Electricity
In chemistry, the concept is widely applied. electricity (EO).
The property of atoms of this element is delayed by electrons from atoms of other elements in compounds is called electronegathy.
Electricity of lithium is conditionally adopted per unit, the EO of other elements is calculated accordingly. There is a scale of EO elements values.
Numeric values \u200b\u200bof EO elements have approximate values: this is a dimensionless value. The higher the EO element, the brighter it is manifested non-metallic properties. By EO elements can be written as follows:
$ F\u003e O\u003e CL\u003e br\u003e s\u003e p\u003e c\u003e h\u003e si\u003e al\u003e mg\u003e ca\u003e na\u003e k\u003e cs $. The greatest value of EO has a fluorine.
Comparing the values \u200b\u200bof EO elements from France $ (0.86) $ to fluorine $ (4.1) $, it is easy to see that the EO is subordinate to the periodic law.
In the periodic system of EO elements in the period, it grows with an increase in the element number (left to right), and in the main subgroups - decreases (from top to bottom).
In periods as the charges of atoms increase, the number of electrons on the outer layer increases, the radius of atoms is reduced, so the ease of electron recoil decreases, the EO increases, therefore, non-metallic properties are increasing.
Degree of oxidation
Complex substances consisting of two chemical elements, Call binary (from lat. bi - two), or two-element.
Recall typical binary compounds that were brought as an example to consider the formation mechanisms of ion and covalent polar communication: $ NaCl $ - sodium chloride and $ HCl $ - chloride. In the first case, the ionic connection: the sodium atom handed its outer electron atom of chlorine and turned into an ion with a charge of $ + $ 1 $, and the chlorine atom accepted the electron and turned into an ion with a charge of $ -1 $. Schematically, the process of converting atoms into ions can be depicted as follows:
$ (Na) ↖ (0) + (CL) ↖ (0) → (Na) ↖ (+1) (CL) ↖ (-1) $.
The molecule of $ HCl $ communication is formed by pairing unpaired external electrons and the formation of a general electron pair of hydrogen atoms and chlorine.
It is more correct to present the formation of a covalent bond in the chlorine-producing molecule as overlapping the one-electron $ s $ -oudoise atom of the hydrogen atom by the one-electron $ p $ -profly the chlorine atom:
With chemical interaction electronic para shifted towards a more electronegative chlorine atom: $ (H) ↖ (Δ +) → (CL) ↖ (Δ -) $, i.e. The electron will not completely switch from the hydrogen atom to the chlorine atom, and partly, thereby determining the partial charge of atoms $ δ $: $ H ^ (+ 0.18) CL ^ (- 0.18) $. If you imagine that in the $ HCl $ molecule, as in $ NaCl $ chloride, the electron completely switched from the hydrogen atom to the chlorine atom, they would get charges $ + 1 $ and $ -1 $: $ (H) ↖ (+1) (CL) ↖ (-1). Such conditional charges are called degree of oxidation. In determining this concept, it is conventionally assumed that in covalent polar compounds, the binders of electrons fully moved to a more electronegative atom, and therefore compounds consist only of positive and negatively charged atoms.
The degree of oxidation is the conditional charge of the atoms of the chemical element in the compound calculated on the basis of the assumption that all compounds (and ionic, and covalently polar) consist only of ions.
The degree of oxidation may have a negative, positive or zero value, which is usually placed on the element symbol from above, for example:
$ (Na_2) ↖ (+1) (s) ↖ (-2), (mg_3) ↖ (+2) (n_2) ↖ (-3), (H_3) ↖ (-1) (N) ↖ (-3 ), (CL_2) ↖ (0) $.
The negative value of the degree of oxidation has those atoms that accepted electrons from other atoms or to which general electronic pairs are shifted, i.e. Atoms of more electronegative elements.
The positive value of the degree of oxidation has those atoms that give their electrons to other atoms or from which general electronic pairs are drawn, i.e. Atoms are less electronegative elements.
The zero value of the degree of oxidation has atoms in molecules of simple substances and atoms in free state.
In the compounds, the total degree of oxidation is always zero. Knowing this and the degree of oxidation of one of the elements, you can always find the degree of oxidation of another element according to the binary connection formula. For example, find the chlorine oxidation degree: $ CL_2O_7 $. Denote the degree of oxygen oxygen: $ (CL_2) (O_7) ↖ (-2) $. Consequently, seven oxygen atoms will have a general negative charge of $ (- 2) · 7 \u003d -14 $. Then the total charge of two chlorine atoms is $ + 14 $, and one chlorine atom $ (+ 14): 2 \u003d + $ 7.
