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1. CHEMISTRY SUBJECT
Chemistry-one of fundamental sciences. What the science chemistry is? The CHEMISTRY is science about substances, their properties, structure and transformations each other.
Substances are what physical bodies consist of. Physical call all bodies which surround us. Any body consists of molecules and atoms. These particles are very small which we cannot see even at strong increase. It is possible to judge the sizes and weight on such example. 18 grams of water contain 602000000000000000000000 or 6,02·1023 molecules. Have presented?
At the moment 117 types of atoms are known. Each certain type of atoms is called differently chemical element. You can find these chemical elementyva, having addressed periodic system of D. I. Mendeleyev (in blue color are designated references to appropriate resources, having clicked which, information page will open), which you will constantly use.
All substances can be divided into two groups: simple substances and difficult. Simple call such substances consisting of atoms of one chemical element (for example hydrogen, oxygen, iron, aluminum), difficult - the substances consisting of atoms of different chemical elements (the water molecule consists of two chemical elements: oxygen and hydrogen).
Simple substances can be one-atomic, or polyatomic (the molecule of oxygen consists of two oxygen atoms, white phosphorus - from four atoms of phosphorus).
Each of chemicals has certain properties (density, temperatures of melting, crystallization, boiling; electro-and heat conductivity; plasticity, fragility, elasticity and many other physical properties. There is no substance with absolutely identical properties). In addition to physical, substances have certain chemical properties (at which there are transformations of one substances into others), with which you will get acquainted a bit later.
Modern chemistry - the extensive field of natural sciences that its many sections represent independent, though closely connected scientific disciplines. On the basis of the studied substances the chemistry can be divided on inorganic and organic.
The chemistry is faced by the major tasks from which it is possible to distinguish the following:
2. Receiving modern materials with certain characteristics.
3. Studying of properties of different substances.
4. Prediction of properties, the substances which are not received yet.
Chemistry role in human life.The role of chemistry is huge. Without it there would be no such major industries as metallurgy, pharmaceutics, neftepereraabotka, radio electronics, etc. Chemists have learned to receive chemicals which in the nature do not exist, and, they often surpass them in different characteristics. Now composite materials which are stronger than staly are received, have before it such advantages as corrosion stability and ease. The chemical industry turns out products for everyday life (find them at yourself in life), agriculture (fertilizers, toxic chemicals, herbicides), etc. By means of chemistry of people creates substances with the set characteristics and properties. Annually scientists-chemists receive tens of thousands of new substances. The chemistry is high-growth science, being the engine of technical progress together with physics.