Chemistry - the science of the transformations of substances associated with a change in the electronic environment of atomic nuclei. In this definition, it is necessary to further clarify the terms "substance" and "science".
According to the Chemical Encyclopedia:
Substance A type of matter that has a rest mass. It consists of elementary particles: electrons, protons, neutrons, mesons, etc. Chemistry studies mainly matter organized into atoms, molecules, ions and radicals. Such substances are usually divided into simple and complex (chemical compounds). Simple substances are formed by atoms of one chemical. element and therefore are a form of its existence in a free state, for example, sulfur, iron, ozone, diamond. Complex substances are formed by different elements and may have a constant composition.
There are many differences in the interpretation of the term "science". René Descartes' (1596-1650) statement is quite applicable here: "Define the meaning of words, and you will save mankind from half of its delusions." Science it is customary to call the sphere of human activity, the function of which is the development and theoretical schematization of objective knowledge about reality; a branch of culture that did not exist at all times and not among all peoples. Canadian philosopher William Hatcher defines modern science as “a way of knowing the real world, including both the reality felt by the human senses and the invisible reality, a way of knowing based on building testable models of this reality.” Such a definition is close to the understanding of science by academician V.I. Vernadsky, the English mathematician A. Whitehead, and other famous scientists.
In scientific models of the world, three levels are usually distinguished, which in a particular discipline can be represented in a different ratio:
* empirical material (experimental data);
* idealized images (physical models);
*mathematical description (formulas and equations).
Visual-model consideration of the world inevitably leads to the approximation of any model. A. Einstein (1879-1955) said "As long as mathematical laws describe reality, they are indefinite, and when they cease to be indefinite, they lose touch with reality."
Chemistry is one of the natural sciences that studies the world around us with all the richness of its forms and the variety of phenomena occurring in it. The specifics of natural science knowledge can be defined by three features: truth, intersubjectivity and consistency. The truth of scientific truths is determined by the principle of sufficient reason: every true thought must be justified by other thoughts, the truth of which has been proven. Intersubjectivity means that each researcher should get the same results when studying the same object in the same conditions. The systematic nature of scientific knowledge implies its strict inductive-deductive structure.
Chemistry is the science of the transformation of substances. It studies the composition and structure of substances, the dependence of the properties of substances on their composition and structure, the conditions and ways of transformation of one substance into another. Chemical changes are always associated with physical changes. Therefore, chemistry is closely related to physics. Chemistry is also related to biology, since biological processes are accompanied by continuous chemical transformations.
The improvement of research methods, primarily experimental technology, led to the division of science into ever narrower areas. As a result, the quantity and "quality", i.e. the reliability of information has increased. However, the impossibility for one person to have complete knowledge even for related scientific fields has created new problems. Just as in military strategy the weakest points of defense and offensive are at the junction of fronts, in science the least developed areas remain those that cannot be unambiguously classified. Among other reasons, one can also note the difficulty in obtaining the appropriate qualification level (academic degree) for scientists working in the areas of the “junction of sciences”. But the main discoveries of our time are also being made there.
In modern life, especially in human production activities, chemistry plays an extremely important role. There is almost no industry that is not related to the use of chemistry. Nature gives us only raw materials - wood, ore, oil, etc. By subjecting natural materials to chemical processing, they obtain various substances necessary for agriculture, industrial production, medicine, everyday life - fertilizers, metals, plastics, varnishes, paints, medicinal substances , soap, etc. For the processing of natural raw materials, it is necessary to know the laws of the transformation of substances, and this knowledge is provided by chemistry. The development of the chemical industry is one of the most important conditions for technological progress.
Chemical systems
Object of study in chemistry - chemical system . A chemical system is a collection of substances that interact and are mentally or actually isolated from the environment. Completely different objects can serve as examples of a system.
The simplest carrier of chemical properties is an atom - a system consisting of a nucleus and electrons moving around it. As a result of the chemical interaction of atoms, molecules (radicals, ions, atomic crystals) are formed - systems consisting of several nuclei, in the general field of which electrons move. Macrosystems consist of a combination of a large number of molecules - solutions of various salts, a mixture of gases above the surface of a catalyst in a chemical reaction, etc.
Depending on the nature of the interaction of the system with the environment, open, closed and isolated systems are distinguished. open system A system is called a system capable of exchanging energy and mass with the environment. For example, when soda is mixed in an open vessel with a solution of hydrochloric acid, the reaction proceeds:
Na 2 CO 3 + 2HCl → 2NaCl + CO 2 + H 2 O.
The mass of this system decreases (carbon dioxide and partially water vapor escape), part of the released heat is spent on heating the surrounding air.
Closed A system is called a system that can only exchange energy with the environment. The system discussed above, located in a closed vessel, will be an example of a closed system. In this case, mass exchange is impossible and the mass of the system remains constant, but the heat of reaction through the walls of the test tube is transferred to the environment.
isolated A system is a system of constant volume in which there is no exchange of mass or energy with the environment. The concept of an isolated system is abstract, because In practice, a completely isolated system does not exist.
A separate part of the system, limited from others by at least one interface, is called phase . For example, a system consisting of water, ice and steam includes three phases and two interfaces (Fig. 1.1). The phase can be mechanically separated from the other phases of the system.Fig.1.1 - Multiphase system.
Not always the phase throughout the same physical properties and uniform chemical composition. An example is the earth's atmosphere. In the lower layers of the atmosphere, the concentration of gases is higher, and the air temperature is higher, while in the upper layers, the air is rarefied and the temperature drops. Those. the homogeneity of the chemical composition and physical properties throughout the entire phase is not observed in this case. Also, the phase can be discontinuous, for example, pieces of ice floating on the surface of the water, fog, smoke, foam - two-phase systems in which one phase is discontinuous.
