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Natural history. Section II. Chemistry with elements of ecology Lesson on the topic: Section of chemistry. Water and its properties. Time: 2 hours Study questions 1. Introduction to chemistry. Theoretical basis chemistry 2. Chemical properties of a substance. 3. Water is all around us. Physical and Chemical properties water.Slide 2
Topic 2.1. Chemistry section. Water and its properties. Question 1. Introduction to chemistry. Theoretical foundations of chemistry. Depending on what substances chemistry studies, it differs: Inorganic chemistry Organic chemistry
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Topic 2.1. Chemistry section. Water and its properties. Question 1. Introduction to chemistry. Theoretical foundations of chemistry. The totality of the chemical properties of substances determines the ability of substances to take part in chemical reactions: oxygen, water, silica, ammonia, soda, etc. methane, acetylene, ethanol, acetic acid, sucrose, etc. Substance is the central concept of chemistry.
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Topic 2.1. Chemistry section. Water and its properties. Question 1. Introduction to chemistry. Theoretical foundations of chemistry. Chemical reactions are the processes of formation of substances of complex composition from simpler ones, the transition of some complex substances to others, the decomposition of complex substances into several substances of simpler composition. Chemical reactions are the transformation of one substance into another. Number chemical reactions in nature is not limited, i.e. immeasurably great.
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Topic 2.1. Chemistry section. Water and its properties. Question 1. Introduction to chemistry. Theoretical foundations of chemistry. Conclusions on 1 question. Chemistry is the most important natural science discipline and its importance in human life cannot be overestimated. Starting from basic cooking to biological processes in the body, nothing can do without chemical processes. Scientific discoveries and practical achievements in the field of chemical knowledge brought enormous damage to humanity (the creation of weapons of mass destruction) and provided salvation from death (the development of medicines for diseases, the cultivation of artificial organs, etc.). It is impossible to be indifferent to this science: so many contradictory discoveries have not occurred in any other field of knowledge.
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Topic 2.1. Chemistry section. Water and its properties. Question 2. Chemical properties of the substance. Each substance has a unique set of characteristics - physical properties that determine the individuality of each substance: density, color, viscosity, volatility, melting and boiling points... The state of aggregation of a substance is the state of the same substance in a certain range of temperatures and pressures. qualitative properties (characteristics) qualitative properties (characteristics) Ability (solid body) or Inability (liquid, gas, plasma) to retain volume and shape; Long-range order in the mutual arrangement of atoms or molecules (solid) and short-range order (liquid)
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Topic 2.1. Chemistry section. Water and its properties. Question 2. Chemical properties of the substance. The chemical properties of a substance do not depend on its state of aggregation, but physical properties, on the contrary, depend. The chemical properties of substances are revealed and characterized by chemical reactions. Chemical reactions are always accompanied by physical effects - this can be the absorption or release of heat, changes in the state of aggregation and color of substances. Reactions can occur both in mixtures of different substances and within a single substance. In the process of chemical reactions, new substances are always formed.
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Topic 2.1. Chemistry section. Water and its properties. Question 2. Chemical properties of the substance. Chemical reactions are depicted in general view reaction equation: Reactants → Products. Reactants are the starting substances taken to carry out a reaction. Products are new substances that are formed as a result of the reaction. Chemical reactions must be distinguished from physical processes, which only change external form or the state of aggregation of a substance (but not its composition). The most common physical processes: crushing, pressing, co-fusion, mixing, dissolving, filtering the precipitate, distillation.
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Topic 2.1. Chemistry section. Water and its properties. Question 2. Chemical properties of the substance. Using chemical reactions, you can obtain any necessary substances that are found in limited quantities in nature ( nitrogen fertilizers) or do not occur at all (synthetic medications, chemical fibers, plastics). Chemistry allows us to synthesize substances necessary for human life. But chemical production has side effects: harms the environment - in the form of pollution, harmful emissions, poisoning of flora and fauna...
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Water surrounds us everywhere. It is around us, above us, below us, in us (plants contain up to 90% water, and in the body of an adult - about 65-80%, in a baby even more). Water covers approximately four-fifths of the earth's surface, and the Earth's mantle contains 10-12 times more water than the World Ocean. Water is hydrogen oxide, the simplest chemical compound of hydrogen with oxygen that is stable under normal conditions, a colorless, odorless and tasteless liquid, a substance that is the fundamental basis of life on Earth, the formation of the physical and chemical environment, climate and weather.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. General information about water: A chemical compound of hydrogen with oxygen. A colorless, odorless and tasteless liquid. A good solvent. The most common substance on the planet. Found in nature in three physical states. It is an accumulator of heat and cold on the planet, regulating the climate. In 1 minute, the Sun evaporates about 1 billion tons of water from the surface of the oceans. Every minute, an amount of heat enters the atmosphere equivalent to that which would be produced by 40 thousand power plants with a capacity of 1 billion kilowatts each. The bond between an oxygen atom and hydrogen atoms is called a hydrogen bond in chemistry.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Scientists consider water to be the heaviest substance studied in chemistry or physics. From a chemistry point of view, water is the only compound that simultaneously combines the properties of both alkali and acid, which makes water the most universal solvent. From the point of view of physics, it is unique only in that it is the only substance whose volume in the solid state is greater than in the liquid state.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Wetting effect Wetting is a physical (surface) phenomenon consisting in the interaction of a liquid with a surface solid or other liquid. If a paraffin-coated sieve is moistened with water, it will not flow through the sieve and will become spherical. No wetting. If you come into contact with the inner surface of the sieve, water will flow into the contact points formed. When a liquid wets a solid surface, it spreads (as in the case of water) and does not spread over the surface (in the case of mercury), i.e. does not wet.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Water when moving from liquid state to solid increases in volume Po chemical composition at 200°C water should be a gas, but it is liquid. There are 5 different states of water in liquid form and 14 states in frozen form: very pure water does not turn into ice when cooled to 0 ° C and remains liquid - even when cooled, to a temperature below the freezing point; at a temperature of -38°C, even the purest supercooled water will suddenly turn into ice. At -120°C, water becomes viscous, like molasses, and at -135°C, it turns into “vitreous” or “vitreous” water, a solid that lacks a crystalline structure.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Every human cell is surrounded by water molecules. Modern man has lost the habit of drinking plain clean water. It was replaced by Pepsicol, lemonade, beer. But the body still turns these liquids into water and spends a huge amount of energy in the process. Drinking plain water improves human memory. After all, it is known that the human brain is 90% water.
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Topic 2.1. Chemistry section. Water and its properties. Question 3. Water is around us. Physical and chemical properties of water. Heavy water. Discovered by American physicists in 1932. Used in nuclear reactors and technical equipment. purposes. Heavy water (deuterium oxide) is heavy hydrogen water. In the chemical formula, instead of two atoms of the usual light isotope of hydrogen, it contains two atoms of the heavy isotope of hydrogen - deuterium. Externally, heavy water looks like an ordinary colorless liquid without taste or smell. Can slow down metabolism and cell division of the body.
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Water has structural memory. It has the property of changing its molecular structure under pulsed external influence. Any mechanical, chemical or electromagnetic influences lead to molecules forming certain Topic 2.1. Chemistry section. Water and its properties. Question 4. Water is a keeper of information. Each cluster resembles a modern computer, containing up to 44,000 information panels. Each panel is responsible for its own type of interaction with environment, in which temporary “memorization”, “storage”, as well as “emission” of information occurs in the form of electromagnetic waves. According to scientists, the minimum water cluster consists of 930 molecules. structures are clusters that can be observed under a microscope with a magnification of 2000 times.
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Water is the most amazing substance on Earth
The presentation was prepared by Valentina Kholodova, a student of grade 8 “B”.
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Water is the most common and most amazing substance on Earth. Water surrounds us everywhere: in reservoirs, on the ground and even in the air - in the form of snow, rain and steam. Water works in industry, agriculture and energy. Water is the main thing component any living organism, be it human, plant or animal. Humans are made up of more than 70% water; it ensures our existence, participates in all vital processes in the body, being a universal solvent and the main means of transport and nutrition, although this happens habitually and almost imperceptibly.
