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Chemical, physical properties of substances

To date, there are about 2.5 million different compounds of both natural origin and man-made synthesized. All of them are very different, some of them are irreplaceable participants of biological processes occurring in living organisms. The compounds differ from one another in the properties of substances. Characteristics and what else allows us to identify this or that chemical molecule, we will consider further.

What is matter?

If we define this concept, then we must point out its connection with physical bodies. After all, matter is considered to be exactly what these bodies consist of. So, glass, iron, sulfur, wood are substances. Examples can be given indefinitely. It is easier to understand the following: the term under consideration denotes all the diversity in the world of various combinations of molecules, as well as simple monatomic particles.

Thus, water, alcohol, acids, alkalis, proteins, carbohydrates, salt, sugar, sand, clay, diamond, gases and so on are all substances. Examples allow more clearly to grasp the essence of this concept.

A physical body is a product that is created by nature or a person on the basis of various compounds. For example, a glass is a body that consists of glass, and a sheet of paper is a body that is treated cellulose or wood.

Of course, all the molecules are different. What underlies their difference is called their properties - physical, organoleptic and chemical. They are determined by means of special methods, which each science has its own. This can be mathematical, analytical, experimental, instrumental methods, and many other very diverse. For example, the science of chemistry uses its own reagent for each substance, or rather, for its identification. It is selected on the basis of the structure of the molecule and the prediction of chemical properties. Then it is checked experimentally, it is confirmed and fixed in the theoretical base.

Classification of substances

The basis for dividing compounds into groups can be laid many different features. For example, the aggregate state. All of them can be on this factor of four kinds:

  • plasma;
  • gas;
  • liquid;
  • Crystalline substance (solid).

If we take as a basis a more "deep" sign, then all substances can be divided into:

  • Organic - the basis of the chain and the cycles of carbon and hydrogen atoms;
  • Inorganic - all the rest.

On the elemental composition, which reflects the formulas of substances, they all are:

  • Simple - from one kind of chemical atom;
  • Complex - two or more different types of elements.

In turn, simple are divided into metals and non-metals. Complexes have many classes: salts, bases, acids, oxides, esters, hydrocarbons, alcohols, nucleic acids and so on.

Different types of compound formulas

What is the visual, that is, the graphic display of connections? Of course, these are formulas of substances. They are different. Depending on the type of information contained in them, the information about the molecule is also different. So, there are such options:

  1. Empirical, or molecular. Reflects the quantitative and qualitative composition of the substance. It includes the symbols of the constituent elements and the index in the lower left corner of it, showing the amount of a given atom in the molecule. For example, H 2 O, Na 2 SO 4 , AL 2 (SO 4 ) 3 .
  2. Electron-graphic. Such a formula shows the number of valence electrons for each element in the compound. Therefore, according to this version, it is already possible to predict some of the chemical and physical properties of substances.
  3. In organic chemistry, it is customary to use complete and abbreviated structural formulas. They reflect the order of bonding of atoms in molecules, in addition, clearly indicate the belonging of the substance to a particular class of compounds. And this allows us to accurately determine a specific type of molecule and predict all its characteristic interactions.

Therefore, chemical symbols and correctly formulated formulas of compounds are the most important part of working with all known substances. This is the theoretical basis that every schoolboy studying chemistry should know.

Physical properties

A very important characteristic is the physical properties of the substances. What is it about this group?

  1. Aggregate state under various conditions, including standard conditions.
  2. Temperatures of boiling, melting, freezing, evaporation.
  3. Organoleptic characteristics: color, smell, taste.
  4. Solubility in water and other solvents (organic, for example).
  5. Density and fluidity, viscosity.
  6. Electrical and thermal conductivity, heat capacity.
  7. Electrical permeability.
  8. Radioactivity.
  9. Absorption and emission.
  10. Inductance.

There are also a number of indicators that are very important for a complete list reflecting the properties of substances. However, they are between physical and chemical. It:

  • Electrode potential ;
  • Type of crystal lattice;
  • Electronegativity;
  • Hardness and brittleness;
  • Ductility and ductility;
  • Volatility or volatility;
  • Biological effect on living organisms (poisonous, asphyxiating, nervously-paralytic, neutral, favorable, etc.).

Often these indicators are mentioned when the chemical properties of substances are already considered. However, you can specify them in the physical section, which will not be a mistake.