A system consisting of substances in the same phase is called homogeneous . A system consisting of substances in different phases and having at least one interface is called heterogeneous .
The substances that make up a chemical system are the components. Component can be isolated from the system and exist outside of it. For example, it is known that when sodium chloride is dissolved in water, it decomposes into Na + and Cl - ions, however, these ions cannot be considered components of the system - a salt solution in water, because they cannot be isolated from a given solution and exist separately. The ingredients are water and sodium chloride.
The state of the system is determined by its parameters. Parameters can be set both at the molecular level (coordinates, momentum of each of the molecules, bond angles, etc.) and at the macro level (for example, pressure, temperature).
The structure of the atom.
Similar information.
As a result of studying this chapter, the student should: know
- basic concepts and specifics of the chemical picture of the world;
- the role of alchemy in the development of chemistry as a science;
- historical stages in the development of chemistry as a science;
- the leading principles of the doctrine of the composition and structure of substances;
- the main factors in the course of chemical reactions and the conditions for their control;
- basic principles of evolutionary chemistry and its role in explaining biogenesis; be able to
- reveal the role of the physics of the microworld for understanding the foundations of chemical science;
- conduct a comparative analysis of the main stages in the development of chemistry;
- argued to show the role of chemistry to explain the structural levels of the systemic organization of matter;
own
- the skills of acquiring and applying knowledge to form a chemical picture of the world;
- skills in using the conceptual apparatus of chemistry to characterize chemical processes.
Historical stages in the development of chemical science
There are many definitions of chemistry that characterize it as a science:
- about chemical elements and their compounds;
- substances, their composition and structure;
- processes of qualitative transformation of substances;
- chemical reactions, as well as the laws and regularities that these reactions obey.
Obviously, each of them reflects only one of the aspects of extensive chemical knowledge, and chemistry itself acts as a highly ordered, constantly developing system of knowledge. Here is a definition from a classic textbook: “Chemistry is the science of the transformations of substances. It studies the composition and structure of substances, the dependence of the properties of substances on their composition and structure, the conditions and ways of transformation of one substance into another.
Chemistry is the science of the transformations of substances.
The most important distinguishing feature of chemistry is that it is in many ways independently forms subject of research, creating substances that did not exist in nature. Like no other science, chemistry simultaneously acts both as a science and as a production. Since modern chemistry solves its problems at the atomic-molecular level, it is closely connected with physics, biology, as well as such sciences as geology, mineralogy, etc. The border areas between these sciences are studied by quantum chemistry, chemical physics, physical chemistry, geochemistry, biochemistry and etc.
More than 200 years ago, the great M. V. Lomonosov spoke at a public meeting of the St. Petersburg Academy of Sciences. in the report "A word about the benefits of chemistry" we read prophetic lines: “Chemistry spreads its hands wide in human affairs ... Wherever we look, wherever we look, everywhere we turn before our eyes the successes of its diligence.” Chemistry began to spread its "diligence" even in Egypt - the advanced country of the Ancient World. Such branches of production as metallurgy, ceramics, glass making, dyeing, perfumery, cosmetics reached significant development there long before our era.
Let's compare the name of the science of chemistry in different languages:
All these words contain the root "chem" or " chem”, which is consonant with the words of the ancient Greek language: “himos” or “hyumos” meant “juice”. This name is found in manuscripts containing information on medicine and pharmacy.
There are other points of view. According to Plutarch, the term "chemistry" comes from one of the ancient names of Egypt - Hemi ("drawing earth"). In its original sense, the term meant "Egyptian art". Chemistry as the science of substances and their interactions was considered in Egypt a divine science and was entirely in the hands of the priests.
One of the oldest branches of chemistry is metallurgy. For 4-3 thousand years BC. began to smelt copper from ores, and later to produce an alloy of copper and tin (bronze). In the II millennium BC. learned how to get iron from ores by raw-blowing process. For 1600 years BC. they began to use natural indigo dye for dyeing fabrics, and a little later - purple and alizarin, as well as prepare vinegar, medicines from plant materials and other products, the production of which is associated with chemical processes.
In the Arab East in the V-VI centuries. the term "alchemy" appears by adding the particle "al-" to the Greco-Egyptian "chemistry". The goal of the alchemists was to create a "philosopher's stone" capable of turning all base metals into gold. It was based on a practical order: gold
in Europe was necessary for the development of trade, and there were few known gold deposits.
Fact from the history of science
The oldest discovered chemical texts are now considered ancient Egyptian "Ebers Papyrus"(named after the German Egyptologist who found it) - a collection of recipes for the manufacture of medicines of the 16th century. BC, as well as the “Brugsch Papyrus” found in Memphis with pharmaceutical prescriptions (XIV century BC).
The prerequisites for the formation of chemistry as an independent scientific discipline were formed gradually during the 17th - the first half of the 18th century. At the same time, despite the variety of empirical material, in this science, until the discovery in 1869 of the periodic system of chemical elements by D. I. Mendeleev (1834-1907), there was no general theory that could be used to explain the accumulated actual material.
