Oxygen plays a role in nature. Oxygen: physical and chemical properties
The light gas oxygen is the most common element on Earth. AT earth's crust its weight is 12 times more than iron, 140 times more than carbon, almost 500 times more than sulfur; it makes up 49.13 percent of the weight of the entire earth's crust.
Such a distribution of oxygen on Earth fully corresponds to its significance in the life of living and dead nature. After all, water is a combination of hydrogen and oxygen (contains 89 percent oxygen), sand is a combination of silicon and oxygen (53 percent oxygen), iron ore is a combination of iron and oxygen. Oxygen is a constituent of many ores and minerals. But greatest value has oxygen for the life of wildlife, for the life of animals and humans. Without oxygen, life on Earth is impossible.
The entire vital activity of the human body, from birth to death, is associated with oxidative processes, in which oxygen plays the main role.
These processes begin with human breathing. The air inhaled by a person enters the lungs. Here, through the walls of the thinnest blood vessels, through which no liquid passes, but gas passes, oxygen penetrates into the blood. The most important process of gas exchange takes place in the blood.
The blood absorbs oxygen and releases the carbon dioxide it contains. Typically, air contains 0.03 percent carbon dioxide The air exhaled by a person contains 4.38 percent of carbon dioxide.
Thus, the content of carbon dioxide in the air exhaled by a person increases 140 times compared to its content in the air. The oxygen content, on the contrary, drops to 16.04 percent, that is, by 1/5 compared to its content in the air.
The oxygen received by the blood is carried throughout the body and oxidizes the nutrients dissolved in it. When oxidized by oxygen, that is, during the slow combustion of nutrients entering the body, carbon dioxide is formed, which is absorbed by the circulating blood. Carbon dioxide is carried by the blood to the lungs and here, with a new gas exchange with fresh oxygen from the air, it is released into the surrounding atmosphere when exhaled.
An adult person absorbs about 850 liters of oxygen every day during breathing. The oxidative processes that take place in our body are accompanied by the release of heat. It is the heat associated with the breathing process that keeps our body temperature around 37 degrees.
When breathing, during combustion, during any other oxidative processes (rusting of metals, decay, etc.), air oxygen is absorbed. Legitimate questions may arise: is the air getting poorer with oxygen, for how long will it be enough for life on Earth? There is no cause for concern in this regard.
The atmosphere contains 1,300,000,000,000,000 tons of oxygen, and although this amount is only one ten thousandth of the total oxygen content in the earth's crust, this number is quite large. But the most important thing is that it practically does not change due to the changes in nature. reverse processes release of oxygen.
These processes of oxygen release occur as a result of the vital activity of plants. By absorbing carbon dioxide from the air for their nutrition, plants decompose it into carbon and oxygen under the action of sunlight. Carbon remains in the plant and is used to build its body, while oxygen is released back into the atmosphere. And although plants also breathe, and they need oxygen for breathing, but in general, the amount of oxygen that plants emit during their nutrition is 20 times more than what they need for breathing. Thus, plants are living factories of oxygen.
That is why planting plants in cities are of great health significance. They not only absorb excess amounts of carbon dioxide accumulated here as a result of the action of factories and plants, but, helping to purify the air from harmful impurities, they enrich it with oxygen that is life-giving for the human and animal organism.
The green ring around cities is a source of oxygen, a source of health.
"Oxygen compounds" - Oxygen compounds N (all nitrogen oxides are endothermic !!!). Oxygen compounds N+5. Halides N. Binding of dianitrogen N2. Oxygen compounds N+3. Thermolysis of ammonium salts. Decomposition of nitrates at T. Oxygen compounds N+2. Opening elements. Nitride. Properties. Oxygen compounds N+4. Similarly for Li2NH (imide), Li3N (nitride).
"Application of oxygen" - The use of oxygen. The patient is in a special apparatus in oxygen atmosphere under reduced pressure. The doctor talks to the patient on the phone. Fireman with self-contained breathing apparatus. Outside the earth's atmosphere, a person is forced to take with him a supply of oxygen. The main consumers of oxygen are energy, metallurgy and the chemical industry.
"Oxygen chemistry" - 1.4 g / l, slightly heavier than air. combustion reactions. Melting temperature. oxygen in nature. Boiling temperature. Aggregate state, color, smell. Physical properties oxygen. Density. Solubility. Oxygen. Oxidation reactions in which heat and light are released are called combustion reactions.
"Test "Air"" - The number of climatic zones. Answer questions in writing. Wind that changes direction twice a year. Air. Unit of measure for pressure. A mixture of different liquids. A device for measuring atmospheric pressure. A gas that does not support combustion. Air density. Generalize and consolidate knowledge.
"Air chemistry" - Ozone holes. Consequences of air pollution. Automotive emissions, industrial emissions. Greenhouse effect. Identify the main ways to solve the problem of air pollution. Variable constituents of air. The main ways to solve the problem of air pollution. Ecological state in the districts of Moscow.
"Oxygen. Ozone. Air" - Perform the test. Complete the task. M.V. Lomonosov. Allotropy. Oxygen. Solve the problem. Air composition. Study the composition of air. biological role. Ozone and oxygen. Getting oxygen. properties of oxygen. A. Lavoisier. Generalization. The use of oxygen. Release of oxygen. Check your answers. Laboratory experience.
In total there are 17 presentations in the topic
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees physical training. End >> End >> > End >>">
Oxygen is the most abundant element on Earth. In the free state, molecular oxygen is part of the air, where its content is 20.95% (by volume). The content in the earth's crust is 47.2% (by mass). oxygen is important component carbohydrates, fats, proteins. It exists in two allotropic modifications– molecular oxygen (dioxygen) and ozone (trioxygen). The most stable molecule is O2, which has paramagnetic properties. Under laboratory conditions, oxygen can be obtained in the following ways: A) Decomposition of Bertolet salt: 3KClO 3 \u003d 2KCl + 3O 2 B) Decomposition of potassium permanganate: 2KMnO 4 \u003d K 2 MnO 4 + MnO 2 + O 2 C) Heating alkali metal nitrates (NaNO 3 , KNO 3); in this case, only 1/3 of the oxygen contained in them is released in a free state: 2NaNO 3 \u003d 2NaNO 2 + O 2 The main source industrial production oxygen is air that is burned and then fractionated. First, nitrogen is released (t kip \u003d -195.8 ° C), and almost pure oxygen remains in the liquid state, since its boiling point is higher (-183 ° C). A method of obtaining oxygen based on the electrolysis of water is widespread. physical properties. Under normal conditions, oxygen is a colorless gas, odorless and tasteless. Boiling point 183˚С, heavier than air, density 1.43 g / cm 3. Under normal conditions, 0.04 g of oxygen dissolves in 1 liter of water. Chemical properties. As an element occupying space in the upper right corner periodic system DI. Mendeleev, oxygen has pronounced non-metallic properties. Having six electrons on the outer energy level, the oxygen atom can pass to the extremely filled 8th electron shell (the condition of maximum chemical stability) by adding 2 electrons. Therefore, in reactions with other elements (except fluorine), oxygen exhibits exclusively oxidizing properties. Oxygen forms compounds with all chemical elements except helium, neon and argon. It interacts directly with most elements, except for halogens, gold and platinum. The reaction rate, both with simple and complex substances, depends on the nature of the substances, temperature and other conditions. Such an active metal as cesium ignites spontaneously in atmospheric oxygen even at room temperature. Oxygen actively reacts with phosphorus when heated to 60˚С, with sulfur - up to 250˚С, with hydrogen - more than 300˚С, with carbon (in the form of coal and graphite) - at ˚С: 4P + 5O 2 = 2P 2 O 5 S + O 2 \u003d SO 2 2H 2 + O 2 \u003d 2H 2 O C + O 2 \u003d CO 2 The combustion of hydrogen in oxygen proceeds according to a chain mechanism. This reaction begins with the formation of active unstable particles - free radical carriers of unpaired electrons: H 2 + O 2 \u003d OH + OH (chain initiation) OH radicals easily react with the H 2 molecule: OH + H 2 \u003d H 2 O + H Hydrogen atom further reacts with an O 2 molecule to form again an OH radical and an oxygen atom, etc. These elementary acts contribute to the development of the chain. When complex substances are burned in excess oxygen, oxides of the corresponding elements are formed: 2H 2 S + 3O 2 \u003d 2SO 2 + 2H 2 OCH 4 + 2O 2 \u003d CO 2 + 2H 2 O Hydrogen sulfideMethane C 2 H 5 OH + 3O 2 \u003d 2CO 2 + 3H 2 O4FeS O 2 = 2Fe 2 O 3 + 8SO 2 Ethanolpyrite The reactions considered are accompanied by the release of both heat and light. Such processes involving oxygen are called combustion. In addition to the indicated type of interaction, there are also those that are accompanied by the release of only heat and heat, and no light is released. First of all, they should include the process of breathing.
