If you entered the university, but by this time have not understood this difficult science, we are ready to reveal a few secrets to you and help you study organic chemistry from scratch (for dummies). All you have to do is read and listen.
Basics of organic chemistry
Organic chemistry is separated into a separate subtype due to the fact that the object of its study is everything that contains carbon.
Organic chemistry is a branch of chemistry that deals with the study of carbon compounds, the structure of such compounds, their properties and methods of joining.
As it turned out, carbon most often forms compounds with the following elements - H, N, O, S, P. By the way, these elements are called organogens.
Organic compounds, the number of which today reaches 20 million, are very important for the full existence of all living organisms. However, no one doubted it, otherwise the person would have simply thrown the study of this unknown into the back burner.
Goals, methods and theoretical ideas organic chemistry are presented as follows:
- Separation of fossil, animal or plant materials into individual substances;
- Purification and synthesis of various compounds;
- Identification of the structure of substances;
- Determination of the mechanics of chemical reactions;
- Finding the relationship between structure and properties organic matter.
A little history of organic chemistry
You may not believe it, but back in ancient times, the inhabitants of Rome and Egypt understood something about chemistry.
As we know, they used natural dyes. And often they had to use not a ready-made natural dye, but extract it by isolating it from a whole plant (for example, alizarin and indigo contained in plants).
We can also remember the culture of drinking alcohol. The secrets of producing alcoholic beverages are known in every nation. Moreover, many ancient peoples knew recipes for preparing “hot water” from starch- and sugar-containing products.
This went on for many, many years, and only in the 16th and 17th centuries did some changes and small discoveries begin.
In the 18th century, a certain Scheele learned to isolate malic, tartaric, oxalic, lactic, gallic and citric acid.
Then it became clear to everyone that the products that had been isolated from plant or animal raw materials had many common features. At the same time, they were very different from Not organic compounds. Therefore, the servants of science urgently needed to separate them into a separate class, and this is how the term “organic chemistry” appeared.
Despite the fact that organic chemistry itself as a science appeared only in 1828 (it was then that Mr. Wöhler managed to isolate urea by evaporating ammonium cyanate), in 1807 Berzelius introduced the first term into the nomenclature in organic chemistry for dummies:
The branch of chemistry that studies substances obtained from organisms.
The next important step in the development of organic chemistry was the theory of valency, proposed in 1857 by Kekule and Cooper, and the theory chemical structure Mr. Butlerov from 1861. Even then, scientists began to discover that carbon was tetravalent and capable of forming chains.
In general, since then, science has regularly experienced shocks and excitement thanks to new theories, discoveries of chains and compounds, which allowed the active development of organic chemistry.
Science itself emerged due to the fact that scientific and technological progress was unable to stand still. He went on and on, demanding new solutions. And when there was no longer enough coal tar in industry, people simply had to create a new organic synthesis, which over time grew into the discovery of an incredibly important substance, which to this day is more expensive than gold - oil. By the way, it was thanks to organic chemistry that its “daughter” was born - a subscience that was called “petrochemistry”.
But this is a completely different story that you can study for yourself. Next, we invite you to watch a popular science video about organic chemistry for dummies:
Well, if you have no time and urgently need help professionals, you always know where to find them.
E.N.Frenkel
Chemistry tutorial
A manual for those who do not know, but want to learn and understand chemistry
Part I. Elements general chemistry
(first difficulty level)
I, Evgenia Nikolaevna Frenkel, Honored Worker high school Russian Federation, graduate of the Faculty of Chemistry of Moscow State University in 1972, teaching experience 34 years. In addition, I am the mother of three children and grandmother of four grandchildren, the eldest of whom is in school.
I am concerned about the problem of school textbooks. The main problem of many of them is the difficult language, which requires additional “translation” into a language that students can understand to present educational material. Students often contact me high school with the following request: “Translate the text of the textbook so that it is clear.” Therefore, I wrote a “Self-Teacher in Chemistry”, in which many complex issues are presented in a completely accessible and at the same time scientific manner. Based on this “Self-Teacher”, which was written in 1991, I developed the program and content preparatory courses. Hundreds of schoolchildren studied there. Many of them started from scratch and after 40 lessons understood the subject so much that they passed exams with “4” and “5”. That’s why in our city my self-teaching manuals are selling like hotcakes.
