Presentation on the topic "Water. Chemical and physical properties." Chemistry presentation on the topic: “Water is an amazing substance in nature.” Use of water chemistry presentation

Water. Water is one of the most unique substances on Earth. Despite the rapid development of modern science, scientists have not yet fully studied the nature of this seemingly simple substance! Because of its apparent simplicity, people on Earth have long considered water to be a simple, indivisible substance. And only thanks to the English scientist G. Cavendish in 1766, people learned that water is not a simple chemical element, but a compound of hydrogen and oxygen. Later, A. Lavoisier (France) proved the same thing in 1783. Water is one of the most unique substances on Earth. Despite the rapid development of modern science, scientists have not yet fully studied the nature of this seemingly simple substance! Because of its apparent simplicity, people on Earth have long considered water to be a simple, indivisible substance. And only thanks to the English scientist G. Cavendish in 1766, people learned that water is not a simple chemical element, but a compound of hydrogen and oxygen. Later, A. Lavoisier (France) proved the same thing in 1783.

Physical properties of water. Water is the only liquid on Earth for which the dependence of specific heat capacity on temperature has a minimum. This minimum is realized at a temperature of +35 0C. The specific heat capacity of water is 4180 J/(kg0C) at 0 0C. The specific heat of melting when ice transforms into a liquid state is 330 kJ/kg, the specific heat of vaporization is kJ/kg at normal pressure and temperature 100 0C. The heat capacity of water is abnormally high. To heat a certain amount of it by one degree, it is necessary to expend more energy than when heating other liquids. This results in the unique ability of water to retain heat. Water is the only liquid on Earth for which the dependence of specific heat capacity on temperature has a minimum. This minimum is realized at a temperature of +35 0C. The specific heat capacity of water is 4180 J/(kg0C) at 0 0C. The specific heat of melting when ice transforms into a liquid state is 330 kJ/kg, the specific heat of vaporization is kJ/kg at normal pressure and temperature 100 0C. The heat capacity of water is abnormally high. To heat a certain amount of it by one degree, it is necessary to expend more energy than when heating other liquids. This results in the unique ability of water to retain heat.

Unique properties of water. Japanese researcher Dr. Masaru Emoto took water from various sources, including distilled water and tap water, and sharply cooled it with liquid nitrogen, resulting in the appearance of ice crystals, which were examined under a high-frequency microscope. After conducting such a study, he found out that the ice crystals obtained from the metropolis's water supply were severely deformed and ugly, in contrast to water from mountain streams, whose crystals were so pure and beautiful that they amazed the imagination. In the following experiments, Dr. Emoto took ordinary distilled water and pasted on the test tubes with inscriptions with positive emotional wishes, for example: Thank you, love, prosperity, etc., and negative ones: you are a fool, evil, hatred, etc. After freezing, the crystals with positive inscriptions became very beautiful, bright and multidimensional, and the water crystals with negative inscriptions turned into dilapidated, ugly and dark. Also, studies have shown that water that is spoken with warm and kind words does not age over time, even after months, and water that is spoken with words with a negative connotation goes rotten literally in a matter of days. Japanese researcher Dr. Masaru Emoto took water from various sources, including distilled water and tap water, and sharply cooled it with liquid nitrogen, resulting in the appearance of ice crystals, which were examined under a high-frequency microscope. After conducting such a study, he found out that the ice crystals obtained from the metropolis's water supply were severely deformed and ugly, in contrast to water from mountain streams, whose crystals were so pure and beautiful that they amazed the imagination. In the following experiments, Dr. Emoto took ordinary distilled water and pasted on the test tubes with inscriptions with positive emotional wishes, for example: Thank you, love, prosperity, etc., and negative ones: you are a fool, evil, hatred, etc. After freezing, the crystals with positive inscriptions became very beautiful, bright and multidimensional, and the water crystals with negative inscriptions turned into dilapidated, ugly and dark. Also, studies have shown that water that is spoken with warm and kind words does not age over time, even after months, and water that is spoken with words with a negative connotation goes rotten literally in a matter of days.

Examples. 13. Sample of Shinagawa tap water, Tokyo. 14. The same pattern after 500 XADO instructors throughout Japan simultaneously sent good thoughts to him. 15. Water taken from Lake Fujiwara before prayer. 16. Water crystal after the prayer of the Buddhist high priest Kato.

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Goals and objectives

• Develop a set of computer slides for demonstration in an 8th grade chemistry lesson
• Consider the basic physical and chemical properties of water, the composition of the water molecule
• Study additional material on the topic
• Show the importance of water in nature, for humans, the most interesting areas of application of water
• Study the material of multimedia textbooks in chemistry

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Water in nature

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Physical states of water

The only substance in nature that exists in three states of aggregation:

• liquid state
• solid state
• gaseous state

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Water molecule

Each water molecule consists of two hydrogen atoms and one oxygen atom, connected by chemical bonds.

