What is called the substance?

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Everything that surrounds us has the physical and chemical nature.What is called matter and what types of it there?It is a physical substance that has a specific chemical composition.In Latin, the word "substance" is termed Substantia, which is also often used scientists.What does it represent?

Today there are more than 20 million different substances.In the air there are all sorts of gases in the ocean, seas and rivers - water with minerals and salts.The solid skin layer of the planet consists of numerous rocks.The vast number of different substances present in every living organism.

General concepts

In modern chemistry, a substance defined as a form of matter to understand, has a rest mass.It consists of elementary particles or quasiparticles.An essential feature of any substance is its weight.Typically, at relatively low densities and temperatures in its composition more common elementary particles such as electrons, neutrons and protons.The last two atomic nuclei are made.All these elementary particles form such substances, molecules and crystals.In essence, their atomic matter (atoms) is made up of electrons, protons and neutrons.

In terms of biology, "stuff" - the concept of matter, which forms the fabric of any organism.It is part of the organelles that are in cells.In general terms "substance" - is a form of matter that are formed all the physical body.

Properties substances

properties of the substances referred to a set of objective characteristics that define personality.They allow to distinguish one substance from another.The most characteristic physical and chemical properties of the substance:

• density;

• boiling point and melting;

• thermodynamic characteristics;

• chemical properties;

• values ​​of the crystal structure.

All of these parameters are unchanging constants.Since all substances differ from each other, they possess certain physical properties.What is meant by this term?Properties of matter called its features defined by measurement or observation, without transforming it into another substance.The most important are:

• physical state;

• color and luster;

• presence of odor;

• taste;

• solubility or insolubility in water;

• melting and boiling points;

• density;

• electrical conductivity;

• thermal conductivity;

• hardness;

• fragility;

• plasticity.

for crystalline materials is still characterized by physical properties such as shape.Color, taste, smell is determined visually and with the help of the senses.Such physical parameters such as density, melting point and boiling point, conductivity was calculated using various measurements.Details about the physical properties of most substances are presented in specific directories.They depend on the state of aggregation of the substance.Thus, the density of water, ice and steam are quite different.Oxygen in the gaseous state is colorless, and a liquid - is blue.Due to differences of physical properties can be distinguished many substances.Thus, copper - the only metal that has a reddish tint.Only rock salt has a salty taste.In most cases, to determine a substance necessary to consider several notable properties.

ratio concepts

Many people confuse the concept of "chemical element", "atom", "simple matter".In fact, they differ among themselves.Thus, the atom - a concrete concept because it really exists.Chemical element - abstract (collective) definition.In nature it exists only in the form of bound or free atoms.In other words, it is a simple or complex substance.Each chemical element has its own symbol - a sign (symbol).In some cases, it expresses the composition of a simple substance (B, C, Zn).But often, this symbol indicates only the chemical element.This clearly shows the formula of oxygen.So about - it's just a chemical element, and a simple substance of oxygen indicated by the formula O2.

There are other differences between these concepts.One should distinguish between the characteristics (properties) of simple substances that constitute the totality of the particles, and chemical element, which is a certain type of atom.There are some differences in the names.In most cases, the chemical designation of the element and the substance is simple.However, there are exceptions to this rule.

Classification of substances

What is called the substance in terms of science?The number of different substances are very large.Natural substances as defined due to its natural origin, it may be organic or inorganic.Many people have learned to synthesize compounds artificially.The term "agent" refers to simple separation of (individual) substances and mixtures thereof.Relationship classification depends on whether the number included therein.

Defining a simple matter to understand abstract concept, which means a set of atoms bound together by certain physical and chemical laws.Despite this, the boundary between it and the mixture is very vague, because some substances have an unstable structure.For them, not even offered a precise formula.Due to the fact that a simple substance is only attainable end its purity, this concept is an abstraction.In other words, in any of them there is a mixture of chemical elements, in which one predominates.Frequently, the purity of the substance directly affects its properties.More generally constructed of a simple substance of atoms of chemical element.For example, oxygen gas molecule contains 2 identical atoms (O2).

What is called a complex matter?Such chemical compounds include various atoms constituting the molecule.Sometimes it is called a mixed chemical substance.Complex substance mixture called whose molecules are formed from two or more atoms of elements.For example, in the water molecule has one oxygen atom and two hydrogen (H2 O).The notion of complex substance meets molecule containing various chemical elements.Such substances are much more than simple.They may be natural and artificial.

Simple and complex matter, the concept of which is to some extent arbitrary, they differ in their properties.For example, titanium becomes strong only when it is relieved of oxygen to less than one hundredth of a percent.Ethers and substances chemically defined a bit difficult to understand, can be of two types: organic and inorganic.

Inorganics

To include all inorganic chemical compounds that do not contain carbon.This group includes some substances, which is composed of the element (cyanides, carbonates, carbides, oxides of carbon and several other substances).They do not have the characteristic of organic substances skeleton.To name a compound of formula everyone can through the periodic system and high-school chemistry.All of them are designated by Latin letters.What is called the substance in this case?All inorganic substances are divided into the following groups: •

simple substances are metals (Mg, Na, Ca);nonmetals (P, S);noble gases (He, Ar, Xe);amphoterics (Al, Zn, Fe);

• complex: salts, oxides, acids, hydroxides.

