"Alcohols" From history  Do you know that back in the IV century. BC e. did people know how to make drinks containing ethyl alcohol? Wine was obtained by fermentation of fruit and berry juices. However, they learned how to extract the intoxicating component from it much later. In the XI century. alchemists caught vapors of a volatile substance that was released when wine was heated. Definition n General formula of monohydric saturated alcohols СnН2n+1ОН Classification of alcohols According to the number of hydroxyl groups CxHy(OH)n Monohydric alcohols CH3 - CH2 - CH2 OH Dihydric glycols CH3 - CH - CH2 OH OH By the nature of the hydrocarbon hydrocarbon radical of the CxHy(OH)n CxHy(OH)n radical Limiting Limiting CH3 CH3 –– CH CH2 CH2 2 ––CH 2 OH OH CH CH2 OH 2 --OH hydrogen corresponding to alcohol, add the (generic) suffix - OL. The numbers after the suffix indicate the position of the hydroxyl group in the main chain: H | H-C-OH | H methanol H H H |3 |2 |1 H- C – C – C -OH | | | H H H propanol-1 H H H | 1 | 2 |3 H - C - C - C -H | | | H OH H propanol -2 TYPES OF ISOMERIA 1. Isomerism of the position of the functional group (propanol–1 and propanol–2) 2. Isomerism of the carbon skeleton CH3-CH2-CH2-CH2-OH butanol-1 CH3-CH-CH2-OH | CH3 2-methylpropanol-1 3. Interclass isomerism - alcohols are isomeric to ethers: CH3-CH2-OH ethanol CH3-O-CH3 dimethyl ether suffix -ol  For polyhydric alcohols, before the suffix -ol in Greek (-di-, -tri-, ...) the number of hydroxyl groups is indicated  For example: CH3-CH2-OH ethanol Types of isomerism of alcohols Structural 1. Carbon chain 2. Functional group positions PHYSICAL PROPERTIES  Lower alcohols (C1-C11) volatile liquids with a pungent odor  Higher alcohols (C12- and higher) solids with a pleasant odor PHYSICAL PROPERTIES Name Formula Pm. g/cm3 tmeltC tbpC Methyl CH3OH 0.792 -97 64 Ethyl C2H5OH 0.790 -114 78 Propyl CH3CH2CH2OH 0.804 -120 92 Isopropyl CH3-CH(OH)-CH3 0.786 -88 82 Butyl CH3CH2CH2CH2OH 0.8108 - Feature 0.8108 - properties: state of aggregation Methyl alcohol (the first representative of the homologous series of alcohols) is a liquid. Maybe it has a high molecular weight? No. Much less than carbon dioxide. Then what is it? R - O ... H - O ... H - O H R R Why? CH3 - O ... H - O ... N - O H N CH3 And if the radical is large? CH3 - CH2 - CH2 - CH2 - CH2 - O ... H - O H H Hydrogen bonds are too weak to hold an alcohol molecule, which has a large insoluble part, between water molecules A feature of physical properties: contraction Why, when solving calculation problems, they never use volume, but only by weight? Mix 500 ml of alcohol and 500 ml of water. We get 930 ml of solution. The hydrogen bonds between the molecules of alcohol and water are so great that the total volume of the solution decreases, its “compression” (from the Latin contraktio - compression). Individual representatives of alcohols Monohydric alcohol - methanol  Colorless liquid with a boiling point of 64C, characteristic odor Lighter than water. Burns with a colorless flame.  It is used as a solvent and fuel in internal combustion engines Methanol is a poison  The toxic effect of methanol is based on damage to the nervous and vascular systems. Ingestion of 5-10 ml of methanol leads to severe poisoning, and 30 ml or more - to death Monohydric alcohol - ethanol Colorless liquid with a characteristic odor and burning taste, boiling point 78C. Lighter than water. Mixes with her in any relationship. Flammable, burns with a faintly luminous bluish flame. Friendship with the traffic police Are spirits friends with the traffic police? But how! Have you ever been stopped by a traffic police inspector? Did you breathe into a tube? If you were unlucky, then the alcohol oxidation reaction took place, in which the color changed, and you had to pay a fine The question is interesting. Alcohol refers to xenobiotics - substances that are not contained in the human body, but affect its vital activity. Everything depends on the dose. 1. Alcohol is a nutrient that provides the body with energy. In the Middle Ages, the body received about 25% of its energy from alcohol consumption; 2. Alcohol is a drug that has a disinfectant and antibacterial effect; 3. Alcohol is a poison that disrupts natural biological processes, destroys internal organs and the psyche, and, if consumed in excess, leads to death Use of ethanol  Ethyl alcohol is used in the preparation of various alcoholic beverages;  In medicine for the preparation of extracts from medicinal plants, as well as for disinfection;  In cosmetics and perfumery, ethanol is a solvent for perfumes and lotions Harmful effects of ethanol  At the beginning of intoxication, the structures of the cerebral cortex suffer; the activity of the brain centers that control behavior is suppressed: reasonable control over actions is lost, and a critical attitude towards oneself decreases. I. P. Pavlov called such a state “violence of the subcortex”  With a very high content of alcohol in the blood, the activity of the motor centers of the brain is inhibited, mainly the function of the cerebellum suffers - a person completely loses orientation Harmful effects of ethanol  Changes in the brain structure caused by many years of alcohol intoxication are irreversible, and even after prolonged abstinence from drinking alcohol, they persist. If a person cannot stop, then organic and, consequently, mental deviations from the norm are on the rise Harmful effects of ethanol  Alcohol has an extremely unfavorable effect on the vessels of the brain. At the beginning of intoxication, they expand, the blood flow in them slows down, which leads to congestion in the brain. Then, when, in addition to alcohol, harmful products of its incomplete decay begin to accumulate in the blood, a sharp spasm sets in, vasoconstriction occurs, and such dangerous complications as cerebral strokes develop, leading to severe disability and even death. QUESTIONS FOR CONSOLIDATION 1. 