With the participation of oxygen, one of the vital processes is performed - respiration. Oxidation of carbohydrates, fats and proteins by oxygen serves as a source of energy for living organisms. In the human body, the oxygen content is 61% of body weight. In the form of various compounds, it is a part of all organs, tissues, biological fluids. A person inhales m 3 of air per day. Oxygen is widely used in almost all branches of the chemical industry: - for the production of nitric and sulfuric acids, - in organic synthesis, - in the processes of roasting ores. The steel production process is impossible without oxygen, metallurgy uses over 60% of all industrial oxygen. The combustion of hydrogen in oxygen is accompanied by the release of significant energy - almost 286 kJ/mol. This reaction is used for welding and cutting metals. Liquid oxygen is used to make explosive mixtures. The huge need for oxygen poses a serious environmental problem for mankind to preserve its reserves in the atmosphere. Until now, the only source that replenishes the atmosphere with oxygen is the vital activity of green plants. Therefore, it is especially important to ensure that their number on Earth does not decrease.
CO 2 (carbon dioxide) has a linear structure. Bonds in a molecule are formed by four electron pairs. In the carbon monoxide (IV) molecule sp-hybridization takes place. The two sp-hybridized carbon orbitals form two sigma bonds with oxygen atoms, and the remaining unhybridized p-orbitals of carbon form pi bonds with two p-orbitals of oxygen atoms, which are located in planes perpendicular to each other. The foregoing explains linear structure CO 2. CO2 is formed during the thermal decomposition of carbonates. In industry, CO2 is obtained by burning limestone: CaCO 3 \u003d CaO + CO 2 In the laboratory, it can be obtained by the action of dilute acids on carbonates: CaCO 3 + 2HCl \u003d CaCl 2 + CO 2 + H 2 O Under normal conditions, CO 2 is a colorless gas in 1 .5 times heavier than air. Let's dissolve in water (at 0 ˚С 1,7 l of CO 2 in 1 l of H 2 O). As the temperature rises, the solubility of CO 2 decreases greatly and its excess is removed from the solution in the form of bubbles that form foam. This property is used to make fizzy drinks. With strong cooling, CO 2 crystallizes in the form of a white snow-like mass, which, when compressed, evaporates very slowly, lowering the ambient temperature. This explains its use as "dry ice". Does not support respiration, but serves as a source of nutrition for green plants (photosynthesis). The property of CO 2 not to sustain combustion is used in fire fighting devices. At high temperatures carbon monoxide (IV) can react with metals whose affinity for oxygen is higher than that of carbon itself (for example, with magnesium): CO 2 + 2Mg \u003d 2MgO + C When CO 2 is dissolved in water, they partially interact, leading to the formation of coal acid H 2 CO 3.
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees of physical fitness. End >> End >> > End >>">
The alveoli of the lungs are hemispherical invaginations of the walls of the alveolar ducts and respiratory bronchioles. The diameter of the alveoli is µm. The number of alveoli in one human lung is on average 400 million (with significant individual variations). Most of the outer surface of the alveoli is in contact with the capillaries of the pulmonary circulation. The total area of these contacts is large - about 90 m 2. The so-called pulmonary membrane separates the blood from the alveolar air, consisting of endothelial cells, two main membranes, squamous alveolar epithelium, and a layer of sufactant. The thickness of the lung membrane is only 0.4 - 1.5 microns. Gas exchange in the lungs is carried out as a result of the diffusion of oxygen from the alveolar air into the blood (about 500 liters per day) and carbon dioxide from the blood into the alveolar air (about 430 liters per day). Diffusion occurs due to the difference in the partial pressure of these gases in the alveolar air and their tension in the blood. The partial pressure of a gas in a gas mixture is proportional to the percentage of gas and the total pressure of the mixture. It does not depend on the nature of the gas. So, at a dry air pressure of 760 mm Hg. partial pressure of oxygen is approximately 21%, i.e. 159 mm Hg. When calculating the partial pressure in the alveolar air, it should be taken into account that it is saturated with water vapor, the partial pressure of which at body temperature is 47 mm Hg. Therefore, the fraction of the partial pressure of gases accounts for 760 - 47 = 713 mm Hg. With an oxygen content in the alveolar air of 14%, its partial pressure will be 99.8 mm Hg. (about 100 mm Hg). With a carbon dioxide content of 5.5%, the partial pressure corresponds to 39.2 mmHg (about 40 mmHg). The partial pressure of oxygen and carbon dioxide in the alveolar air is the snare with which the molecules of these gases tend to penetrate the alveolar membrane into the blood. In the blood, gases are in a dissolved (free) and chemically bound state. Diffusion involves only dissolved gas molecules. The amount of gas that dissolves in a liquid depends on: 1) The composition of the liquid, 2) The volume and pressure of the gas above the liquid, 3) The temperature of the liquid, 4) The nature of the gas under study. The higher the pressure of a given gas and the lower the temperature, the more the gas dissolves in the liquid. At a pressure of 760 mm Hg. and a temperature of 38 ˚C in 1 ml of blood dissolves 2.2% oxygen and 5.1% carbon dioxide. The dissolution of a gas in a liquid continues until a dynamic equilibrium is reached between the number of gas molecules dissolving and escaping into the gaseous medium. The force with which the molecules of a dissolved gas tend to escape into a gaseous medium is called the tension of the gas in the liquid. Thus, in a state of equilibrium, the gas pressure is equal to the partial pressure of the gas over the liquid. If the partial pressure of a gas is higher than its voltage, the gas will dissolve. If the partial pressure of the gas is below its voltage, then the gas will come out of solution into the gaseous medium. The permeability of the lung membrane for gas is expressed by the diffusion capacity of the lungs. This is the amount of gas that penetrates through the lung membrane in 1 minute per 1 mm Hg. pressure gradient. The diffusion capacity of the lungs is proportional to the thickness of the membrane. Normally, the diffusion capacity of the lungs for oxygen is about 25 ml / min mm Hg. For carbon dioxide, due to the high solubility of this gas in the lung membrane, the diffusion capacity is 24 times higher. The partial pressure and tension of oxygen and carbon dioxide in the lungs are shown in the table. Partial pressure and tension of oxygen and carbon dioxide in the lungs (mmHg) Oxygen diffusion is provided by a partial pressure difference of about 60 mmHg, and carbon dioxide - only about 6 mmHg. The time of blood flow through the capillaries of the small circle (on average 0.7 s) is sufficient for almost complete equalization of partial pressure and gas tension: oxygen dissolves in the blood, and carbon dioxide passes into the alveolar air with a relatively small pressure difference due to the high diffusion capacity of the lungs for this gas. Gases Venous blood Alveolar air Arterial blood O2O CO
Hemoglobin is the main integral part erythrocytes and provides the respiratory function of the blood, being a respiratory enzyme. It is located inside the erythrocytes, and not in the blood plasma, which: A) Provides a decrease in blood viscosity (dissolving the same amount of hemoglobin in plasma would increase blood viscosity several times and would greatly impede the work of the heart and blood circulation); B) Reduces plasma onocotic pressure, preventing tissue dehydration; C) Prevents the body from losing hemoglobin due to its filtration in the glomeruli of the kidneys and excretion in the urine. According to the chemical structure, hemoglobin is a chromoprotein. It consists of the protein globin and the heme prosthetic group. A hemoglobin molecule contains one globin molecule and 4 heme molecules. Heme has an iron atom in its composition, capable of attaching and donating an O 2 molecule. At the same time, the valency of iron does not change, that is, it remains divalent. Iron is part of all respiratory enzymes in tissues. Such an important role of iron in respiration is determined by the structure of its atom - a large number of free electrons, the ability to complex formation and to participate in oxidation-reduction reactions. The blood of healthy men contains on average hemoglobin 145 g/l, with fluctuations from 130 to 160 g/l. In the blood of women is about 130 g / l with fluctuations from 120 to 140 g / l. In the clinic, a color indicator is often determined - the relative saturation of red blood cells with hemoglobin. Normally, it is 0.8-1. Erythrocytes with this indicator are called normochromic. If the index is greater than 1, then the erythrocytes are called hyperchromic, and if it is less than 0.8, they are called hypochromic. Hemoglobin is synthesized by erythroblasts and normoblasts in the bone marrow. When erythrocytes are destroyed, hemoglobin, after heme is cleaved off, turns into the bile pigment bilirubin. The latter enters the intestine with bile, where it turns into stercobilin and urobilin, which are excreted in feces and urine. About 8 g of hemoglobin, that is, about 1% of hemoglobin in the blood, is destroyed and converted into bile pigments per day.