Organic substances

Determination of organic matter is quite simple.These substances include chemical compounds, which include those available carbon.This class of substances is the most extensive.However, this rule there are exceptions.Thus, to organic substances does not include the carbon oxides, carbides, carbonates, carbonic acid, cyanides and thiocyanates.

answer to the question "What are organic substances" includes a number of complex compounds.These include amines, amides, ketones, anhydrides, aldehydes, nitriles, carboxylic acids, organic sulfur compounds, hydrocarbons, alcohols, ethers, esters, amino acids.

The main classes of biological organic compounds include lipids, proteins, nucleic acids, carbohydrates.They, in addition to carbon, are composed of hydrogen, oxygen, phosphorus, sulfur, nitrogen.What are the characteristics of organic matter from?Their variety and diversity is explained by the peculiarities of the structure of carbon atoms, which are capable of forming strong bonds with the compound in the chain.In this way a very stable molecule.Carbon atoms form a zigzag chain which is characteristic of organic substances.This molecular structure directly affects the chemical properties.The carbon in organic materials can be combined in the open and cyclic (closed) circuit.

Aggregate states

definition of "substance" in the chemistry does not give full-scale concept of its state of aggregation.They differ by the role played by their existence in the interaction of molecules.There are three aggregate states of matter:

• A solid in which the molecules are firmly connected.Between them established a strong attraction.In the solid state molecular substances are not able to move freely.They may only oscillate.Due to this solids perfectly retain its shape and volume.

• The liquid in which the molecules have more freedom and can move from one place to another.Thanks to these properties, any fluid may take the form of the vessel and flow.

• Gaseous in which the elementary particles of matter moving freely and chaotically.Molecular Communication in this state is so weak that they may be far from each other.The gaseous substance is able to fill a large volume.

For example, the water is easy to understand the difference between ice, liquid and vapor.All of these states of aggregation does not apply to the individual characteristics of the chemical.They correspond to the states only the existence of the substance, independent of the external physical conditions.That is why water can not be unequivocally attributed to a sign of fluid.When conditions change, many chemicals pass from one state to another.In the process, discovered intermediate (borderline) types.The most famous of these is the amorphous state called vitreous.This definition of "substance" in the chemistry associated with its structure (in Greek amorphos - formless).

in physics is considered another aggregate state called plasma.It is completely or partially ionized, and is characterized by equal density of positive and negative charges.In other words, the plasma is electrically neutral.This state of matter occurs only at extremely high temperatures.Sometimes they reach thousands of degrees Kelvin.For some properties is the opposite of the plasma gas.The latter has a low electrical conductivity.The gas consists of particles which are similar to each other.However, they are rarely encountered.Plasma has a high electrical conductivity.It consists of elementary particles of differing electric charge.They constantly interact with each other.

There are also intermediate states of matter such as liquid crystal and polymer (elastomeric).Due to the presence of these transitional forms specialists often use the broader concept of "phase."Under certain circumstances, quite different from the usual, some substances pass into a special state, for example, superconducting and superfluid.

Crystals Crystals are solids having a natural shape of regular polyhedra.It is based on its internal structure and depends on the location of its constituent atoms, molecules and ions.In chemistry, it is called a lattice.Such a structure is individual for each substance, so it is one of the basic physical and chemical parameters.

distances between the particles comprising crystals, called the lattice parameters.They are defined by using physical methods of structural analysis.Often, solids are more than one form of the crystal lattice.Such structures are called polymorphs.Among the simple substances common rhombic and monoclinic form.Such substances include graphite, diamond, sulfur representing hexagonal and cubic modification of carbon.This form of notes and complex substances, such as quartz, cristobalite, tridymite, which is a modification of the silica.

substance as a form of matter

Despite the fact that in its meaning of "substance" and "matter" are very similar, they are not fully equivalent.It is claimed by many scientists.So, at the mention of the term "matter" often involve tough, inert and dead reality exposed to the dominance of mechanical laws.Under the definition of "substance" more aware of material which, due to its shape, is the idea of ​​life and fitness design.

today, scientists believe the matter of objective reality that exists in space, and changes over time.It can be represented in two forms:

• has a first wave nature.It includes weightlessness, constant continuity.It can spread at the speed of light.

• Second - corpuscular having a rest mass.It is composed of elementary particles, differing in their localization.She malopronitsaema or impermeable, and can not be spread with the speed of light.

first form of existence of matter is called the field, and the second - a substance.They have a lot in common, because even the electrons have the properties of particles and waves.They manifest themselves at the microworld.That is why the separation of the field and the substance is very convenient.

unity of substance and field

Scientists have long established that the heavier and larger than the elementary particle of matter, the sharper expressed her personality and delineated.This brightly visible contrast between the substance and the field, which is characterized by continuity.The less elementary particles of matter, the less weight.In this case, the contrast between it and the field becomes more complicated.In various mikrovolneniyah it generally makes no sense, because different elementary particles - photons is excited states of different fields (electromagnetic - photons, nuclear - mesons).

unity of substance and field and the lack of a clear boundary between them is expressed in the fact that under certain conditions the particles arise from the field, and the other cases - on the contrary.A good example of this is the phenomenon of the annihilation (the phenomenon of transformation of elementary particles).Any material body - it is a stable unit, due to the possible connection of elements through the fields.