2. 3. 4. 5. 6. 7. 8. There is water in one unsigned vessel, and alcohol in the other. Is it possible to use an indicator to recognize them? Who has the honor of obtaining pure alcohol? Can alcohol be a solid? The molecular weight of methanol is 32, and carbon dioxide is 44. Make a conclusion about the state of aggregation of alcohol. Mixed a liter of alcohol and a liter of water. Determine the volume of the mixture. How to conduct a traffic police inspector? Can anhydrous absolute alcohol release water? What are xenobiotics and how do they relate to alcohols? ANSWERS 1. 2. 3. 4. 5. 6. 7. 8. You can't. Indicators do not affect alcohols and their aqueous solutions. Of course, the alchemists. Maybe if this alcohol contains 12 carbon atoms or more. From these data, no conclusion can be drawn. Hydrogen bonds between alcohol molecules at a low molecular weight of these molecules make the boiling point of alcohol abnormally high. The volume of the mixture will not be two liters, but much less, approximately 1 liter - 860 ml. Don't drink while driving. Maybe if you heat it up and add conc. sulfuric acid. Do not be lazy and remember everything that you have heard about alcohols, decide for yourself once and for all what dose is yours……. and is it needed at all? Polyhydric alcohol ethylene glycol  Ethylene glycol is a representative of limiting dihydric alcohols - glycols;  Glycols got their name due to the sweet taste of many representatives of the series (Greek “glycos” - sweet);  Ethylene glycol is a syrupy liquid of sweet taste, odorless, poisonous. Mixes well with water and alcohol, hygroscopic Use of ethylene glycol  An important property of ethylene glycol is the ability to lower the freezing point of water, from which the substance has found wide application as a component of automotive antifreeze and antifreeze liquids;  It is used to obtain lavsan (a valuable synthetic fiber) Ethylene glycol is a poison  Doses that cause fatal ethylene glycol poisoning vary widely - from 100 to 600 ml. According to some authors, the lethal dose for humans is 50-150 ml. Mortality due to ethylene glycol is very high and accounts for more than 60% of all cases of poisoning;  The mechanism of the toxic action of ethylene glycol has not been sufficiently studied so far. Ethylene glycol is rapidly absorbed (including through the pores of the skin) and circulates in the blood unchanged for several hours, reaching a maximum concentration after 2-5 hours. Then its content in the blood gradually decreases, and it is fixed in the tissues. Colorless, viscous, hygroscopic, sweet-tasting liquid. Miscible with water in all proportions, good solvent. Reacts with nitric acid to form nitroglycerin. Forms fats and oils with carboxylic acids CH2 – CH – CH2 OH OH OH Application of glycerin  Used in     production of nitroglycerine explosives; When processing the skin; As a component of some adhesives; In the production of plastics, glycerin is used as a plasticizer; In the production of confectionery and beverages (as food additive E422) Qualitative reaction to polyhydric alcohols Qualitative reaction to polyhydric alcohols  The reaction to polyhydric alcohols is their interaction with a fresh precipitate of copper (II) hydroxide, which dissolves to form a bright blue-violet solution Tasks Complete work card for the lesson;  Answer the test questions;  Solve the crossword puzzle  Working card of the lesson “Alcohols”  General formula of alcohols  Name the substances:  CH3OH  CH3-CH2-CH2-CH2-OH  CH2(OH)-CH2(OH) the atomicity of the alcohol?  List the uses of ethanol  What alcohols are used in the food industry?  What alcohol causes fatal poisoning when 30 ml is ingested?  What substance is used as antifreeze liquid?  How to distinguish polyhydric alcohol from monohydric alcohol? Production methods Laboratory  Hydrolysis of haloalkanes: R-CL+NaOH R-OH+NaCL  Hydration of alkenes: CH2=CH2+H2O C2H5OH  Hydrogenation of carbonyl compounds Industrial  Synthesis of methanol from synthesis gas CO+2H2 CH3-OH (at elevated pressure, high temperature and zinc oxide catalyst)  Hydration of alkenes  Fermentation of glucose: C6H12O6 2C2H5OH+2CO2 Chemical properties I. Reactions with RO–H bond breaking  Alcohols react with alkali and alkaline earth metals, forming salt-like compounds - alcoholates 2СH CH CH OH + 2Na  2CH CH CH ONa + H  2CH CH OH + Ca  (CH CHO) Ca + H  3 2 3 2 2 3 3 2 2 2 2 2 2  Interaction with organic acids (esterification reaction) leads to the formation of esters. CH COOH + HOC H  CHCOOC H (acetic ethyl ether (ethyl acetate)) + HO 3 2 5 3 2 5 2 II. Reactions with R–OH bond cleavage With hydrogen halides: R–OH + HBr  R–Br + H2O III. Oxidation reactions Alcohols burn: 2C3H7OH + 9O2  6CO2 + 8H2O Under the action of oxidizing agents:  primary alcohols are converted into aldehydes, secondary into ketones IV. Dehydration Occurs when heated with water-removing reagents (conc. H2SO4). 1. Intramolecular dehydration leads to the formation of alkenes CH3–CH2–OH  CH2=CH2 + H2O 2. Intermolecular dehydration gives ethers R-OH + H-O–R  R–O–R(ether) + H2O