In the first 7-12 weeks of intrauterine development of the embryo, its red blood cells contain primitive hemoglobin. At the 9th week, fetal hemoglobin appears in the blood of the fetus, and before birth, adult hemoglobin appears. During the first year of life, fetal hemoglobin is almost completely replaced by adult hemoglobin. Significantly, fetal Hb has a higher affinity for O 2 than adult hemoglobin, allowing it to saturate at a lower oxygen tension. The heme of different hemoglobins is the same, while globins differ in their amino acid composition and properties. Normally, hemoglobin is contained in the form of 3 physiological compounds. Hemoglobin, which has attached oxygen, turns into oxyhemoglobin - HbO 2. This compound differs in color from hemoglobin, so arterial blood has a bright scarlet color. Oxyhemoglobin that has given up oxygen is called reduced or deoxyhemoglobin (Hb). It is found in venous blood, which is darker in color than arterial blood. In addition, venous blood contains a compound of hemoglobin with carbon dioxide - carbohemoglobin, which transports CO 2 from tissues to the lungs. Hemoglobin and oxyhemoglobin absorb light rays differently in length, which formed the basis of the method for assessing blood oxygen saturation - oxygemometry. According to this method, an auricle or a cuvette with blood is illuminated with an electric light bulb and, using a photocell, the saturation of hemoglobin with oxygen is determined. Hemoglobin has the ability to form and pathological events. One of them is carboxyhemoglobin, a compound of hemoglobin with carbon monoxide(HbCO). The affinity of hemoglobin iron for CO 2 exceeds its affinity for O 2, so even 0.1% CO in the air leads to the conversion of 80% of hemoglobin into HbCO, which is not able to attach oxygen, which is life-threatening. Mild carbon monoxide poisoning is a reversible process. When breathing fresh air, CO is gradually split off. Breathing pure oxygen increases the rate of HbCO breakdown by 20 times. Methemoglobin Me (Hb) is also a pathological compound, it is an oxidized hemoglobin, in which, under the influence of strong oxidizing agents (ferricyanide, potassium permanganate, amyl and propyl nitrite, aniline, berthollet salt, phenacetin), iron heme from divalent turns into trivalent. With the accumulation of large amounts of methemoglobin in the blood, oxygen transport to tissues is destroyed and death can occur. Myoglobin. Muscle hemoglobin, called myoglobin, is found in skeletal muscle and myocardium. Its prosthetic group is identical to blood hemoglobin, and the protein part - globin - has a smaller molecular weight. Human myoglobin binds up to 14% of the total amount of oxygen in the body. This property plays an important role in the supply of working muscles. When muscles contract, blood capillaries are squeezed, and blood flow decreases or stops. However, due to the presence of oxygen associated with myoglobin, the supply of oxygen to muscle fibers is maintained for some time.
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees of physical fitness. End >> End >> > End >>">
Hypoxia is a pathological condition characterized by reduced oxygen tension in the cells and tissues of the body. The reasons that determine the development of oxygen starvation are different, therefore, the hypoxic states themselves are heterogeneous in terms of the physiological mechanism of development. This determined the need to classify hypoxia, among which four main forms are distinguished: - hypoxic, - circulatory, - hermic, - histotoxic. A decrease in the partial pressure of oxygen in the inhaled air leads to the development of arterial hypoxemia, which is a trigger for the development of a hypoxic state, causing at least three interconnected sets of phenomena. Firstly, under the influence of hypoxemia, there is a reflex increase in the tension of the function of systems that are specifically responsible for the transport of oxygen from the environment and its distribution within the body, that is, hyperventilation of the lungs, an increase in minute volume of blood circulation, dilation of the vessels of the brain and heart, narrowing of the vessels of the abdominal cavity and muscles. . Secondly, activation of the adrenergic and pituitary-adrenal systems develops, that is, the stress response. This nonspecific component of adaptation plays a role in the mobilization of the circulatory and external respiration apparatus, but at the same time, an excessively pronounced stress reaction due to catabolic action can lead to a breakdown of adaptive processes in the body. The leading link in the pathogenesis of the hypoxic state is energy deficiency associated with the transition of metabolism to a less energetically favorable anaerobic pathway and a violation of the coupling of oxidation and phosphorylation processes. The process of mutual oxidation - phosphorylation of electron carriers in the respiratory chain of mitochondria is disrupted. Following the violation of the redox potential of carriers by electrons, oxidative phosphorylation, energy production and the process of energy accumulation in the macroergic bonds of ATP and creatipphosphate decrease. By limiting the re-synthesis of ATP in mitochondria, acute hypoxia causes a direct depression of the functions of a number of body systems, primarily the central nervous system, myocardium, and liver. In intensively working organs, there is an increased breakdown of glycogen, dystrophic phenomena occur, and the “oxygen debt” of the body increases. The resulting changes are even more intensified under the influence of underoxidized metabolic products. The observed pattern of hypoxic hypoxia depends on the decrease in the partial pressure of oxygen in the inhaled air. Starting from a height of 1000 m, an increase in pulmonary ventilation is observed, initially due to an increase in the depth of breathing, and at an altitude of more than 2000 m, hyperventilation of the lungs is also due to an increase in the respiratory rate. At the same time, the depth of breathing can decrease due to an increase in the tone of the respiratory muscles and a rise in the diaphragm, an increase in the residual volume and a decrease in the expiratory reserve volume, which is subjectively assessed as a feeling of chest swelling. At altitudes above 3000m, hyperventilation leads to hypocapnia, which can lead to periodic breathing and a decrease in severe hyperventilation. As a result of the direct action of a reduced partial pressure of oxygen on the smooth muscles of the pulmonary vessels and the release of biologically active substances, it increases pulmonary arterial pressure. An increase in pressure in the pulmonary artery is a factor that determines the increase in blood flow through the gas exchange structures of the lungs. At the same time, the narrowing of the lumen of small pulmonary vessels determines the uniform blood supply to various parts of the lungs and an increase in their diffusion capacity. In parallel with changes in the external respiratory system, there is an increase in the minute volume of blood flow, mainly due to transient tachycardia, starting from a height of 2510 m, and in persons with a disorder of the cardiorespiratory system - reduced physical endurance from a height of 1500 m. In the genesis of tachycardia, the reflexes from the chemoreceptors of the sinocarotid and aortic vascular regions are triggered by adrenergic influences associated with the mobilization phase of the stress reaction and realized through myocardial adrenoreceptors. The existence of an influence on the clinical picture of hypoxic hypoxia is exerted by higher increases in heart rate when performing even light physical work or during an orthostatic test. The most sensitive to oxygen deficiency is the central nervous system, from which the following changes in higher psychological functions are observed: - the level of emotional excitability increases, - decreases critical thinking, - finely coordinated reactions are slowed down. At altitudes of m, there are disturbances in the function of the visual and auditory analyzer, mental activity decreases, short-term and operative memory are disturbed. At high altitudes, heaviness in the head, drowsiness, headache, weakness and nausea join these phenomena. The development of these symptoms is usually preceded by euphoria. Short-term exposure to moderate hypoxia can have a stimulating effect on physical and mental performance, but staying more than 30 minutes at altitudes of m can already lead to a decrease in physical and mental performance with excessive functioning of the cardiorespiratory system. So, already in the first day of stay at an altitude of 3000m, maximum physical performance can decrease by 20-45%, depending on individual stability and hypoxia. Therefore, physical work of even low intensity under hypoxic conditions can be assessed by the body as work of submaximal or maximum power, and therefore quickly lead to fatigue and depletion of the body's reserve capabilities.