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Structure of a water molecule: A water molecule consists of 2 hydrogen atoms and 1 oxygen atom, which are located at an angle of 105° relative to each other, its chemical formula H2O. Molar mass≈ 18 g/mol. Physical properties of water: Pure water is a colorless, odorless and tasteless liquid. The only substance that exists on Earth in 3 states of aggregation Boiling point 100°C Melting point 0°C Water has the highest heat capacity (4200 J/kg ∙ °C) Pure water does not conduct electricity Density of water 1000 kg/m³ The density of ice is less than that of liquid water, which is its anomalous property
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The presence of water in nature: 3/4 of the globe 97% oceans and seas 3% lakes, rivers, underground waters 70% contain animal organisms 90% contain cucumber and watermelon fruits 65% of human body weight
Types of snowflakes - accretions of ice crystals formed during the condensation of water vapor in the upper layers of the atmosphere
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Interesting Facts: A liter of the most expensive water costs $90 and is sold in Los Angeles. It is known that 70% of the Earth is covered with water, of which 3% is fresh (mostly glaciers), and only 1% is suitable for drinking. There is a unique Lake Cirknitskoe in Yugoslavia. It behaves cyclically - completely disappearing in winter and summer, and replenishing along with fish in spring and autumn. There is a unique lake in Algeria that is filled with “ink”. You can even write with this water. And in Antarctica there is a lake with a salinity 11 times greater than sea water. It is so salty that it does not freeze even at -50 degrees Celsius. Azerbaijan can boast of flammable water. It is enough to bring a match to the water and it will light up with a blue flame. The most dangerous water can be found in Sicily. It collects in a lake, at the bottom of which there are two sources of sulfuric acid. Now scientists estimate fresh water reserves at 3 million cubic kilometers, and 1 trillion tons evaporate from the earth’s surface every day. It turned out that sea water contains as much as 1.5 grams of protein per 1 cubic centimeter, and other nutrients are present in it. Thus only in Atlantic Ocean 20,000 harvests were dissolved, equivalent to the annual harvest across the fields of the entire Earth. Economic fact. If there is a leak in the house, then a trickle just a needle thick can carry 840 liters per day.
Types of water Water on Earth can exist in three main states - liquid, gaseous and solid - and take on various forms that can simultaneously coexist with each other. Water vapor and clouds in the sky, sea water and icebergs, mountain glaciers and mountain rivers, aquifers in the ground. Water can dissolve many substances in itself, acquiring one or another taste. Because of the importance of water "as the source of life", it is often divided into types according to different principles.
According to the characteristics of origin, composition or application, they distinguish, among other things: Soft water and hard water according to the content of calcium and magnesium cations According to the isotopes of the molecule: Light water (in composition almost identical to ordinary water) Heavy water (deuterium) Super-heavy water (tritium) Melt water Fresh water Rain water Sea water The groundwater Mineral water Brackish water Drinking water, Tap water Distilled water and deionized water Waste water Storm water or surface water Dead water and Living water types of water from fairy tales (with fabulous properties) Holy water a special type of water according to religious teachings Polywater Structured water a term used in various non-academic theories.
Physical properties Water under normal atmospheric conditions retains a liquid state of aggregation, while similar hydrogen compounds are gases. This is explained by the special characteristics of the atoms that make up the molecule and the presence of bonds between them. The hydrogen atoms are attached to the oxygen atom forming an angle of 104.45°, and this configuration is strictly preserved. Due to the large difference in electronegativity between hydrogen and oxygen atoms, the electron clouds are strongly biased towards oxygen. For this reason, the water molecule is an active dipole, where the oxygen side is negative and the hydrogen side is positive. As a result, water molecules are attracted by their opposite poles and form polar bonds, which require a lot of energy to break. In the composition of each molecule, the hydrogen ion (proton) does not have internal electronic layers and is small in size, as a result of which it can penetrate into the electronic shell of the negatively polarized oxygen atom of a neighboring molecule, forming a hydrogen bond with another molecule. Each molecule is connected to four others through hydrogen bonds, two of which form an oxygen atom and two hydrogen atoms. The combination of these bonds between polar and hydrogen water molecules determines its very high boiling point and specific heat of vaporization. As a result of these connections, a pressure of thousands of atmospheres arises in the aquatic environment, which explains the reason why water is difficult to compress, so with an increase in atmospheric pressure by 1 bar, water is compressed by 0.00005 of its initial volume.
