Application of water chemistry presentation. Presentation on chemistry on the topic: "Water is an amazing substance in nature." Physical states of water

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 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 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, crystals with positive inscriptions became very beautiful, bright and multidimensional, and crystals from water 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, crystals with positive inscriptions became very beautiful, bright and multidimensional, and crystals from water 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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WATER - H2O (hydrogen oxide) is the simplest stable compound of hydrogen and oxygen.

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3/4 of the surface of the globe is covered with water in the form of oceans, seas, rivers and lakes. WATER is very important in the life of plants, animals and humans. The origin of life on Earth is due to WATER. Water is an ancient universal symbol of purity, fertility and the source of life itself. WATER is part of comets, most of the planets of the solar system and their satellites. WATER is the most abundant substance on Earth. Water molecules have been discovered in interstellar space.

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WATER is odorless, colorless and tasteless. WATER is very difficult to oxidize, burn, or decompose into its constituent parts. WATER is a chemically resistant substance. WATER is a universal solvent. It dissolves more salts and other substances than any other substance. It oxidizes almost all metals and destroys even the hardest rocks. The water is very unusual in its physical and chemical properties. Many properties of water are anomalous.

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WATER is the only substance known to us that occurs naturally on the surface of the Earth in solid, liquid and gaseous states. Arrangement of molecules Orderly rows A bit cramped Space

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Among liquids existing in nature, the SURFACE TENSION OF WATER is second only to mercury. WATER has a great affinity for itself, the greatest of all liquids. Therefore, water exists in the form of spherical droplets - a sphere has the smallest surface area for a given volume. The surface tension of water is associated with its strong wetting effect (the ability to “stick” to the surface of many solids).

8 slide

WATER has abnormally high freezing temperatures (0°C) and boiling points (+100°C). (Sea water freezes at a lower temperature: - 1.9° at a salinity of 35%) Water is a poor conductor of electricity, but becomes a good conductor if even small amounts of ionic substances are dissolved in it. The heat of evaporation of WATER is higher than the heat of evaporation of any other liquids, and the heat of crystallization is second only to ammonia.

Slide 9

Water has an abnormal density. She is twofold. Firstly, after melting ice at atmospheric pressure is accompanied by a decrease in volume by 9%. LET'S CONDUCT AN EXPERIMENT: To determine the difference in volume during the transition from the solid state of water to the liquid state, ice was taken in the form of a cylinder with a radius of R = 4 cm and a height of H = 5 cm. After the ice melts, the radius of the water column is 4 cm, height is 4.55 cm. The volume of the cylinder is calculated according to the formula: V=πR²H Volume of ice: Vl=251.2 (cm³) Volume of water: Vв=228.592 (cm³) Result: Vв< Vл на 9%

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This property of water is very valuable for life. As the temperature decreases, the cooled layer, which has a lower density, remains on the surface, freezes, and thereby protects the underlying layers from further cooling and freezing. In the liquid state at 4°C its density is maximum and is greater than the density of ice. Therefore, ice floats on the surface of the water. Secondly, the DENSITY of WATER during its transition from a solid to a liquid state does not decrease, like that of other substances, but increases. Ice density - 916.7 kg/m³ water - 999.8 kg/m³

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WATER has an abnormally high HEAT CAPACITY. Therefore, at night, as well as during the transition from summer to winter, the water cools down slowly, and during the day, or during the transition from winter to summer, it also slowly heats up, thus being a TEMPERATURE REGULATOR ON THE EARTH.

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A water molecule (H216O) consists of two hydrogen atoms (H) and one oxygen atom (16O). The whole variety of properties of water and the unusualness of their manifestation is determined by the physical nature of these atoms, the way they are combined into a molecule and the grouping of the resulting molecules. The anomalous properties of water are explained by the existence of hydrogen bonds in it, which bind molecules together in both liquid and solid states. The anomalous properties of water are caused by the structural features of its molecule.