In the complex structure of compensatory-adaptive processes developing in the human body to hypoxic exposure, Meyerson F.Z. identified 4 levels of mechanisms coordinated among themselves: 1. Mechanisms, the mobilization of which can ensure sufficient oxygen supply to the body, despite its deficiency in environment(hyperventilation, hyperfunction of the myocardium, providing the volume of pulmonary circulation; and a corresponding increase in the oxygen capacity of the blood). 2. Mechanisms that make possible a sufficient supply of oxygen to the brain, heart and other vital organs, despite hypoxia (decrease in the diffuse distance for oxygen between the capillary wall and mitochondria of cells due to the formation of new capillaries and increase the permeability of cell membranes; increase the ability of cells to utilize oxygen due to an increase in the concentration of myoglobin; facilitation of the dissociation of oxyhemoglobin). 3. An increase in the ability of cells and tissues to utilize oxygen in the blood and form ATP, despite its deficiency (an increase in the affinity of cytochrome oxidase, newly formed mitochondria, an increase in the coupling of oxidation with phosphorylation). 4. An increase in anaerobic ATP resynthesis due to the activation of glycolysis. Should be considered limited opportunities these mechanisms, the limiting link of which is the limited reserves of functional systems. Thus, the efficiency of external respiration is sharply reduced when the minute volume of respiration exceeds 45 l / min; the possibilities of hemodynamics are limited by the chronotropic and inotropic reserve of the myocardium. The limiting value of the reserve systems of the body is especially clearly revealed in situations of their deficiency (diseases of the cardiorespiratory system, intense physical activity, etc.), when dysadaptation syndromes (acute headache, high-altitude pulmonary edema, focal myocardial dystrophy) can develop even when staying at a relatively low altitude (m). If the reserve capabilities of physiological systems make it possible to maintain the vital activity of the organism at the proper level, then gradually other mechanisms are connected to the mobilization mechanisms aimed at the formation of long-term sustainable adaptation. The stage of an urgent reaction to hypoxia is replaced by a transitional one. In the transitional stage, a deficiency of macroergic compounds in cells that perform an increased function and are exposed to hypoxia causes activation of the synthesis nucleic acids and proteins. This activation of protein synthesis covers an unusually wide range of organs and systems and leads to the formation of an extensive systemic structural trace of adaptation. Thus, the activation of the synthesis of nucleic acids and proteins in the bone marrow becomes the basis for the proliferation of erythroid cells, in the lung tissue it leads to hypertrophy of the lung tissue and an increase in their respiratory surface. Activation of adaptive protein synthesis in the myocardium leads to an increase in the power of adrenergic regulation of the heart, a significant increase in the concentration of myoglobin, the throughput of the coronary bloodstream, and, in general, an increase in the power of the heart's energy supply system. In the transitional stage, mechanisms begin to actively function that provide an increase in the ability of tissues and cells to utilize oxygen from the blood and form ATP, despite its lack (an increase in the redox potential of tissue respiration enzymes, an increase in the number of mitochondria, the degree of oxidation and phosphorylation of substrates). There is also an increase in the intensity of anaerobic processes and processes of neutralization of underoxidized metabolic products, such as glycolysis, gluconeogenesis, shunting of the limiting links of the tricarboxylic acid cycle. There is a formation of a new level of hormonal regulation of the physiological systems of the body, leading to a decrease in basal metabolism and a more economical use of oxygen by tissues.
