Organic call compounds of carbon with other chemical elements, and science which studies laws of their transformations, organic chemistry. The number of the studied organic compounds exceeds 10 million, such variety is caused by features of carbon atoms.
Instruction
1. One of the most important features of atoms of carbon is their ability to form strong communications with each other. Because of it molecules which contain chains of carbon atoms are steady under usual conditions.
2. Studying organic compounds by means of X-rays showed that in them atoms of carbon are located not on one straight line, and in zigzag fashion. The fact is that four valencies of atom of carbon are directed in a certain way on the relation to each other - their relative positioning corresponds to the lines coming from the center of a tetrahedron and going to its corners.
3. Not all compounds of carbon are considered as organic, for example, carbon dioxide, hydrocianic acid, traditionally carry carbon sulfur to inorganic. It is considered to be that a prototype of organic compounds is methane.
4. In molecules of organic compounds of a chain of carbon atoms can be both opened, and closed. Derivatives of the first type call connections with an open chain, and others — cyclic.
5. Hydrocarbons are the connections consisting only of atoms of carbon and hydrogen, all of them form ranks. In them each subsequent member can be made from previous by addition of one group. Such ranks are called homologous, they are distinguished from each other on the first member. For example, the hydrocarbons belonging to a homologous number of methane are its homologs.
6. Members of the same homological row are similar at each other in the chemical relation. For example, for homologs of methane the same reactions, as are characteristic of him, distinctions consist only in ease of their course.
7. Physical constants of homologs change quite naturally. For a homological number of methane the increase in molecular weight is followed by increase of temperature of boiling and melting. Similar regularities, as a rule, remain also for other ranks, however in relation to density they sometimes have the return character.
8. One of the most important features of course of organic reactions - the vast majority of organic compounds is not exposed to electrolytic dissociation. The small polarity of communications as valent communications of carbon with hydrogen and various metalloids on durability are close to each other is the reason. Externally it is shown in rather low temperatures of boiling and melting of the majority of organic matter.
9. Other feature is that time necessary for completion of reactions between organic connections, is often measured not seconds or minutes, but hours, at the same time reactions proceed with a noticeable speed only at the increased temperatures and, as a rule, do not reach the end.