Chemical reaction- this is the “transformation” of one or more substances into another substance, with a different structure and chemical composition. The resulting substance or substances are called “reaction products.” During chemical reactions, nuclei and electrons form new compounds (redistributed), but their quantity does not change and the isotopic composition of chemical elements remains the same.

All chemical reactions are divided into simple and complex.

Based on the number and composition of the starting and resulting substances, simple chemical reactions can be divided into several main types.

Decomposition reactions are reactions in which several other substances are obtained from one complex substance. At the same time, the formed substances can be both simple and complex. As a rule, for a chemical decomposition reaction to occur, heating is necessary (this is an endothermic process, heat absorption).

For example, when malachite powder is heated, three new substances are formed: copper oxide, water and carbon dioxide:

Cu 2 CH 2 O 5 = 2CuO + H 2 O + CO 2

malachite → copper oxide + water + carbon dioxide

If only decomposition reactions occurred in nature, then all complex substances that can decompose would decompose and chemical phenomena could no longer occur. But there are other reactions.

In compound reactions, several simple or complex substances produce one complex substance. It turns out that the compound reactions are the reverse of the decomposition reactions.

For example, when copper is heated in air, it becomes covered with a black coating. Copper is converted to copper oxide:

2Cu + O 2 = 2CuO

copper + oxygen → copper oxide

Chemical reactions between a simple and a complex substance, in which the atoms that make up the simple substance replace the atoms of one of the elements of the complex substance, are called substitution reactions.

For example, if you dip an iron nail into a solution of copper chloride (CuCl 2), it (the nail) will begin to become covered with copper released on its surface. And by the end of the reaction, the solution turns from blue to greenish: instead of copper chloride, it now contains ferric chloride:

Fe + CuCl 2 = Cu + FeCl 2

Iron + copper chloride → copper + ferric chloride

The copper atoms in copper chloride were replaced by iron atoms.

An exchange reaction is a reaction in which two complex substances exchange their constituent parts. Most often, such reactions occur in aqueous solutions.

In the reactions of metal oxides with acids, two complex substances - an oxide and an acid - exchange their constituent parts: oxygen atoms for acid residues, and hydrogen atoms for metal atoms.

For example, if copper oxide (CuO) is combined with sulfuric acid H 2 SO 4 and heated, a solution is obtained from which copper sulfate can be isolated:

CuO + H 2 SO 4 = CuSO 4 + H 2 O

copper oxide + sulfuric acid → copper sulfate + water

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Quartz contains two elements - silicon and oxygen. From what simple substances can quartz be obtained? What are two ways to prove that quartz contains oxygen and silicon?

Answers:

Quartz contains two elements - silicon and oxygen. From what simple substances can quartz be obtained? What are two ways to prove that quartz contains oxygen and silicon? The fluorite mineral consists of two elements - calcium and fluorine. N Its melting point is 1400 °C. What structure does this Substance have - molecular or non-molecular? What class (simple or complex) of substances does fluorite belong to? Write a formula for this substance if there are 2 fluorine atoms per 1 calcium atom. Give fluorite a chemical name. Which phrases talk about simple and which ones talk about complex substances: a) a sulfur molecule consists of eight sulfur atoms; b) methane decomposes into carbon and hydrogen; c) a graphite crystal consists of carbon atoms; d) hydrogen sulfide can be obtained from hydrogen and sulfur; e) magnesia can be obtained from magnesium and oxygen; f) are there copper atoms at the nodes of the copper crystal lattice? G Several substances - coal, soda, magnesium, malachite powder - were heated separately. At the same time, soda and malachite decomposed into new substances, and coal and magnesium combined with oxygen. What conclusion about the composition of the studied substances can be drawn from observations? What do the chemical formulas of complex substances of molecular and non-molecular structure express? What do subscripts mean in chemical formulas? Make up formulas for complex substances, the molecular models of which are shown in Fig. 23. What is the ratio of atoms of chemical elements in the composition of non-molecular complex substances: copper oxide Cu20, potassium sulfate K2S04, sodium carbonate (soda) