Physical and chemical phenomena - Knowledge Hypermarket. Presentation "chemical and physical phenomena" Physical phenomena in chemistry presentation

Slide 6

Diagram of a distillation column for oil distillation

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Filtration

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Separating funnel, separating a mixture of water and oil

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Sublimation of iodine

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Conditions for the occurrence and occurrence of reactions

Contact of reactants Grinding and mixing Heating

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Signs of chemical reactions occurring

Formation of precipitate Emission of gas Change in color Odor release Emission of heat (light) from combustion reaction

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Classification of reactions

Exothermic reactions occur with the release of heat. Endothermic reactions occur with the absorption of heat.

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1. How do physical phenomena differ from chemical phenomena? 2. Which of the listed phenomena are physical and which are chemical:

In winter, frost on the window draws patterns from glass, makes dishes, oxygen supports the burning of candles, purifies natural water from impurities by filtration, yellowing of leaves in autumn, attracts iron with a magnet, iron rusts in moist air

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What phenomenon, physical or chemical, is referred to in the Russian proverb “Water wears away stones.” Is fire a physical or chemical phenomenon? What signs of a chemical phenomenon can be observed?

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Homework

§25, 26 ex. 3.4 p. 134; Exercise 1.2 p. 138 Reports on the use of physical and chemical phenomena.

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Option 1 writes down the numbers of chemical phenomena, Option 2 - physical phenomena: Compression of a spring Scale formation on the walls of a teapot Rotting of plant residues Ice drift on the river Forging of metal Souring of apple juice Appearance of plaque on copper and bronze monuments Charring of splinters Freezing of water Souring of milk Combustion of natural gas Formation of frost

Explanatory note

Introduction (7 hours)

Bodies and substances (19 h)

Temperature. Thermometers.

Divisibility of substances. Structure of atom and ion.

Solutions and suspensions.

Class

Physical and chemical phenomena (8 hours)

Chemical reactions as processes of formation of some substances from others. Signs of chemical phenomena and conditions for their occurrence.

Explanation of chemical reactions from a molecular point of view. The breakdown of substances and molecules into atoms or ions, the formation of new substances from them. Conservation of mass of substances in chemical reactions.

Repetition of signs of chemical elements. Compound and decomposition reactions. Drawing up equations for compounding and decomposition reactions.

Substances in nature. The concept of classes of inorganic and organic substances (15 h)

Oxides are complex substances consisting of two chemical elements, one of which is oxygen. Examples of the most common oxides, their distribution in nature and use.

Acids. Basic information about acids, examples of the most common acids. Use of acids in the household and everyday life. Rules for handling acids. Acid recognition.

Grounds. General information about bases, soluble bases - alkalis; lime water, slaked lime. Application of principles in the national economy and everyday life. Rules for handling grounds. Recognition of bases. Neutralization reaction.

The concept of indicators. The effect of acids and bases on indicators.

Salts are complex substances that contain metal ions and acidic residues. Examples of salts, their distribution in nature. Properties and uses of a number of salts: table salt, soda, copper sulfate, etc.

Organic and inorganic substances. Proteins, fats and carbohydrates are the most important nutrients for the human body. Recognition of certain proteins, fats, carbohydrates.

Natural gas and oil. The origin of natural gas, oil, coal as products of decay of various organic residues without air access at high pressures. The most important oil and gas fields in Russia, their importance as sources of various types of fuel and as the most important raw material for the chemical industry.

Man and nature (11 h)

Energy sources. Various types of energy sources: solar energy, mineral fuel, nuclear fuel. Flammable energy sources. Digestion as a process of human energy replenishment. The importance of solar energy for life on Earth.

Outstanding natural scientists, their role in creating the foundations of natural science. The main directions of modern scientific research in the field of physics and chemistry.

The need to create artificial materials. Examples of artificial materials and their use: ceramics, ferrites, super-strong alloys, artificial diamonds, liquid crystals, etc. Information on methods of growing artificial crystals. Instructions for conducting a home experiment on growing a crystal.

Polymers. Polyethylene, polyvinyl chloride, polystyrene and other plastics. Natural and chemical fibers. Use of these materials in everyday life.

Rubber and rubber. Recognition of natural and chemical fibers. Rubber, its properties and production. Vulcanization of rubber, rubber and ebonite.

Environmental pollution. The main factors of the harmful effects of human activity on the environment. Environmental disasters, military actions. Harmful production emissions. The need to monitor the state of the atmosphere and the main methods of its implementation. The need to combat environmental pollution.

The need to save natural resources and use new technology. Discussion of the environmental condition at the school and in the area adjacent to it. Drawing up a plan for specific tasks to improve the environmental situation, which can be completed during summer school practice.

Modern science and production. Means of communication. Knowledge, its role in human life and society. How people understand the world around them (science yesterday, today, tomorrow).

Production management: the role of automation, electronics. Computerization of production. Robots.

Communications and information transmission: telephone, radio, television.