Maybe others will find my work useful too?
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Preface
Dear readers! The “Chemistry Self-Teacher” we bring to your attention is not an ordinary textbook. It does not simply state some facts or describe the properties of substances. "Tutorial" explains and teaches even in in that case, if, unfortunately, you do not know and do not understand chemistry, and you cannot turn to the teacher for clarification or are embarrassed. In manuscript form, this book has been used by schoolchildren since 1991, and there has not been a single student who failed the chemistry exam both at school and in universities. Moreover, many of them did not know chemistry at all.
The “Self-Teacher” is designed for independent work by the student. The main thing is to answer the questions that appear in the text as you read. If you could not answer the question, then read the text carefully again - all the answers are nearby. It is also advisable to perform all the exercises that occur during the explanation of new material. Numerous training algorithms that are practically not found in other textbooks will help with this. With their help you will learn:
Draw up chemical formulas based on valency;
Draw up equations of chemical reactions, arrange coefficients in them, including in equations of redox processes;
Compose electronic formulas (including short ones) electronic formulas) atoms and determine the properties of the corresponding chemical elements;
Predict the properties of certain compounds and determine whether a given process is possible or not.
The manual has two difficulty levels. Self-instruction manual first difficulty level consists of three parts.
Part I. Elements of general chemistry ( published).
Part II. Elements of inorganic chemistry.
Part III. Elements of organic chemistry.
Books second difficulty level also three.
Theoretical foundations general chemistry.
Theoretical foundations of inorganic chemistry.
Theoretical foundations of organic chemistry.
|
Chapter 1. Basic concepts of chemistry.
Chapter 2. The most important classes inorganic compounds.
Chapter 3. Basic information about the structure of the atom. Periodic law of D.I.Mendeleev.
Chapter 4. The concept of chemical bonding. Chapter 5. Solutions. Chapter 6. Electrolytic dissociation.
Chapter 7. The concept of redox reactions. Chapter 8. Calculations using chemical formulas and equations.
Application. |
Chapter 1. Basic concepts of chemistry
What is chemistry? Where do we encounter chemical phenomena?
Chemistry is everywhere. Life itself is a countless variety of chemical reactions thanks to which we breathe, see blue sky, we feel the amazing smell of flowers.
What does chemistry study?
Chemistry studies substances, as well as the chemical processes in which these substances participate.
What is a substance?
Matter is what the world around us and ourselves are made of.
What is a chemical process (phenomenon)?
TO chemical phenomena These include processes that result in changes in the composition or structure of the molecules that form a given substance*. The molecules have changed - the substance has changed (it has become different), its properties have changed. For example, fresh milk turned sour, green leaves turned yellow, raw meat changed its smell when fried.
All these changes are a consequence of complex and diverse chemical processes. However, the signs of simple chemical reactions, as a result of which the composition and structure of molecules change, are the same: a change in color, taste or smell, the release of gas, light or heat, the appearance of a precipitate.
What are molecules, the change of which entails such diverse manifestations?
Molecules are the smallest particles of matter, reflecting its qualitative and quantitative composition and its chemical properties.
By studying the composition and structure of one molecule, it is possible to predict many properties of a given substance as a whole. Such research is one of the main tasks of chemistry.
How are molecules structured? What are they made of?
Molecules are made up of atoms. The atoms in a molecule are connected by chemical bonds. Each atom is designated by symbol (chemical sign). For example, N - hydrogen atom, O – oxygen atom.
The number of atoms in a molecule is indicated using index – numbers at the bottom right after the symbol.
For example:
Examples of molecules:
O 2 is a molecule oxygen substances, consisting of two oxygen atoms;
H 2 O is a molecule water substances, consisting of two hydrogen atoms and one oxygen atom.
If the atoms are not connected by a chemical bond, then their number is indicated using coefficient – numbers before the symbol:
The number of molecules is depicted similarly:
2H 2 – two hydrogen molecules;
3H 2 O – three water molecules.
Why do hydrogen and oxygen atoms have different names and different symbols? Because these are atoms of different chemical elements.
A chemical element is a type of atom with the same nuclear charge.
What is the nucleus of an atom? Why is the nuclear charge a sign that an atom belongs to a given chemical element? To answer these questions, it is necessary to clarify: do atoms change in chemical reactions, what does an atom consist of?
