaction.

It refers to the reaction that can be carried out in the direction of both the positive reaction and the reverse reaction under the same conditions. Most of the reactions are reversible, some reactions are not reversible under general conditions, and changing conditions, such as placing reactants in a closed environment, high-temperature reactions, etc., will become reversible reactions.

For a reversible reaction, under certain conditions, the same equilibrium state can be established for the reaction, whether it starts from the positive reaction or the reverse reaction, that is, different starting conditions can reach the same equilibrium state.

The confrontation reaction, also known as the reversible reaction, refers to the reaction that can be carried out in the direction of the positive reaction party chain and the reverse reaction under the same conditions. Most of the reactions are reversible, and some reactions are not reversible under general conditions, and changing conditions, such as placing reactants in a closed environment, high-temperature reactions, etc., will become reversible.

When the reversible reaction reaches equilibrium ():

a.The positive and negative reactions stopped.

b.The mass fraction of reactants and products no longer varies due to changes in temperature and pressure.

c.The mass fraction of reactants and products is the same.

d.The mass fraction of reaction carry-ons and products no longer changes over time.

Correct answer: d

The condition for a chemical reaction to reach equilibrium is: v positive = v inverse

Chemical equilibrium characteristics (1) Fixed: The percentage content of each component remains unchanged.

2) Dynamic: dynamic equilibrium (that is, the reaction is not static, but is constantly in the dynamic equilibrium of forward and reverse reactions, and the appearance looks as if it is stationary) (3) Change: the conditions remain unchanged, and the equilibrium state remains unchanged.

According to the principle of equilibrium movement, the factors that affect chemical equilibrium are: changing the concentration of reactants or products, the pressure, and the temperature at the time of the reaction. Because some reactions are endothermic and some are exothermic.

Catalysts can only accelerate the reaction to equilibrium, but cannot change the reaction equilibrium.

The essential sign of the state of chemical equilibrium is that the rate of positive reaction is equal to the rate of reverse reaction, but not equal to zero, for the same reactant or the same product. For a reaction, the rate at which the reactant is consumed by the positive reaction is equal to the rate at which the reactant is formed by the reverse reaction.

The mass does not change: the mass of each component does not change, the total mass of each reactant or product does not change (not the total mass of the product of the reactant does not change), and the mass fraction of each component does not change.

The quantity of the substance does not change: the quantity of the substances of the components does not change, the quantity fraction of the substances of the components does not change, and the total amount of the substances of the reactants or products does not change. Reactions in which the number of molecules of the gas does not change before and after the reaction, such as: except

For gaseous substances: If the substances before and after the reaction are all gases, and the stoichiometric numbers are different, the amount of total substances, the total pressure (constant temperature, constant volume), the average molar mass, and the density of the mixed gas (constant temperature, constant pressure) remain unchanged. However, it is not suitable for this type of reaction where the stoichiometric number is equal before and after the reaction

The conversion rate of the reactant and the yield of the product remain unchanged.

The color of a system with a color change no longer changes.

The amount and concentration of the substance no longer change.

A state of chemical equilibrium is reached when the concentration of substances of the individual components (excluding solids or pure liquids) no longer changes.

Chemical equilibrium is a dynamic equilibrium, when the reaction reaches the equilibrium state, it is filial, and the reaction rate of the positive and negative reactions is equal, but not 0, so the answer is: