The composition of matter causes the diversity of substances. One of the reasons for the diversity of organic substances. What does the molecular formula of CH4 show?

Slide 7

At the beginning of the 20th century, a scandalous story took place in a warehouse of military equipment in St. Petersburg: during an audit, to the horror of the quartermaster, it turned out that the tin buttons for soldiers' uniforms had disappeared, and the boxes in which they were stored were filled to the brim with gray powder. And although it was bitterly cold in the warehouse, the unfortunate quartermaster became hot. Still: he, of course, will be suspected of theft, and this promises nothing but hard labor. The poor fellow was saved by the conclusion of the chemical laboratory, where the auditors sent the contents of the boxes: “The substance you sent for analysis is undoubtedly tin. Obviously, in this case, a phenomenon known in chemistry under the name "tin plague" took place. ?

Slide 8

"Tin Plague"

White tin is stable at t0 >130С Gray tin is stable at t0

Slide 9

Allotropy is the ability of atoms of one chemical element to form several simple substances. Allotropic modifications are simple substances formed by atoms of the same chemical element.

Slide 10

Allotropic modifications of oxygen

O2 - oxygen is a colorless gas; has no smell; poorly soluble in water; boiling point -182.9 C. O3 - ozone ("smelling") gas of a pale purple color; has a pungent odor; dissolves 10 times better than oxygen; boiling point -111.9 C; the most bactericidal.

slide 11

Allotropic modifications of carbon

Graphite Diamond Soft Has a gray color Low metallic luster Electrically conductive Leaves a mark on paper. Hard Colorless Cuts glass Refracts light Dielectric

slide 12

Fullerene Carbin Graphene Harder and stronger than diamond, but stretches a quarter of its length like rubber. Graphene does not pass gases and liquids, conducts heat and electricity better than copper. Fine-grained black powder (density 1.9-2 g/cm³), semiconductor.

slide 13

Rhombic sulfur is a type of octahedron with cut corners. Light yellow powder. Monoclinic sulfur - in the form of needle-like crystals of yellow color. Plastic sulfur is a rubbery mass of dark yellow color. Can be obtained in the form of threads.

Slide 14

Allotropic modifications of phosphorus

P (red phosphorus) (white phosphorus) P4 Odorless, does not glow in the dark, is not poisonous! Has a garlic smell, glows in the dark, poisonous!

slide 15

C4H8

Before you is a painting by an unknown artist. The one who offers the most isomers will be able to buy it. Starting price - 2 isomers.

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CH2 \u003d CH - CH2 - CH3 CH2 \u003d C - CH3 Butene-1CH3 2-methylpropene-1 (methylpropene) Butene-2 ​​CH3 CH \u003d CH-CH3 C \u003d C C \u003d C CH3 CH3 CH3 CH3 H H H H H Cis - butene - 2 Trans - butene - 2 H2C CH2 H2C CH2 Cyclobutane H2C CH CH3 CH2 methylcyclopropane