Similarly, knowing the degrees of oxidation of elements, it is possible to form a compound formula, for example, aluminum carbide (aluminum and carbon compounds). We write the signs of aluminum and carbon nearby - $ ALC $, and first - the sign of aluminum, because This is a metal. We define the number of external electrons on the table of the Mendeleev elements: a $ al $ is $ $ 3 an electron, in $ with $ - $ 4 $. The aluminum atom will give its three an electron coating with carbon and will receive the degree of oxidation of $ + $ 3, equal to the ion charge. The carbon atom, on the contrary, will take the missing $ 4 $ 4 $ an electron to the "cherished eight" and will receive a degree of oxidation of $ -4 $. We write these values \u200b\u200bin the $ ((AL) ↖ (+3) (c) ↖ (-4)) $ and find the lowest total multiple for them, it is equal to $ 12. Then we calculate the indexes:
Valence
Very important in the description chemical structure organic compounds has a concept valence.
Valence characterizes the ability of atoms of chemical elements to the formation of chemical bonds; It determines the number of chemical bonds that this atom is connected to other atoms in the molecule.
The valence of the atom of the chemical element is determined primarily by the number of unpaired electrons participating in the formation of a chemical bond.
The valence capabilities of atoms are determined:
- the number of unpaired electrons (single-electron orbitals);
- the presence of free orbital;
- the presence of marginal electrons.
IN organic chemistry The concept of "valence" replaces the concept of "the degree of oxidation", with which it is familiar to working in inorganic chemistry. However, this is not the same thing. The valence does not have a sign and cannot be zero, while the degree of oxidation is necessarily characterized by the sign and may have a value equal to zero.
Valence and degree of oxidation
Valence - the ability of atoms of this element to attach a certain number of atoms of other elements.
The hydrogen atom will never attach more than one atom of another element. Therefore, the valence of hydrogen was taken per unit of measuring the valence of elements.
For example, in compounds: HCl - chlorine is monovalent, H 2 O - oxygen bivalent, NH 3 - nitrogen trivalent, CH 4 - carbon tetravalenten. In these compounds, the valence of elements we determine by the formulas of hydrogen compounds - this valuation of hydrogen.
Oxygen always has valence two. If we know the formula of compounds of elements with oxygen, then you can determine oxygen valence. For example, in the following compounds, elements have such valence (marked with Roman numbers):
The task:Determine the valence of elements.
II III IV V VI VII
Na 2 O, Cao, Al 2 O 3, CO 2, P 2 O 5, CRA 3, Mn 2 O 7.
If we know the valence of elements, we can easily make a formula of a substance that consists of two elements. For example, if the substance consists of magnesium (valence two) and chlorine (valence one), then the formula, MGCl 2 substance.
In molecule complex substance A. X.B. y.which consists of element A with valence p and element in valence m., the product of valence on the number of atoms of one element is equal to the product of valence to the number of atoms of another element: pC \u003d TU. For example, in the Al 2 O 3 molecule, the product of aluminum valence on the number of atoms is equal to the product of the oxygen valence by the number of its atoms (3 '2 \u003d 2' 3).
Valence is an important qualitative characteristic of the element.
Graphic image of formulas. Formulas molecules can be depicted graphically. In graphic images of formulas, every valence is denoted by means. For example, a graphic image of the formula
H 2 O (water molecules) H - O - H,
cO 2 formulas (carbon monoxide, (iv)) O \u003d C \u003d O,
al 2 O 3 formulas (aluminum oxide) O \u003d A1 - O - Al \u003d O.
The electronic theory of the structure of the atom explained the physical meaning of valence and structural formulas.
The valence of the element is determined by the number of common electronic pairs that bind the atom of this element with other atoms.
Valence can not be negative and cannot be zero. The concept of "valence" can be used only to covalent bond compounds.
To characterize the state of the atom in the connection, the concept of "oxidation" is used.
The degree of oxidation is the conditional charge of the atom in the molecule, which would arise on the atom, if the general electronic pairs were completely shifted to a more electronegative atom (that is, atoms would turn into ions).
The degree of oxidation is not always numerically equal to valence. To determine the degree of oxidation of each element in the connection you need to remember the following:
1. The degree of oxidation of the atom in the molecule can be zero or expressed by a negative or positive number.
2. The molecule is always electronic: the sum of positive and negative formal charges, which characterize the degree of oxidation of atoms forming the molecule is zero.
3. The degree of hydrogen oxidation in all compounds, with the exception of metal hydrides (NAH, KH, CAH 2, etc.), equal to + 1. In the hydrides of the metals, its degree of oxidation is equal to 1.