A neutral atom has no charge, although it consists of a positively charged nucleus and negatively charged electrons:
During chemical reactions the number of electrons of any atom can change, but the charge of the atomic nucleus does not change. Therefore, the charge of the nucleus of an atom is a kind of “passport” of a chemical element. All atoms with a nuclear charge of +1 belong to the chemical element called hydrogen. Atoms with a nuclear charge of +8 belong to the chemical element oxygen.
Each chemical element is assigned a chemical symbol (sign), a serial number in D.I. Mendeleev’s table (the serial number is equal to the charge of the atomic nucleus), a specific name, and for some chemical elements a special reading of the symbol in the chemical formula (Table 1).
Table 1
Symbols (signs) of chemical elements
| No. | No. in the table of D.I. Mendeleev | Symbol | Reading in the formula | Name |
| 1 | 1 | H | ash | Hydrogen |
| 2 | 6 | C | this | Carbon |
| 3 | 7 | N | en | Nitrogen |
| 4 | 8 | O | O | Oxygen |
| 5 | 9 | F | fluorine | Fluorine |
| 6 | 11 | Na | sodium | Sodium |
| 7 | 12 | Mg | magnesium | Magnesium |
| 8 | 13 | Al | aluminum | Aluminum |
| 9 | 14 | Si | silicium | Silicon |
| 10 | 15 | P | pe | Phosphorus |
| 11 | 16 | S | es | Sulfur |
| 12 | 17 | Cl | chlorine | Chlorine |
| 13 | 19 | K | potassium | Potassium |
| 14 | 20 | Ca | calcium | Calcium |
| 15 | 23 | V | vanadium | Vanadium |
| 16 | 24 | Cr | chromium | Chromium |
| 17 | 25 | Mn | manganese | Manganese |
| 18 | 26 | Fe | ferrum | Iron |
| 19 | 29 | Cu | cuprum | Copper |
| 20 | 30 | Zn | zinc | Zinc |
| 21 | 35 | Br | bromine | Bromine |
| 22 | 47 | Ag | argentum | Silver |
| 23 | 50 | Sn | stannum | Tin |
| 24 | 53 | I | iodine | Iodine |
| 25 | 56 | Ba | barium | Barium |
| 26 | 79 | Au | aurum | Gold |
| 27 | 80 | Hg | hydrargyrum | Mercury |
| 28 | 82 | Pb | plumbum | Lead |
There are substances simple And complex . If a molecule consists of atoms of one chemical element, it is simple substance. Simple substances - Ca, Cl 2, O 3, S 8, etc.
Molecules complex substances consist of atoms of different chemical elements. Complex substances - H 2 O, NO, H 3 PO 4, C 12 H 22 O 11, etc.
Task 1.1. Indicate the number of atoms in the molecules of complex substances H 2 O, NO, H 3 PO 4, C 12 H 22 O 11, name these atoms.
The question arises: why is the formula H 2 O always written for water, and not HO or HO 2? Experience proves that the composition of water obtained by any method or taken from any source always corresponds to the formula H 2 O ( we're talking about about clean water).
The fact is that the atoms in a water molecule and in a molecule of any other substance are connected through chemical bonds. Chemical bond connects at least two atoms. Therefore, if a molecule consists of two atoms and one of them forms three chemical bonds, then the other also forms three chemical bonds.
Number of chemical bonds formed by an atom is called valence.
If we designate each chemical bond with a dash, then for a molecule of two AB atoms we obtain AB, where three dashes indicate the three bonds formed by elements A and B among themselves.
In this molecule, atoms A and B are trivalent.
It is known that the oxygen atom is divalent, the hydrogen atom is monovalent.
Question. How many hydrogen atoms can attach to one oxygen atom?
ANSWER: Two atoms. The composition of water is described by the formula H–O–H, or H 2 O.
REMEMBER! A stable molecule cannot have “free” or “extra” valences. Therefore, for a two-element molecule, the number of chemical bonds (valencies) of the atoms of one element is equal to the total number of chemical bonds of the atoms of the other element.
Valence of atoms of some chemical elements constant(Table 2).
Table 2
The value of constant valences of some elements
For other atoms, valency** can be determined (calculated) from the chemical formula of the substance. In this case, it is necessary to take into account the rule stated above about chemical bonds. For example, let's define the valency x manganese Mn according to the formula of the substance MnO 2:
Total number the chemical bonds formed by one and the other element (Mn and O) are the same:
x· 1 = 4; II · 2 = 4. Hence X= 4, i.e. In this chemical formula, manganese is tetravalent.
PRACTICAL CONCLUSIONS
1. If one of the atoms in the molecule is monovalent, then the valence of the second atom is equal to the number of atoms of the first element (see index!):
2. If the number of atoms in a molecule is the same, then the valence of the first atom is equal to the valence of the second atom:
3. If one of the atoms does not have an index, then its valency is equal to the product of the valence of the second atom and its index:
4. In other cases, put the valences “crosswise”, i.e. the valency of one element is equal to the index of another element:
Task 1.2. Determine the valencies of elements in compounds:
CO 2, CO, Mn 2 O 7, Cl 2 O, P 2 O 3, AlP, Na 2 S, NH 3, Mg 3 N 2.
Clue. First, indicate the valence of atoms for which it is constant. The valence of atomic groups OH, PO 4, SO 4, etc. is determined in the same way.
Task 1.3. Determine the valencies of atomic groups (underlined in the formulas):
H 3 P.O. 4 ,Ca( OH) 2 , Ca 3 ( P.O. 4) 2, H 2 SO 4,Cu SO 4 .
(Note! The same groups of atoms have the same valences in all compounds.)
Knowing the valencies of an atom or group of atoms, you can create a formula for a compound. To do this, use the following rules.
If the valencies of the atoms are the same, then the number of atoms is the same, i.e. We don’t put indexes:
If the valences are multiples (both are divided by the same number), then the number of atoms of the element with a lower valency is determined by division:
In other cases, the indices are determined “crosswise”:
Task 1.4. Compose chemical formulas connections:
Substances whose composition is reflected by chemical formulas can participate in chemical processes (reactions). Graphic entry corresponding to this chemical reaction, called reaction equation. For example, when coal burns (interacts with oxygen), a chemical reaction occurs:
C + O 2 = CO 2.
The recording shows that one carbon atom C, combining with one molecule of oxygen O 2, forms one molecule of carbon dioxide CO 2. The number of atoms of each chemical element before and after the reaction must be the same. This rule is a consequence of the law of conservation of mass of matter. Law of conservation of mass: the mass of the starting substances is equal to the mass of the reaction products.
The law was discovered in the 18th century. M.V. Lomonosov and, independently of him, A.L. Lavoisier.
In fulfilling this law, it is necessary to arrange the coefficients in the equations of chemical reactions so that the number of atoms of each chemical element does not change as a result of the reaction. For example, the decomposition of Berthollet salt KClO 3 produces salt KCl and oxygen O 2:
KClO 3 KCl + O 2.
The number of potassium and chlorine atoms is the same, but the number of oxygen atoms is different. Let's equalize them:
Now the number of potassium and chlorine atoms before the reaction has changed. Let's equalize them:
Finally, you can put an equal sign between the right and left sides of the equation:
2KClO 3 = 2KСl + 3О 2.
The resulting record shows that the decomposition of the complex substance KClO 3 produces two new substances - the complex KCl and the simple one - oxygen O 2. The numbers in front of the formulas of substances in the equations of chemical reactions are called coefficients.
When selecting coefficients, it is not necessary to count individual atoms. If the composition of some atomic groups has not changed during the reaction, then the number of these groups can be taken into account, considering them as a single whole. Let's create an equation for the reaction of the substances CaCl 2 and Na 3 PO 4:
CaCl 2 + Na 3 PO 4 ……………….
SEQUENCE OF ACTIONS
1) Let's determine the valency of the starting atoms and the PO 4 group:
2) Let’s write the right side of the equation (without subscripts for now, the formulas of the substances in brackets need to be clarified):
3) Let’s compose the chemical formulas of the resulting substances based on the valences of their constituent parts:
4) Let's pay attention to the composition of the most complex compound Ca 3 (PO 4) 2 and equalize the number of calcium atoms (there are three of them) and the number of PO 4 groups (there are two):
5) The number of sodium and chlorine atoms before the reaction is now six. Let's put the corresponding coefficient on the right side of the diagram before the NaCl formula:
3CaCl 2 + 2Na 3 PO 4 = Ca 3 (PO 4) 2 + 6NaCl.
Using this sequence, it is possible to equalize the schemes of many chemical reactions (with the exception of more complex redox reactions, see Chapter 7).
Types of chemical reactions. Chemical reactions are of different types. The main four types are connection, decomposition, substitution and exchange.
1. Compound reactions– from two or more substances one substance is formed:
For example:
Ca + Cl 2 = CaCl 2.
2. Decomposition reactions– from one substance two or more substances are obtained:
For example:
Ca(HCO 3) 2 CaCO 3 + CO 2 + H 2 O.
3. Substitution reactions– simple and complex substances react, simple and complex substances are also formed, and the simple substance replaces part of the atoms of the complex substance:
A + BX AX + B.
For example:
Fe + CuSO 4 = Cu + FeSO 4.
4. Exchange reactions– here two complex substances react and two complex substances are obtained. During the reaction, complex substances exchange their constituent parts:
Exercises for Chapter 1
1. Learn the table. 1. Test yourself, write chemical symbols: sulfur, zinc, tin, magnesium, manganese, potassium, calcium, lead, iron and fluorine.
2. Write the symbols of the chemical elements that are pronounced in formulas as: “ash”, “o”, “cuprum”, “es”, “pe”, “hydrargyrum”, “stannum”, “plumbum”, “en”, “ferrum” , "ce", "argentum". Name these elements.
3. Indicate the number of atoms of each chemical element in the formulas of the compounds:
Al 2 S 3, CaS, MnO 2, NH 3, Mg 3 P 2, SO 3.
4. Determine which substances are simple and which are complex:
Na 2 O, Na, O 2, CaCl 2, Cl 2.
Read the formulas of these substances.
5. Learn the table. 2. Make up chemical formulas of substances based on the known valency of elements and atomic groups:
6. Determine the valence of chemical elements in compounds:
N 2 O, Fe 2 O 3, PbO 2, N 2 O 5, HBr, SiH 4, H 2 S, MnO, Al 2 S 3.
7. Arrange the coefficients and indicate the types of chemical reactions:
a) Mg + O 2 MgO;
b) Al + CuCl 2 AlCl 3 + Cu;
c) NaNO 3 NaNO 2 + O 2;
d) AgNO 3 + BaCl 2 AgCl + Ba(NO 3) 2;
e) Al + HCl AlCl 3 + H 2;
e) KOH + H 3 PO 4 K 3 PO 4 + H 2 O;
g) CH 4 C 2 H 2 + H 2 .
* There are substances that are not built from molecules. But these substances will be discussed later (see Chapter 4).
** Strictly speaking, according to the rules below, it is not the valency that is determined, but the oxidation state (see Chapter 7). However, in many compounds the numerical values of these concepts coincide, so the valence can also be determined using the formula of a substance.
Reprinted with continuation
Chemistry. Self-instruction manual. Frenkel E.N.
M.: 20 1 7. - 3 51 p.
The tutorial is based on a technique that the author has been successfully using for more than 20 years. With her help, many schoolchildren were able to enroll in chemistry departments and in medical universities. This book is a Self-Teacher, not a Textbook. You will not encounter here a simple description of scientific facts and properties of substances. The material is structured in such a way that, if you encounter complex questions that cause difficulties, you will immediately find the author’s explanation. At the end of each chapter there are test tasks and exercises to consolidate the material. For an inquisitive reader who simply wants to expand his horizons, the Self-Teacher will give the opportunity to master this subject “from scratch.” After reading it, you can't help but fall in love with this most interesting science- chemistry!