Attempts to periodize chemical knowledge were made as early as the 19th century. According to the German scientist G. Kopp - the author of a four-volume monograph "History of Chemistry"(1843-1847), the development of chemistry took place under the influence of a certain guiding idea. He identified five stages:
- the era of the accumulation of empirical knowledge without attempts to theoretically explain them (from ancient times to the 4th century AD);
- alchemical period (IV - beginning of the 16th century);
- period of iatrochemistry, i.e. "Chemistry of Healing" (second quarter of the 16th - mid-17th centuries);
- the period of creation and dominance of the first chemical theory - the theory of phlogiston (mid-17th - third quarter of the 18th century);
- period of quantitative research (last quarter of the 18th - 1840s) 1 .
However, according to modern concepts, this classification refers to those stages when chemical science has not yet been constituted as a systemic theoretical knowledge.
Domestic historians of chemistry distinguish four conceptual levels, which are based on a way to solve the central problem of chemistry as a science and as a production (Fig. 13.1).
First conceptual level - study of the structure of a chemical substance. At this level, various properties and transformations of substances were studied depending on their chemical composition.
Rice. 13.1.
It is easy to see the analogy of this concept with the physical concept of atomism. Both physicists and chemists sought to find the original basis by which it would be possible to explain the properties of all simple and complex substances. This concept was formulated quite late - in 1860, at the first International Congress of Chemists in Karlsruhe, Germany. The chemists proceeded from the fact that All substances are made up of molecules and all molecules, in turn are made up of atoms. Both atoms and molecules are in continuous motion, while atoms are the smallest, and then indivisible parts of molecules 1.
The significance of the Congress was clearly expressed by D. I. Mendeleev: G. A.), chemists of all countries accepted the beginning of the unitary system; now it would be a great inconsistency, recognizing the beginning, not recognizing its consequences.
Second conceptual level - study of the structure of chemicals, identification of a specific method of interaction of elements in the composition of specific chemicals. It was found that the properties of substances depend not only on their constituent chemical elements, but also on the relationship and interaction of these elements during a chemical reaction. So, diamond and coal have different properties precisely because of the difference in structures, although their chemical composition is similar.
Third conceptual level Chemistry is generated by the needs of increasing the productivity of chemical industries and explores the internal mechanisms and external conditions for the occurrence of chemical processes: temperature, pressure, reaction rate, etc.
Fourth conceptual level - level of evolutionary chemistry. At this level, the nature of the reagents involved in chemical reactions, the specifics of the action of catalysts, which significantly accelerate their rate, are studied in more depth. It is at this level that the process of origin is comprehended. alive matter from inert matter.
- Glinka II. L. General chemistry. 2b ed. L .: Chemistry: Leningrad branch, 1987. S. 13.
- Cit. Quoted from: Koltun M. World of Chemistry. M .: Children's literature, 1988. S. 7.
- Mendeleev D. I. Op. in 25 vols. L. - M.: Publishing House of the Academy of Sciences of the USSR, 1949. T. 15. S. 171-172.
Lesson #1
Subject: Chemistry is a natural science.
Target: give the concept of chemistry as a science; show the place of chemistry among the natural sciences; to acquaint with the history of the origin of chemistry; consider the importance of chemistry in human life; learn the rules of conduct in the chemistry room; to acquaint with scientific methods of knowledge in chemistry; develop the logic of thinking, the ability to observe; to cultivate interest in the subject being studied, perseverance, diligence in studying the subject.
During the classes.
IClass organization.
IIUpdating of basic knowledge.
What natural sciences do you know, study?
Why are they called natural?
IIIThe message of the topic, the objectives of the lesson, the motivation of educational activities.
After reporting the topic and purpose of the lesson, the teacher poses a problematic question.
What do you think chemistry studies? (Students express their assumptions, all of them are written on the board). Then the teacher says that during the lesson we will find out which assumptions are correct.
IIILearning new material.
Before starting our lesson, we must learn the rules of conduct in the chemistry room. Look in front of you on the wall stand on which these rules are written. Every time you enter the office, you must repeat these rules, know them and strictly follow them.
(We read aloud the rules of conduct in the chemistry room.)
Rules of conduct for students in the chemistry classroom.
You can enter the chemistry room only with the permission of the teacher
In the chemistry room you need to walk with a measured step. In no case should you move sharply, as you can overturn the equipment and reagents standing on the tables
During the experimental work in the chemistry room, it is necessary to be in a dressing gown.
When conducting experimental work, you can start work only after the permission of the teacher.
When performing experiments, work calmly, without fuss. Don't push your roommate. Remember! Accuracy is the key to success!
After completing the experiments, it is necessary to put the workplace in order and wash your hands thoroughly with soap and water.
Chemistry is a natural science, the place of chemistry among the natural sciences.
The natural sciences include physical geography, astronomy, physics, biology, ecology and others. They study the objects and phenomena of nature.
Let us consider what place chemistry occupies among other sciences. It provides them with substances, materials and modern technologies. And at the same time, he uses the achievements of mathematics, physics, biology, ecology for his own further development. Therefore, chemistry is a central, fundamental science.
The boundaries between chemistry and other natural sciences are increasingly blurred. Physical chemistry and chemical physics arose at the boundary of the study of physical and chemical phenomena. Biochemistry - biological chemistry - studies the chemical composition and structure of compounds found in living organisms.
The history of the origin of chemistry.
The science of substances and their transformations originated in Egypt, the technically most advanced country of the ancient world. Egyptian priests were the first chemists. They held many hitherto unsolved chemical secrets. For example, techniques for embalming the bodies of dead pharaohs and nobles, as well as obtaining some paints.
Such branches of production as pottery, glassmaking, dyeing, perfumery, reached significant development in Egypt long before our era. Chemistry was considered a "divine" science, was entirely in the hands of the priests and was carefully hidden by them from all the uninitiated. However, some information still penetrated beyond Egypt.