4. The degree of oxidation of oxygen in most compounds is - 2. Exceptions are:
a) peroxides of type H 2 O 2, Na 2 O 2, BaO 2, in which the degree of oxidation of oxygen is equal to 1; And his valence is two (H - O - Oh ¾ H,
Na - O - O - Na).
b) Superoxides of type KO 2, RBO 2, CSO 2, in which the degree of oxidation
-1 has a complex senker ion [o 2] -1 and, therefore, formally the degree of oxidation of the oxygen atom is - ½;
c) Ozonidis type KO 3, RBO 3, CSO 3, in which the degree of oxidation -1 has a complex ozonide ion [o 3] -1 and, therefore, formally the degree of oxidation of the oxygen atom is 1/3;
d) mixed peroxide-naval oxide compounds of type m 2 o 3 (m 2 o 2 × 2m 2), where m - k, rb, cs, in which oxygen atoms are formally characterized by the degrees of oxidation -1 and - ½;
e) oxide F 2 O and peroxide F 2 O 2 fluorine, in which the degree of oxidation of oxygen atoms is respectively +2 and +1.
5. The degree of oxidation of atoms in simple substances equal to zero:
C1 2, H 2, N 2, P 4, S 8.
6. The degree of oxidation of metals atoms in the compounds is always positive. At the same time, many of them have a constant degree of oxidation. For example, alkali metal atoms (Li, Na, K, Rb, CS, FR) in all compounds have an oxidation degree of + 1, and alkaline-earth metals atoms (CA, SR, BA, RA) are oxidation degrees +2.
7. The degrees of oxidation of many elements of variables.
For example, the degree of sulfur oxidation in hydrogen sulfide H 2 S is - 2, in sulfur oxide (IV) SO 2 + 4, in sulfur oxide (VI) SO 3 + 6.
8. The highest degree of element oxidation is usually equal to the number number in which the element is located in the periodic system of elements.
For example, MG magnesium is in the second group and its highest degree of oxidation is + 2. The MN manganese is located in the seventh group and its highest degree of oxidation is + 7.
9. Knowing the degrees of oxidation of some elements, you can determine the degree of oxidation of other elements in this connection. For this, it is necessary to remember that the algebraic sum of the oxidation of all elements in the compound (taking into account the number of atoms) is always zero.
For example, we define the degree of oxidation of nitrogen in nitric acid HNO 3 and in nitrate acid HNO 2. In nitric acid, the degree of hydrogen oxidation +1, oxygen -2, the degree of oxidation of nitrogen x:
1 +x. + (-2 '3) \u003d 0,
In nitrogenous acid degree of nitrogen oxidation:
1 + x. + (-2 '2) \u003d 0,
The ability of the chemical element atom to attach or replace a certain number of atoms of another element to form a chemical bond is called the element valence.
Valence is expressed by a whole positive number lying in the interval from I to VIII. Valence, equal to 0 or more VIII. Permanent valence Expose hydrogen (I), oxygen (II), alkali metals - elements of the first group the main subgroup (I), alkaline earth elements - elements of the second group of the main subgroup (II). Atoms of other chemical elements exhibit a variable valence. So, transition metals - elements of all side subgroups - Show from I to III. For example, iron in compounds can be two or trivalent, copper - single and bivalent. Atom of the remaining elements may exhibit valence in compounds equal to the number of the group and intermediate valence. For example, the highest sulfur valence is equal to IV, lower - II, and intermediate - I, III and IV.
Valency is equal to the number of chemical bonds that a chemical element atom is associated with the atoms of other elements in chemical compound. Chemical bond is denoted by a dash (-). Formulas that show the order of the compound of atoms in the molecule and the valence of each element are called graphic.
Degree of oxidation - This is the conditional charge of an atom in the molecule, calculated under the assumption that all links are of ionic character. This means that a more electronegative atom, shifting a completely one electron pair, acquires 1-. The non-polar covalent bond between the same atoms does not give the contribution to the degree of oxidation.
To calculate the degree of oxidation of the element in the compound, it should be processed from the following provisions:
1) the degree of oxidation of elements in simple substances is taken equal to zero (Na 0; O 2 0);
2) the algebraic amount of degrees of oxidation of all atoms included in the molecule is zero, and in the complex ion, this amount is equal to the ion charge;
3) the constant degree of oxidation have atoms: alkali metals (+1), alkaline earth metals, zinc, cadmium (+2);
4) the degree of hydrogen oxidation in compounds +1, except for metal hydrides (NaH, etc.), where the degree of hydrogen oxidation -1;
5) The degree of oxidation of oxygen in compounds -2, except for peroxides (-1) and oxygen fluoride of 2 (+2).