All substances can be in different states of aggregation - solid, liquid, gaseous and plasma. In ancient times, it was believed: the world consists of earth, water, air and fire. Aggregate states of substances correspond to this visual division. Experience shows that the boundaries between aggregate states are very arbitrary. Gases at low pressures and low temperatures are considered ideal, the molecules in them correspond to material points that can only collide according to the laws of elastic impact. The forces of interaction between molecules at the moment of impact are negligible, the collisions themselves occur without loss of mechanical energy. But as the distance between molecules increases, the interaction of molecules must also be taken into account. These interactions begin to affect the transition from a gaseous state to a liquid or solid. Various kinds of interactions can occur between molecules.

The forces of intermolecular interaction do not have saturation, differing from the forces of chemical interaction of atoms, leading to the formation of molecules. They can be electrostatic when interacting between charged particles. Experience has shown that the quantum mechanical interaction, which depends on the distance and mutual orientation of molecules, is negligible at distances between molecules of more than 10 -9 m. In rarefied gases, it can be neglected or it can be assumed that the potential energy of interaction is practically zero. At small distances, this energy is small, at , the forces of mutual attraction act

at - mutual repulsion and force

attraction and repulsion of molecules are balanced and F= 0. Here the forces are determined by their connection with the potential energy. But the particles move, having a certain reserve of kinetic energy

gee. Let one molecule be motionless, and another collide with it, having such a supply of energy. When the molecules approach each other, the forces of attraction do positive work and the potential energy of their interaction decreases to a distance. At the same time, the kinetic energy (and speed) increases. When the distance becomes less, the attractive forces will be replaced by repulsive forces. The work done by the molecule against these forces is negative.

