Chemical process: principles, types, examples

On the contrary, the physical process occurs without altering the composition or identity of the materials. For example, ethanol can be subjected to distillation, by means of its evaporation and subsequent condensation, without it reacting or breaking its bonds. The evaporated and distilled liquid will continue to be ethanol.

Chemical reactions are the main component of chemical processes. They are a set of changes that involve an exchange of the atoms of the compounds that take part in chemical reactions, which produces the disappearance of some compounds and the appearance of new ones.

A chemical process can occur in one or more stages, as occurs in the production of some compounds in industry. Similarly in living beings, many chemical processes occur in stages that complement and regularize each other.

Elementary principles of chemical processes

Some of the elementary principles for any chemical process are the following:

Reagents and products

They are the substances that will react and be produced, respectively, at the end of the process.

Yield of reaction

Indicates how complete the reaction was carried out. A 100% yield would be ideal. The quality of this value is relative, depending on the complexity of the process.


It is the vessel, container, volume , etc., where the chemical reaction takes place. For example, our stomachs could be considered as a kind of biological reactors.

Process units

Chemical processes require drying, condensing, mixing, filtration units, among others. Their purpose is to provide the reagents in optimal conditions, as well as to improve the quality of the product obtained and purify it from residues and waste.

Types of chemical processes

The types of chemical processes are mostly related to a branch of chemistry called physicochemistry. It addresses chemical processes, as well as their connection to physical processes. Therefore, in the types of chemical processes it is not always easy to establish the limits with the physical processes.


The chemical process occurs at a constant temperature, and also the internal energy of the system remains constant.


The chemical process is carried out in isolation, in such a way that there is no heat exchange with the surrounding environment. Under these conditions, the amount of heat (enthalpy) in the system remains constant.


The chemical process is carried out at constant pressure.

Isochoric or isovolumic

The chemical process is carried out at a constant volume.


 The force” that drives a chemical process in one direction is slightly greater than the “force” that drives it in the opposite direction. The reactants are transformed into products, and these in turn can react with each other to regenerate the reactants.


The orientation of a chemical process is strongly directed in one direction, so very large changes are required in the conditions under which the chemical process is carried out to produce its change in orientation.


The chemical process consists of several intermediate steps, at the end of which it returns to the initial state.

Examples of chemical processes

– Chemical processes in the human body

The digestion

It is a physiological process that includes numerous chemical reactions. Man, like other mammals, ingests their food and digestive action begins in their oral cavity with the action of salivary amylase on starch.

The food bolus is transferred to the stomach and there, due to its acidic condition, pepsin is activated: an enzyme that begins the digestion of proteins. This digestion ends in the small intestine by the action of pancreatic proteases. In general, digestion is a chemical process carried out within various organs.

The breathing

It is a chemical process that allows the exchange of carbon dioxide and oxygen between man and his environment. Hemoglobin reaches the lungs loaded with carbon dioxide and there, it releases it and exchanges it for oxygen.

Hemoglobin carries oxygen to the different tissues and in them performs an inverse process to that carried out in the lungs: it captures carbon dioxide and releases oxygen.


Coagulation is a natural activity present in many living beings, including humans. It consists of a change in the consistency of the blood, from liquid to a kind of gel. It is a natural response of the body to prevent blood loss.

– Chemical processes in industry


Some fermented foods

It is an incomplete oxidation process where a reactive agent (such as yeast) causes the accelerated proliferation of microorganisms normally fed glucose to form other derivatives such as carbohydrates or alcohol.

It occurs naturally in living beings, however its use at an industrial level is used for the creation of numerous foods, especially liquors such as wine and beer, and basic foods, such as bread, yogurt, cucumbers, peppers or cheese. .


This process occurs when applying an electrical charge generates ions that pass from one conductor to another to artificially create atoms or molecules, such as ozone.

It has several uses, such as water purification.

Oil refineries

Industrial refinery plant

They are facilities where a chemical process is carried out. In them, the oil extracted from the earth is treated to obtain many products of great use to man. Oil refineries are made up of a set of units, including the following:

  • Crude distillation unit (CDU) : in it the crude oil is heated and divided into several fractions.
  • Naphtha Hydrotreater Unit : Used to desulfurize the naphtha produced in the CDU.
  • Catalytic reforming unit : it is used for the production of high octane molecules through the use of catalysts.
  • Isomerization unit : it is used in the conversion of pentane, butane and isobutene, in high octane molecules.

PVC production

The production of PVC is a chemical process carried out in several stages. PVC is a widely used plastic material, which requires salt (sodium chloride) and petroleum as its main raw materials.

Sodium chloride is used for the electrolytic production of chlorine, while acetylene is obtained from oil. Chlorine reacts with acetylene to form vinyl dichloride, which is converted to vinyl chloride monomer at high temperatures. This finally polymerizes to form the PVC.


In metallurgy, the process and material obtained by combining one metal element with another is called an alloy, whether this is a metal or not.

It is used to obtain materials that are stronger, more resistant to corrosion or more visible to the eye. Bronze, steel, and brass are examples of alloys.

– Chemical processes in everyday life

Frying an egg

An egg is an unfertilized ovum, made up of a translucent liquid, the white of the egg; and a yellow liquid, the egg yolk. Proteins such as ovotransferrin, ovalbumin, lysozyme, etc. are in solution in the egg white.

When the egg is heated, the proteins in the egg white coagulate. These precipitate and interact with each other to form a compact white mass. Meanwhile, in the yolk, the proteins, lipids and nucleic acids present in it are compacted.

Whitening of clothes

Sodium hypochlorite is a highly oxidizing chemical agent, which acts on the molecules of the stains causing a chemical change that reduces their capacity to capture the wavelengths of light, corresponding to those of colors.

This blocks the display of colors in the stain, causing white to be seen instead.

– Others


It is a chemical reaction of the reduction – oxidation type, where one element gains electrons while another loses them (the oxidant) significantly modifying its characteristics.

In the case of metals, corrosion causes loss of hardness, malleability and electrical conductivity.


Process by which an acid or a salt is dissolved in water to cause the exchange of anions and cations to decompose the elements.

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