A substance in chemistry is a physical substance with a specific chemical composition. In the philosophical dictionary of Grigory Teplov in 1751, the Latin term Substantia was translated as substance. In modern physics, matter is usually understood as a type of matter consisting of fermions or containing fermions along with bosons; has a rest mass, unlike some types of fields, such as electromagnetic. Usually (at relatively low temperatures and densities) a substance consists of particles, among which electrons, protons and neutrons are most often encountered. The last two form atomic nuclei, and all together - atoms (atomic substance), of which - molecules, crystals, etc. Under certain conditions, such as in neutron stars, quite unusual types of matter can exist. Substance in biology is the matter that forms the tissues of organisms, which is part of the organelles of cells. Inorganic substances - a chemical substance, a chemical compound that is not organic, that is, it does not contain carbon: Salts, Acids, Bases, Oxides. All inorganic compounds are divided into two large groups: Simple substances - consist of atoms of one element; Compound substances - consist of atoms of two or more elements. Simple substances are divided by chemical properties into: metals (Li, Na, K, Mg, Ca, etc.) non-metals (F2, Cl2, O2, S, P, etc.) ; amphoteric simple substances (Zn, Al, Fe, Mn, etc.); noble gases (He, Ne, Ar, Kr, Xe, Rn). According to their chemical properties, complex substances are divided into: oxides: basic oxides (CaO, Na2O, etc.); acid oxides (CO2, SO3, etc.); amphoteric oxides (ZnO, Al2O3, etc.); double oxides (Fe3O4, etc.); non-salt-forming oxides (CO, NO, etc.); Hydroxides; bases (NaOH, Ca(OH)2, etc.); acids (H2SO4, HNO3, etc.); mphoteric hydroxides (Zn(OH)2, Al(OH)3, etc.); salts: medium salts (Na2SO4, Ca3(PO4)2, etc.); acid salts (NaHSO3, CaHPO4, etc.); basic salts (Cu2CO3(OH)2, etc.); double and/or complex salts (CaMg(CO3)2, K3, KFeIII, etc.); binary compounds: oxygen-free acids (HCl, H2S, etc.) oxygen-free salts (NaCl, CaF2, etc.); other binary compounds (AlH3, CaC2, CS2, etc.).Organ. substances - a class of chemical compounds containing carbon (excluding carbides, carbonic acid, carbonates, carbon oxides and cyanides): Amines, Ketones and aldehydes, Nitriles, Organo-sulphur compounds, Alcohols, Hydrocarbons, Ethers and esters, Amino acids organic compounds of biological origin - proteins, lipids, carbohydrates, nucleic acids - contain, in addition to carbon, mainly hydrogen, nitrogen, oxygen, sulfur and phosphorus. That is why "classical" organic compounds contain primarily hydrogen, oxygen, nitrogen and sulfur - despite the fact that the elements that make up organic compounds, in addition to carbon, can be almost any element. Compounds of carbon with other elements constitute a special class of organic compounds - organoelement compounds. Organometallic compounds contain a metal-carbon bond and constitute an extensive subclass of organoelement compounds. There are several important properties that distinguish organic compounds into a separate, unlike anything else, class of chemical compounds. The different topology of the formation of bonds between the atoms that form organic compounds (primarily carbon atoms) leads to the appearance of isomers - compounds that have the same composition and molecular weight, but have different physicochemical properties. This phenomenon is called isomerism. The phenomenon of homology is the existence of series of organic compounds in which the formula of any two neighbors of the series (homologues) differs by the same group - the homological difference CH2. A number of physicochemical properties, in the first approximation, change symbatically in the course of the homologous series. This important property is used in materials science when searching for substances with predetermined properties.

2Preparation of alcohols from saturated and unsaturated hydrocarbons. Industrial synthesis of methanol.

3. Experiment. Realization of transformations: salt - insoluble base - metal oxide.

Sulfuric acid reacts with copper(II) oxide when heated. Cu 2+ ions pass into the solution and give it a blue color.

CuO + H 2 SO 4 \u003d СuSO 4 (copper sulfate salt) + H 2 O,

CuO + 2H + = Сu 2+ + H 2 O.

An alkali solution is added to the filtrate, a blue precipitate is observed:

CuSO 4 + 2NaOH \u003d Cu (OH) 2 (insoluble copper oxide) + Na 2 SO 4,

Cu 2+ + 2OH - \u003d Cu (OH) 2.

when the blue precipitate of copper (II) hydroxide is heated, a black substance is formed - this is copper (II) oxide and water:
Cu(OH)2 = CuO + H2O

1. Higher oxygen-containing chemical elements of the third period, their composition and comparative characteristics of properties.

Phosphorus forms a number of oxygen-containing acids (oxoacids). Some of them are monomeric. for example, phosphinic, phosphorous, and phosphoric(V) (orthophosphoric) acids. Phosphorus acids can be monobasic (single-protonic) or polybasic (multi-protonic). In addition, phosphorus also forms polymeric oxoacids. Such acids may have an acyclic or a cyclic structure. For example, diphosphoric(V) (pyrophosphoric) acid is a dimeric phosphorus oxoacid.

The most important of all these acids is phosphoric(V) acid (its other name is orthophosphoric acid). Under normal conditions, it is a white crystalline substance that deliquesces when it absorbs moisture from the air. Its 85% aqueous solution is called "phosphoric acid syrup". Phosphorous(V) acid is a weak tribasic acid:

Chlorine forms several oxygen-containing acids. The higher the oxidation state of chlorine in these acids, the higher their thermal stability and acid strength:

HOCl< НСlO2 < НСlO3 < НClO4

HClO3 and HClO4 are strong acids, and HClO4 is one of the strongest among all known acids. The remaining two acids only partially dissociate in water and exist in aqueous solution predominantly in molecular form. Among the oxygen-containing acids of chlorine, only HclO4 can be isolated in free form. Other acids exist only in solution.

The oxidizing ability of oxygen-containing acids of chlorine decreases with an increase in its oxidation state:

HOCl and HClO2 are particularly good oxidizing agents. For example, an acidic solution of HOCl:

1) oxidizes iron (II) ions to iron (III) ions:

2) decomposes in sunlight to form oxygen:

3) when heated to approximately 75 ° C, it disproportionates into chloride ions and chlorate (V) ions:

The remaining higher acid-containing acids of the elements of the third period (H3AlO3, H2SiO3) are weaker than phosphoric acid. Sulfuric acid (H2SO4) is less strong than perchloric (VII) acid, but stronger than phosphoric acid. In general, with an increase in the oxidation state of an element that forms an acid, the strength of the acid itself increases:

H3AlO3< H2SiO3 < H3PO4 < H2SO4 < НСlO4

2. General characteristics of macromolecular compounds: composition, structure, reactions underlying their production (for example, polyethylene or synthetic rubber).