Chemical properties of substances

This group includes all possible types of interactions of the molecule in question with other simple and complex substances. That is, it is directly chemical reactions. For each type of connection, they are strictly specific. However, general group properties are distinguished for a whole class of substances.

For example, all acids are able to react with metals according to their position in the electrochemical series of metal stresses. Also for all reactions of neutralization with alkalis, interaction with insoluble bases are characteristic. However, concentrated sulfuric and nitric acids are special, since the products of their interaction with metals differ from those obtained as a result of reactions with other representatives of the class.

There are a lot of chemical properties for each substance. Their number is determined by the activity of the compound, that is, the ability to react with other components. There are highly reactive, there are almost inert. This is a strictly individual indicator.

Simple substances

These include those that consist of one type of atoms, but of different numbers. For example, S 8, O 2, O 3, Au, N 2, P 4, CL 2, Ar, and others.

The chemical properties of simple substances are reduced to the interaction with:

  • Metals;
  • Nonmetals;
  • Water;
  • Acids;
  • Alkalis and amphoteric hydroxides;
  • Organic compounds;
  • Salts;
  • Oxides;
  • Peroxides and anhydrides and other molecules.

Again, it should be pointed out that this is a narrowly specific characteristic for each specific case. Therefore, the physical and chemical properties of simple substances are considered individually.

Complex substances

This group includes such compounds, the molecules of which are formed by two or more different chemical elements. The number of each of them can be different. For understanding, here are a few simple examples:

  • H 3 PO 4 ;
  • K 3 [Fe (CN) 6 ];
  • Cu (OH) 2 ;
  • LiF;
  • AL 2 O 3 and others.

Since they all belong to different classes of substances, it is impossible to single out general physical and chemical characteristics for all. These are specific properties, peculiar and individual in each case.

Inorganic substances

For today there are more than 500 thousand. There are both simple and complex. In total, there are several basic classes of inorganic compounds that represent all of their diversity.

  1. Simple substances are metals.
  2. Oxides.
  3. Simple substances are non-metals.
  4. Noble or inert gases.
  5. Peroxides.
  6. Anhydrides.
  7. Volatile hydrogen compounds.
  8. Hydrides.
  9. Salt.
  10. Acids.
  11. Grounds.
  12. Amphoteric connections.

Any representative of each of the classes has its own set of physico-chemical properties that make it possible to distinguish it among other compounds and to identify it.

Properties of organic substances

Organic is a branch of chemistry that deals with the study of compounds other than inorganic compounds and their properties. At the heart of their structure lie carbon atoms, capable of connecting with each other in various structures:

  • Linear and branched chains;
  • Cycles;
  • Aromatic rings;
  • Heterocycles.

Living organisms are composed of such compounds, because the basis of life is proteins, fats and carbohydrates. All of them are representatives of organic substances. Therefore, their properties are special. However, in any case, regardless of which molecule is involved, it will still be characterized by a certain set of physico-chemical properties, which we have already mentioned.

What is living matter?

The living substance is the substance from which the entire biomass of our planet is composed. That is, those organisms that make up life on it:

  • Bacteria and viruses;
  • Protozoa;
  • plants;
  • Animals;
  • Mushrooms;
  • people.

Since the main part of the compounds in the composition of a living being is organic, it is them that can be attributed to a group of living matter. However, not all. Only those without which the existence of representatives of the living biosphere is impossible. These are proteins, nucleic acids, hormones, vitamins, fats, carbohydrates, amino acids and others. The term "living matter" was introduced by Vernadsky, the founder of the theory of the biosphere of the planet.

Properties of living matter:

  • Possession of energy with the possibility of its transformation;
  • Self-regulation;
  • Voluntary movement;
  • Alternation of generations;
  • Extreme diversity.

Crystals and metallic substances

Crystalline refers to all compounds having a certain type of structure of the spatial lattice. There are compounds with an atomic, molecular or metallic crystal lattice. Depending on the type, the properties of the crystalline substances also differ . Typical solid compounds having the form of fine or coarse-grained crystals are various salts.

There are also simple substances with a similar structure, for example, diamond or graphite, precious and semiprecious stones, minerals, rocks. The main properties of them:

  • hardness;
  • Fragility;
  • Average melting and boiling points.

However, as always, each characteristic can not be suitable for everyone.

Metallic properties of the substance are exhibited by metals, their alloys. For them, you can select a set of common characteristics:

  • Ductility and ductility;
  • High boiling point, melting point;
  • Electrical and thermal conductivity;
  • Metallic sheen.

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