Chemical reaction

Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Based on this idea and the atomic theory of John Dalton, Joseph Proust had developed the law of definite proportions, which later resulted in the concepts of stoichiometry and chemical equations.

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.

The IUPAC Nomenclature for Transformations is a methodology for naming a chemical reaction.

Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants.

Products are the species formed from chemical reactions.

Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants.

These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.

Different chemical reactions are used in combinations during chemical synthesis in order to obtain a desired product.

Chemical synthesis is a purposeful execution of chemical reactions to obtain a product, or several products.

Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism.

An elementary reaction is a chemical reaction in which one or more chemical species react directly to form products in a single reaction step and with a single transition state.

Enzymes increase the rates of biochemical reactions, so that metabolic syntheses and decompositions impossible under ordinary conditions can occur at the temperatures and concentrations present within a cell.

Metabolism (, from μεταβολή metabolē, "change") is the set of life-sustaining chemical reactions in organisms.

In biochemistry, a consecutive series of chemical reactions (where the product of one reaction is the reactant of the next reaction) form metabolic pathways.

In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell.

Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration.

Consider a typical chemical reaction:

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.

Chemical substances may be combined or converted to others by means of chemical reactions.

It postulated the existence of a fire-like element called "phlogiston", which was contained within combustible bodies and released during combustion.

Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.

Based on this idea and the atomic theory of John Dalton, Joseph Proust had developed the law of definite proportions, which later resulted in the concepts of stoichiometry and chemical equations.

Stoichiometry is the calculation of reactants and products in chemical reactions.

A double arrow pointing in opposite directions is used for equilibrium reactions.

In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.

More elaborate reactions are represented by reaction schemes, which in addition to starting materials and products show important intermediates or transition states.

The transition state of a chemical reaction is a particular configuration along the reaction coordinate.

Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

Radiochemistry is the chemistry of radioactive materials, in which radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable).

The general concept of a chemical reaction has been extended to reactions between entities smaller than atoms, including nuclear reactions, radioactive decays, and reactions between elementary particles, as described by quantum field theory.

Kinetic energy may be released during the course of a reaction (exothermic reaction) or kinetic energy may have to be supplied for the reaction to take place (endothermic reaction).

In the first case, the bond is divided so that each product retains an electron and becomes a neutral radical.

With some exceptions, these unpaired electrons make radicals highly chemically reactive.

The forward and reverse reactions are competing with each other and differ in reaction rates.

Chemical kinetics includes investigations of how different experimental conditions can influence the speed of a chemical reaction and yield information about the reaction's mechanism and transition states, as well as the construction of mathematical models that can describe the characteristics of a chemical reaction.

Dissociation plays an important role in triggering chain reactions, such as hydrogen–oxygen or polymerization reactions.

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks.

Reactions can be exothermic, where ΔH is negative and energy is released.

An exothermic reaction is a chemical reaction that releases energy through light or heat.

They consist of chemical or structural formulas of the reactants on the left and those of the products on the right.

Chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution.

They consist of chemical or structural formulas of the reactants on the left and those of the products on the right.

These systematic chemical names can be converted to structural formulas and vice versa, but chemists nearly always describe a chemical reaction or synthesis using structural formulas rather than chemical names, because the structural formulas allow the chemist to visualize the molecules and the structural changes that occur in them during chemical reactions.

With the development of the lead chamber process in 1746 and the Leblanc process, allowing large-scale production of sulfuric acid and sodium carbonate, respectively, chemical reactions became implemented into the industry.

This chemical reaction had been discovered in 1772 by the Swedish chemist Carl Wilhelm Scheele.

More realistic models are tailored to a specific problem and include the transition state theory, the calculation of the potential energy surface, the Marcus theory and the Rice–Ramsperger–Kassel–Marcus (RRKM) theory.

Transition state theory (TST) explains the reaction rates of elementary chemical reactions.

Chemical reactions are determined by the laws of thermodynamics.

Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field.