What does the degree of chemical reaction have to do with the reversible reaction

In fact, there is a reaction equilibrium in any reaction, when this equilibrium is reached, the concentration of reactants and products no longer changes, then if the conditions are changed, such as increasing pressure, or heating, etc., the reaction equilibrium can move in the direction of weakening change, that is, when the pressure is increased, the reaction is carried out in the direction of decreasing pressure, and when heating, the reaction is carried out in the direction of endothermy. For example, the catalytic oxidation of sulfur dioxide in industry produces sulfur trioxide: O2 (gas) + 2SO2 (gas) = 2SO3, and when the pressure is increased, the reaction proceeds in the direction of SO3 generation.

Knowing the above concepts, you will easily understand that the progress of a chemical reaction is the degree to which the reaction is carried out in a certain direction when it reaches equilibrium, and people call the reaction that is relatively complete under certain conditions (such as normal temperature and pressure, high temperature and high pressure) as an irreversible reaction, for example, H2 + Cl2 = 2HCl This reaction is relatively complete at room temperature and pressure, and when the reaction reaches equilibrium, it is basically all HCl, which is called an irreversible reaction. Because it is very difficult to make HCL become H2 and Cl2. For industrial ammonia synthesis, 3h2+n2 = 2nh3 can only be carried out under higher temperature and pressure, and when the equilibrium is reached, the three substances account for a considerable proportion, so it is said to be reversible.

The reversibility of the reaction is only meaningful under certain conditions, and with the change of conditions, the irreversible response becomes reversible, and the reversible may also become irreversible, but in an absolute sense, all reactions are reversible, and when the conditions reach a certain extent, they proceed in the opposite direction.

There is a chemical equilibrium in any chemical reaction, and the degree is the ratio of the conversion of reactants to the products, and high school chemistry, in order to simplify, some reactions that are more completely transformed are classified as irreversible reactions, and not completely as reversible reactions.

Reversible reaction. There are many, and here are five:

1、co2+h2o⇌h2co3；

2、n2+3h2⇌2nh3；

3、cl2+h2o⇌hcl+hclo；

so2+o2⇌2so3；

5、nh3+h2o⇌nh3•h2o。

A reversible reaction is also called a confrontation reaction.

Under the same conditions of burning slag, the reversible reaction can not only quietly proceed in the direction of the positive reaction, but also react in the direction of the reverse reaction, and most of the chemical reactions can occur.

There is a certain degree of reversibility, but it is not a reversible reaction under general conditions, and when the reaction conditions are changed, it may become a reversible reaction. Reversible reactions cannot be completely reactive, and reactants cannot be 100% converted into products.

Reversible reactions are divided into forward and reverse, if the forward reaction rate is greater than the reverse rate, it is said to be forward movement; And vice versa. When other conditions remain unchanged, the concentration of reactants is increased or decreased, and the equilibrium moves to the direction of positive reaction, that is, to the direction of reactants. Decreasing the concentration of reactants or increasing the concentration of products, the equilibrium moves in the direction of the reverse reaction, that is, in the direction of the generated reactants.

Increase the concentration of reactants or decrease the concentration of the products, and the equilibrium moves in the direction of the products, and increase the concentration of the products or decrease the concentration of the reactants, and the balance moves in the direction of the reactants.

Because some chemical reactions have an excess of a reactant, when the reaction is carried out to a certain extent, the target product has been obtained, and if the excess reactant continues to exist, it will further react to form undesirable products, so it needs to be quenched.

The principle of quenching is to react with another compound that is more likely to react with the excess compound, thereby removing it from the system.

According to the method in the physical chemistry book, the first is whether the non-volumetric work is less than Gibbs free energy under isothermal and isobaric conditions, which is less than reversible and greater than irreversible. Under isothermal isochoric conditions, whether the non-volumetric work is less than the free energy, if it is equal to, then equilibrium, less than reversible, greater than irreversible.

Under the same conditions, the reaction that can be carried out in both the direction of the positive reaction and the direction of the reverse reaction is called a reversible reaction. Most of the reactions are reversible, some reactions are not reversible under normal conditions, and changing the conditions (such as placing reactants in a closed environment, high-temperature reactions, etc.) will become reversible reactions. Many of the reactions we were exposed to before learning about reversible reactions were reversible, but they were ignored to a lesser extent.

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. 1. The reaction cannot be carried out to the end, and no matter how long the reversible reaction is carried out, it is impossible for all reactants to be converted into products 100%. 2. The reversible reaction must be a reaction that can be converted into each other under the same conditions, such as sulfur dioxide and oxygen under the condition of catalyst and heating to generate sulfur trioxide; Sulphur trioxide can be decomposed into sulphur dioxide and oxygen under the same conditions.

3. Reactions that occur at the same time.

1. The characteristics are different.

Reversible reactions: The chemical reaction can be carried out on both sides without directionality.

Irreversible Reaction Equation Chemical reactions are directional.

2. The results are different.

The reversible reaction cannot be carried out to the end. No matter how long a reversible reaction is underway, it is not possible to convert all reactants to the product 100%.

The irreversible reaction reactant can be completely turned into a product, and the reaction can be carried out to the end.

3. The process is different.

Reversible reaction: Chemicals on both sides of the equation can form with each other.

Irreversible reaction reactants form products, and products cannot form reactants.

N2+3H2=2NH3, industrial synthesis of ammonia 2SO2+O2=2SO3, catalytic oxidation of SO2 Cl2+H2O=HCl+HCl+HClO H2+I2=2Hi, similar to the reaction between S and H2, that is, Hi, H2S are unstable, easy to decompose CO2+H2O=H2CO3, similar to SO2 CO+H2O=CO2+H2 2NO2=N2O4 NH3+H2O= Esterification reaction of carboxylic acids and alcohols in organic in the presence of concentrated sulfuric acid, Hydrolysis reaction of esters when catalyzed by acids. In addition, the ionization of weak electrolytes such as weak acids, such as acetic acid, ammonia monohydrate, etc.; The hydrolysis of salts, such as NH4Cl, CH3Coona, etc., is also reversible. Reversible reactions are defined as:

Under the same conditions, reactants and products can be converted into each other. Therefore, the reactions of organic matter are not all reversible reactions, like esterification reactions are reversible reactions, while substitution reactions are not, and the conditions are differentSuch as:

Halogenated hydrocarbons to alcohols and alcohols to halogenated hydrocarbons, the former condition is an aqueous solution of sodium hydroxide, and the latter is heating. Therefore, the judgment of whether a reaction is reversible or not can be easily defined as mathematics, physics. Thanks for adopting!

Sulfur dioxide and water reaction: SO2+H2O=H2SO3; Excess carbon dioxide reacts with sodium carbonate solution: CO2 + NaCO3 + H2O = 2NaHCO3