The maximum positive degree of element oxidation usually coincides with its group number in the periodic system. The maximum negative degree of oxidation of the element is equal to the maximum positive degree of oxidation minus eight.
The exception is fluorine, oxygen, iron: their highest degree of oxidation is expressed by the number, the value of which is lower than the number of the group to which they relate. At the elements of the copper subgroup, on the contrary, the highest degree of oxidation is greater than the unit, although they refer to the I group.
Atoms of chemical elements (except for noble gases) can interact with each other or with atoms of other elements forming B.M. Complex particles - molecules, molecular ions and free radicals. Chemical Communication is due electrostatic forcesbetween atoms , those. Forces of the interaction of electrons and nuclei of atoms. In the formation of chemical bond between atoms, the main role is played valence electrons. Electrons located on the outer shell.
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All the themes of this section:
Part I. Theoretical Chemistry
Chapter 1. Basic concepts and laws of chemistry ............................................ ......................................... 3 Chapter 2. Building atom and Periodic Law .................
Part II. INORGANIC CHEMISTRY
Chapter 11. The most important classes of inorganic compounds ........................................... ........... 55 Chapter 12. Elements of group I (hydrogen, lithium, sodium, subgroup
Part III. ORGANIC CHEMISTRY
Chapter 20. The overall characteristics of organic compounds ........................................... .......... 124 Chapter 21. Alkans ................................... .........
The main positions of atomic molecular theory
1. All substances consist of molecules. The molecule is the smallest particle of a substance with its chemical properties. 2. Molecules consist of atoms. Atom - the smallest particle
The law of equivalents - for molecular compounds the number of components of the elements is proportional to their chemical equivalents.
Equivalent (E) - a particle of a substance that in this acid-base reaction is equivalent to one hydrogen ion or in this oxidative and reductive reaction one
Gas laws
Study of the properties of gas different substances and chemical reactions with gases played such an important role in becoming atomic molecular theorythat gas laws deserve joint ventures
Charles Act: With a constant volume, the gas pressure varies directly proportional to the absolute temperature.
P1 / t1 \u003d p2 / t2, or p / t \u003d const. These three laws can be combined into one universal gas
Models of the structure of the atom
The direct proof of the complexity of the structure of the atom was the discovery of spontaneous decay of atoms of certain elements, called radioactivity (A. Becquer, 1896). That followed
Quantum numbers of electrons
The main quantum number P determines the total energy of the electron on this orbital (n \u003d 1, 2, 3, ...). The main quantum number for atoms is
Electronic configurations atoms
Since the chemical reactions of the core of the reactant atoms remain unchanged (with the exception of radioactive transformations), the chemical properties of atoms depend on the structure of their ele
Pauli principle or Pauli prohibition (1925): There can be no two electrons in the atom with the same properties.
Since the properties of electrons are characterized by quantum numbers, the Pauli principle is often formulated as: in the atom there can be no two electrons, in which all four quantum numbers would be one
The core of the atom and radioactive transformations
Along with the chemical reactions in which only electrons take part, there are various transformations in which the cores of atoms (nuclear reactions) are subjected to change.
Periodic law
Opened in 1869 D.I. Mendeleev Periodic law It is one of the fundamental laws in modern natural science. Placing all the elements in ascending order atomic masses D.
Covalent Communication - Communication carried out by the formation of electronic pairs, to the same extent belonging to both atoms.
N · + · n® n: n or n - n
Communication is called the bond arising from the generalization of electronic clouds of two atoms if the clouds overlap along the line connecting atoms.
But in the acetylene molecule in each of the carbon atoms, there are still two P-electrons, which do not take part in the formation of σ-links. Acetylene molecule has a flat line
Combination can be called a covalent bond formed by overlapping atomic orbitals outside the line connecting atoms.
σ-bonds are more durable than π-bonds, which explains the large reactivity of unsaturated hydrocarbons compared with the limit. Another kind of g
Ion communication
Ion communication - Electrostatic attraction between ions formed by the complete shift of the electronic pair to one of the atoms. Na +.
Metal communication
Metals combine properties that have a general nature and differing from the properties of other substances. These properties are relatively high temperatures melting, ability to
Intermolecular interactions
Electrically neutral atoms and molecules are capable of additional interaction with each other. Hydrogen bond - the relationship between positively
Units of temperature measurement T, pressure P and volume V.
When measuring the temperature, two scales are most often used. The absolute temperature scale uses Kelvin (K) as a unit. In absolute scale zero point (0 k) n
Chemical thermodynamics
Chemical thermodynamics answers questions about the principal possibility of flowing in this chemical reaction under certain conditions and about the final equilibrium system of the system
Reactions, as a result of which enthalpy increases (ΔH\u003e 0) and the system absorbs heat from the outside (QP< 0) называются эндотермическими.
