Chemical Reactions - Meaning, Characteristics, Types, Equations, FAQs

A chemical reaction is a process in which one or more substances, called reactants, undergo a transformation to form new substances, known as products. This change involves the breaking of old chemical bonds and the formation of new ones. Chemical reactions are fundamental to the study of chemistry, as they explain how and why substances combine, separate, or change properties.

It is also necessary to understand physical and chemical changes. Chemical reactions are an essential aspect of technology, society, and life itself. Many activities involving chemical reactions that have been understood and practised for thousands of years include burning fuels, smelting iron, creating glass and pottery, brewing beer, and making wine and cheese. Chemical reactions exist in Earth's geology, the atmosphere and oceans, and a wide range of complex processes that occur in all biological systems.

Physical changes include state changes such as ice melting to water and water evaporating to vapour. When a substance undergoes a physical transformation, its physical attributes change, but its chemical identity remains unchanged. Water (H₂O) is the same composition regardless of its physical state, with each molecule consisting of two hydrogen atoms and one oxygen atom. When water, as ice, liquid, or vapour, comes into contact with sodium metal (Na), the atoms are rearranged, yielding the new substances molecular hydrogen (H₂) and sodium hydroxide (NaOH).

What are the characteristics of chemical reactions?

Chemical reactions include the following general characteristics of chemical reactions:

1. A gas's evolution

2. Precipitation formation

3. Temperature shift

4. Alteration in state

5. Formation of a new substance

6. Some reactions results in change in colour

Chemical Equations

Because there are so many chemical reactions going on around us, a nomenclature was established to help us express in a chemical reactions in the form of a chemical equation. A chemical equation is nothing more than a mathematical statement that represents the product production from reactants while expressing particular conditions for how the reaction was carried out.

The reactants are on the left, while the products are created on the right, and they are connected by one-headed or two-headed arrows. As an example, consider a reaction.

A + B → C + D

The reactants in this case are A and B, which react to generate the products C and D. Reactants are denoted by their chemical formula in a real-world chemical equation. A chemical equation must be balanced to ensure the law of conservation of mass, which means that the number of atoms on both sides must be equal. This is the equation's balancing.

For example:

hydrogen + oxygen ---> water

iron + oxygen ---> rust

potassium and chlorine gas ---> chloride

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Types of Chemical reactions with examples class:

The product created, the changes that occur, the reactants involved, and so on constitute the basis for various types of reactions.

1. Combustion reaction

2. Decomposition reaction

3. Neutralization reaction

4. Redox reaction

5. Precipitation or Double-Displacement Reaction

6. Synthesis reaction

1. Combustion Reaction:

A combustion reaction is a reaction between a combustible material and an oxidizer that results in an oxidized product. An oxidizer is a chemical that a fuel requires to burn, typically oxygen. Consider the burning of magnesium metal.

2Mg+O₂→2MgO+Heat

2. Decomposition Reaction

A decomposition reaction occurs when a single component degrades into several products. Certain changes in energy in the environment, such as heat, light, or electricity, must be made to break the bonds of the molecule. Consider the disintegration of calcium carbonate, which produces CaO (Quick Lime), a significant component of cement.

CaCO₃(s)→CaO(s)+CO₂(g)

3. Neutralization Reaction

A neutralization reaction is essentially a reaction between an acid and a base that produces salt and water as byproducts. The water molecule is created by combining OH^– ions with H⁺ ions. When a strong acid and a strong base are neutralized, the overall pH of the products is 7. Consider the neutralization reaction between hydrochloric acid and sodium hydroxide, which produces sodium chloride (common salt) and water.

HCl+NaOH→NaCl+H₂O

4. Redox Reaction

A Reduction Oxidation reaction occurs when electrons are transferred across chemical species. Consider the following electrochemical cell-like redox process between Zinc and Hydrogen.

Zn+2H+→Zn₂⁺+H₂

5. Precipitation or the Double-Displacement Reaction

It is a sort of displacement reaction in which two compounds react and their anions and cations switch positions, resulting in the formation of two new products. Consider the reaction between silver nitrate and sodium chloride as an example. After the double-displacement process, the products will be silver chloride and sodium nitrate.

AgNO₃+NaCl→AgCl+NaNO₃

6. Synthesis Reaction

A synthesis reaction is one of the most fundamental types of reactions in which numerous simple molecules combine under specific physical circumstances to produce a complex product. The end result is invariably a compound. Consider the sodium chloride synthesis process with the reactants solid sodium and chloride gas.

2Na(s)+Cl(g)→2NaCl(s)

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