Most people do not think about the composition of the objects surrounding them, substances, matter. Atoms, molecules, electrons, protons - these concepts seem not only incomprehensible, but also far from reality. However, this opinion is erroneous. Almost everything that surrounds us consists of chemical bonds. Chemical compounds are quite complex forms of substances. In the world around us, a great many such connections. However, compounds consisting of only one chemical element can relate to them, for example, oxygen or chlorine. Therefore, it is worth examining the question in more detail: "Chemical compounds - what is this?"
The complex "chemical" world
Few people think that the world around us consists of complex structures, macromolecules and tiny particles. It is amazing how heterogeneous even the sizes of atoms are for different elements. The differences in atomic masses are also impressive - beryllium with its 9 a. E. m. - "lightweight" compared with the "heavyweight" astatine: its atomic weight is 210 a. e. m. (a. e. m. - atomic mass units - a unit of measurement of the mass of atoms, molecules, nuclei, which is 1/12 of the mass of a carbon atom in the ground state).
The variety of elements determines the presence of many chemical compounds (in simple words, a combination of interconnected atoms of different and, in some cases, identical parts). Most objects, substances are precisely this kind of compound. Oxygen, table salt, acetone, necessary for life ... It is possible to enumerate examples for a very long time that are well-known and understandable only to narrow specialists. What are these chemical compounds?
Definition, difference from mixtures
Chemical compounds are complex substances that consist of atoms of different chemical elements interconnected, but there are exceptions: simple substances also belong to chemical compounds (that is, they consist of atoms of one element) if the atoms of these substances are connected by a covalent bond (it is formed by common for both atoms by electrons). Such substances include nitrogen, oxygen, and most halogens (in the periodic table elements of the seventh group of the main subgroup; fluorine, chlorine, bromine, iodine, and presumably astatine).
Often confused with each other are the concepts of "chemical compound" and "mixture of simple substances." A mixture of substances is, as one can deduce from the name, not an independent substance, but a system of two or more components. The very composition of these two units of chemicals is the main difference between them. As already mentioned, the combination of chemical elements and a mixture of simple (or complex) substances are not the same thing. Properties, methods of preparation, methods of separation into components are also distinctive criteria for mixtures and compounds. It is important to note that it is impossible to obtain or separate chemical compounds without carrying out chemical reactions, and mixtures are possible.
Compounds of substances or elements?
A lot of people also confuse the phrase “compound of chemicals” and “compound of elements”. For unknown reasons, but most likely due to their incompetence, most of them do not see the difference between the first and second scientific concepts. It is worth knowing and understanding that there is no such terminology as “compounding chemicals”. Do not repeat after others the errors of the etymology of certain not only expressions, but also words.
How to determine the properties of compounds
Often the properties of chemical compounds are very different from the properties of the elements of which they are composed. For example, a molecule of ethyl alcohol consists of two carbon atoms, six hydrogen atoms and one oxygen atom, but its properties are very different from the properties of all elements of its composition. Due to the fact that there are different classes of compounds, the properties of each of them are different. Most reactions, of course, are characteristic of many compounds, but the mechanisms of their manifestation are different.
What classes are the chemical compounds classified into?
Depending on their nature, there are classes of chemical compounds such as organic and inorganic. It is worth saying that organic matter is called substances (compounds), in which carbon is present (exceptions are some compounds containing carbon, but related to inorganic, they are given below). The main groups of organic compounds are hydrocarbons, alcohols, aldehydes, ketones, esters, carboxylic acids, amides and amines. Inorganic substances (compounds) do not contain carbon atoms in their composition, however, carbides, cyanides, carbonates and carbon oxides can be distinguished among them, since they, along with organic compounds, contain its atoms in their composition. Both those and other compounds have their own characteristics, their properties, and different groups of compounds of the same class can have different characteristics.
Inorganic compounds: basic properties
All inorganic compounds can be divided into several groups. Each of these types of compounds has common properties, which often do not coincide with other groups of the same class. So, the answer to the questions, which chemical compounds are inorganic, which groups form and what properties they have, can be represented as follows:
- The first group is simple inorganic compounds of non-metallic nature. This category of compounds combines properties such as the ability to be in a gaseous state. Solid compounds of a non-metallic nature have a non-molecular structure, and therefore are capable of forming crystals.
- The second group is complex inorganic compounds. They can be divided into four subgroups.
Complex inorganic compounds, their properties
As mentioned earlier, the second group of inorganic compounds can be divided into four subgroups:
- Oxides This subgroup of inorganic compounds is characterized by reactions with water, acids and acid oxides (they have the corresponding oxygen-containing acid).
- Acids. These compounds interact with water, alkalis and basic oxides (they have an appropriate base).
- Amphoteric compounds are compounds that can behave both as acids and as bases (they possess both of these properties). Such compounds react with both acid oxides and bases.
- Hydroxides. These substances unlimitedly dissolve in water, change color when exposed to alkalis.
Organic Compounds
Most items that a person encounters daily are made from organic compounds. Organic chemical compounds represent an extensive class of bonds, the compositions and properties of groups, the interaction of which they differ in an enviable variety. It is worth considering in more detail the groups of these compounds.
Groups of organic compounds and some of their properties
- Hydrocarbons. They are compounds of only hydrogen and carbon atoms. One can distinguish limiting and unsaturated, linear (acyclic) and carbocyclic, aromatic and non-aromatic; alkanes, alkenes, alkynes, dienes, naphthenes. For all of these hydrocarbons, their miscibility with water is a common property. For the limit, substitution reactions are typical, and for the unsaturated, additions are typical.
- Alcohols are compounds containing a hydroxyl (—OH) group in their composition (of course, organic compounds). They have the properties of weak acids, they are characterized by nucleophilic substitution reactions and oxidation reactions, and alcohols themselves can act as nucleophiles.
- Ethers and esters. Ethers are slightly soluble in water, have weakly basic properties. Esters act as carriers of electrophilic reagents, enter into substitution reactions.
- Aldehydes (contain an aldehyde-CHO group). They enter into reactions such as addition, oxidation, reduction, conjugate addition.
- Ketones They are characterized by hydrogenation, condensation, nucleophilic substitution.
- Carboxylic acids. They exhibit, of course, acidic properties. Reduction, halogenation, nucleophilic substitution reactions at the acyl carbon atom, production of amides and nitriles, decarboxylation are the main characteristic reactions.
- Amides. Hydrolysis, decomposition, acidity and basicity are the main intrinsic reactions for amides.
- Amines. Are grounds; interact with water, with acids, with anhydrides, halogens and haloalkanes.