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Table of contents
From the author 7
PART 1. ELEMENTS OF GENERAL CHEMISTRY 9
Chapter 1. Basic concepts and laws of the subject “Chemistry” 9
1.1. The simplest concepts: substance, molecule, atom, chemical element 9
1.2. Simple and complex substances. Valence 13
1.3. Chemical reaction equations 17
Chapter 2. Main classes of inorganic compounds 23
2.1. Oxides 23
2.2. Acids 32
2.3. Bases 38
2.4. Salts 44
Chapter 3. Basic information about the structure of the atom 55
3.1. Structure Periodic table Mendeleeva 55
3.2. Nucleus of an atom. Isotopes 57
3.3. Distribution of electrons in the field of the nucleus of an atom 60
3.4. Atomic structure and properties of elements 65
Chapter 4. The concept of chemical bonding 73
4.1. Ionic bond 73
4.2. Covalent bond 75
4.3. Chemical bond and states of aggregation substances. Crystal lattices 80
Chapter 5. Rate of chemical reaction 87
5.1. Dependence of the rate of a chemical reaction on various factors 87
5.2. Reversibility of chemical processes. Le Chatelier's principle 95
Chapter 6. Solutions 101
6.1. Concept of solutions 101
6.2. Electrolytic dissociation 105
6.3. Ionic-molecular reaction equations 111
6.4. The concept of pH (hydrogen value) 113
6.5. Hydrolysis of salts 116
Chapter 7. The concept of redox reactions123
PART 2. ELEMENTS OF INORGANIC CHEMISTRY 130
Chapter 8. General properties metals 130
8.1. Internal structure And physical properties metals 131
8.2. Alloys 133
8.3. Chemical properties metals 135
8.4. Metal corrosion 139
Chapter 9. Alkali and alkaline earth metals 142
9.1. Alkali metals 142
9.2. Alkaline earth metals 145
Chapter 10. Aluminum 153
Chapter 11. Iron 158
11.1. Properties of iron and its compounds 158
11.2. Production of iron (iron and steel) 160
Chapter 12. Hydrogen and oxygen 163
12.1. Hydrogen 163
12.2. Oxygen 165
12.3. Water 166
Chapter 13. Carbon and silicon 170
13.1. Atomic structure and properties of carbon 170
13.2. Properties of carbon compounds 173
13.3. Atomic structure and properties of silicon 176
13.4. Silicic acid and silicates 178
Chapter 14. Nitrogen and phosphorus 182
14.1. Atomic structure and properties of nitrogen 182
14.2. Ammonia and ammonium salts 184
14.3. Nitric acid and its salts 187
14.4. Atomic structure and properties of phosphorus 189
14.5. Properties and significance of phosphorus compounds 191
Chapter 15. Sulfur 195
15.1. Atomic structure and properties of sulfur 195
15.2. Hydrogen sulfide 196
15.3. Sulfur dioxide and sulfurous acid 197
15.4. Sulfuric anhydride and sulfuric acid 198
Chapter 16. Halogens 202
16.1. Atomic structure and properties of halogens 202
16.2. Hydrochloric acid 205
SECTION 3. ELEMENTS OF ORGANIC CHEMISTRY 209
Chapter 17. Basic concepts of organic chemistry 210
17.1. Subject of organic chemistry. Theory of the structure of organic substances 210
17.2. Features of the structure of organic compounds 212
17.3. Classification of organic compounds 213
17.4. Formulas of organic compounds 214
17.5. Isomerism 215
17.6. Homologues 217
17.7. Names of hydrocarbons. Rules of international nomenclature 218
Chapter 18. Alkanes 225
18.1. Concept of alkanes 225
18.2. Homologous series, nomenclature, isomerism 225
18.3. Molecular structure 226
18.4. Properties of alkanes 226
18.5. Preparation and use of alkanes 229
Chapter 19. Alkenes 232
19.1. Homologous series, nomenclature, isomerism 232
19.2. Molecular structure 234
19.3. Properties of alkenes 234
19.4. Preparation and use of alkenes 238
19.5. The concept of alkadienes (dienes) 239
Chapter 20. Alkynes 244
20.1. Definition. Homologous series, nomenclature, isomerism 244
20.2. Molecular structure 245
20.3. Properties of alkynes 246
20.4. Preparation and use of acetylene 248
Chapter 21. Cyclic hydrocarbons. Arenas 251
21.1. The concept of cyclic hydrocarbons. Cycloalkanes 251
21.2. The concept of aromatic hydrocarbons 252
21.3. History of the discovery of benzene. Molecule structure 253
21.3. Homologous series, nomenclature, isomerism 255
21.4. Properties of benzene 256
21.5. Properties of benzene homologues 259
21.6. Preparation of benzene and its homologues 261
Chapter 22. Alcohols 263
22.1. Definition 263
22.2. Homologous series, nomenclature, isomerism 264
22.3. Molecular structure 265
22.4. Properties of monohydric alcohols 266
22.5. Preparation and use of alcohols (for example ethyl alcohol) 268
22.6. Polyhydric alcohols 269
22.7. The concept of phenols 271
Chapter 23. Aldehydes 276
23.1. Definition. Homologous series, nomenclature, isomerism 276
23.2. Molecular structure 277
23.3. Properties of aldehydes 278
23.4. Preparation and use of aldehydes using the example of acetaldehyde 280
Chapter 24. Carboxylic acids 282
24.1. Definition 282
24.2. Homologous series, nomenclature, isomerism 283
24.3. Molecular structure 284
24.4. Properties of acids 285
