What is organic inorganic in basic terms
The item Basic chemical terms provides a brief introduction to the basic terms and concepts in chemistry and refers to the relevant specialist articles.
Basic terms and concepts in chemistry
Substances, substances, compounds
The matter surrounding us consists of substances. A gold ring, a gold chain and a lump of gold have different shapes, but the concept of chemical substance abstracts from the external shape and size and emphasizes that there are many similarities between the three objects, which are summarized in the substance term "gold". The size (volume and mass) is also abstracted: a drop of water and the filling of a drinking water reservoir have such a large number of properties in common ("liquid", "colorless" and many more) that both can be found under the substance name " Water ”.
Mixture - compound - element
Mixtures of substances can be separated from one another using mechanical methods (example: sugar and cinnamon; oxygen and nitrogen in the air). Chemically uniform substances are called pure substances. On the one hand, there are the chemical compounds that can be broken down into their components again using chemical or thermal methods (examples: water, table salt, sugar). On the other hand, these are the chemical elements that cannot be further broken down using chemical or thermal methods (examples: gold, iron, aluminum, oxygen).
Different elements differ in the number of simply positively charged protons contained in their atomic nucleus, i.e. H. the atomic numbers (another term for this: atomic numbers) are the same for the atoms of a certain element, but different for different elements. The atoms of the elements consist of a shell with simply negatively charged electrons rotating around the atomic nucleus. Atoms are electrically neutral to the outside world: the number of electrons is identical to the number of protons.
Elements contain only a single type of atom, all of which have the same structure with regard to their electron shell. Compounds contain different types of atoms. Chemistry deals with the elements and above all with their compounds, their analysis and synthesis.
- Only the electron shell is decisive for chemistry.
- The atomic nuclei are the working area of physics:
- In addition to protons, atomic nuclei contain neutrons. Each type of atom characterized by a certain atomic number (number of protons) and a certain number of neutrons is called a nuclide. Isotopes are nuclides of an element with the same atomic number (i.e. the same number of protons and thus electrons and consequently also chemically the same behavior) but different numbers of neutrons. If there is only one isotope of an element, it is called a pure element; if there are several isotopes, it is called a mixed element.
- Elements can be converted into other elements by fission or fusion. Such nuclear transformations differ from chemical reactions in that the energies are considerably - around a million times - higher that are required for them or are obtained in the process.
- The periodic table is an ordered listing of all elements; they are arranged according to the increasing atomic number.
- A chemical formula indicates which elements a compound contains, at the same time it indicates which atoms a molecule or a unit of the compound contains. Ions are electrically charged atoms or molecules.
- Isomerism is the term used to describe the occurrence of different molecules with the same empirical formula. A special case is stereoisomerism, see stereochemistry and chirality.
- The atoms are linked to one another in molecules or salts by chemical bonds.
- Chemical reactions are linked to a turnover of energy, usually in the form of heat. Chemical thermodynamics is concerned with such energy and heat changes and chemical equilibrium. This is achieved when chemical reactions can take place but there is no longer any net sales. The law of mass action describes the relationship between the concentrations (or more precisely: the activities) of the starting materials and products that are then present.
- The breaking down of connections is called analysis. In contrast, synthesis is the process of building a connection. The investigation of a mixture of substances is also called analysis, see analytical chemistry.
Substances and groups of substances
The substances can be divided into categories according to various criteria.
- Carbon-containing compounds are summarized as organic substances, all others are inorganic substances.
- Metals, non-metals and semiconductors differ particularly in their electrical conductivity.
- Acids and bases (dissolved as lye) release or absorb protons. - The same amounts of acids and bases result in water and a salt - salt former
- Groups of the periodic table, that is, groups of elements that are among each other in the periodic table and have chemical similarities to each other, are, for example, the alkali metals, the alkaline earth metals, the halogens and the noble gases. The transition metals, the lanthanoids and the actinides, which occur side by side according to the periodic table, also have a lot in common.
- Important substances are for example water, carbon dioxide, ammonia, 1-butanol and benzene.
- Plastics are also known as polymers; they are made from the monomers that ultimately form the plastic as repeatedly repeated building blocks.
- Real solutions, emulsion, colloid
Separation and analysis
- Process for the separation of mixtures of substances
- The separation of mixtures of substances and the purification of substances are mostly carried out using physical processes. These make use of differences in physical properties such as density or boiling point and take place without any material conversion. Nevertheless, they are among the most important and frequent tasks of the chemist.
- A chemical reaction is the conversion of a substance. The reaction rate indicates how fast the conversion takes place; it can be accelerated with a catalyst. Chemical reactions are represented symbolically in the form of a reaction scheme ("reaction equation").
- Combustion is a special case of oxidation. The opposite of this is reduction. Oxidation and reduction occur together in the redox reaction.
- Acids and bases react with each other in an acid-base reaction. Neutralization is a special case; for this purpose, in the simplest case of monovalent and strong acids and bases, equal amounts of acid and base have to be combined.
- The decomposition of a substance is also called analysis. During synthesis, a substance is specifically produced, whereby the desired molecule is often built up in several steps. The planning of a synthesis that takes place backwards from the target molecule to simple substances is called retrosynthesis, the identification of an unknown substance through the synthesis of easily recognizable, characteristic products detection reaction.
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