Slide 13

A special group of properties of water - MEMORY OF WATER The features of the physical properties of water and numerous short-lived hydrogen bonds between neighboring hydrogen and oxygen atoms in a water molecule create favorable opportunities for the formation of special associated structures (clusters) that perceive, store and conveying a wide variety of information. V O D A – keeper and transmitter of information

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WATER, consisting of many clusters of various types, forms a hierarchical spatial liquid crystal structure that can perceive and store huge amounts of information. Research has shown that the sensitivity of the water information system turned out to be so high that it is able to sense the influence of not only certain field influences, but also the shapes of surrounding objects, the influence of human emotions and thoughts.

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Crystal of distilled water, unaffected Crystal of spring water Crystal of Antarctic ice

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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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Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested in this work, please download the full version.

The purpose of the lesson: study the composition and structure of the water molecule, physical and chemical properties, the importance of water for living organisms, as well as find out environmental problems associated with water pollution.

Lesson objectives:

• Educational: to form students’ knowledge about the composition, structure and properties of water, to consolidate knowledge about the types of chemical reactions, to repeat the ORR, to teach how to comment on slides and to work with computer diagrams. Continue developing the ability to work independently with a textbook, notebook, and tests.
• Educational: develop observation skills and memory when viewing a computer presentation and conducting a demonstration experiment. Develop the ability to compare, predict, generalize and draw conclusions. Develop the information culture of students.
• Educational: to cultivate a careful and economical attitude towards water resources, to continue environmental education of schoolchildren, to instill concern for the environment and their health, and to develop a sense of beauty.

Developed chemical knowledge, skills and abilities of students: systematization of students' knowledge about the prevalence of water in nature, physical and chemical properties, areas of application of water, expanding students' knowledge about environmental problems associated with water purification.

Formed competencies:

• educational and cognitive competence: development of skills to compare, analyze, prove, draw up diagrams based on working with text, to be able to solve the following vital and practical problems: the ability to assess the state of the environment, put forward their ideas for protecting the water resources of their native land;
• information competence: development of the ability to analyze and select the necessary information, the ability to prepare and make messages, the ability to use the Boarding School to search for educational information;
• communicative competence: development of skills to conduct a conversation, dialogue, ask questions.

Forms of organizing children's work: group (viewing a presentation, practical work, solving problems), individual (conversation, working with a workbook), problem-based learning (solving problematic issues).

Forms of organizing the work of a teacher: organizes the emotional mood of students, introduces children to the topic of the lesson, summarizes previously acquired knowledge, organizes a conversation based on slides and experiments, analyzes and supplements children’s answers, creates problematic situations.

Computer presentation for the lesson allowsatincreasingly frequent:

1. Gain knowledge about the properties and importance of water.
2. Acquire skills in working with substances and equipment.
3. Get an idea of ​​the prevalence of water in nature.
4. Gain knowledge about the problems of reducing the amount of fresh water.

Equipment: Computer, multimedia projector.

Laboratory equipment: cup of water, sodium metal, phenolphthalein, glasses of water from various sources (tap, sea, distilled).

Intersubject communication: chemistry, biology, geography, ecology, literature, Russian language, physics.

During the classes

I. Introduction.

Epigraph (1 slide).

Teacher: Guys, in today's lesson we will get acquainted with the amazing substance of life - water, its physical properties, anomalies, location in nature, meaning and natural reserves.

“Water... You have no taste, no color, no smell, you cannot be described - you are enjoyed without knowing what you are. 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."

The French writer Antoine de Saint-Exupéry wrote these words about water.

And our lesson is dedicated to the most familiar and at the same time the most mysterious substance - water.

We write in notebooks: Lesson topic: “ Water". ( 2 slide).

The purpose of the lesson: Study the composition and structure of the water molecule, physical and chemical properties, significance, as well as find out environmental problems associated with water pollution.

(lesson plan written on the board)

1. Spread of water.
2. Physical properties of water.
3. Features of water.
4. Structure of a water molecule
5. Chemical properties of water.
6. The water cycle in nature.
7. Protection of water resources.