The molecule will approach the immobile molecule until its kinetic energy is completely converted into potential. Minimum distance d, which molecules can approach each other is called effective molecular diameter. After stopping, the molecule will begin to move away under the action of repulsive forces with increasing speed. Having passed the distance again, the molecule will fall into the region of attractive forces, which will slow down its removal. The effective diameter depends on the initial stock of kinetic energy, i.e. this value is not constant. At distances equal to the potential energy of interaction has an infinitely large value or "barrier" that prevents the centers of molecules from approaching at a shorter distance. The ratio of the average potential energy of interaction to the average kinetic energy determines the state of aggregation of a substance: for gases for liquids, for solids

Condensed media are liquids and solids. In them, atoms and molecules are located close, almost touching. The average distance between the centers of molecules in liquids and solids is about (2 -5) 10 -10 m. Their densities are approximately the same. Interatomic distances exceed the distances over which electron clouds penetrate each other so much that repulsive forces arise. For comparison, in gases under normal conditions, the average distance between molecules is about 33 10 -10 m.

AT liquids intermolecular interaction is more pronounced, the thermal motion of molecules manifests itself in weak oscillations around the equilibrium position and even jumps from one position to another. Therefore, they have only short-range order in the arrangement of particles, i.e., consistency in the arrangement of only the nearest particles, and characteristic fluidity.

Solids are characterized by rigidity of the structure, have a precisely defined volume and shape, which change much less under the influence of temperature and pressure. In solids, amorphous and crystalline states are possible. There are also intermediate substances - liquid crystals. But the atoms in solids are not at all motionless, as one might think. Each of them fluctuates all the time under the influence of elastic forces that arise between neighbors. Most elements and compounds have a crystal structure under a microscope.

So, salt grains look like ideal cubes. In crystals, atoms are fixed at the nodes of the crystal lattice and can only vibrate near the lattice nodes. Crystals constitute true solids, and such solids as plastic or asphalt occupy, as it were, an intermediate position between solids and liquids. An amorphous body, like a liquid, has a short-range order, but the probability of jumps is small. So, glass can be considered as a supercooled liquid, which has an increased viscosity. Liquid crystals have the fluidity of liquids, but retain the orderliness of the arrangement of atoms and have anisotropy of properties.

The chemical bonds of atoms (and on about in) in crystals are the same as in molecules. The structure and rigidity of solids is determined by the difference in electrostatic forces that bind together the atoms that make up the body. The mechanism that binds atoms into molecules can lead to the formation of solid periodic structures, which can be considered as macromolecules. Like ionic and covalent molecules, there are ionic and covalent crystals. Ionic lattices in crystals are held together by ionic bonds (see Fig. 7.1). The structure of table salt is such that each sodium ion has six neighbors - chloride ions. This distribution corresponds to a minimum of energy, i.e., when such a configuration is formed, the maximum energy is released. Therefore, as the temperature drops below the melting point, a tendency to form pure crystals is observed. With an increase in temperature, the thermal kinetic energy is sufficient to break the bond, the crystal will begin to melt, and the structure will collapse. Crystal polymorphism is the ability to form states with different crystal structures.

When the distribution of electric charge in neutral atoms changes, a weak interaction between neighbors can occur. This bond is called a molecular or van der Waals bond (as in a hydrogen molecule). But the forces of electrostatic attraction can also arise between neutral atoms, then no rearrangements in the electron shells of atoms occur. Mutual repulsion during the approach of electron shells shifts the center of gravity of negative charges relative to positive ones. Each of the atoms induces an electric dipole in the other, and this leads to their attraction. This is the action of intermolecular forces or van der Waals forces, which have a large radius of action.

Since the hydrogen atom is very small and its electron is easily displaced, it is often attracted to two atoms at once, forming a hydrogen bond. The hydrogen bond is also responsible for the interaction of water molecules with each other. It explains many of the unique properties of water and ice (Figure 7.4).

covalent bond(or atomic) is achieved due to the internal interaction of neutral atoms. An example of such a bond is the bond in the methane molecule. A highly bonded form of carbon is diamond (four hydrogen atoms are replaced by four carbon atoms).