24.5. Preparation and use of acids 287
Chapter 25. Esters. Fats 291
Chapter 26. Carbohydrates 297
Chapter 27. Nitrogen-containing compounds 304
27.1. Amines 304
27.2. Amino acids 306
27.3. Proteins 308
Chapter 28. Concept of polymers 313
PART 4. SOLVING PROBLEMS 316
Chapter 29. Basic calculation concepts 317
Chapter 30. Problems solved using standard formulas 320
30.1. Problems on the topic “Gases” 320
30.2. Problems on the topic “Methods of expressing the concentration of solutions” 324
Chapter 31. Problems solved using reaction equations 330
31.1. Preparation of calculations using reaction equations 330
31.2. Problems on the topic “Quantitative composition of mixtures” 333
31.3. Problems on “excess-deficiency” 337
31.4. Problems to establish the formula of a substance 342
31.5. Problems that take into account the “yield” of the resulting substance 349
Everyone knows that the school course is the basis that gives the most necessary knowledge about the world in which we live. This is indeed true, and such a subject as chemistry is an excellent confirmation of this, since, in fact, absolutely everything that surrounds us is chemistry - chemical elements, their connections, interaction processes, etc. Therefore, it is not surprising that the school course includes a lot topics in chemistry.
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What is preparation for the Unified State Exam in Chemistry?
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While studying chemistry online and free, you adopt many years of experience in an easy-to-digest form and gain a wealth of systematized knowledge. Everyone can choose different modes and training options for themselves. Graduates can repeat the material covered at school and fill existing knowledge gaps by completing assignments of varying complexity and studying chemistry topics according to the system on which the Unified State Exam is based. Of course, no one will provide ready-made answers, especially since the list of questions and tasks changes every year. However, the structure remains largely the same, allowing developers to improve assessment effectiveness and students to reach their fullest potential. Perhaps this will help schools show better performance of their students.
In addition, online chemistry lessons are convenient and can also be useful for both practicing teachers to learn from experience, and for parents to be aware of how their children’s learning process is structured today. Online chemistry classes will help refresh the knowledge of future applicants who want to get another education. Therefore, it is difficult to argue that thanks to the capabilities of the Internet, learning is becoming easier for absolutely everyone.
The science of chemistry is very interesting, and knowledge of it can be useful in life for absolutely every person. But it turns out that it is not so easy to understand it by studying school textbook, especially considering that the teacher does not always have time to answer all the students’ questions. This self-instruction book, compiled by E. N. Frenkel, was created precisely in order to find answers to all your questions in it.
The information in the book is presented in such a way that it is as understandable as possible, i.e. There are no just dry facts here. You can read a theoretical statement and immediately see explanations that are not found in ordinary textbooks. The book also explains how to solve problems, gives tasks to reinforce the material, and includes tasks found in the Unified State Exam. This book will be useful to everyone who wants to better understand the school chemistry course, deepen their knowledge, and remember what they have learned previously. It can be used by schoolchildren and applicants when preparing for exams at medical universities or chemistry departments. It will also be of interest to anyone who is simply interested in the science of chemistry, but for some reason did not pay enough attention to it at school. After studying the book, you come to the understanding that chemistry is not so complicated, and most importantly, it is an interesting science.
The work belongs to the genre of educational literature. It was published in 2016 by AST Publishing House. The book is part of the series “Middle and High School. Best practices training." On our website you can download the book "Chemistry. Self-instruction manual. A book for those who want to pass exams, as well as understand and love chemistry. Elements of general, inorganic and organic chemistry" in fb2, rtf, epub, pdf, txt format or read online. The book's rating is 4.46 out of 5. Here, before reading, you can also refer to the reviews of readers already familiar with the book and find out their opinion In our partner's online store you can buy and read the book in paper form.
