How to speed up the reaction?
Today, the life of a person, as well as the life of his distant ancestors, is directly connected with various circumstances and factors. The main for him are reactions of physical and chemical order. Without them, the world would become a static substance, incapable of any development and movement, the birth of a living organism and its evolution. Man already knows quite a lot about the nature of substances. He knows how substances are arranged, what reactions they enter into, as well as how to speed up the reaction of their interaction in order to get results faster.
The concept of "chemical reaction"
By this phrase, they understand the interaction of several substances called reagents, the result of which is a substance of a completely new quality. In other words, in reactions of this order from one substance, by breaking one bond and forming a completely new bond, new substances are also formed. Chemical reactions are often confused with nuclear reactions, this is wrong, because during nuclear reactions, it is not the formation of a new substance, but the transformation of the initial one into a substance of another order.
By the type of substances obtained, chemical reactions are classified into reactions:
- single and double substitution,
Each describes a specific chemical equation. The substances interact with each other as a result of mixing or physical contact. These processes can proceed in different ways, consider different types of chemical reactions.
- Spontaneous reaction.
- Thermal (high temperature exposure).
- Catalysis (with the participation of the catalyst).
- Photochemical (under the influence of light).
- Electrode (exposure to electric charges).
- Radiation-chemical (exposure to ionizing radiation).
- Mechanochemical (mechanical effect).
- Plasmochemical (on low-temperature plasma).
Chemical reactions: main types
By the number of substances entering into the reaction, they are divided into two basic groups:
Complex chemical reactions
- Reagents (starting materials).
- Reaction products (those substances that are the result of the reaction).
- The catalyst of the reaction (a substance that accelerates a chemical reaction is called its catalyst).
Simple chemical reactions
- Reagents (starting materials).
- Reaction products (those substances that are obtained as a result of a chemical reaction).
Man has long learned to accelerate the reaction of interaction of substances. For example, everyone knows that sugar dissolves faster in a cup with a hot coffee drink than in cooled coffee. The dissolution reaction (sugar in the coffee beverage) was accelerated under the influence of an elevated reagent temperature (hot coffee). This reaction itself can be attributed to the thermal type.
Accelerate chemical reaction
Interacting at the molecular level, all substances are involved in various chemical reactions, the latter can occur in different ways in time. Some are faster, others are slow or almost imperceptible to human eyes. How to speed up the reaction of the interaction of substances with each other?
Consider another example: if you try to set fire to sugar refined sugar, you can see that when it is very hot, it melts to form brown caramel and its characteristic smell. At the same time, sugar does not ignite. You can burn it, if you use an additional substance - tobacco ash.It is enough to sprinkle a piece of sugar with this ash and bring it into open fire, it will immediately catch fire.
In the last example, the desired chemical reaction was carried out using a special substance. All chemical reactions that do not want to proceed independently or go at a very slow pace can be accelerated through a kind of “stimulus”. So, a substance that accelerates a chemical reaction is called a catalyst, and the chemical reaction itself is called catalysis.
The concept of "Catalysis" and its types
The catalyst may be another chemical substance that promotes the acceleration of a particular reaction. By the way, the amount of catalyst after the completion of the reaction does not change, which is not inherent in reagents. In other words, the catalyst does not participate in such a reaction, it cannot be considered a reagent, it only helps them to react, accelerating the speed of their interaction. Catalysts should never be confused with initiators, since the latter are consumed during the course of the reaction.
Molecules can interact in cycles, with a sufficient amount of reagent. The active position in these reactions belongs to ions, radicals and coordination-saturated compounds.The degree of concentration of active particles, the difference between the energy of the bond being formed and the bond that is broken, determine the rate of flow of a chemical reaction.
By catalysis is meant a process that influences the rate of flow of a reaction, with the participation of active substances called catalysts. The principle of its operation is simple: the catalyst accelerates a chemical reaction due to the fact that reacting with the reagent, contributes to the early formation of an intermediate compound. Under the influence of a number of transformations, splitting of this compound occurs. At the output we get the reaction product and the catalyst, ready to re-enter into a similar reaction with the reagent (according to the cycle).
Types of catalysis
The essence of the processes of catalysis can be considered the same, based on the formation of a number of intermediate compounds of the catalyst and reagent. Formally, all chemical processes associated with catalysis are divided into three types:
This process involves the formation of a common phase between the catalyst and the reactants. Most often it is a liquid or gaseous substance.
This type of catalysis is carried out in the liquid phase with the participation of various colloidal particles acting as catalysts.For example, with enzymatic catalysis, which occurs in cells of plant and animal origin, the catalysts of biological order are proteins that accelerate reactions - these are common enzymes. Such reactions are characterized by a high degree of selectivity, without them life is impossible for any organism.
In the interaction of reagents and catalyst, different phases are formed, and the catalytic reaction itself proceeds at the boundary separating them. In such reactions, the catalysts are solids, and the reactants are liquids or gases.
There are such concepts as catalysis negative (slowing down the reaction under the influence of "anti-catalysts" - inhibitors) and positive (accelerating the reaction with a catalyst).
The theory of catalytic processes cannot be called simple, it is rather complex and belongs to the little-studied areas of modern science. Today, several theories are being studied regarding the mechanisms of action of catalysts. The theory of intermediates is considered the most acceptable in physical chemistry.