Approximately in the 7th century. AD The Arabs adopted the property and methods of work of the Egyptian priests and enriched mankind with new knowledge. The Arabs added the prefix al to the word Hemi, and the leadership in the study of substances, which became known as alchemy, passed to the Arabs. It should be noted that alchemy was not widespread in Rus', although the works of alchemists were known, and even translated into Church Slavonic. Alchemy is a medieval art of obtaining and processing various substances for practical needs. Unlike the ancient Greek philosophers, who only observed the world, and the explanation was based on assumptions and reflections, alchemists acted, experimented, making unexpected discoveries and improving the experimental methodology. Alchemists believed that metals are substances consisting of three main elements: salt - as a symbol of hardness and the ability to dissolve; sulfur - as a substance that can heat up and burn at high temperatures; mercury - as a substance capable of evaporation and possessing brilliance. In this regard, it was assumed that, for example, gold, which was a precious metal, also has exactly the same elements, which means that it can be obtained from any metal! It was believed that obtaining gold from any other metal is associated with the action of the philosopher's stone, which alchemists unsuccessfully tried to find. In addition, they believed that if you drink an elixir made from the philosopher's stone, you will gain eternal youth! But the alchemists failed to find and obtain neither the philosopher's stone nor gold from other metals.
The role of chemistry in human life.
Students list all aspects of the positive impact of chemistry on human life. The teacher helps and guides the thoughts of the students.
Teacher: But is chemistry only useful in society? What problems arise in connection with the use of chemical products?
(Students are trying to find the answer to this question as well.)
Methods of knowledge in chemistry.
A person receives knowledge about nature with the help of such an important method as observation.
Observation- this is the concentration of attention on cognizable objects in order to study them.
With the help of observation, a person accumulates information about the world around him, which he then systematizes, revealing general patterns of observation results. The next important step is to search for reasons that explain the patterns found.
In order for the observation to be fruitful, a number of conditions must be met:
clearly define the subject of observation, i.e., what the observer’s attention will be drawn to - a specific substance, its properties or the transformation of some substances into others, the conditions for the implementation of these transformations, etc.;
to formulate the purpose of the observation, the observer must know why he conducts the observation;
develop an observation plan to achieve the goal. To do this, it is better to put forward an assumption, that is, a hypothesis (from the Greek. Hypothesis - foundation, assumption) about how the observed phenomenon will occur. A hypothesis can also be put forward as a result of observation, that is, when a result is obtained that needs to be explained.
Scientific observation is different from observation in the everyday sense of the word. As a rule, scientific observation is carried out under strictly controlled conditions, and these conditions can be changed at the request of the observer. Most often, such observation is carried out in a special room - a laboratory.
Experiment- scientific reproduction of a phenomenon for the purpose of its study, testing under certain conditions.
Experiment (from lat. experimentum - experience, test) allows you to confirm or refute the hypothesis that arose during the observation, and formulate a conclusion.
Let's conduct a small experiment to study the structure of the flame.
Light a candle and carefully examine the flame. It is heterogeneous in color, has three zones. The dark zone (1) is at the bottom of the flame. She is the coldest among the others. The dark zone is bordered by the bright part of the flame (2), the temperature of which is higher than in the dark zone. However, the highest temperature is in the upper colorless part of the flame (zone 3).
To make sure that different zones of the flame have different temperatures, you can conduct such an experiment. Let's place a splinter or match in the flame so that it crosses all three zones. You will see that the splinter is charred in zones 2 and 3. This means that the temperature of the flame is the highest there.
The question arises whether the flame of an alcohol lamp or dry fuel will have the same structure as the flame of a candle? The answer to this question can be two assumptions - hypotheses: 1) the structure of the flame will be the same as the flame of a candle, because it is based on the same process - combustion; 2) the structure of the flame will be different, since it arises as a result of the combustion of various substances. In order to confirm or refute one of these hypotheses, let us turn to the experiment - we will conduct an experiment.
We investigate with the help of a match or a splinter the structure of the flame of an alcohol lamp.
Despite the differences in shape, size and even color, in both cases the flame has the same structure - the same three zones: the inner dark (coldest), the middle luminous (hot) and the outer colorless (hottest).
Therefore, on the basis of the experiment, we can conclude that the structure of any flame is the same. The practical significance of this conclusion is as follows: in order to heat any object in a flame, it must be brought into the upper, i.e., the hottest, part of the flame.
It is customary to draw up experimental data in a special laboratory journal, for which an ordinary notebook is suitable, but strictly defined entries are made in it. They note the date of the experiment, its name, the course of the experiment, which is often drawn up in the form of a table.
Try to describe an experiment on the structure of a flame in this way.
All natural sciences are experimental. And to set up an experiment, special equipment is often required. For example, in biology, optical instruments are widely used, which allow you to magnify the image of the observed object many times over: a magnifying glass, a microscope.
Physicists in the study of electrical circuits use instruments to measure voltage, current, and electrical resistance.
Scientists-geographers are armed with special instruments - from the simplest (compass, meteorological probes) to research ships, unique space orbital stations.
Chemists also use special equipment in their research. The simplest of them is, for example, a heating device already familiar to you - an alcohol lamp and various chemical utensils in which transformations of substances are carried out, that is, chemical reactions.
IV Generalization and systematization of acquired knowledge.
So what does chemistry study? (During the lesson, the teacher paid attention to the correctness or incorrectness of the children's assumptions about the subject of chemistry. And now the time has come to summarize and give the final answer. We derive the definition of chemistry).