So, carbon, built on a covalent bond, forms a crystal in the form of a diamond. Each atom is surrounded by four atoms forming a regular tetrahedron. But each of them is simultaneously the vertex of the neighboring tetrahedron. Under other conditions, the same carbon atoms crystallize into graphite. In graphite, they are also connected by atomic bonds, but they form planes of hexagonal honeycomb cells capable of shearing. The distance between the atoms located at the vertices of the hexagons is 0.142 nm. The layers are located at a distance of 0.335 nm, i.e. weakly bound, so graphite is plastic and soft (Fig. 7.5). In 1990, there was a boom in research work, caused by a message about the receipt of a new substance - fullerite, consisting of carbon molecules - fullerenes. This form of carbon is molecular; The smallest element is not an atom, but a molecule. It is named after the architect R. Fuller, who in 1954 received a patent for building structures from hexagons and pentagons that make up a hemisphere. Molecule from 60 carbon atoms with a diameter of 0.71 nm was discovered in 1985, then molecules were discovered, etc. All of them had stable surfaces,

but the molecules C 60 and FROM 70 . It is logical to assume that graphite is used as a feedstock for the synthesis of fullerenes. If so, then the radius of the hexagonal fragment should be 0.37 nm. But it turned out to be equal to 0.357 nm. This difference of 2% is due to the fact that carbon atoms are located on the spherical surface at the vertices of 20 regular hexagons inherited from graphite and 12 regular pentahedrons, i.e. the design resembles a soccer ball. It turns out that when "stitching" into a closed sphere, some of the flat hexagons turned into pentahedrons. At room temperature, C 60 molecules condense into a structure where each molecule has 12 neighbors spaced 0.3 nm apart. At T= 349 K, a first-order phase transition occurs - the lattice is rearranged into a cubic one. The crystal itself is a semiconductor, but when an alkali metal is added to a C 60 crystalline film, superconductivity occurs at a temperature of 19 K. If one or another atom is introduced into this hollow molecule, it can be used as the basis for creating a storage medium with ultrahigh information density: the recording density will reach 4-10 12 bits/cm2. For comparison, a film of ferromagnetic material gives a recording density of the order of 10 7 bits / cm 2, and optical discs, i.e. laser technology, - 10 8 bits/cm 2 . This carbon also has other unique properties that are especially important in medicine and pharmacology.

manifests itself in metal crystals metallic bond, when all the atoms in a metal donate their valence electrons "for collective use". They are weakly bound to atomic cores and can freely move along the crystal lattice. About 2/5 of the chemical elements are metals. In metals (except mercury), a bond is formed when the vacant orbitals of metal atoms overlap and electrons are detached due to the formation of a crystal lattice. It turns out that the cations of the lattice are shrouded in electron gas. A metallic bond occurs when atoms approach each other at a distance less than the size of the outer electron cloud. With this configuration (Pauli principle), the energy of external electrons increases, and the nuclei of the neighbors begin to attract these external electrons, blurring the electron clouds, evenly distributing them over the metal and turning them into an electron gas. This is how conduction electrons arise, which explain the high electrical conductivity of metals. In ionic and covalent crystals, the outer electrons are practically bound, and the conductivity of these solids is very low, they are called insulators.

The internal energy of liquids is determined by the sum of the internal energies of the macroscopic subsystems into which it can be mentally divided, and the interaction energies of these subsystems. The interaction is carried out through molecular forces with a range of about 10 -9 m. For macrosystems, the interaction energy is proportional to the contact area, so it is small, like the fraction of the surface layer, but this is not necessary. It is called surface energy and should be taken into account in problems related to surface tension. Typically, liquids occupy a larger volume with equal weight, i.e., have a lower density. But why do the volumes of ice and bismuth decrease upon melting and even after the melting point retain this trend for some time? It turns out that these substances in the liquid state are denser.

In a liquid, each atom is acted upon by its neighbors and oscillates within the anisotropic potential well they create. Unlike a solid body, this well is not deep, since distant neighbors have almost no effect. The nearest environment of particles in a liquid changes, i.e., the liquid flows. When a certain temperature is reached, the liquid boils; during boiling, the temperature remains constant. The incoming energy is spent on breaking bonds, and when they are completely broken, the liquid turns into a gas.