So, the oxidation of glucose oxygen occurs with the release of a large amount of heat (Qp \u003d 2800 kJ / mol), i.e. This process is exothermic. The corresponding thermochemical u
The speed of the chemical reaction is determined by the amount of substance that has reacted into a unit of time per unit volume.
V \u003d ΔC / Δτ mol / (L · C) The reaction rate depends on the nature of the reactant substances and on the conditions in which the reaction proceeds. The most important of them are
Reversible and irreversible reactions. State of chemical equilibrium
Chemical reaction does not always "reach to the end", i.e. The initial substances are not always completely converted to the reaction products. This is because as products accumulate
A condition in which the rate of reverse reaction becomes equal to the rate of direct reaction, is called chemical equilibrium.
The condition of the chemical equilibrium of reversible processes is quantitatively characterized by a equilibrium constant. So for reversible chemical reaction: AA + BW
Ideal and real solutions. Dissolution as a physico-chemical process
Two main solutions are known: physical and chemical. The physical theory of solutions is proposed by Vant-Hoff and Arrhenius. According to this theory, solvent
The dependence of the solubility of various substances from the nature of the solvent, temperature and pressure
The solubility of substances in various solvents, for example in water, fluctuates widely. If in 100 g of water at room temperature dissolves more than 10 g of things
Laws of diluted solutions
When dissolved in a non-flutter solvent, the pressure of the solvent pair over the solution decreases, which causes an increase in the boiling point of the solution and a decrease in temperature
Methods for expressing the concentration (composition) of solutions
Quantitative composition The solution is most often expressed by the concept of "concentration", i.e. The content of the dissolved substance in a unit of mass or volume. eleven.
Electrolytes and electrolytic dissociation
Electric current solutions are called electrolyte solutions. There are two main reasons for the passage of electric current through conductors: either by transferring
Optical and molecular kinetic properties of dispersed systems
Optical property of colloidal systems - opalescence, i.e. Dispersion of light by small particles, leading, in particular, to the emergence of the Faraday-Tyndal effect
Surface and adsorption phenomena
The differences in the composition and structure of contacting phases, as well as the nature of molecular interactions in their volume, determine the occurrence of a peculiar molecular power field on the surface of the difference
Colloid (colloid-dispersed) systems
Colloidal systems (eval) are heterogeneous systems consisting of particles of the size of about 10-7-10-9 m. In terms of particles, colloid systems occupy
Redox reactions - reactions accompanied by a change in the degree of oxidation of elements included in the reacting substances.
The degree of oxidation is the conditional charge of the atom in the molecule, calculated from the assumption that the molecule consists of ions and in general e-mail. Substance
The electrochemical reaction of the reduction oxidation can be carried out so that the electrons will move from the reducing agent to the oxidizing agent in the form of an electric current, i.e. There will be conversion x
Corrosion Metals
Corrosion - the destruction of metals as a result of a chemical or electrochemical environmental impact. Corrosion - spontaneous process leaking with a decrease with
Electrolysis
Electrolysis is a redox process that flows on the electrodes by passing a constant electric current through a solution or melt of an electrical
Electrolysis of electrolyte melts
Electrolyte melt electrolysis circuit: KTAN ↔ KTN + + ANM- Cathode- | KTN +.
Electrolysis of aqueous solutions of electrolytes
Electrolysis of solutions differs from electrolysis of electrolyte melts by the presence of water molecules, which can also participate in oxidative-reducing electrolysis reactions. Due to
Water is restored restored water and metal cations restored metal cations
Anode process: 1. On insoluble anodes in competition of anion oxygenic acids (CL-, BR-, I-, S2-
Qualitative analysis
The task of high-quality analysis-identification chemical composition The compound under study. Qualitative analysis is carried out by chemical, physical and physico-chemical
Quantitative analysis
The task of quantitative analysis is determining the quantitative content of chemical elements (or their groups) in compounds. Methods of quantitative ana
Acid
An acid is called a compound that forms during dissociation in aqueous solution of positive ions only hydrogen ions H + (by electrolytic theory
Hydrogen
Hydrogen - the first element and one of the two representatives of the period I Periodic system. The hydrogen atom consists of two particles - proton and electron, between which there are only attraction forces. IN
Beryllium
In all stable compounds, the degree of oxidation of beryllium +2. The content of beryllium in the earth's crust is small. Major Minerals: Beerill BE3AL2 (SiO
Aluminum
Aluminum is a typical amphoter element, the degree of oxidation is most typical. Unlike boron, not only anionic, but also cationic complexes are characteristic.