What role does chemistry play in human life and society?
What methods of knowledge in chemistry do you now know.
What is observation? What conditions must be met in order for the observation to be effective?
What is the difference between a hypothesis and a conclusion?
What is an experiment?
What is the structure of a flame?
How should the heating be done?
V Reflection, summing up the lesson, grading.
VI Communication of homework, briefing on its implementation.
Teacher: You must:
Learn the base notes for this lesson.
Describe the experiment to study the structure of the flame using the table below.
Chemistry as a science
Chemistry- a science that studies the structure of substances and their transformations, accompanied by a change in composition and (or) structure. Modern chemistry faces three main tasks:
- Firstly, the fundamental direction in the development of chemistry is the study of the structure of matter, the development of the theory of the structure and properties of molecules and materials. It is important to establish a connection between the structure and various properties of substances and, on this basis, to construct theories of the reactivity of a substance, the kinetics and mechanism of chemical reactions and catalytic phenomena. The implementation of chemical transformations in one direction or another is determined by the composition and structure of molecules, ions, radicals, and other short-lived formations. Knowing this makes it possible to find ways to obtain new products that have qualitatively or quantitatively different properties than the existing ones.
- secondly, the implementation of a directed synthesis of new substances with desired properties. Here it is also important to find new reactions and catalysts for a more efficient synthesis of already known and commercially important compounds.
- third - analysis. This traditional problem of chemistry has taken on special significance. It is associated both with an increase in the number of chemical objects and studied properties, and with the need to determine and reduce the consequences of human impact on nature.
The chemical properties of substances are determined mainly by the state of the outer electron shells of the atoms and molecules that form substances; states of nuclei and internal electrons in chemical processes almost do not change. The object of chemical research is chemical elements and their combinations, i.e. atoms, simple (single-element) and complex (molecules, ions, radical ions, carbees, free radicals) chemical compounds, their associations (associates, clusters, solvates, clathrates, etc.), materials, etc.
Modern chemistry has reached such a level of development that there are a number of its special sections, which are independent sciences. Depending on the atomic nature of the substance under study, the types of chemical bonds between atoms, inorganic, organic and organoelement chemistry are distinguished. The object of inorganic chemistry are all chemical elements and their compounds, other substances based on them. Organic chemistry studies the properties of a vast class of compounds formed through the chemical bonds of carbon with carbon and other organogenic elements: hydrogen, nitrogen, oxygen, sulfur, chlorine, bromine, and iodine. Organoelement chemistry is at the interface between inorganic and organic chemistry. This "third" chemistry refers to compounds involving the chemical bonds of carbon with the rest of the non-organogen elements in the Periodic Table. The molecular structure, the degree of aggregation (combination) of atoms in the composition of molecules and large molecules - macromolecules bring their own characteristic features to the chemical form of the motion of matter. Therefore, there are chemistry of macromolecular compounds, crystal chemistry, geochemistry, biochemistry and other sciences. They study large associations of atoms and giant polymer formations of various nature. Everywhere the central question for chemistry is the question of chemical properties. The subject of study is also the physical, physicochemical and biochemical properties of substances. Therefore, not only are their own methods intensively developed, but other sciences are also involved in the study of substances. So important components of chemistry are physical chemistry and chemical physics, which study chemical objects, processes and accompanying phenomena with the help of the calculation apparatus of physics and physical experimental methods. Today, these sciences combine a number of others: quantum chemistry, chemical thermodynamics (thermochemistry), chemical kinetics, electrochemistry, photochemistry, high-energy chemistry, computer chemistry, etc. its impact on our daily lives. There are many directions in the development of applied chemistry, designed to solve specific problems of human practical activity. Chemical science has reached such a level of development that it began to generate new industries and technologies.
Chemistry as a system of knowledge
Chemistry as a system of knowledge about substances and their transformations is contained in a stock of facts - reliably established and verified information about chemical elements and compounds, their reactions and behavior in natural and artificial environments. Criteria for the reliability of facts and ways to systematize them are constantly evolving. Large generalizations that reliably connect large sets of facts become scientific laws, the formulation of which opens up new stages in chemistry (for example, the laws of conservation of mass and energy, Dalton's laws, Mendeleev's periodic law). Theories, using specific concepts, explain and predict the facts of a more particular subject area. In fact, experiential knowledge becomes a fact only when it receives a theoretical interpretation. So, the first chemical theory - the theory of phlogiston, being incorrect, contributed to the formation of chemistry, because. connected facts into a system and allowed the formulation of new questions. Structural theory (Butlerov, Kekule) streamlined and explained the vast material of organic chemistry and led to the rapid development of chemical synthesis and the study of the structure of organic compounds.
Chemistry as knowledge is a very dynamic system. The evolutionary accumulation of knowledge is interrupted by revolutions - a deep restructuring of the system of facts, theories and methods, with the emergence of a new set of concepts or even a new style of thinking. Thus, the revolution was caused by the works of Lavoisier (the materialistic theory of oxidation, the introduction of quantities, experimental methods, the development of chemical nomenclature), the discovery of Mendeleev's periodic law, the creation of new analytical methods at the beginning of the 20th century (microanalysis, chromatography). The emergence of new areas that develop a new vision of the subject of chemistry and influence all its areas (for example, the emergence of physical chemistry based on chemical thermodynamics and chemical kinetics) can also be considered a revolution.
