Encyclopedia about Chemistry

Chemistry is the science of substances, or materials, their composition and characteristics, and the reactions which take place between those substances. It is concerned with chemical elements in their pure state and when they are combined, that is, reactions of these elements and the compounds which they form. The scientist who wants to do chemistry must first be able to understand its building blocks, substances in their pure state. Only then can the chemist use that knowledge to comprehend more complicated phenomena, and begin to perform his own experiments.

Every chemical reaction can be represented with the help of atoms and molecules. It was necessary, therefore, to develop a special system of chemical symbols. Substances in their pure state, called elements, were sometimes named after the scientists who discovered them. From those names, abbreviations were derived (like O for oxygen). These chemical symbols are used to denote various chemical reactions. Every element, then, has a letter or letters associated with it, most of these coming from the element’s Latin name. It is natural that each element has its own original abbreviation.

Chemistry deals with reactions at the atomic level of substances. It attempts to experimentally decipher what happens between the individual atoms of a reaction, the "secret" of each reaction. In turn, these secrets help chemists formulate chemical laws and scientific information, which help them to better understand the world around us. One of the goals of chemistry is the development of new substances and materials, and their production. With the help of these new materials, those already in use can be replaced by more effective, higher quality ones, to make our lives easier and better.

In our daily lives, chemistry can be found around every corner. Without commercial fertiliser, medicines, plastics and other chemical products, it would be difficult to imagine our lives as they are today. We human beings have chemistry to thank for the tablets we take to make us feel better, for cleaning products, as well as for cosmetics and foods and other grocery products which contain preservatives to make them last longer.

Of course, what seemed to be promising chemical discoveries can also be the cause of environmental disasters. For example, DDT (dichlorophenyltrichloretane), an insecticide, or freon (composed of flourine and chlorine with hydrocarbons), and the dissolved gases in aerosol sprays and cooling fluids for refrigerators have all caused problems. When these problems arise, however, it is chemistry which has to step in to offer a solution.

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One example is the use of fire by early peoples as a source of light and heat: This is an oxidation reaction taking place.

The real beginnings of chemistry must be attributed to the developed cultures of times past. We can assume that the Egyptians, as well as the Chinese and ancient Greeks, were at the centre of the progress made in olden times. The inventions and discoveries made back then were often revolutionary, like the invention of gunpowder, which the Chinese discovered in the year 900 A.D. These discoveries often served to spark great progress in the field of natural sciences.

The ancient Greeks explained the nature of matter two different ways. Some claimed that all materials were made of four basic building blocks, or elements: air, water, earth and fire. Others believed that all materials were made up of incredibly minute particles, so-called atoms (Greek atomos = invisible). Chemistry as a science had first to be founded from a philosophical perspective. Only later could fields of study like metallurgy and alchemy be developed.

For a long period of time, alchemy concerned itself with the discovery of what was then known as the "philosophers’ stone". Alchemists attempted to turn simple metals, such as lead, into gold. This discipline came into being in the sixth century B.C. in Egypt. The word alchemy as such means "black element".

In the Middle Ages, chemistry began to have close ties with medicíne. Only a short time later, science began to be perceived as a series of factual and methodical processes, and old-style mythological beliefs slowly faded into the sunset. Antoine Lavoisier began the modern era of chemistry by proving the existence of "Oxygenia" through a combustion experiment.

The 18^th century saw scientific progress accelerated in an unprecedented fashion. New elements were discovered. The foundations of both electrochemistry and organic chemistry were laid. and, scientists began to try to organise matter, or the elements, in a systematic way. In the end, it was Mendel and Meyer who found the answer in what is now known as the periodic table of the elements, which is in use to this day.

The discovery of molecular orbitals in the 20^th century helped to explain covalent bonding. Thanks to that discovery, more and more synthetic products (artificially produced) were developed. In addition, one of the most revolutionary discoveries of recent history was the "untangling" of the structure of the DNA molecule, the building block of all organic matter.

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