Lantanoids
The Lantanoid family includes CERIES CE 4F25S25P65D06S2, PRASODYM PR 4F3, Neodymium ND 4F4, and
Aktinoids
The Aktinoid family includes thorium TH 5F06S26P66D27S2, Protactivity PR 5F2 6D17S2
Carbon
In most inorganic compounds, carbon exhibits the degree of oxidation -4, +4, +2. In nature, the carbon content is 0.15% (they say. Shares) and is mainly in
Silicon
Silicon in compounds has oxidation degree +4 and -4. For him, the most characteristic of Si-F and Si-oh-oh-o. On the prevalence on earth 20% (mol. Share) silicon is inferior
Oxygen
Like Fector, oxygen forms connections with almost all the elements (except helium, neon and argon). The degree of oxygen oxidation in the overwhelming majority of compounds is -2. Chrome
Formulas of organic compounds
The molecular formula reflects the qualitative and quantitative elemental composition of the substance. In the molecular formula, they first write carbon atoms, then hydrogen atoms, then -
Nomenclature of organic compounds
Currently, the systematic nomenclature of the Jewberry (IUras is the International Union of Theoretical and Applied Chemistry). Among options
Isomerius of organic compounds
Isomeria - the existence of different substances with the same molecular formula. This phenomenon is due to the fact that the same atoms can interconnect differently
And the reactivity of organic compounds
The chemical properties of atoms included in the molecules are changing depending on which other atoms they are connected. The most affected by each other directly related atoms, however
General characteristics of organic reactions
The classification of organic reactions may be based on various principles. I. Classification of chemical reactions according to the result of chemical transformation: 1.
Industrial production of organic compounds
The increasing role of organic compounds in modern world It causes the need to create industrial production capable of producing them in sufficient quantity. For such production
Nomenclature and isomeria
Alkans are saturated, or limit, hydrocarbons, since all free valence of carbon atoms are occupied (completely "saturated") atoms of hydrogen. Simplest Pr.
Physical properties
Under normal conditions, the first four members of the homologous series of alkanes (C1 - C4) are gases. Normal alkanes from pentane to heptadekan (C5 - C17) - fluids
Methods for getting
The main natural sources of alkanan - oil and natural gas. Various oil fractions contain alkanes from C5H12 to C30H62. Natural gas consists of methane
Chemical properties
Under normal conditions, alkanes are chemically inert. They are resistant to many reagents: do not interact with concentrated sulfur and nitric acids, with concentrated and molten
Nomenclature and isomeria
Cycloalkanes are limiting cyclic hydrocarbons. The simplest representatives of this series: common
Chemical properties
Poche properties are small and conventional cycles differ significantly among them. Cyclopropin and cyclobutane are prone to attachment reactions, i.e. Similar in this respect with alkenes. Cyclopentan I.
Nomenclature and isomeria
Alkenes are uninhabited hydrocarbons whose molecules contain one double bond. The first representative of this class is ethylene CH2 \u003d CH2,
Obtaining
In nature, alkenes are rare. Since alkenes are valuable raw materials for industrial organic synthesis, many methods of their preparation have been developed. 1. The main industrial isto
Chemical properties
The chemical properties of alkenes are determined by the presence in their double-bond molecules. The electronic density of π-bond is quite mobile and easily reacts with electric floors.