Chemistry as an academic discipline
Chemistry is a general theoretical discipline. It is designed to give students a modern scientific understanding of matter as one of the types of moving matter, about the ways, mechanisms and methods of transforming one substance into another. Knowledge of the basic chemical laws, knowledge of the technique of chemical calculations, understanding of the opportunities provided by chemistry with the help of other specialists working in its individual and narrow areas, significantly accelerate the receipt of the desired result in various fields of engineering and scientific activity. Chemistry acquaints the future specialist with specific manifestations of a substance, makes it possible to “feel” a substance with the help of a laboratory experiment, to learn its new types and properties. A feature of chemistry as a discipline for students of non-chemical specialties is that in a small course it is necessary to have information from almost all branches of chemistry that have taken shape as independent sciences and are studied by chemists and chemist-technologists in special disciplines. In addition, the diversity of interests of representatives of different specialties often leads to the creation of specialized courses in chemistry. With all the positive aspects of such an orientation, there is also a serious drawback - the specialist's worldview narrows, the freedom of his orientation in the properties of the substance and the methods of its production and application decreases. Therefore, a chemistry course for future specialists not in the field of chemistry and chemical technology should be broad enough and, to the extent necessary, thorough to give a holistic view of the possibilities of chemistry as a science, as a branch of industry, as the basis for scientific and technological progress. The theoretical foundations for understanding the diverse and complex picture of chemical phenomena are laid by general chemistry. The chemistry of elements introduces into the concrete world of substances formed by chemical elements. A modern engineer who does not have special chemical training needs to understand the properties of various types of materials, compositions and compounds. Often, in one way or another, he has to deal with fuels, oils, lubricants, detergents, binders, ceramic, structural, electrical materials, fibers, fabrics, biological objects, mineral fertilizers, and many others. Other courses may not always give a first impression of this. This gap needs to be filled. This section belongs to the most dynamically changing part of chemistry and, of course, quickly becomes obsolete. Therefore, the timely and careful selection of material here is essential for the regular renewal of the discipline. All this leads to the expediency of introducing a separate section of applied chemistry into the course of chemistry for students of non-chemical specialties.
Chemistry as a social system
Chemistry as a social system is the largest part of the entire community of scientists. The formation of a chemist as a type of scientist was influenced by the features of the object of his science and the mode of activity (chemical experiment). The difficulties of mathematical formalization of the object (in comparison with physics) and at the same time the variety of sensory manifestations (smell, color, biological and other activity) from the very beginning limited the dominance of mechanism in the thinking of the chemist and left, therefore, a field for intuition and artistry. In addition, the chemist has always used an instrument of non-mechanical nature - fire. On the other hand, unlike the biologist's stable objects given by nature, the chemist's world has an inexhaustible and rapidly growing diversity. The irremovable mystery of the new substance gave the chemist's attitude to the world responsibility and caution (as a social type, a chemist is conservative). The chemical laboratory has developed a rigid mechanism of "natural selection", rejection of presumptuous and error-prone people. This gives originality not only to the style of thinking, but also to the spiritual and moral organization of the chemist.
The community of chemists consists of people who are professionally involved in chemistry and who identify themselves with this field. Approximately half of them work, however, in other areas, providing them with chemical knowledge. In addition, many scientists and technologists adjoin them - to a large extent chemists, although they no longer consider themselves chemists (mastering the skills and abilities of a chemist by scientists in other areas is difficult due to the above features of the subject).
Like any other close-knit community, chemists have their own professional language, system of personnel reproduction, communication system [journals, congresses, etc.], their own history, their own cultural norms and style of behavior.
Chemistry as an industry
The modern standard of living of mankind is simply impossible without the products and methods of chemistry. They decisively determine the modern face of the world around us. So many products of chemistry are required that in developed countries there are chemical industries. The chemical industry is one of the most important industries in our country. The chemical compounds produced by it, various compositions and materials are used everywhere: in mechanical engineering, metallurgy, agriculture, construction, electrical and electronic industries, communications, transport, space technology, medicine, everyday life, etc. About a thousand different chemical compounds, and in total for practical needs the industry produces more than a million substances. The economic well-being and defense capability of the country largely depends on chemistry. Therefore, in order not to hinder the development of other industries and to provide them with new compounds and materials with the required set of properties in a timely manner, chemical science and the chemical industry must develop at a faster pace, expanding the range of products, improving their quality and increasing production volumes. In our country there are:
- inorganic production of basic chemistry, producing acids, alkalis, salts and other compounds, fertilizers;
- petrochemical industries: production of fuels, oils, solvents, monomers of organic chemistry (hydrocarbons, alcohols, aldehydes, acids), various polymers and materials based on them, synthetic rubber, chemical fibers, plant protection products, feed and feed additives, household goods chemistry;
- small chemistry, when the volumes of products produced are small, but its range is very wide. Such products include auxiliaries for the production of polymeric materials (catalysts, stabilizers, plasticizers, flame retardants), dyes, drugs, disinfectants and other sanitation and hygiene products, agricultural chemicals - herbicides, insecticides, fungicides, defoliants, etc.
The main directions of development of the modern chemical industry are: the production of new compounds and materials and increasing the efficiency of existing industries. To do this, it is important to find new reactions and catalysts, to elucidate the mechanisms of ongoing processes. This determines the chemical approach in solving engineering problems of increasing production efficiency. A typical feature of the chemical industry is a relatively small number of employees and high requirements for their qualifications, and the relative number of chemical specialists is small, and there are more representatives of other specialties (mechanics, heat power engineers, specialists in production automation, etc.). Characterized by large amounts of energy and water consumption, high environmental requirements for production. In non-chemical industries, many technological operations are associated with the preparation and cleaning of raw materials and materials, painting, gluing, and other chemical processes.