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees of physical fitness. End >> End >> > End >>">
Indicators of pulmonary ventilation are subdivided (conditionally) into anatomical values. They depend on gender, age, weight, height. A correct assessment of the functional state of the external respiration apparatus is possible only by comparing absolute indicators with the so-called due values - the corresponding values in a healthy person of the same age, weight, sex, height. There are lung volumes and capacities. 1) Lung volumes: - tidal volume (depth of breathing); - inspiratory reserve volume (additional air); - expiratory reserve volume (reserve air); - residual volume (residual air) 2) Lung capacity: - vital capacity of the lungs (the sum of the respiratory volume of the reserve volume of inhalation and exhalation); - total lung capacity (sum of vital lung capacity and residual volume); - functional residual capacity (sum of residual volume and expiratory reserve volume) - inspiratory capacity - sum of tidal volume and inspiratory reserve volume). The function of external respiration is studied using devices of closed and open type. With a closed method for studying gas exchange (spirography), domestic spirographs of the Kyiv and Kazan medical equipment plants are used. In closed-type devices, the subject inhales air from the device and exhales it there, that is, the airways and the device form a closed system. There is a carbon dioxide absorber in the path of the exhaled air. On a moving paper tape, a breathing recording curve is recorded - a spirogram. It determines the frequency and depth of breathing, minute volume, vital capacity of the lungs and its fractions, oxygen uptake per unit of time, calculate respiratory rates and basal metabolism. The study can be carried out while breathing both atmospheric air and oxygen. A prerequisite is a preliminary acquaintance with the nature of the study (training breathing in a spirograph, Douglas bag). The results can be considered reliable if the connection of the system does not change the natural pattern of breathing. An open method for studying gas exchange (the method of Douglas and Holden). In open-type devices, the subject inhales atmospheric air from the outside through the valve box. The exhaled air enters a Douglas bag (a plastic or rubber bag with a capacity of litres) or a gas meter that continuously measures the volume of exhaled air. Connection to the system is made simultaneously with the start of the stopwatch. The collected air in the Douglas bag is mechanically mixed and taken for analysis. The remaining air is passed through a gas watch to determine the volume of exhaled air. The latter, divided by the number of minutes of the study, is given according to special tables to normal conditions (barometric pressure 760 mm Hg and temperature 0 ˚С). The resulting figure is the value of the minute volume of breathing. Analysis of a sample of exhaled air in the gas analysis (Holden apparatus) allows you to determine the percentage of oxygen uptake and carbon dioxide release. Using special tables, they calculate the utilization of oxygen in the lungs, the release of carbon dioxide, respiratory coefficient, main exchange. The Belau apparatus also belongs to the open type systems, which makes it possible to continuously record the content of oxygen and carbon dioxide in the exhaled air. Pneumography. Method for studying the respiratory movements of the chest. The respiratory curve (pneumogram) is recorded using a rubber cuff, which is placed on the chest and connected to Marey's capsule and a writing device. Piezo sensors have also become widespread, converting mechanical movements chest in electricity. In this case, the pneumogram is recorded using an oscilloscope. The pneumography method allows you to determine the frequency and rhythm of breathing, changes in the phases of the respiratory cycle. Normally, the ratio of the duration of inhalation and exhalation is 1:1.2 and 1.5. It is recommended to record a pneumogram for a long time, if possible, in a calm state of the subject. The pneumography method is widely used to study breathing in children. early age, while the use of open and closed studies of gas exchange at this age is difficult. Pneumotachometry. Method for measuring the power of forced inhalation and exhalation. Used to judge airway resistance (bronchial patency). The pneumotachometer sensor is a metal tube with a diaphragm. The pressure drop that occurs when air passes through the apertures of the diaphragm is measured with a special pressure gauge. The subject is asked to take the tip of the tube into his mouth and exhale as quickly as possible. Then, after a short rest and switching the tap, a quick breath is taken. The arrow of the school of the device shows the power of the air flow in liters per second. Measurements are made three times, the largest result is taken into account. Clinical Significance. In diseases accompanied by a violation of bronchial patency (chronic pneumonia, bronchial asthma), a decrease in the power of the forced exit and, to a lesser extent, inhalation is usually observed. Respiratory volume. (DO) - the volume of inhaled and exhaled air during each respiratory cycle. It is determined by dividing the minute volume and respiratory rate by the number of breaths per minute. The value of DO depends on age, physical development and lung capacity. The study of respiratory volume and respiratory rate allows you to objectively assess the nature of pulmonary ventilation. Deep and rare breathing creates the best conditions for pulmonary gas exchange. Frequent and shallow breathing, on the contrary, is ineffective due to the increased role of "harmful space" (air that fills the respiratory tract and does not participate in gas exchange) and uneven ventilation of different parts of the lungs. In childhood, there is a significant lability of indicators of external respiration and, first of all, the frequency and depth of respiration. The child's breathing from an early age is frequent and superficial. With age, breathing in children becomes less frequent (from 48 to 17 breaths per 1 minute) and the tidal volume increases (from 30 ml at the age of one month to 275 ml at 15 years old - average data according to N.A. Shalkov). clinical significance. Of practical importance is the value of the volume of respiration in combination with the frequency of respiration. So, in acute pneumonia and chronic respiratory diseases (bilateral diffuse pneumosclerosis, pneumofibrosis), the respiratory volume decreases, while the respiratory rate increases. A decrease in respiratory volume is observed in patients with severe circulatory failure, severe stagnation in the lungs, chest rigidity, with inhibition of the respiratory center. Inspiratory reserve volume is the maximum volume of air that can be inhaled after a normal inspiration. Determined by spirogram. After a quiet breath, the subject is asked to take the deepest possible breath, after seconds the recording of the maximum breath is repeated. The height of the peak inspiratory wave is measured. The height of the maximum inspiratory wave is measured from the level of a quiet breath. In accordance with the scale of the scale of the spirograph, a conversion to milliliters is made. In children, the reserve volume varies widely ml. Expiratory reserve volume is the maximum volume of air that can be exhaled after a normal exhalation. After a quiet exhalation, the subject is asked to exhale as much as possible into the spirometer, or spirograph. The maximum expiration tooth value is measured from the level of a calm exhalation to the top of the tooth and recalculated into milliliters. The value of the expiratory reserve volume in children varies within ml, accounting for approximately 20-25% of the vital capacity of the lungs. clinical significance. A significant decrease in the reserve volumes of inhalation and exhalation is observed with a decrease in the elasticity of the lung tissue, bronchial asthma, emphysema. The practical significance of the inspiratory and expiratory reserve volumes is insignificant due to significant individual variability. Vital capacity of the lungs (VC) - maximum amount air that can be exhaled after a maximum inhalation. It is measured using a spirometer or spirograph. The VC value increases with age. According to N.A. Shalkov, the average data at the age of 4-6 years is 1100 - 1200 ml, increasing to ml by the age. Boys have more vital capacity than girls. It is recommended to evaluate the VC of the person under study by comparing it with the due vital capacity (JLC). Various formulas for determining the long-term vital capacity of the lungs have been proposed: JEL = (27.63-0.112 · age) · standing height (for males); or (21.78-0.101 age) standing height (for females). According to Anthony: JEL = proper basal metabolism 2.3 (for women) or 2.6 (for men). The value thus obtained is then multiplied by a correction factor of 1.21. A decrease in VC below 80% of the proper value is regarded as a pathological phenomenon. clinical significance. A decrease in VC is observed in children with acute pneumonia and chronic respiratory diseases. It progresses as respiratory failure increases. VC decreases in diseases of the cardiovascular system, with limited mobility of the chest, diaphragm. Re-measurement of VC over time is essential. In children, VC increases during sports.