3. 3 a da cha. Calculation of the mass of the starting substance, if the practical yield of the product is known and its mass fraction (in percent) of the theoretically possible yield is indicated.

Task. Determine the mass of magnesium carbonate reacted with hydrochloric acid if 8.96 liters of carbon monoxide (IV) were obtained, which is 80% of the theoretically possible yield.

Ticket number 25.

General methods for obtaining metals. The practical significance of electrolysis on the example of salts of anoxic acids.

Metals are found in nature mainly in the form of compounds. Only metals with low chemical activity (noble metals) are found in nature in a free state (platinum metals, gold, copper, silver, mercury). Of the structural metals, only iron, aluminum, and magnesium are found in nature in the form of compounds in sufficient quantities. They form powerful deposits of deposits of relatively rich ores. This makes it easier to harvest them on a large scale.

Since the metals in the compounds are in an oxidized state (have a positive oxidation state), getting them in a free state is reduced to a reduction process:

This process can be carried out chemically or electrochemically.

In chemical reduction, coal or carbon monoxide (II), as well as hydrogen, active metals, and silicon are most often used as a reducing agent. With the help of carbon monoxide (II), iron is obtained (in the blast furnace process), many non-ferrous metals (tin, lead, zinc, etc.):

Hydrogen reduction is used, for example, to produce tungsten from tungsten(VI) oxide:

The use of hydrogen as a reducing agent ensures the highest purity of the resulting metal. Hydrogen is used to produce very pure iron, copper, nickel and other metals.

The method of obtaining metals, in which metals are used as a reducing agent, is called metallothermic. In this method, active metals are used as a reducing agent. Examples of metallothermic reactions:

aluminothermy:

magnesiumthermy:

Metal-thermal experiments for obtaining metals were first carried out by the Russian scientist N. N. Beketov in the 19th century.

Metals are most often obtained by the reduction of their oxides, which in turn are isolated from the corresponding natural ore. If the original ore is sulfide minerals, then the latter are subjected to oxidative roasting, for example:

Electrochemical production of metals is carried out during the electrolysis of melts of the corresponding compounds. In this way, the most active metals, alkali and alkaline earth metals, aluminum, and magnesium are obtained.

Electrochemical reduction is also used for refining(purification) of "raw" metals (copper, nickel, zinc, etc.) obtained by other methods. In electrolytic refining, a “rough” (with impurities) metal is used as an anode, and a solution of compounds of this metal is used as an electrolyte.

Methods for obtaining metals, carried out at high temperatures, are called pyrometallurgical(in Greek pyr - fire). Many of these methods have been known since ancient times. At the turn of the XIX-XX centuries. begin to develop hydrometallurgical methods of obtaining metals (in Greek hydor-water). With these methods, the ore components are transferred into an aqueous solution and then the metal is isolated by electrolytic or chemical reduction. So get, for example, copper. Copper ore containing copper (II) oxide CuO is treated with dilute sulfuric acid:

To reduce copper, the resulting solution of copper (II) sulfate is either subjected to electrolysis, or the solution is treated with iron powder.

The hydrometallurgical method has a great future, as it makes it possible to obtain a product without extracting the ore from the ground.

2. Types of synthetic rubbers, their properties and applications.

3. Experience. Obtaining the named gaseous substance and carrying out reactions that characterize its properties; (carbon dioxide)

CO2 is a typical acidic oxide: it reacts with alkalis (for example, causes lime water to become cloudy), with basic oxides and with water.

Carbon dioxide is obtained by acting on salts of carbonic acid - carbonates with solutions of hydrochloric, nitric and even acetic acids. In the laboratory, carbon dioxide is produced by the action of hydrochloric acid on chalk or marble:

CaCO3 + 2HCl = CaCl2 + H20 + CO2 it's carbon dioxide

In industry, large amounts of carbon dioxide are obtained by burning limestone:

CaCO3 = CaO + CO2

Chemical reactions with carbon dioxide

When carbon monoxide (IV) is dissolved in water, carbonic acid H2CO3 is formed, which is very unstable and easily decomposes into its original components - carbon dioxide and water:

CO2 + H20 -> H2CO3

It does not burn and does not support combustion (Fig. 44) and therefore is used to extinguish fires. However, magnesium continues to burn in carbon dioxide to form oxide and release carbon as soot.