Chemistry is the basis of scientific and technological progress
Compounds, compositions and materials created by chemistry play a crucial role in increasing labor productivity, reducing energy costs for the production of necessary products, and mastering new technologies and equipment. There are many examples of the successful influence of chemistry on the methods of machine-building technology, methods of operating machines and devices, the development of the electronics industry, space technology and jet aviation, and many other areas of scientific and technological progress:
- the introduction of chemical and electrochemical methods of metal processing dramatically reduces the amount of waste that is inevitable in metal cutting. At the same time, restrictions on the strength and hardness of metals and alloys, the shape of the part are removed, high surface cleanliness and dimensional accuracy of parts are achieved.
- Materials such as synthetic graphite (which is stronger than metals at high temperatures), corundum (alumina-based) and quartz (silica-based) ceramics, synthetic polymer materials, and glass can exhibit unique properties.
- crystallized glasses (sitalls) are obtained by introducing substances into molten glass that promote the emergence of crystallization centers and the subsequent growth of crystals. Such glass-ceramic as "pyroceram" is nine times stronger than rolled glass, harder than high-carbon steel, lighter than aluminum and close to quartz in terms of heat resistance.
- modern lubricants can significantly reduce the coefficient of friction and increase the wear resistance of materials. The use of oils and lubricants containing molybdenum disulfide increases the service life of vehicle components and parts by 1.5 times, individual parts - up to two times, while the friction coefficient can be reduced by more than 5 times.
- organoelement substances - polyorganosiloxanes are characterized by flexibility and a spiral structure of molecules that form coils as the temperature decreases. Thus, they retain slightly varying viscosity over a wide temperature range. This allows them to be used as a hydraulic fluid in a wide variety of conditions.
- The protection of metals from corrosion has acquired a purposefulness of action after the creation of the electrochemical theory of corrosion and makes it possible to avoid significant economic costs for the renewal of metal products.
At present, chemistry, together with other sciences, technology and industry, faces many urgent and complex tasks. The synthesis and practical application of suitable high-temperature and, further, hot superconductors will significantly change the methods of energy storage and transmission. New materials are needed, among which metal-based materials, polymers, ceramics and composites stand out. So the problem of creating an environmentally friendly engine, which is based on the reaction of hydrogen combustion in oxygen, is to create materials or processes that prevent the penetration of hydrogen through the walls of hydrogen storage tanks. The creation of new chemical technologies is also an important area of scientific and technological progress. Thus, the task is to provide new types of liquid and gaseous fuels obtained during the processing of coal, shale, peat, and wood. This is possible on the basis of new catalytic processes.
Subject: Chemistry is a natural science. Chemistry in the environment.
Target: to interest students in a new subject for them - chemistry;
reveal the role of chemistry in human life; educate children
responsible attitude towards nature.
Tasks: 1. consider the meaning of the word chemistry, as one of the natural
2. determine the meaning and relationship of chemistry with others
3. find out what effect chemistry has on a person and
Equipment and materials:"Chemistry in the Guinness Book of Records";
Chemical market: related articles; scientists' statement about
chemistry; mineral water; bread, iodine; shampoo, tablets, toothpaste
paste, varnish, etc.
Terms and concepts: chemistry; substances: simple and complex; chemical
element; atom, molecule.
Lesson type: learning new material.
During the classes
I. organizational stage.
The bell rang
The lesson has begun. We came here to study
Don't be lazy, but work hard.
We work diligently
We listen carefully.
Hello guys
II. Actualization and motivation of educational activities. Today, you start studying a new subject - chemistry.
You already got acquainted with some concepts of chemistry at the lessons of natural history. . Give examples
(Body, substance, chemical element, molecule, atom).What substances do you use at home? (water, sugar, salt, vinegar, soda, alcohol, etc.) What do you associate the word chemistry with??(Food, clothing, water, cosmetics, home). We cannot imagine our life without such means: as toothpaste, shampoo, powders, hygiene products that keep our body and clothes clean and tidy. The objects that surround us consist of substances: simple or complex, and they, in turn, from the chemical elements of one or many. Our body also includes almost the entire periodic table, for example: the blood contains the chemical element Ferum (Iron), which, when combined with Oxygen, is part of hemoglobin, forming red blood cells - erythrocytes, the stomach contains Hydrochloric acid, which contributes to a faster the breakdown of food, our body consists of 70% water, without which human life is not possible .. We will get acquainted with this and other substances throughout the course of chemistry.
Of course, in chemistry, as in any science, except for the entertaining, there will also be difficult ones. But it is difficult and interesting - this is exactly what a thinking person needs, so that our mind is not in idleness and laziness, but constantly works and works. Therefore, the theme of the first lesson is an introduction to chemistry as one of the natural sciences.
We write in a notebook:
Classwork.
Topic: Chemistry is a natural science. Chemistry in the environment.
III. Learning new material.
Epigraph:
O you happy sciences!
Stretch out your hands diligently
And look to the farthest places.
Pass the earth and the abyss,
And the steppes, and the deep forest,
And the very height of heaven.
Everywhere explore all the time,
What is great and beautiful
What the world has not yet seen ... ..
In the bowels of the earth you, Chemistry,
Penetrated the sharpness of the gaze,
And what does Russia contain in it,
Open the treasure treasures...