Trees, bushes, wires seem to be dressed in lace. And it seems like a fairy tale, But it’s all just water. The boundless expanse of the ocean And the quiet backwater of the pond, The cascade of the waterfall and the splashes of the fountain But in essence, this is water. Tall oxen rise, The sea water rages, And drowns and destroys, playing, Large sea vessels. Here they lay a white blanket on the native land of snow... And the time will come - everything will melt, And there will be plain water. A. Fet
The structures of water and ice are very similar to each other. In water, as in ice, molecules try to arrange themselves in a certain order to form a structure, but thermal movement prevents this. At the temperature of transition to the solid state, the thermal movement of molecules no longer prevents the formation of a structure, and the water molecules are ordered, during this process the volumes of voids between the molecules increase and the overall density of water decreases, which explains the reason for the lower density of water in the ice phase. During evaporation, on the contrary, all bonds are broken. Breaking bonds requires a lot of energy, which is why water has the highest specific heat of any liquid or solid. In order to heat one liter of water by one degree, 4.1868 kJ of energy is required. Due to this property, water is often used as a coolant. However, the specific heat capacity of water, unlike other substances, is not constant: when heated from 0 to 35 degrees Celsius, its specific heat capacity drops, while for other substances it is constant as the temperature changes. In addition to its high specific heat capacity, water also has high specific heats of fusion (0 °C and 333.55 kJ/kg) and vaporization (2250 kJ/kg [)
Water also has the highest surface tension among liquids, second only to mercury. The relatively high viscosity of water is due to the fact that hydrogen bonds prevent water molecules from moving at different speeds. For similar reasons, water is a good solvent for polar substances. Each molecule of the solute is surrounded by water molecules, and the positively charged parts of the molecule of the solute attract oxygen atoms, and the negatively charged hydrogen atoms. Since a water molecule is small in size, many water molecules can surround each solute molecule. This property of water is used by living beings. In a living cell and in the intercellular space, solutions of various substances in water interact. Water is necessary for the life of all single-celled and multicellular living creatures on Earth without exception. Water has a negative surface electrical potential.
Pure (free from impurities) water is a good insulator. Under normal conditions, water is weakly dissociated and the concentration of protons (more precisely, hydronium ions H 3 O +) and hydroxyl ions HO is 0.1 µmol/l. But since water is a good solvent, certain salts are almost always dissolved in it, that is, there are positive and negative ions in water. Thanks to this, water conducts electricity. The electrical conductivity of water can be used to determine its purity. Water has a refractive index n=1.33 in the optical range. However, it strongly absorbs infrared radiation, and therefore water vapor is the main natural greenhouse gas, responsible for more than 60% of the greenhouse effect. Due to the large dipole moment of the molecules, water also absorbs microwave radiation, which is what the operating principle of a microwave oven is based on.
Water is the most common solvent on planet Earth, which largely determines the nature of terrestrial chemistry as a science. Most of chemistry, at its inception as a science, began precisely as the chemistry of aqueous solutions of substances. It is sometimes considered as an ampholyte and an acid and a base at the same time (cation H + anion OH). In the absence of foreign substances in water, the concentration of hydroxide ions and hydrogen ions (or hydronium ions) is the same, pK a approx. 16. Water is a chemically quite active substance. Strongly polar water molecules solvate ions and molecules, forming hydrates and crystalline hydrates. Solvolysis, and in particular hydrolysis, occurs in living and nonliving nature, and is widely used in the chemical industry.
Water reacts at room temperature: with active metals (sodium, potassium, calcium, barium, etc.) with halogens (fluorine, chlorine) and interhalide compounds with salts formed by a weak acid and a weak base, causing their complete hydrolysis with carboxylic anhydrides and halides and inorganic acids with active organometallic compounds (diethylzinc, Grignard reagents, methyl sodium, etc.) with carbides, nitrides, phosphides, silicides, hydrides of active metals (calcium, sodium, lithium, etc.) with many salts, forming hydrates with boranes , silanes with ketenes, not to carbon monoxide with fluorides of noble gases Water reacts when heated: with iron, magnesium with coal, methane with some alkyl halides Water reacts in the presence of a catalyst: with amides, esters of carboxylic acids with acetylene and other alkynes with alkenes with nitriles
Biological role Water plays a unique role as a substance that determines the possibility of existence and the very life of all creatures on Earth. She plays the role universal solvent, in which the basic biochemical processes of living organisms occur. The uniqueness of water is that it dissolves both organic and inorganic substances quite well, ensuring a high rate of chemical reactions and, at the same time, sufficient complexity of the resulting complex compounds. Thanks to hydrogen bonding, water remains liquid in a wide range of temperatures, and precisely in the one that is widely represented on planet Earth at the present time.