Oxygen atom + Hydrogen atoms = Water molecule

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Physical properties of water

Aggregate states of water:

• Liquid (water)
• Solid (ice)
• Gaseous (steam)

Physical properties of water:

• colorless, tasteless, odorless, transparent
• has weak electrical conductivity
• t boil = 100 °C, t melt = 0 °C

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Water is a solvent

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Chemical properties of water

1. Interaction of water with active metals

• 2Na + H2O = 2NaOH + H2 (Sodium Hydroxide)
• Li + H2O = LiOH + H2
• K + H2O = KOH + H2

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2. Interaction of water with non-metals

• C + H2O = CO + H2 (Water gas)

4. Interaction of water with acid oxides

• CO2 +H2O = H2CO3 (Carbonic acid)

3. Interaction of water with basic oxides

• Na2O + H2O = 2NaOH

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Water cycle in nature

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The importance of water for humans

Directly in the form of free liquid (various drinks or liquid food), an adult on average consumes about 1.2 liters of water per day (48% of the daily requirement). Porridge contains up to 80% water, bread - about 50%, meat - 58-67%, fish - almost 70%, vegetables and fruits - up to 90%

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Basically, water is excreted from the body through the kidneys, on average 1.2 liters per day - or 48% of the total volume, and also through sweating (0.85 liters - 34%). Part of the water is removed from the body by breathing (0.32 l per day - about 13%) and through the intestines (0.13 l - 5%).

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Daily water requirement

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Water is fuel

The sci-fi future is slowly but surely making its way into our homes. And now you can easily buy yourself a watch that receives electricity for its work from ordinary water.

How does this miracle watch work? Inside is a converter that “extracts” electrons from liquid molecules, and works like a fuel cell for a watch. Water consumption is very small. It is reported that one refill of the tank will be enough for “several weeks” of uninterrupted operation.

Multimedia textbook "Chemistry" 8th grade, M., Prosveshchenie, 2002

Educational collection 1C “Chemistry for everyone-XXI”, M., 2004

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Water. Water in nature. Water is a very common substance on Earth. Physical properties of water. Pure water is a colorless, transparent liquid. Chemical properties of water. Water molecules are highly resistant to heat. Interaction. C + H2O = H2 + CO. Lime slaking. - Water.ppt

Water lesson

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To consolidate knowledge about the composition, structure and properties of water. Show that water is a unique natural compound. Expand knowledge about the role of water and solutions in nature and human life. Address environmental and moral issues of water protection. Lesson plan: Legends of water. Many deities were born in water or could walk on water. She could have drowned her, destroyed her for nothing. History of discovery. June 24, 1783 Lavoisier and Laplace. Synthesis of water from “combustible air” (hydrogen) and “dephlogisticated air” (oxygen). Lavoisier. Experiments on water decomposition. 1785 Lavoisier and Meunier. The composition of the water was determined to be 85% oxygen and 15% hydrogen. - Water lesson.ppt

Water chemistry

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Goals and objectives. Water. Chemical and physical. Properties. Water in nature. The only substance in nature that exists in three states of aggregation. Liquid state. Solid state. Gaseous state. Oxygen atom. Hydrogen atoms. Water molecule. Aggregate states of water. Physical properties of water. (Water). Solid. (Ice). Gaseous. (Steam). Liquid. Water is a solvent. 1. Interaction of water with active metals. Chemical properties of water. Cold air. Warm air. Steam. Ice crystals. Water drops. The cloud is transferred. Air current. Precipitation. Rain. Snow. Hail. - Water chemistry.ppt

Chemistry Water

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Integrated project “Water, water, water all around.” Authors of the project. Duration of the project: 1-3 academic quarters. Fundamental question: What is unique about water? Problematic questions Where is water found in nature? What chemical properties are characteristic of water? What states of aggregation are characteristic of water? How to determine the quality of water in a reservoir based on the state of coastal vegetation? What features are characteristic of the Moshlyaiki River? What is the significance of the river for the village of Tulinovka? Academic subjects. Geography Chemistry Biology Physics Ecology. Educational topics Inland waters of Russia. Solutions. Solubility of substances in water. - Chemistry water.ppt

Substance water

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Water is the most amazing substance on Earth. Is any water healthy? Group work Water! Subject CHEMISTRY Performers “Theorists” - students of group 29 - PKD. Has color; has no color. Has taste; has no taste. Has a smell; has no smell. Transparent; not transparent Has fluidity; does not have fluidity. Has a shape; has no form. Retains heat for a long time; cools down quickly. Dissolves sand and chalk; dissolves salt and sugar. Conducts electric current; does not conduct electric current Polar; not polar. Water is the source of life. Subject BIOLOGY, FUNDAMENTALS OF ECOLOGY Performers “Ecologists” - students of group 28 - PKD. - Substance water.ppt