Total lung capacity (TLC) is the amount of air in the lungs after a maximum inhalation. It is calculated after determining the residual volume and vital capacity of the lungs. Depends on its constituent lung volumes. TL increases with age in children. To determine the proper total vital capacity (DOVEL), it is proposed to proceed from the value of the proper VC. According to Anthony: DEGEL is equal to JEL multiplied by 1.32. Fluctuations from these average values by ± 15-20% are allowed. clinical significance. A sharp decrease in TRL is observed in diffuse pulmonary fibrosis, to a lesser extent it is expressed in pneumosclerosis and heart failure. Under the influence of playing sports, the TEL in children increases. Pulmonary ventilation. Minute respiratory volume (MOD) - the amount of air ventilated in the lungs per minute. It can be measured by breathing into a Douglas bag, on a gas watch, or by a spirogram. On the spirogram, the sum of respiratory movements is determined for 3-5 minutes and then the average value per minute is calculated. MOD in conditions of basal metabolism (at rest, lying down, on an empty stomach) is a relatively constant value. average value MOD in healthy children increases from 2000 ml at the age of 1 year to 5000 ml at the age of 15 years. MOD in children in ml per 1 m2 of body surface decreases with age from 7800 ml at the age of 1 year to 3750 ml at the age of 15. To assess compliance with the MOD, it is proposed to calculate the respiratory equivalent (DE), expressing the number of liters of air that must be ventilated in order to use 100 ml of oxygen. DE is equal to the actual MOD divided by the proper oxygen uptake multiplied by 10. The higher the DE, the more intense the pulmonary ventilation and the less effective the respiratory function. The high frequency and shallow depth of breathing in young children cause less effective respiratory function compared to older children. This causes a gradual decrease in DE with the age of children (on average, from 3.8 at the age of 5 months to 2.4 by 15 years). clinical significance. An increase in MOD (hyperventilation) is observed due to excitation of the respiratory center, an increase in the body's need for oxygen and a deterioration in the conditions of pulmonary gas exchange: a decrease in the respiratory surface of the lungs, difficulty in oxygen diffusion, etc. A decrease in MOD (hypoventilation) is observed due to inhibition of the respiratory center, a decrease in the elasticity of the lung tissue, restriction of lung mobility (pleural effusion, pneumothorax, etc.) Great importance to identify early (hidden) forms of respiratory failure, it acquires the definition of MOD during exercise. In case of respiratory failure, the transition from breathing air to breathing oxygen is often accompanied by a decrease in MOD, which is not observed in healthy individuals. Maximum lung ventilation (MVL) (respiratory limit, maximum minute volume, maximum respiratory capacity) - the maximum amount of air that can be ventilated per minute. MVL is determined using a gas clock, Douglas bag, direct spirography. In childhood, the most common method for determining MVL is arbitrary forced breathing for 15 seconds (longer hyperventilation leads to increased release of carbon dioxide from the body and hypocapnia). According to the spirogram, the sum of the values of the teeth (in millimeters) is calculated and, in accordance with the scale of the scale of the spirograph, the conversion to milliliters is carried out. The measured amount of exhaled air is reduced by 4. MVL is determined in the sitting position, several times, preferably within a few days. In repeated studies, the largest value is taken into account. MVL in children increases with age from 42 at 6-8 years to 80 liters per year. clinical significance. A decrease in MVL is observed in diseases accompanied by a decrease in lung compliance, impaired bronchial patency, and heart failure. Pulmonary gas exchange. Oxygen uptake (PO 2) is the amount of oxygen uptake per minute. It is determined by the spirographic method of studying the function of external respiration either by the level of the slope of the spirogram (in devices without automatic oxygen supply), or by the oxygen supply registration curve (in devices with automatic oxygen supply, the spirogram record is horizontal). Taking into account the scale of the spirograph scale and the speed of the paper, the amount of oxygen absorbed per minute is calculated. Oxygen consumption increases with age. In children at the age of 1 year, it averages 60 ml, in years - 200 ml per minute. The determination of PO 2 is carried out under conditions of basal metabolism. By dividing the proper basal metabolism by 7.07, the proper value of PO 2 is obtained. A deviation from the average due value of ± 20% is acceptable. clinical significance. An increase in PO 2 is noted with an increase in oxidative processes in the body, with an increase in pulmonary ventilation. With physical activity, PO 2 increases. A decrease in PO 2 is observed in heart and lung failure, with a significant increase in minute ventilation. Oxygen utilization coefficient (OI) - the amount of ml of oxygen absorbed from 1 liter of ventilated air. It is calculated by dividing the amount of oxygen absorbed per minute by the value of the MOD (in l). The determination is carried out according to the same spirogram, at the same time interval. Use the actual values of MOD and PO 2 determined at room temperature. The value of CI increases with the age of children from 20 ml in the first year of life to 36 ml by 15 years. clinical significance. A decrease in CI indicates a deterioration and decrease in the efficiency of pulmonary ventilation, a violation of diffusion processes. The test with oxygen breathing is accompanied in some patients by an increase in CI. This circumstance, in combination with other symptoms, can be considered as a manifestation of respiratory failure. Under the influence physical activity in healthy children, CI increases, which is an indicator of good use of ventilated air. With latent respiratory failure, there is a decrease in the oxygen utilization factor even with moderate physical exertion, with obvious - at rest.
Tests with breath holding on inhalation (Bar) and on exhalation (Gencha) are simple and accessible. They are widely used to assess the functional state of the respiratory and cardiovascular systems. The study is carried out in a sitting position after resting for 5-7 minutes, preferably on an empty stomach. Stange test. The child is offered to take 3 deep breaths and exhale, at the height of the fourth breath, hold his breath, holding his nose with his fingers. On a stopwatch, the time from the end of a deep breath to the resumption of breathing is noted. The duration of breath holding on inspiration in healthy children aged 6-18 years varies within seconds. Gencha test. The child is offered to take 3 deep breaths and exhalations, and after the third exhalation, hold his breath, holding his nose with his fingers. The stopwatch records the time from the end of the third expiration to the resumption of breathing. In healthy people school age this time is equal to seconds. Combined test with breath holding (A.F. Serkin test) 1st phase. The time during which the subject can hold his breath while inhaling in a sitting position is determined. 2nd phase. The time of holding the breath in the inhalation phase is determined immediately after twenty squats performed within 30 seconds. 3rd phase. A minute later, phase 1 is repeated. clinical significance. The duration of breath holding on inhalation and exhalation usually decreases in diseases of the cardiovascular and respiratory systems. It depends on many factors: the excitability of the respiratory center, the intensity of tissue metabolism, volitional qualities, the discipline of the child, etc. The reaction of the external respiration apparatus to physical activity. Functional tests with physical activity are used to assess the reserve capacity of the external respiration system and to identify latent respiratory failure. As a physical activity, running in place, climbing stairs, deep squats, working on a bicycle ergometer, etc. are used. A “differentiated functional test” has become widespread in medical practice. With a favorable reaction to the load, the minute volume of breathing increases mainly due to the deepening of breathing. The vital capacity of the lungs remains unchanged or increases slightly. All indicators return to their original level after 3-5 minutes. If a child has respiratory failure, an unfavorable reaction is observed: after physical activity, an increase in the minute volume of breathing occurs mainly due to its increase. The vital capacity of the lungs often decreases. The respiratory equivalent increases. The recovery period is usually extended. The systems of external respiration and blood circulation perform a single function in the body - they provide tissue respiration, which determines their interconnection and interdependence. Therefore, the study of the cardiovascular and respiratory systems should be comprehensive, especially when conducting stress functional tests.
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees of physical fitness. End >> End >> > End >>">
Schoolchildren who are not involved in sports and schoolchildren-athletes at the age of years took part in the research. The total number of surveyed - 40 people. To determine the indicators of external respiration in the examined, the respiratory rate, tidal volume, and vital capacity of the lungs were measured. The following functional tests were carried out: Stange and Gencha. The results of the study of indicators of external respiration are presented in the table. As follows from the data obtained, the indicators of external respiration have the highest values among schoolchildren involved in sports. Thus, the tidal volume in athletes is 33% higher, and the vital capacity of the lungs is 27%. Subject population Respiratory rate Respiratory volume, l Vital lung capacity, l Untrained schoolchildren15 ± 1.30.24 ± 0.192.2 ± 0.56 Athlete schoolchildren17 ± 0.980.32 ± 0.182.8 ± 0.46 The results of the Stange and Gench tests are displayed on diagram. As follows from the presented diagram, the time from the end of a deep breath to the resumption of breathing is significantly higher in schoolchildren-athletes by almost 50%. The same picture is observed when considering the results obtained during the Gench test. The time from the end of expiration to the resumption of breathing is significantly higher by 38%.
1. Chemical nature of oxygen and carbon dioxide Oxygen The role of oxygen in nature and its application in technology Carbon monoxide (IV). 2. Participation of oxygen and carbon dioxide in the exchange of gases in the human body Partial pressure of oxygen and carbon dioxide Hemoglobin Varieties of hemoglobin in humans. 3. Hypoxia. Effect of hypoxia on the functional state of a person. 4. Methods for studying the function of external respiration. functional tests. 5. The study of the state of external respiration in schoolchildren with varying degrees of physical fitness. End >> End >> > End >>">
1. All energy transformations in the body are carried out with the participation of oxygen. First of all, the respiratory and circulatory systems react to oxygen deficiency, ensuring a rational redistribution of blood. 2. Conditions in which the amount of oxygen in the human blood decreases (in particular, hypoxia) are pathological changes in the cells and tissues of the body. The reasons that determine the development of oxygen starvation are different, therefore, the hypoxic states themselves are heterogeneous in terms of the physiological mechanism of development. 3. The study of respiratory parameters (volume and frequency of breathing) allows you to objectively assess the nature of pulmonary ventilation. It was noted that deep and rare breathing creates the best conditions for pulmonary gas exchange. 4. As a result of the study, it was found that the indicators of external respiration in schoolchildren-athletes are significantly higher than in their peers who do not go in for sports.