Interesting facts *On average, the body of plants and animals contains more than 50% water. *The Earth’s mantle contains three times more water than the amount of water in the World Ocean. *With an average depth of 3.6 km, the oceans cover about 71% of the planet's surface and contain 97.6% of the world's known free water. *If there were no depressions and bulges on the Earth, water would cover the entire Earth, and its thickness would be 3 km. *If all glaciers melted, the water level on Earth would rise by 64 m and about 1/8 of the land surface would be flooded with water. *Sea water at its usual salinity of 35 freezes at a temperature of 1.91 °C. *Sometimes water freezes at positive temperatures. *Under certain conditions (inside nanotubes), water molecules form a new state in which they retain the ability to flow even at temperatures close to absolute zero. *Among the liquids existing in nature, the surface tension of water is second only to mercury. *Water reflects 5% of the sun's rays, while snow reflects about 85%. Only 2% penetrates under ocean ice sunlight. *Blue color clean ocean water is explained by the selective absorption and scattering of light in the water. *Using drops of water from taps, you can create a voltage of up to 10 kilovolts, the experiment is called the “Kelvin Dropper”. *There is the following saying using the water formula H 2 O: “My boots let H 2 O through.” Instead of boots, other shoes with holes may also be included in the saying. *Water is one of the few substances on Earth that expand during the transition from the liquid phase to the solid (besides water, bismuth, gallium, lead and some compounds and mixtures have this property). *Water can burn if placed in an atmosphere containing fluorine, sometimes even explosively. This releases oxygen. *There is a widespread belief that it is undesirable to mix boiled water with unboiled water, allegedly drinking such water can cause diarrhea. *Water is the only substance that can exist on earth in three states of aggregation.
Key quality indicators drinking water organoleptic turbidity color taste smell Chemical pH permanganate oxidability total water hardness mineralization (dry residue) phenolic index of surfactants and other content of anions (nitrates, nitrites, sulfates, cyanides, chlorides and bicarbonates) content of aluminum, barium, beryllium, boron, iron, cadmium , manganese, copper, molybdenum, arsenic, nickel, mercury, selenium, lead, strontium, chromium and zinc bacteriological total microbial number total coliform bacteria radiological
Type of water Source water Water after purification initial total hardness W total initial, mEq/L carbonate hardness W h, mEq/L non-carbonate hardness W n, mEq/L l pH softening by Na-cation softening by H-cation desalting by sequential H-cation and OH-anionization residual total hardness J about ref, mEq/l pH residual total hardness J about ref, mEq/l pH residual total hardness t F o ost, mEq/l Alkalinity (acidity) pHpH Tap water 2.52,10,46,50,056,60,032,50.02-7 “Raifa spring” bottled drinking water 3 ,83,20,66,60,056,70,033,00,02-7 Artesian well water 7,06,01,07,30,067,50,043,60,04-7 River water Volga 8,471,47,50,067,60,054,00,05-7
The message Save water At the end of the 19th century. One and a half buckets of water per day were enough for a city dweller - both for washing and even for extinguishing fires. The current norm is over 18 buckets, i.e. 220 liters. In fact, we don’t even meet this standard, spending buckets per person. A gentle stream of water fills a reference 12-liter bucket in a minute. You stood in the shower for 5 minutes - 60 liters. The waters ran into the sewer. This is more than enough to carefully wash an elephant. A liter jar is filled with a stream the thickness of a match in 3 minutes. This experiment allows us to establish that a minimum amount of water flows out of a faulty tap per day. There is a common belief that industry wastes the lion's share of water. In fact, it takes 150 m to produce 1 ton of steel, 1000 m of cotton fabric every day, factories take only a quarter. The same amount goes to canteens, kindergartens, and hospitals. The rest goes to residential buildings.
But saving water without any hygienic damage is not at all difficult. For example, after brushing, you can rinse your teeth from a glass by closing the tap. Savings – 5 l. Water per person cleaning. While shaving, you can, instead of opening the tap with hot water, pour water from a kettle into a glass, as in the old days, and shaving will take not 5-10 liters, but only 0.2, and there are millions of people shaving. Housewives believe that they should rinse clothes after washing in running water. Of course, this way the laundry is rinsed faster, since the concentration gradient of the washing powder on the surface of the laundry and the water washing it is greater than in static water, which means the diffusion rate is greater. But the water consumption is high. Modern detergents are washed out of clean laundry even after it has been left in standing water for several minutes. After changing the water, the laundry can be rinsed clean. By the way, in washing machines The laundry is also rinsed in two or three waters, and not in running water. It is best to wash dishes in a sink with two compartments and drain plugs. You can also wash vegetables.