Water as a substance

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Water. Content. Composition and structure of the molecule. Methods for determining the composition of substances. Water in nature. Water purification methods. Physical properties. Chemical properties. Application of water. What kind of water is there? A water molecule consists of one oxygen atom and two hydrogen atoms. There is a covalent polar bond between atoms. The molecule has an angular structure. Methods for determining the composition of a substance. Water is the most abundant substance on Earth. Rivers, seas, oceans, lakes are filled with it. Water vapor is contained in the air. Water is found in the bodies of animals and plants. Under certain conditions it occurs in all three states of aggregation. - Water as a substance.ppt

Water is a substance

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Water is a unique substance of nature. Water. Lesson topic. Spread of water. Hydrosphere is the watery shell of the Earth. Rivers, lakes, atmospheric moisture. Water in the human body. Methods for determining the composition of water. Composition of water molecule H2O - molecular formula. Physical properties of water. Features of water. Water has a very high specific heat of vaporization. High heat capacity. Chemical properties of water. Water decomposition reaction. Photosynthesis. The water cycle in nature. Oil pollution of the world's oceans. Hydroelectric power stations. - Water is a substance.ppt

Water purification

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I. General recommendations II. Water purification 1. Boiling 2. Filtration 3. Disinfection IV. Desalination of water 1. Freezing 2. Distiller V. Conclusions. I. General recommendations. Finding a water source is one of the main tasks. Water can be obtained using moisture condensers and plastic bags. Do not drink sea water or soapy water. There is no use in eating snow. Water purification. 1. BOILING (10 min.). Water purification 2. FILTERING. 3. Disinfection. Desalination of water 1. Freezing. Ice, if not all the water has frozen, is fresher than the original water. Water desalination 2. Distiller. How much water should a person drink per day? - Water purification.ppt

Water settling

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Water purification at home is a vital necessity. Settling Procedure: Pour some tap water into one. Cover with a cloth to prevent foreign impurities from entering the water. Precipitation varies in color saturation and quantity. After settling, the water must be boiled (Part 2). Boiling Procedure: I pour water from the tap, which looks completely clear. I boil water. When heated, the water changes color to yellow (precipitation of iron salts). As the temperature rises, the water acquires a reddish hue. After boiling the water for at least 5 minutes, I carry out settling. - Water settling.ppt

Water in human life

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Integrated lesson in chemistry and geography. “Water is the basis of life on Earth.” It cannot be said that you are necessary for life! You are life itself! You fill us with joy that cannot be explained by our feelings... You are the greatest wealth in the world...” Antoine de Saint-Exupery. The structure of a water molecule. Physical properties of H2O. Hydrosphere. Fresh water. Salty water. Water in the atmosphere. Sushi waters. Glaciers. The groundwater. Lakes. Rivers. Swamps. Diagram of the World Water Cycle. Baikal. Decomposition (electrolysis) of water. The length of the river is 3530 kilometers (before the construction of reservoirs - 3690 kilometers). Of the 100 cities in the country with the most polluted atmosphere, 65 are located in the Volga basin. - Water in human life.ppt

The role of water in the human body

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The role of water in the human body. What is water? The role of water. The role of water in the human body from a physics point of view. Heat capacity and thermal conductivity. Heat of evaporation and cooling of the body. The role of water in the human body from a chemical point of view. Anion. Chemical composition of water. Inorganic compounds. Lead. Negative effects of substances on the human body. Iron. Positive effects of substances. Potassium. Balance. Water standards. Water. Complex of minerals. Water purification. The role of water in the human body from a biological point of view. Amount of water. Blood. Life process. - The role of water in the human body.pptx

Mineral water

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The value of mineral water for humans. Mineral waters are most often underground, less often surface. Underground waters are divided into medicinal and table waters, medicinal waters and table waters. Different layers of soil serve as a kind of filter. The effects of mineral waters are very diverse and affect all organs and systems. It would seem that it could be simpler - minerals and gases dissolved in water. Otherwise, you can get the opposite effect of the healing effect. What do Bon Aqua and Borjomi have in common? Almost nothing. The second is for medical dining rooms, which should not be overdone. -

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 Underground water 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 beliefs Polywater teachings Structured water is 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 simple 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. It acts as a 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 water that is several times greater 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 reserves. *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% of sunlight penetrates under the ocean ice. *The blue color of clear ocean water is due to 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.