Description of the presentation on individual slides:
1 slide
Description of the slide:
2 slide
Description of the slide:
oxygen OXYGEN (lat. Oxygenium), O (read "o"), chemical element with atomic number 8, atomic mass 15.9994. In Mendeleev's periodic table of elements, oxygen is located in the second period in group VIA. Natural oxygen consists of a mixture of three stable nuclides with mass numbers 16 (dominates in the mixture, it contains 99.759% by mass), 17 (0.037%) and 18 (0.204%). In its free form, oxygen is a colorless, odorless, and tasteless gas. Features of the structure of the O2 molecule: atmospheric oxygen consists of diatomic molecules. The energy of dissociation of the O2 molecule into atoms is quite high and amounts to 493.57 kJ/mol.
3 slide
Description of the slide:
Chemical properties of oxygen: Oxygen is the second most electronegative element after fluorine, so it exhibits strong oxidizing properties. It reacts with most metals already at room temperature, forming basic oxides. With non-metals (with the exception of helium, neon, argon), oxygen reacts, as a rule, when heated. So, it reacts with phosphorus at a temperature of ~ 60 ° C, forming P2O5, with sulfur - at a temperature of about 250 ° C: S + O2 \u003d SO2. Oxygen reacts with graphite at 700 °C C + O2 = CO2. The interaction of oxygen with nitrogen begins only at 1200 ° C or in an electric discharge N2 + O2 2NO - Q. Oxygen also reacts with many complex compounds, for example, with nitric oxide (II), it reacts already at room temperature: 2NO + O2 \u003d 2NO2.
4 slide
Description of the slide:
Hydrogen sulfide, reacting with oxygen when heated, gives sulfur 2H2S + O2 = 2S + 2H2O or sulfur oxide (IV) 2H2S + 3O2 = 2SO2 + 2H2O, depending on the ratio between oxygen and hydrogen sulfide. In the above reactions, oxygen is an oxidizing agent. In most oxidation reactions involving oxygen, heat and light are released - such processes are called combustion. An even stronger oxidizing agent than oxygen O2 is ozone O3. It is formed in the atmosphere during lightning discharges, which explains the specific smell of freshness after a thunderstorm. Usually, ozone is produced by passing a discharge through oxygen (the reaction is endothermic and highly reversible; ozone yield is about 5%): 3O2<=>2O3 - 284 kJ. When ozone interacts with a solution of potassium iodide, iodine is released, while this reaction does not occur with oxygen: 2KI + O3 + H2O = I2 + 2KOH + O2. The reaction is often used as a qualitative one for the detection of I- or ozone ions. To do this, starch is added to the solution, which gives a characteristic blue complex with released iodine. The reaction is also qualitative because ozone does not oxidize Cl- and Br- ions.
5 slide
Description of the slide:
6 slide
Description of the slide:
Obtaining oxygen in industry oxygen is obtained: by fractional distillation of liquid air (nitrogen, which has a lower boiling point, evaporates, and liquid oxygen remains); water electrolysis. Every year over 80 million tons of oxygen are received all over the world. Under laboratory conditions, oxygen is obtained by decomposition of a number of salts, oxides and peroxides: 2KMnO4 -> K2MnO4 + MnO2 + O2, 4K2Cr2O7 -> 4K2CrO4 + 2Cr2O3 + 3O2, 2KNO3 -> 2KNO2 + O2, 2Pb3O4 -> 6PbO + O2, 2HgO -> 2Hg + O2, 2ВаО -> 2ВаО + О2, 2Н2O2 -> 2Н2О + О2. Oxygen is especially easily released as a result of the last reaction, since in hydrogen peroxide H2O2 is not double, but single bond between oxygen atoms -О-О-.
7 slide
Description of the slide:
Application The main quantities of oxygen obtained from the air are used in metallurgy. Oxygen (rather than air) blast in blast furnaces makes it possible to significantly increase the speed of the blast-furnace process, save coke and obtain better quality pig iron. Oxygen blast is used in oxygen converters during the conversion of cast iron into steel. Pure oxygen or air enriched with oxygen is also used in the production of many other metals (copper, nickel, lead, etc.). Oxygen is used in cutting and welding metals. be under pressure up to 15 MPa. The oxygen cylinders are blue. Liquid oxygen is a powerful oxidizing agent, it is used as a component of rocket fuel. Easily oxidized materials impregnated with liquid oxygen, such as sawdust, cotton wool, coal powder, etc. (these mixtures are called oxyliquites), are used as explosives used, for example, when laying roads in the mountains.
8 slide
9 slide
Description of the slide:
In every plant or animal, there is much more oxygen than any other element (about 70% on average). Human muscle tissue contains 16% oxygen, bone tissue - 28.5%; in total, the body of an average person (body weight 70 kg) contains 43 kg of oxygen. Oxygen enters the body of animals and humans mainly through the respiratory organs (free oxygen) and with water (bound oxygen). The body's need for oxygen is determined by the level (intensity) of metabolism, which depends on the mass and surface of the body, age, gender, nutrition, external conditions, etc. In ecology, the ratio of total respiration (that is, total oxidative processes) of the community is determined as an important energy characteristic. organisms to its total biomass. Small amounts of oxygen are used in medicine: oxygen (from the so-called oxygen pillows) is given some time to breathe for patients who have difficulty breathing. However, it must be borne in mind that prolonged inhalation of air enriched with oxygen is dangerous to human health. High oxygen concentrations cause the formation of free radicals in tissues that disrupt the structure and functions of biopolymers. Ionizing radiation has a similar effect on the body. Therefore, a decrease in the oxygen content (hypoxia) in tissues and cells during irradiation of the body with ionizing radiation has a protective effect - the so-called oxygen effect.
10 slide
Description of the slide:
Distribution and forms of oxygen in nature Oxygen is the most widespread element of the solid earth's crust, hydrosphere, and living organisms. Its clarke in the lithosphere is 47%, the clarke in the hydrosphere is even higher - 82% and living matter - 70%. More than 1400 oxygen-containing minerals are known, in which dozens of elements of the periodic system are its companions. Oxygen is a cyclic element of V. I. Vernadsky's classification; it participates in numerous cycles of various scales - from small ones, within a specific landscape, to grandiose ones, connecting the biosphere with magmatism centers. Oxygen accounts for approximately half of the entire mass of the earth's crust, 89% of the mass of the world's oceans. In the atmosphere, oxygen makes up 23% by mass and 21% by volume.
11 slide
Description of the slide:
On the earth's surface Green plants decompose water during photosynthesis and release free oxygen (O2) into the atmosphere. As Vernadsky noted, free oxygen is the most powerful agent of all known chemical bodies in the earth's crust. Therefore, in most systems of the biosphere, for example, in soils, ground, river and sea waters, oxygen acts as a real geochemical dictator, determines the geochemical originality of the system, the development of oxidative reactions in it. Over billions of years of geological history, plants have made the atmosphere of our planet oxygenated, the air we breathe is made of life. The number of oxidation reactions that consume free oxygen is enormous. In the biosphere, they are mainly of a biochemical nature, that is, they are carried out by bacteria, although purely chemical oxidation is known. In soils, silts, rivers, seas and oceans, groundwater horizons - wherever there are organic substances and water, the activity of microorganisms that oxidize organic compounds develops.