The densities of liquids are much greater than the densities of gases at the same pressures and temperatures. Thus, the volume of water at boiling is only 1/1600 of the volume of the same mass of water vapor. The volume of a liquid depends little on pressure and temperature. Under normal conditions (20 °C and a pressure of 1.013 10 5 Pa), water occupies a volume of 1 liter. With a decrease in temperature to 10 ° C, the volume will decrease only by 0.0021, with an increase in pressure - by a factor of two.

Although there is as yet no simple ideal model of a liquid, its microstructure has been sufficiently studied and makes it possible to qualitatively explain most of its macroscopic properties. The fact that the cohesion of molecules in liquids is weaker than in a solid was noticed by Galileo; he was surprised that large drops of water accumulate on cabbage leaves and do not spread over the leaf. Spilled mercury or water drops on a greasy surface take the form of small balls due to adhesion. When the molecules of one substance are attracted to the molecules of another substance, it is called wetting, for example, glue and wood, oil and metal (despite the enormous pressure, the oil is retained in the bearings). But water rises in thin tubes, called capillaries, and rises the higher, the thinner the tube. There can be no other explanation than the effect of wetting water and glass. Wetting forces between glass and water are greater than between water molecules. With mercury, the effect is reversed: the wetting of mercury and glass is weaker than the cohesive forces between mercury atoms. Galileo noticed that a greased needle can float on water, although this contradicts the law of Archimedes. When the needle floats,

but notice a slight deflection of the surface of the water, tending to straighten out, as it were. The cohesive forces between the water molecules are sufficient to prevent the needle from falling into the water. The surface layer, like a film, protects water, this is surface tension, which tends to give the shape of water the smallest surface - spherical. But the needle will no longer float on the surface of alcohol, because when alcohol is added to water, the surface tension decreases, and the needle sinks. Soap also reduces surface tension, so hot soap suds, penetrating into cracks and crevices, is better at removing dirt, especially grease, while pure water would simply curl up into droplets.

Plasma is the fourth aggregate state of matter, which is a gas from a collection of charged particles interacting at large distances. In this case, the number of positive and negative charges is approximately equal, so that the plasma is electrically neutral. Of the four elements, plasma corresponds to fire. To transform a gas into a plasma state, it is necessary to ionize strip electrons from atoms. Ionization can be carried out by heating, by the action of an electric discharge or by hard radiation. Matter in the universe is mostly in an ionized state. In stars, ionization is caused thermally, in rarefied nebulae and interstellar gas, by ultraviolet radiation from stars. Our Sun also consists of plasma, its radiation ionizes the upper layers of the earth's atmosphere, called ionosphere, the possibility of long-range radio communication depends on its condition. Under terrestrial conditions, plasma is rare - in fluorescent lamps or in an electric arc. In laboratories and technology, plasma is most often produced by an electric discharge. In nature, this is done by lightning. During ionization by a discharge, electron avalanches arise, similar to the process of a chain reaction. To obtain thermonuclear energy, the injection method is used: gas ions accelerated to very high speeds are injected into magnetic traps, attract electrons from the environment, forming a plasma. Pressure ionization is also used - shock waves. This method of ionization is found in superdense stars and, possibly, in the Earth's core.

Any force acting on ions and electrons causes an electric current. If it is not connected with external fields and is not closed inside the plasma, it is polarized. Plasma obeys gas laws, but when a magnetic field is applied, which regulates the movement of charged particles, it exhibits properties that are completely unusual for a gas. In a strong magnetic field, particles begin to spin around the lines of force, and along the magnetic field they move freely. It is said that this helical motion shifts the structure of the field lines and the field is "frozen" into the plasma. A rarefied plasma is described by a system of particles, while a denser plasma is described by a fluid model.