Main indicators of drinking water quality 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 putting out 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, instead of opening a tap with hot water, you can pour water from a kettle into a glass, as in the old days; 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, clothes are 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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Slide captions:

“Water... You have no taste, no color, no smell, you cannot be described - you are enjoyed. You are not just necessary for life, you are life itself. You are a deity, you are perfection, you are the greatest wealth in the world "Antoine de Saint-Exupery

Objective of the lesson: consider the distribution of water, study the composition and structure of the water molecule, physical and chemical properties, consider environmental problems associated with water pollution. Lesson topic: “Water”

1. Spread of water. Water is the most abundant mineral on Earth. Almost ¾ of the surface of the globe is covered with water, forming oceans, seas, rivers and lakes. A lot of water is in a gaseous state in the form of vapor in the atmosphere, and it lies in the form of huge masses of snow and ice all year round on the tops of high mountains and in polar countries. Natural water is never completely pure. Rainwater is the purest water, while seawater contains the most impurities.

97% - sea water 3% - fresh water Glaciers 79% Groundwater 20% Rivers, lakes, atmospheric moisture 1%

Water in the human body Without water, a person can live only 3 days, while without food 30-50 days. Different human organs contain different proportions of water: Vitreous body of the eye - 99% Blood plasma - 92% Brain - gray matter 83%, white matter 70%; Kidneys - 82% Heart - 79% Lungs - 79% Muscles - 75% Spinal cord - 74.8% Skin - 72% Liver -70% Skeleton - 46% Tooth enamel - 0.2%

The world's oceans, surface waters of land and underground waters are filled with liquid water. Solid ice can be seen both in the form of snowflakes and in the form of frost. Water vapor is part of the atmosphere 2. Physical properties of water Water is a liquid, without color, taste and smell. At 0 C it turns into a solid state (ice), at 100 C it boils and turns into a gaseous state (water vapor). Water is the only substance that is found on Earth in all three states of aggregation.

3. The structure of the water molecule. H 2 O M = 18 g/mol Problem. Calculate the mass fractions of elements in water. W (H) = 11% W (O) = 89% Water is a complex substance, hydrogen oxide, molecular structure, polar covalent bond.

Structure of a water molecule. The water molecule is polar, it is a dipole O H H + -

Association of water molecules (H 2 O) x, where x = 2,3,4, etc. Due to the high polarity of molecules, water is a universal solvent; it dissolves ionic compounds and substances consisting of polar molecules well.

Water is one of the most reactive substances. + acidic oxide = acid 1.Water + basic oxide = soluble base 4. Chemical properties of water

Water - as an oxidizing agent: 2. Interacts with active (alkali and alkaline earth metals) Na + H 2 O = ? Demonstration of experience When heated, water can also interact with less active metals, such as magnesium. Mg+ H 2 O t°C ?

Water - as a reducing agent 3. Interacts with an oxidizing agent such as fluorine (water burns in fluorine). 2 F 2 +2H 2 O = 4HF+ O 2

At t = 2000 °C or when an electric current is passed, water decomposes into simple substances - oxygen and hydrogen 2 H 2 O 2 H 2 + O 2 5. Water reacts with some salts, forming crystalline hydrates. CuSO 4 + 5 H 2 O = CuSO 4 5 H 2 O 4. Reaction of water decomposition: el. current

A minute of psychological relief. Compiling syncwine in workbooks. The syncwine will consist of 5 lines. In one word (noun) express the topic of today's lesson. Choose 2 adjectives for this word. Choose 3 verbs for this word. Compose a phrase that reflects the significance of this word. Choose a synonym for this word.

5. The water cycle in nature. Water reserves remain unchanged for billions of years because... water undergoes a constant cycle. Groundwater Water evaporation Precipitation Precipitation Water evaporation condensation

Oil pollution of the world's oceans

It is difficult to imagine an area of ​​human activity where water would not be used Hydroelectric power station Agriculture Mechanical engineering Construction In everyday life

6. Protection of water resources. Natural water is never completely pure; it contains impurities: soluble and insoluble substances. Quality of drinking water It is legally determined that drinking water supplied to the consumer must be organoleptically pleasant and safe for health; The content of impurities in water should not exceed the maximum permissible concentrations.

Water treatment scheme

World water consumption (in m3 per person per day)

Test answers Option -1 Option -2 2, 3, 2, 4, 4 2, 2, 4, 3, 2 The key to assessing the quality of the test: “5” - 0 errors; “4” - 1 error; “3” - 2 errors.

Conclusions: Water is the most abundant substance on Earth. Water occurs in nature in all three states of aggregation. The bond between atoms in a water molecule is polar covalent. Water has weak redox properties. Water decomposes under the influence of electric current or at t= 2000 °C.