Teacher. Before we begin to study water, let's listen to how poets of different times sang about water. ( 3 slide).

Looks like they're wearing lace
Trees, bushes, wires.
And it seems like a fairy tale,
And it's all just water.
The vast expanse of the ocean
And the quiet backwater of the pond,
Cascade of a waterfall and splashes of a fountain,
But in essence, it is water.
Rising high waves,
The sea water is raging,
And he drowns and destroys while playing,
Large sea vessels.
Here they lay a white blanket
To the native land of snow...
And the time will come - everything will melt,
And there will be plain water.
A. Fet

II. Spread of water.

4 slide, 5 slide

Teacher. From your geography course you know that water is the most common substance on Earth.

Message 1. “Water on Earth”

Water is the most important, most important substance in the world around us. It is both familiar and unfamiliar, famous and mysterious... Natural water! Look at the sky and you will see clouds or clouds that stretch for many kilometers. How easily they float! But don't imagine that they are weightless. The mass of 1 km 3 of clouds is about 2000 tons, and in the Earth’s atmosphere there is about 12,300 km 3 of water vapor, and this is also natural water. Everyone knows the flows of land: streams, rivulets, rivers. Sometimes they spread widely and freely across the plain, sometimes they form powerful rapids, fall from a height of tens and hundreds of meters in waterfalls, carrying their waters into the oceans and seas. About 71% of the surface of our Earth is covered by the World Ocean, which makes up about 97% of all surface waters and half of lithospheric waters.

Is there much or little water on Earth? Very little! Of the total volume of the Earth, water accounts for about 2.5 billion km 3.

The Earth's water cover is 1.5 billion km 3, and the rest is located in the deep layers of the earth's crust. Most of the water is salty, and only about 5 million km 3 is suitable for life. Every year, people need more and more fresh, clean water. Humanity is facing a crisis due to water pollution. Some countries are already experiencing a shortage of clean fresh water and are forced to import it from abroad. Water must be conserved.

Teacher: But it turns out there is water in space too.

Message 2. “Water in space”

The first information about extraterrestrial water was obtained by the Italian Pesali in 1864 while studying a meteorite. It contained 13.9% water. The chronicle of Hungary for 1802 indicates the fall of ice blocks weighing 0.5 tons and in Holland weighing 6 kg.

Using the RATAN-600 telescope, radiation with a wavelength of 1.35 cm was detected. This radiation is produced by water molecules. Space travelers - comets, approaching the Sun from the depths of space, are decorated with a long train. This tail consists of gases, one of which is water vapor. Explorations of Venus in the sixties by spacecraft showed that there, in the clouds, there is about 1% water vapor.

On December 8, 1900, in a telegram, W. Pickering reported a bright flash observed on Mars for 70 minutes. A ball of water in the form of ice has been discovered in the atmosphere of Mars. The bright flashes are explained by the reflection of sunlight from icy surfaces. Are there bodies of water on Mars? Television cameras did not show anything resembling areas covered with water.

Of the major planets, only Jupiter is believed to have water in three states. Information about other planets is very scarce. Water on Saturn can only be judged by the presence of snow rings.

Teacher. You know from your biology course that water is inseparably linked to the existence of life on Earth.

How much water is in the human body? (65–75%)

Did you know that the brain contains 80% water? 6 slide.

Message 3. “Water in a living organism”

All living things on our planet are 2/3 water. Microorganisms are in first place in living matter by mass, plants are in second, animals are in third, and humans are in last place.

Bacteria consist of 81% water, spores 50%, animal tissue on average 70%, lymph - 90%. The richest tissue in water is the vitreous body of the eye, which contains up to 99% moisture, the poorest is tooth enamel - only 0.2%.

Water in the body performs several functions: substances dissolved in it react with each other, water helps remove metabolic waste, serves as a temperature regulator, being a good heat transfer agent, and also a lubricant.