The high electrical conductivity of plasma is its main difference from gas. The conductivity of cold plasma on the surface of the Sun (0.8 10 -19 J) reaches the conductivity of metals, and at thermonuclear temperature (1.6 10 -15 J) hydrogen plasma conducts current 20 times better than copper under normal conditions. Since plasma is capable of conducting current, the model of a conducting liquid is often applied to it. It is considered a continuous medium, although compressibility distinguishes it from an ordinary liquid, but this difference is manifested only in flows whose speed is greater than the speed of sound. The behavior of a conductive fluid is studied in a science called magnetic hydrodynamics. In space, any plasma is an ideal conductor, and the laws of the frozen field are widely used. The model of a conducting fluid makes it possible to understand the mechanism of plasma confinement by a magnetic field. Thus, plasma streams are ejected from the Sun, affecting the Earth's atmosphere. The flow itself does not have a magnetic field, but an extraneous field cannot penetrate into it according to the freezing law. Plasma solar streams push extraneous interplanetary magnetic fields out of the vicinity of the Sun. A magnetic cavity appears, where the field is weaker. When these corpuscular plasma flows approach the Earth, they collide with the Earth's magnetic field and are forced to flow around it according to the same law. It turns out a kind of cavern where the magnetic field is collected and where plasma flows do not penetrate. Charged particles accumulate on its surface, which were detected by rockets and satellites - this is the outer radiation belt of the Earth. These ideas were also used in solving problems of plasma confinement by a magnetic field in special devices - tokamaks (from the abbreviation of words: toroidal chamber, magnet). With fully ionized plasma held in these and other systems, hopes are pinned for obtaining a controlled thermonuclear reaction on Earth. This would provide a clean and cheap source of energy (sea water). Work is also underway to obtain and retain plasma using focused laser radiation.

Presentation on the topic "Alcohols" in chemistry in powerpoint format. The presentation for schoolchildren contains 12 slides, which, from the point of view of chemistry, talk about alcohols, their physical properties, reactions with hydrogen halides.

Fragments from the presentation

From the history

Do you know that even in the 4th c. BC e. did people know how to make drinks containing ethyl alcohol? Wine was obtained by fermentation of fruit and berry juices. However, they learned how to extract the intoxicating component from it much later. In the XI century. alchemists caught vapors of a volatile substance that was released when wine was heated.

Physical properties

• Lower alcohols are liquids that are highly soluble in water, colorless, with an odor.
• Higher alcohols are solids, insoluble in water.

Feature of physical properties: state of aggregation

• Methyl alcohol (the first representative of the homologous series of alcohols) is a liquid. Maybe it has a high molecular weight? No. Much less than carbon dioxide. Then what is it?
• It turns out that it's all about the hydrogen bonds that form between alcohol molecules, and do not allow individual molecules to fly away.

Feature of physical properties: solubility in water

• Lower alcohols are soluble in water, higher alcohols are insoluble. Why?
• Hydrogen bonds are too weak to hold an alcohol molecule, which has a large insoluble portion, between water molecules.

Feature of physical properties: contraction

• Why, when solving computational problems, they never use volume, but only mass?
• Mix 500 ml of alcohol and 500 ml of water. We get 930 ml of solution. The hydrogen bonds between the molecules of alcohol and water are so great that the total volume of the solution decreases, its "compression" (from the Latin contraktio - compression).

Are alcohols acids?

• Alcohols react with alkali metals. In this case, the hydrogen atom of the hydroxyl group is replaced by a metal. It looks like acid.
• But the acid properties of alcohols are too weak, so weak that alcohols do not act on indicators.

Friendship with the traffic police.

• Alcohols are friends with the traffic police? But how!
• Have you ever been stopped by a traffic police inspector? Did you breathe into a tube?
• If you were unlucky, then the alcohol oxidation reaction took place, in which the color changed, and you had to pay a fine.

We give water 1

Withdrawal of water - dehydration can be intramolecular if the temperature is more than 140 degrees. In this case, a catalyst is needed - concentrated sulfuric acid.

We give water 2

If the temperature is reduced, and the catalyst is left the same, then intermolecular dehydration will take place.

Reaction with hydrogen halides.

This reaction is reversible and requires a catalyst - concentrated sulfuric acid.

To be friends or not to be friends with alcohol.

The question is interesting. Alcohol refers to xenobiotics - substances that are not contained in the human body, but affect its vital activity. Everything depends on the dose.

1. Alcohol is a nutrient that provides the body with energy. In the Middle Ages, the body received about 25% of energy through alcohol consumption.
2. Alcohol is a drug that has a disinfectant and antibacterial effect.
3. Alcohol is a poison that disrupts natural biological processes, destroys internal organs and the psyche, and, if consumed in excess, leads to death.