Chemistry

Article

August 13, 2022

Chemistry or chemistry is the natural science that focuses on the study of the composition and structure of substances, the chemical changes that take place under certain conditions, and the laws that can be distilled from them. Chemistry is closely related to biology and physics. The branch of science that connects the two are respectively biochemistry and physical chemistry. New disciplines have also emerged at the interface with other natural sciences, such as geochemistry and computational chemistry. The term chemistry was coined by the scientist Simon Stevin.

General description of chemistry

All substances consist of atoms. Atoms can chemically bond with each other to form larger groups. Substances consisting of atoms of a single species or chemical element are called simple substances. Substances that consist of several types of atoms are called compound substances. The atoms consist of a number of protons, neutrons and electrons. The total number of protons is always equal to the number of electrons. This makes a molecule electrically neutral. Atoms can share their electrons with each other and this is the basis for the chemical bond. One can still distinguish in the way in which the electrons are shared. When the electrons are shared equally between two neighboring atoms, it is called a covalent bond. However, electrons can be shared among more than two atoms. In metals there is even a sea of ​​electrons distributed over all atoms. The distribution can also be uneven, with electrons being partially transferred from one atom to another. This is referred to as an ionic bond. When substances are combined without changing the molecular structure of the various components, we speak of a mixture. A chemical compound can be created by the action of, for example, an elevated temperature, light, or vibration, whether or not under the influence of catalysts, radiation or pressure. Sometimes it is simply the joining of reactants that creates a chemical reaction. A chemical reaction changes the way the different atoms are bonded to each other. Reactions can be very slow (like the rusting of a car) or lightning fast, like the explosion of dynamite. Also in the body of living beings assimilation (construction) and dissimilation (breakdown) of connections takes place continuously. This is collectively called the metabolism. The individual chemical elements are identified by chemical symbols, usually the first letter or first two letters of the Latin name for the substance. Example: 'C' for 'carbon' (carbonum) and 'Fe' for 'iron' (ferrum). All known elements (currently 118), can be arranged in a logical way by placing them in the periodic table. About 92 elements of these also occur in nature (up to uranium); the others are only made in a lab, usually disintegrate spontaneously in fractions of seconds (radioactive decay).

History and development of chemistry

The study and use of chemistry actually predates modern humans (Homo sapiens), because one of the first pieces of technology our even more ape-like ancestors internalized was fire. Fire is nothing more than a cloud of mixed gases (fuel and oxygen from the air) that chemically react with each other, releasing enough heat to volatilize more fuel. In more recent antiquity, a number of other chemical techniques were added to the fire. First, man learned to release metals from their ores. The metallurgy of copper is a very old form of chemistry and a number of elements were already known in ancient Egypt. Metals were soon used as a means of payment and with the minting of