In living organisms, water can be synthesized in tissues. For example, in a camel, the fat in the hump, when oxidized, can produce up to 40 liters of water. A person, drinking 2.5 liters of water per day, rinses the stomach with 10 liters of liquid daily and evaporates 0.7 liters of water.

III. Physical properties (work with the textbook).

7 slide.

On the board there is a table “Properties of water”.

Tell us what physical properties water has (students’ answer).

IV. Features of water.

8 slide.

Message 4. Water anomalies.

In 1913, sad news spread throughout the world. The giant ocean liner Titanic sank after colliding with an iceberg. Experts explained the causes of the disaster in different ways. It was agreed that in the fog the captain did not see a huge floating ice mountain and, having run into it, the ship ended his earthly existence. If we look at this unfortunate event through the eyes of a chemist, we will come to a very unexpected conclusion: the Titanic fell victim to one of the water anomalies. Frightening ice blocks - icebergs float like a cork on the surface of the water.

Blocks of tens of thousands of tons do not sink, and all because ice is lighter than water. Try to melt any metal and throw a piece of the same metal into the melt: it will instantly sink. The solid state of any substance has a higher density than the liquid state. Ice and water are surprising exceptions to this rule. Without this exception, all bodies of water in the middle latitudes would quickly freeze to the bottom: all living things would die.

It takes a lot of heat to melt ice. Incomparably more than for melting any other substance taken in the same quantity. When the water freezes, this heat is released again. Ice and snow, giving back heat, heat the ground and air. They soften the abrupt transition to harsh winter and allow autumn to reign for a few weeks. In spring, melting ice delays the onset of hot days. The cosmic cold would have penetrated the Earth long ago if she had not been dressed in a warm fur coat. The fur coat is the atmosphere of the planet, and the role of warm water is played by water vapor. If it were not for the extreme heat capacity of water, our planet would have cooled long ago and life on it would have died out.

Water has high surface tension. According to K.S. Losev, near absolutely clear water, this value is so great that one could skate on it as if on ice.

The boiling point of water is 100°C, the melting point is 0°C. These are also abnormally high values. Scientists explain this fact by the fact that water molecules are capable of joining into aggregates using hydrogen bonds, which require a large amount of thermal energy to break when heated.

V. The structure of the water molecule.

Slide 9

Teacher. You know that the bond between atoms in a water molecule is polar covalent.

Where do the electrons move?

The water molecule is polar. It has an angular structure (demonstration of the diagram).

This explains the ability of water molecules to combine into larger complexes. It is called association.

What about the opposite process? – dissociation

The association of water molecules explains the high boiling point.

(projector turns off)

Due to the high polarity of molecules, water is capable of dissolving many substances with ionic and covalent polar bonds.

In relation to water, substances are divided into:

• soluble
• insoluble
• sparingly soluble

Consider the table of solubility of substances.

Working with cards.(1 student completes the task on the board)

Task 1. Using the solubility table, distribute the substances into groups.

Substances given:

Ba(OH) 2, KCl, BaSO 4, CaSO 4, NaNO 3, CuSO 4, HNO 3, AgCl, FeS, Ca(OH) 2

VI. Chemical properties. Repetition.

Water is one of the most reactive substances.

From the material you have covered, you know that oxides interact with water.

1. What is formed when an acid oxide reacts with water?
2. What is formed when the main oxide reacts with water?

Working with cards(2 students work on the board)

Task 2. Complete the reaction equations. Name the type of reactions

• SO 2 + H 2 O =
• CaO + H 2 O =
• CuO + H2O =
• N 2 O 5 + H 2 O =
• SiO 2 + H 2 O =

Additional questions.

1. Which oxides do not react with water?
2. Name the type of reactions
3. Does the oxidation state change in these reactions?

There are reactions involving water in which the oxidation state changes. Water exhibits oxidizing properties in reaction with active metals, such as sodium.

Demonstration experience (conducted by teacher)