Creative break Compiling a syncwine in workbooks. This is a Japanese word that literally means emotional attitude. The syncwine will consist of 5 lines. 1) In one word (noun) express the topic of today's lesson 2) Select 2 definitions for this word 3) Select 3 verbs for this word 4) Compose a phrase that reflects the significance of this word 5) Select a synonym for this word.
30 Test (differentiated) 1) Water occurs in nature: a) in liquid form b) in solid form c) in gaseous form d) all of the above 2) In liquid form it covers: a) ½ of the earth’s surface b) 3/ of the earth's surface c) 1/5 of the earth's surface d) 1/6 of the earth's surface 3) To obtain pure water, substances dissolved in it are removed: a) by distillation b) by irradiation c) by filtration d) by exfoliation
4) Determine the reaction equation where water acts as an oxidizing agent: a) 2 k+2H2O 2 con+H2 b) F2+2H2O 4HF+O2 c) P2O5+3H2O 2H3PO4 d) H2O 2H2+O2 5) Determine the reaction equation where water acts as a reducing agent: a) H2O+Ce2 HCe+HCeO b) 2H2O+2NaCe Ce2+H2+2NaOH c) H2O+Ca Ca(OH)2 +H2 d) SO3+H2O H2SO4 6) Water reacts with all the substances in the set: a )N2;Na b) Na2O;SiO2 c) So3;Ca d) P2O5;S
7) The main water pollutants are: a) pathogenic viruses, helminths, viruses b) compounds of non-oxic metals c) organic substances, mineral substances d) all of the above 8) Fresh water accounts for: a) 97% b) 50% c) 3% d) 2% 9) Carry out chemical transformations: H2 X1 Ca(OH)2 X2 X3 1) O2; H2O;CaCe2 2) O2; H2O;AgCe 3)H2O;CaCe2;AgCe
Test Option 1 A1 The most impurities are contained in water 1. rain 2. sea 3. river 4. spring A2 Does not dissolve in water 1. CuSO4 2. NaOH 3. AgCL 4. KNO3 A3 When SO3 oxide reacts with water, 1.H2S is formed 2. H2SO4 3. H2SO3 4. SO2 A4 Does not relate to the physical properties of water 1. Density 2. color 3. odor 4. ability to decompose A5 The oxidation state of hydrogen in the H2O molecule
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A water molecule consists of one oxygen atom linked by a covalent bond to two hydrogen atoms H2O Structure of a water molecule
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Water is a colorless liquid, without taste or smell. Water boils at 100 degrees Celsius (at a pressure of 101.3 kPa) Freezes at a temperature of 0 degrees. The maximum density of water (at 4 degrees) is 1 g/cm3. Physical properties
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Water is of great importance for the normal functioning of the human body. All physiological fluids: blood, lymph, saliva, gastric juice, pancreatic juice, bile, intercellular and intracellular fluid and all others are aqueous solutions. All biochemical and metabolic processes, the entire metabolism of the human body occurs in an aquatic environment. It has been established that in a newborn child water makes up up to 90% of body weight, in an adult - 70-80%. And the figure of 55% is considered critical - this is exactly how much water is contained in the body of a person dying of old age. It is no coincidence that they often say about old people: dried up, shriveled up, dried up... It turns out that this is not a metaphor at all... The role of water in the human body
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Both a lack of water and its excess are harmful to our body. With insufficient water consumption, dehydration of the body can occur - an extremely unpleasant condition that leads to severe dysfunction of various organs. Excessive fluid consumption negatively affects the functioning of the heart, excretory organs, digestion and a number of other body systems, overloading them, increasing sweating, and promoting the leaching of vitamins and mineral salts from the organs. What causes excess and lack of water in the human body?
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We must not forget that water is contained in significant quantities in almost all the products that we eat. Thus, most vegetables, fruits and berries contain 75-90% water, meat, eggs, potatoes up to 75%, milk, cream, kefir, drinking yoghurts - 80-88%, bread of various types - 35-45% , of course not dried out :).