M.V. Lomonosov "Ode of Gratitude"
Fiz minute
Handles pulled to the sky (pull up)
The spine was stretched (spread apart)
We all had time to rest (shake your hands)
And sat down at the desk again.
The word "chemistry" comes from the word "himi" or "huma" from ancient Egypt, as black earth, that is, black as earth, which deals with various minerals.
In everyday life, you often encounter chemical reactions. For example:
Experience: 1. Drop a drop of iodine on bread, potatoes - blue color, which is a qualitative reaction to starch. You can test yourself on other objects for their starch content.
2. Open a bottle of carbonated water. There is a decomposition reaction of carbonic or carbonate acid into carbon dioxide and water.
H2CO3 CO2 + H2O
3. Acetic acid + soda carbon dioxide + sodium acetate. Grandmothers and mothers bake pies for you. In order for the dough to be soft and fluffy, soda slaked with vinegar is added to it.
All these phenomena are explained by chemistry.
Some interesting facts related to chemistry.:
Why is the bashful mimosa called that?
The bashful mimosa plant is known for the fact that its leaves fold when someone touches it, and after a while they straighten again. This mechanism is due to the fact that specific areas on the plant stem, when externally stimulated, release chemicals, including potassium ions. They act on the cells of the leaves, from which the outflow of water begins. Because of this, the internal pressure in the cells drops, and, as a result, the petiole and petals on the leaves curl up, and this effect can be transmitted along the chain to other leaves.
Use of toothpaste: removes plaque from tea on the cup, as it contains soda, which cleans it.
Inquiry into the death of Emperor Napoleon .
The captured Napoleon, accompanied by his escort in 1815, arrived on the island of St. Helena, in good enviable health, but in 1821 he died. He was diagnosed with stomach cancer. Locks of the deceased's hair were cut and distributed to the emperor's devoted supporters. So they have reached our time. In 1961, studies of Napoleon's hair for arsenic were published. It turned out that the hair contained an increased content of arsenic and antimony, which were gradually mixed into food, which caused gradual poisoning. Thus, chemistry, a century and a half after death, helped to solve some crimes.
Working with the textbook 5 find and write down the definition of the concept of chemistry.
Chemistry is the science of substances and their transformations. As a science, it is exact and experimental, since it is accompanied by experiments, or an experiment, at the same time, the necessary calculations are carried out and after that only conclusions are drawn.
Chemists study the variety of substances and their properties; phenomena that occur with substances; composition of substances; structure; properties; transformation conditions; possibilities of use.
Distribution of substances in nature. Consider Figure 1. What conclusion can be drawn from this.(Substances exist not only on Earth, but also beyond it.) But all substances are made up of chemical elements. Some information about chemical elements and substances is listed in the Guinness Book of Records: for example
The most common element: in the lithosphere - oxygen (47%), in the atmosphere - Nitrogen (78%), outside the Earth - Hydrogen (90%), the most expensive - California.
The most malleable metal - Gold from 1 g can be drawn into a wire 2.4 km long (2,400 m), the hardest - chromium, the most warm - and electrically conductive - silver. The most expensive substance is interferon: one millionth microgram of a pure drug costs $10.
Chemistry is closely related to other natural sciences. What natural sciences can you name?
Consider diagram 1. 6
Ecology Agriculture Agrochemistry
Physchemistry
Physics Chemistry Biology Biochemistry Medicine
Mathematics Geography Astronomy Cosmochemistry
pharmaceutical chemistry
But besides this, chemistry itself can also be classified:
Chemistry classification
Inorganic Organic Analytical
general chemistry
All this will be studied throughout the school chemistry course.
Man must exist in harmony with nature, but at the same time he himself destroys it. Each of you can both protect and pollute nature. Paper, polyethylene, plastic - you need to throw only in special bins, and not scatter where you are, as they do not decompose. When burning plastic and polyethylene, very toxic substances are released that affect humans. In the autumn, when the leaves are burned, toxic substances are also formed, although they can be piled up for the rotting process, and then used as biological fertilizers. The use of household chemicals leads to water pollution. Therefore, the preservation of nature for future generations depends on the careful attitude of each of us to it, on the level of culture, chemical knowledge.
IV. Generalization and systematization of knowledge.
1. Continue the definition:
Chemistry is……………………………………………………………………..
2. Choose the correct statements:
A. Chemistry - Humanities
b. Chemistry is a natural science.
V. Knowledge of chemistry is necessary only for biologists.
d. Chemicals are found only on Earth.
e. For life, breathing, a person needs carbon dioxide.
e. Life on the Planet is not possible without oxygen.
3. From the given sciences that are interconnected with chemistry, select those related to definitions.
Biochemistry, Ecology, Physical chemistry, Geology, Agrochemistry
1. Chemical processes occurring in the human body are studied by science - Biochemistry.
2. The science of environmental protection is called Ecology
3. Exploration of minerals - Geology
4. The transformation of some substances into others is accompanied by the absorption or release of heat, the science of Physical Chemistry studies
5. The study of the effect of fertilizers on soil and plants is the science of Agrochemistry.
4. What influence does Chemistry have on nature.
V. Summing up the lesson.
From the material presented it follows that Chemistry is the science of substances and their transformations. In the modern world, a person cannot imagine his life without chemicals. There is practically no industry where chemical knowledge would not be needed. The impact of chemistry and chemicals on humans and the environment, both positive and negative. Each of us can save a piece of nature, such as it is. Protect the environment.
VI. Homework.
2. Answer the questions on p. 10 . 1- orally, 2-4 in writing.
3. Prepare reports on the topic: "The history of the development of chemistry as a science"