Application
Lower alkenes are important source substances for industrial organic synthesis. Ethyl alcohol, polyethylene, polystyrene receive from ethylene. Propen is used for polypropylene synthesis, phenol,
Nomenclature and isomeria
Alkadians are unsaturated hydrocarbons containing two double bonds. The total formula of alkadienne CNN2N-2. If double bonds are divided into carbon circuit
Obtaining
The main industrial method of obtaining dienes is dehydrogenation of alkanes. Butadiene-1.3 (Divinyl) is obtained from Bhutan:
Chemical properties
For alkadiennes are characterized by conventional reactions of electrical connection aue, characteristic of alkenes. The peculiarity of conjugate diene is that two double bonds in their
Nomenclature and isomeria
Alkins are called unsaturated hydrocarbons whose molecules contain one triple connection. General formula of the homologous series of alkinov CNN2
Physical properties
Physical properties Alkins are similar to the properties of alkanes and alkenes. Under normal conditions (C2 - C4) - gases, (C5 - C16) - liquids, starting with C17
Obtaining
1. The general method of obtaining alkins is the cleavage of two halogen hydrogen molecules from digalohenans, which contain two halogen atoms or in neighboring, or in one carbon atom, under
Chemical properties
The chemical properties of alkins are due to the presence in their triple bond molecules. Typical reactions for acetylene and its homologues are the reactions of electrophile accession AE
Application
On the basis of acetylene, many industries of organic synthesis developed. The above mentioned the possibility of obtaining acetic aldehyde from acetylene and various ketones of acetyl homologues
Nomenclature and isomeria
Aromatic hydrocarbons (arena) refer to substances in which one or more benzene rings are contained - cyclic groups of carbon atoms with
Physical properties
The first members of the homologous series of benzene are colorless liquids with a specific smell. They are lighter than water and are not soluble in it. Well soluble in organic solvents and themselves are choir
Methods for getting
1. Preparation from aliphatic hydrocarbons. To obtain benzene and its homologs in the industry, the aromatization of limit hydrocarbons included in the oil is used. When pro
Chemical properties
The aromatic core with a mobile system of π-electrons is a convenient object for the attack by electropal reagents. This also contributes to the spatial location
Rules of orientation (substitution) in the benzene ring
The most important factor determining the chemical properties of the molecule is the distribution of electron density in it. The nature of the distribution depends on the mutual influence of atoms. In molecules
Application
Aromatic hydrocarbons are essential raw materials for the synthesis of valuable substances. Phenol, aniline, styrene, from which, in turn, receive phenol formaldehyde resins, dyes, polisol
Nomenclature and isomeria
The total formula of the homologous series of limit monohydric alcohols is CNH2N + 1OH. Depending on what carbon atom is hydroxyl gru
Obtaining
1. A general method of obtaining alcohols, which has industrial importance - hydration of alkenes. The reaction goes when the alkene is passing with water vapors over the phosphate acid catalyst (H3PO
Chemical properties
The chemical properties of alcohols are determined by the presence in their group molecules -on. Communication C-O and O-N are very polar and capable of rupture. Distinguish two basic types of alcohol reactions with participation
Reactions with a break-up O-N.
1. Acid properties of alcohols are very weak. Lower alcohols are rapidly reacting with alkaline metals:
Reactions with a break of communication C-O.
1) The dehydration reactions occur when heating alcohols with water-based substances. With strong heating, intramolecular dehydration occurs with the formation of alkenes:
Application
Alcohols are mainly used in the industry of organic synthesis. Methyl alcohol3on - a poisonous liquid of boiling temperature 65 ° C, easily mixed
Chemical properties
For two and truchatic alcohols, the main reactions of single-butym alcohols are characteristic. One or two hydroxyl groups can participate in the reactions. The mutual effect of hydroxyl groups is manifested in
Application
Ethylene glycol is used for the synthesis of polymeric materials and as antifreeze. In large quantities, it is also used to obtain dioxane, important (albeit toxic) laboratory
Physical properties
Phenols are mostly crystalline (meta-cresol - liquid) at room temperature. They have a characteristic odor, quite poorly soluble in cold water,
Methods for getting
1. Preparation from halogenbenzenes. When the chlorobenzene and sodium hydroxide is heated under pressure, sodium phenolines are obtained, with further processing of which phenol is formed by acid:
Chemical properties
In phenols, the p-orbital of the oxygen atom forms a single π system with an aromatic ring. Due to this interaction, electron density at an oxygen atom decreases, and in benzene count
Nomenclature and isomeria
Organic compounds, in the molecule of which there is a carbonyl group, called carbonyl
Obtaining
1. Hydration of alkins. Aldehyde is obtained from acetylene, from his homologues - ketones: due to
Chemical properties
The chemical properties of aldehydes and ketones are determined by the fact that the composition of their molecules includes a carbonyl group with a polar double bond. Aldehydes and ketones - chemically active compounds
Application
Formaldehyde - gas with a sharp annoying smell. 40% aqueous solution of formaldehyde is called formalin. Formaldehyde is obtained in industry on large oxidation of methane or methanol
Nomenclature and isomeria
Carboxylic acids are called compounds, containholderboxyle group
Physical properties
Saturated aliphatic monocarboxylic acids form a homologous series, which is characterized by the general formula CNH2N + 1COOH. Lower members of this series are common