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Our body has an excellent indicator of lack of water - a feeling of thirst. one must distinguish between true and false thirst. True thirst is caused by a real lack of water in the body, and false thirst is caused by drying out of the mucous membranes of the respiratory tract. To quench false thirst, simply rinse your mouth or slowly drink a few small sips of water. Lack of water in the body, causing true thirst, can occur either due to insufficient fluid intake, so-called water starvation, or as a result of significant loss of water (with severe vomiting, excessive sweating, burns, etc.). In the first case, it is recommended to quench your thirst with plain water, in the second - with salted or mineral water. But it’s better not to drink carbonated water: it contains carbon dioxide can increase thirst, and besides, it does not have the most favorable effect on the functioning of the digestive system.
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“The opinion that tea, coffee, alcohol and artificial drinks can satisfy the body’s needs for pure natural water is an elementary mistake, especially in a situation where the body is under the stress of daily problems. All of these drinks do contain water, but most also contain dehydrating agents such as caffeine. They remove water from the body, as well as some water from its reserves. Another way to remove water after drinking hot drinks is through increased sweating in order to cool the body, which is heated from the inside. “When a person does not drink enough water and his body becomes dehydrated, the cells release the energy they have accumulated. As a result, they become more dependent on the energy supplied by food than on the energy supplied by water. In such a situation, the body is forced to accumulate fat and use its reserves of protein and starch - after all, it is easier for it to break down these compounds than accumulated fat.”
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Studies have been carried out, during which it turned out that for every thousand kilocalories consumed, you need to drink about a liter of water. Typically, the daily diet modern man“pulls” 2000 kcal. But a person gets almost a liter of water from food - soup, fruits and vegetables. In addition, pouring 2 liters into yourself means creating extreme conditions for the body to function. - You need to drink more than 1.5 liters per day only in hot weather or during significant physical activity. And people suffering from high blood pressure, heart disease, kidney disease should generally limit the amount of fluid consumed. The body needs increased fluid intake: in case of poisoning during air travel in hot weather, in case of urolithiasis, in intense sports activities, in case of urinary tract infections, in acute infectious diseases. How much fluid should you drink?
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When water freezes, it expands by 9% relative to its previous volume. Therefore, ice is always lighter than unfrozen water and floats up, and therefore a rare body of water freezes to the bottom. The ice covering it on top is a good heat insulator: after all, the thermal conductivity of ice, like water, is very low. Under such a “fur coat”, even in winter in the Arctic, marine animals are not very cold. Interesting facts about water
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All substances expand when heated and contract when cooled. Water also shrinks from the cold. But it shrinks while the temperature drops, but at +4°C the limit comes. Here it begins to expand again, although the temperature continues to drop. Therefore, water is the densest and heaviest at +4° C. In winter, having cooled to +4° C, it sinks to the bottom and remains here throughout the winter. That is why in winter it is relatively warm at the bottom of a pond, lake, or river. This amazing anomaly saves the lives of all freshwater animals.
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Of all liquids except mercury, water has the highest surface tension. The surface of the water is always covered the thinnest film from molecules. To break it, you need strength, and considerable strength. Insects run across this film - whirligigs and water striders. Mosquito larvae cling to it, hanging upside down, and even snails with massive shells crawl on it. They are heavier than water, but do not fall through: the film supports them. Even lizards run on water and don’t drown! Physicists have calculated exactly what weight needs to be suspended from a column of water 3 centimeters thick in order to break it. You will need a huge weight - more than 100 tons! But this is when the water is exceptionally clean. There is no such water in nature. There is always something dissolved in it, even if only a little. Foreign substances break links in the strong chain of water molecules, and the adhesion forces between them are greatly reduced. But in laboratories, scientists managed to obtain almost pure water, and it was as difficult to break it as the steel itself. the best variety. Surface tension forces pull water up from the depths of the soil, feeding plants with salts and moisture. Carried away by them, it flows along the roots and stems of the plants themselves and fills our capillaries with blood.
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Water is the best solvent in the world. It dissolves many substances, but itself remains inert and does not change from many substances that it dissolves. Thanks to this quality, water was able to become a carrier of life. Solutions of all substances circulating in our body are prepared in water. They change little in such a solution, and the solvent itself - water - can be used repeatedly.
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