QUESTIONS ABOUT PHYSICS

1. What does physics study? Physical body, physical phenomenon, physical quantity, substance.

2. Measurements. Measuring instruments.

3. Aggregate states of matter.

4. Movement and interaction of particles of matter.

5. Mass of the substance. Density.

6. Interaction of bodies. Force.

7. Body pressure on the support.

8. Pressure in liquids and gases.

9. Mechanical movement. Speed

10. Thermal expansion. Heat transfer

11. Electrification of bodies.

12. Electric current. Current sources.

13. Light sources. Reflection and refraction of light.

14. Simple mechanisms

15. Permanent magnets. Magnetic interaction

Sample practical tasks

Draw a table in your notebook and distribute the following words in it: lead, thunder, rails, blizzard, aluminum, dawn, blizzard, Moon, alcohol, scissors, mercury, snowfall, table, copper, helicopter, oil, boiling, blizzard, shot, flood .

Carefully pour a full teaspoon of granulated sugar into a glass filled to the brim with tea, so that the tea does not overflow over the edge of the glass. Why?

Why do we pass by the dining room and know what dish they prepare there?

Which shoes make your feet feel colder: loose or tight ones? What role can a wool sock play?

Why are the handles of pliers always longer than the cutting part?

Explanatory note

The proposed program is implemented in the textbook “Introduction to Natural Science Subjects. Natural science. 5-6 grades”, authors A.E. Gurevich, D.A. Isaev, L.S. Pontak.

The program is compiled on the basis of the fundamental core of the content of general education and the requirements for the results of mastering the basic educational program of basic general education, presented in the Standard of Basic General Education.

Introduction (7 hours)

Nature is living and inanimate. Natural phenomena. Man is part of nature. Man influences nature. The need to study nature and respect it. Protection of Nature.

Chemistry is the science of nature. Bodies and substances. What does chemistry study? Scientific methods of studying nature: observation, experience, theory.

Introduction to the simplest chemical equipment: test tube, flask, beaker, funnel, pipette, spatula, plastic and metal stands, test tube holder. Heating device, features of the flame. Rules for heating a substance.

Measuring instruments: scales, thermometer, beaker (units of measurement, instrument scale, division value, measurement limit, rules of use).

Bodies and substances (19 h)

Characteristics of bodies and substances (shape, volume, color, smell). Solid, liquid and gaseous states of matter.

Temperature. Thermometers.

Divisibility of substances. Molecules, atoms, ions. An idea of ​​the particle size of a substance. Movement of particles of matter. Relationship between particle speed and temperature. Diffusion in solids, liquids and gases. Interaction of particles of matter and atoms. Explanation of the structure of solids, liquids and gases from a molecular point of view. Structure of atom and ion.

Chemical elements (oxygen, nitrogen, hydrogen, iron, aluminum, copper, phosphorus, sulfur). Signs of chemical elements. Periodic system D.I. Mendeleev.

Simple and complex substances (oxygen, nitrogen, water, carbon dioxide, table salt).

Oxygen. Combustion in oxygen. Photosynthesis. Air is a mixture of gases.

Solutions and suspensions.

Water. Water as a solvent. Purification of natural water.

Physical and chemical phenomena (8 hours)

Melting and solidification. Melting snow, freezing water, smelting iron and steel, making casting parts.

Evaporation of liquids. Condensation.

Key words of the abstract: Physical phenomena, chemical phenomena, chemical reactions, signs of chemical reactions, the meaning of physical and chemical phenomena.

Physical phenomena- these are phenomena in which usually only the state of aggregation of substances changes. Examples of physical phenomena are the melting of glass and the evaporation or freezing of water.

Chemical phenomena- these are phenomena as a result of which other substances are formed from given substances. In chemical phenomena, starting substances are transformed into other substances that have different properties. Examples of chemical phenomena are the combustion of fuel, the rotting of organic matter, the rusting of iron, and the souring of milk.

Chemical phenomena are also called chemical reactions.

Conditions for the occurrence of chemical reactions

The fact that during chemical reactions some substances are converted into others can be judged by external signs: release of heat (sometimes light), change in color, appearance of odor, formation of sediment, release of gas.

For many chemical reactions to begin, it is necessary to bring them into close contact of reacting substances . To do this, they are crushed and mixed; The contact area of ​​the reacting substances increases. The finest crushing of substances occurs when they dissolve, so many reactions are carried out in solutions.

Grinding and mixing substances is only one of the conditions for the occurrence of a chemical reaction. For example. When sawdust comes into contact with air at normal temperatures, the sawdust does not ignite. In order for a chemical reaction to begin, in many cases it is necessary to heat substances to a certain temperature.

It is necessary to distinguish between concepts "conditions of occurrence" And “conditions for the flow of chemical reactions” . So, for example, in order for combustion to begin, heating is only necessary at the beginning, and then the reaction proceeds with the release of heat and light, and further heating is not required. And in the case of water decomposition, an influx of electrical energy is necessary not only to start the reaction, but also for its further course.

The most important conditions for the occurrence of chemical reactions are:

• thorough grinding and mixing of substances;
• preheating substances to a certain temperature.

The meaning of physical and chemical phenomena

Chemical reactions are of great importance. They are used to produce metals, plastics, mineral fertilizers, medicines, etc., and also serve as a source of various types of energy. Thus, when fuel burns, heat is released, which is used in everyday life and in industry.

All vital processes (respiration, digestion, photosynthesis, etc.) occurring in living organisms are also associated with various chemical transformations. For example, chemical transformations of substances contained in food (proteins, fats, carbohydrates) occur with the release of energy, which is used by the body to support vital processes.

Lesson summary “Physical and chemical phenomena (chemical reactions).”