12 slide
Description of the slide:
Most natural waters containing free oxygen - a strong oxidizing agent, there are organic compounds - strong reducing agents. Therefore, all geochemical systems with free oxygen are non-equilibrium and rich in free energy. Non-equilibrium is expressed the more sharply, the more living matter in the system. Everywhere in the biosphere, where waters that do not contain free oxygen (with a reducing environment) meet this gas, an oxygen geochemical barrier arises, on which Fe, Mn, S and other elements are concentrated with the formation of ores of these elements. Previously, there was a misconception that as one deepens into the thickness of the earth's crust, the environment becomes more reducing, but this does not fully correspond to reality. On the earth's surface, in the landscape, both sharply oxidizing and sharply reducing conditions can be observed. Redox zoning is observed in lakes - photosynthesis develops in the upper zone and saturation and oversaturation with oxygen is observed. But in the deep parts of the lake, in the mud, only decomposition takes place. organic matter. Below the biosphere, in the zone of metamorphism, the degree of reduction of the environment often decreases, as in magma chambers. The most reducing conditions in the biosphere occur in areas of vigorous decomposition of organic matter, and not at maximum depths. Such areas are characteristic of both the earth's surface and aquifers.
13 slide
Description of the slide:
The oxygen cycle Oxygen is the most abundant element on earth. Sea water contains 85.82% oxygen, atmospheric air 23.15% by weight or 20.93% by volume, and 47.2% by weight in the earth's crust. This concentration of oxygen in the atmosphere is maintained constant through the process of photosynthesis. In this process, green plants under the action sunlight convert carbon dioxide and water into carbohydrates and oxygen. The main mass of oxygen is in a bound state; the amount of molecular oxygen in the atmosphere is estimated at 1.5 * 1015 m, which is only 0.01% of the total oxygen content in the earth's crust. In the life of nature, oxygen is of exceptional importance. Oxygen and its compounds are indispensable for sustaining life.
14 slide
Description of the slide:
They play an important role in metabolic processes and respiration. Oxygen is a part of proteins, fats, carbohydrates from which organisms are "built"; in human body, for example, contains about 65% oxygen. Most organisms obtain the energy they need to perform their vital functions by oxidizing certain substances with the help of oxygen. The decrease in oxygen in the atmosphere as a result of the processes of respiration, decay and combustion is compensated for by oxygen released during photosynthesis. Deforestation, soil erosion, various mine workings on the surface reduce the total mass of photosynthesis and reduce the circulation over large areas. Along with this, a powerful source of oxygen is, apparently, the photochemical decomposition of water vapor in the upper layers of the atmosphere under the influence of the ultraviolet rays of the sun. Thus, in nature, the oxygen cycle is continuously performed, maintaining the constancy of the composition atmospheric air. In addition to the oxygen cycle described above in an unbound form, this element also performs the most important cycle, being a part of water. The water cycle (H2O) consists in the evaporation of water from the surface of land and sea, its transfer by air masses and winds, vapor condensation and subsequent precipitation in the form of rain, snow, hail, fog.
Among all substances on earth special place occupies what provides life - oxygen gas. It is its presence that makes our planet unique among all others, special. Thanks to this substance, so many beautiful creatures live in the world: plants, animals, people. Oxygen is an absolutely irreplaceable, unique and extremely important compound. Therefore, we will try to find out what it is, what characteristics it has.
The first method is especially used. After all, a lot of this gas can be released from the air. However, it will not be completely clean. If you need a product more High Quality, then electrolysis processes are launched. The raw material for this is either water or alkali. Sodium or potassium hydroxide is used to increase the electrical conductivity of the solution. In general, the essence of the process is reduced to the decomposition of water.
Obtaining in the laboratory
Among laboratory methods, the heat treatment method is widely used:
- peroxides;
- salts of oxygen-containing acids.
At high temperatures, they decompose with the release of gaseous oxygen. The process is most often catalyzed by manganese (IV) oxide. They collect oxygen by displacing water, and they find it with a smoldering splinter. As you know, in an oxygen atmosphere, the flame flares up very brightly.
Another substance used to produce oxygen at school lessons chemistry, - hydrogen peroxide. Even a 3% solution under the action of a catalyst instantly decomposes with the release of pure gas. It just needs to be collected. The catalyst is the same - manganese oxide MnO 2 .
The most commonly used salts are:
- Berthollet salt, or potassium chlorate;
- potassium permanganate, or potassium permanganate.
An equation can be given to describe the process. Oxygen is released enough for laboratory and research needs:
2KClO 3 \u003d 2KCl + 3O 2.
Allotropic modifications of oxygen
There is one allotropic modification that oxygen has. The formula of this compound is O 3, it is called ozone. This is the gas that is produced in natural conditions when exposed to ultraviolet and lightning discharges on atmospheric oxygen. Unlike O 2 itself, ozone has a pleasant smell of freshness, which is felt in the air after rain with lightning and thunder.
The difference between oxygen and ozone lies not only in the number of atoms in the molecule, but also in the structure of the crystal lattice. Chemically, ozone is an even stronger oxidizing agent.
Oxygen is a component of air
The distribution of oxygen in nature is very wide. Oxygen is found in:
- rocks and minerals;
- salt and fresh water;
- soil;
- plant and animal organisms;
- air, including the upper atmosphere.
It is obvious that all the shells of the Earth are occupied by it - the lithosphere, hydrosphere, atmosphere and biosphere. Especially important is its content in the composition of the air. After all, it is this factor that allows life forms, including humans, to exist on our planet.
The composition of the air we breathe is extremely heterogeneous. It includes both constant components and variables. The permanent and always present are:
- carbon dioxide;
- oxygen;
- nitrogen;
- noble gases.
Variables include water vapor, dust particles, foreign gases (exhaust, combustion products, decay, and others), plant pollen, bacteria, fungi, and others.
Importance of oxygen in nature
It is very important how much oxygen is contained in nature. After all, it is known that trace amounts of this gas were found on some satellites of the major planets (Jupiter, Saturn), but there is no obvious life there. Our Earth has enough of it, which, in combination with water, makes it possible for all living organisms to exist.
In addition to being an active participant in respiration, oxygen also conducts countless oxidation reactions, as a result of which energy is released for life.
The main suppliers of this unique gas in nature are green plants and some types of bacteria. Thanks to them, a constant balance of oxygen and carbon dioxide is maintained. In addition, ozone builds a protective shield over the entire Earth, which does not allow a large amount of destructive ultraviolet radiation to penetrate.
Only some types of anaerobic organisms (bacteria, fungi) are able to live outside an oxygen atmosphere. However, there are far fewer of them than those who really need it.
The use of oxygen and ozone in industry
The main areas of application of allotropic modifications of oxygen in industry are as follows.
- Metallurgy (for welding and cutting metals).
- The medicine.
- Agriculture.
- as rocket fuel.
- Synthesis of many chemical compounds, including explosives.
- Purification and disinfection of water.
It is difficult to name at least one process in which this great gas, a unique substance, oxygen, does not take part.
- The displacement is called the vector connecting the start and end points of the trajectory The vector connecting the beginning and end of the path is called
- Trajectory, path length, displacement vector Vector connecting the initial position
- Calculating the area of a polygon from the coordinates of its vertices The area of a triangle from the coordinates of the vertices formula
- Acceptable Value Range (ODZ), theory, examples, solutions