Obtaining
1. Oxidation of primary alcohols is a general method for producing carboxylic acids. As oxidants, use KMNO4 and K2SR2O7.
Chemical properties
Carboxylic acids are stronger acids than alcohols, since a hydrogen atom in the carboxyl group has increased mobility due to the influence of the group -o. In aqueous solution, carbon ki
Application
Saturated acids. Formic acid nson. The name is due to the fact that the acid is contained in the secretions of ants. Widely used in pharmaceutical and food industrial
Nomenclature and isomeria
Among the functional derivatives of carboxylic acids, esters are occupied by a special place - compounds representing carboxylic acids, in which a hydrogen atom in the carboxyl group is replaced
Physical properties
The esters of lower carboxylic acids and alcohols are volatile, low-soluble or practically insoluble liquid water. Many of them have a pleasant smell. So, for example
Chemical properties
1. The reaction of hydrolysis or washed. The response of esterification is reversible, therefore, in the presence of acids, the reverse reaction will flow, called hydrolysis, to the result
Fats and oils
Among the esters of esters, natural esters are occupied - fats and oils, which are formed by trihatic alcohol glycerin and higher fatty acids with unbranched carbon
Nomenclature and isomeria
The simplest monosaccharide is glycerin aldehyde, C3N6O3: Ost
Physical and chemical glucose properties
Glucose C6H12O6 is white crystals, sweet taste, well soluble in water. In the linear form of the glucose molecule contain one al
Disaccharides
The most important disaccharides are sucrose, maltose and lactose. All of them are isomers and have the Formula C12N22O11, but their structure is different. Molek
Polysaccharides
Molecules of polysaccharides can be considered as a product of polycondensation of monosaccharides. The general formula of polysaccharides (C6H10O5) n. We will consider the most important
Nomenclature and isomeria
The total formula of limit aliphatic amines CNH2N + 3N. Aminov names are usually produced by lifying hydrocarbon radicals (in alphabetical order) and
Physical properties
Methyline, dimethylamine and trimethylamine - gases, average members of an aliphatic series - liquid, higher - solids. Between the amine molecules in the liquid phase are formed weak hydrogen bonds, po
Obtaining
1. The main method of obtaining amines is alkylation of ammonia, which occurs when heated alkyl halides with ammonia:
Chemical properties
1. Due to the presence of an electronic pair on a nitrogen atom, all amines have basic properties, and aliphatic amines are stronger bases than ammonia. Aqueous amine solutions
Aromatic amines
Aniline (phenylamine) C6H5NH2 - a height of class aromatic amines, in which the amino group is directly related to the benzene ring. This St.
Physical properties
Aniline is a colorless oily liquid, a little heavier than water, a little soluble in water, soluble in ethyl alcohol and in benzene. The main way to obtain aniline - the restoration of nitrob
Chemical properties
1. Aniline is a much weaker base than aliphatic amines (Kb \u003d 5.2-10-10). This is explained by the fact that the electronic pair of the nitrogen atom, which causes the OSN
Nomenclature and isomeria
Amino acids are organic bifunctional compounds, which include a carboxyl group -Oson and amino group -NH2. Depending on the mutual location of both functions.
Chemical properties
Amino acids are organic amphoteric compounds. They contain two functional groups of the opposite as part of the molecule: an amino group with basic properties and carboxyl
Peptides.
Peptides can be considered as condensation products of two or more amino acid molecules. Two amino acid molecules can react with each other with the cleavage of water molecule and the formation of products
Chemical properties
1. The destruction of the secondary and tertiary protein structure with the preservation of the primary structure is called denaturation. It occurs when heated, the change in acidity with
Biological significance of proteins
The biological importance of proteins is extremely large. 1. Absolutely, all chemical reactions in the body proceed in the presence of catalysts - enzymes. Even such a simple reaction
Sixted heterocycles
Pyridine C5H5N is the simplest six-membered aromatic heterocycle with one nitrogen atom. It can be considered as an analogue of benzene in which one group of CH for
Five heterocycles
Pyrrol C4H4NH is a five-membered heterocycle with one nitrogen atom.
The structure of nucleic acids
Nucleic acids are natural high-molecular compounds (polynucleotides) that play a huge role in the storage and transfer of hereditary information in living organisms. Molecule
Biological role of nucleic acids
DNA - the main molecule in the living organism. It stores genetic information that transmits from one generation to another. In the DNA molecules in the encoded form, the composition of all proteins organ was recorded
Cytosin Guanin
Thus, the information contained in DNA, as if reprinting into mRNA, and the latter delivers it in ribosomes. 2. Transport RNA (TRNA) transfers amino acids to ribosomams,
General characteristics of polymers
Often general formula Polymers can be written in the form (-x-) n, where the fragment is called an elementary link, and the number N is the degree of polymerization
Plastics
Plastics is called polymer-based materials capable of changing their shape when heated and maintain a new form after cooling. Due to this property of plastics, furs
Fiber
One of the important areas of the use of polymers is the manufacture of fibers and fabrics. Consider two V.
Rubbers
Rubbers are the polymerization products of dienes and their derivatives. Natural rubber is obtained from latex - juice of some tropical plants. His structure can be installed