The whole surrounding world consists of microscopic particles. Combining, they form simple and complex substances of various properties and character. How to distinguish one from the other? What are the characteristics of complex chemicals?
Substance
Science knows 118 chemical elements. All of them represent atoms - the smallest particles that can enter into reactions. The chemical properties of the elements depend on their structure. Independently, they cannot exist in nature and will certainly unite with other atoms. So they form simple and complex substances.
They are called simple if they consist of only one type of atom. For example, oxygen (O) is an element. Its two atoms, connected together, form a molecule of a simple oxygen substance with the formula O 2 . When three oxygen atoms are combined into a molecule, ozone - O 3 is obtained.
A complex substance is the combination of different elements. For example, water has the formula H 2 O. Each of its molecules consists of two hydrogen atoms (H) and one oxygen atom. In the nature of such substances is much more than simple. These include sugar, salt, sand, etc.
Complex substances
Complex compounds are formed as a result of chemical reactions, with the release or absorption of energy. During such reactions, hundreds of different processes are carried out in the world, many of them directly important for the life of living organisms.
Depending on the composition, complex substances are divided into organic and inorganic. All of them have a molecular or non-molecular structure. If the structural unit of matter is atoms and ions, these are non-molecular compounds. Under normal conditions, they are solid, melt and boil at high temperatures. It can be salts or various minerals.
In a different type of structure, two or more atoms combine into a molecule. The bonds inside it are very strong, but with other molecules it interacts weakly. They come in three states of aggregation, usually volatile, often have a smell.
Organic compounds
In nature, there are about three million organic compounds. Carbon is necessarily present in their composition. In addition to it, compounds often contain some metals, hydrogen, phosphorus, sulfur, nitrogen and oxygen. Although, in principle, carbon is able to connect with almost any element.
These substances are part of living organisms. These are valuable proteins, fats, carbohydrates, nucleic acids and vitamins. They are found in foods, dyes, fuels, form alcohols, polymers and other compounds.
Organic matter, as a rule, has a molecular structure. In this regard, they often exist in a liquid and gaseous state. They have lower melting and boiling points than inorganic compounds, form covalent bonds.
Carbon connects with other elements, forming closed or open chains. Its main feature is the ability to homology and isomerism. Homologs are formed when other CH 2 pairs are added to the CH 2 (methane) pair, forming new compounds. Methane can be converted to ethane, propane, butane, pentane, etc.
Isomers, on the other hand, represent compounds with the same mass and composition, but different in the way atoms are joined. In this regard, their properties are also different.
Inorganic compounds
Inorganic complex substances do not contain carbon. The only exceptions are carbides, carbonates, cyanides and carbon oxides, for example, chalk, soda, carbon dioxide and carbon monoxide and some other compounds.
There are fewer complex inorganic compounds in nature than organic ones. They are characterized by a non-molecular structure and the formation of ionic bonds. They form rocks and minerals, are present in water, soil and in living organisms.
Based on the properties of substances, they can be divided into:
- oxides - the connection of an element with oxygen with an oxidation state minus two (hematite, alumina, magnetite);
- salts - a bond of metal ions with an acid residue (rock salt, lapis, magnesium salt);
- acids - a bond of hydrogen and an acid residue (sulfuric, silicic, chromic acid);
- bases - a bond of metal ions and ion hydroxides (caustic soda, hydrated lime).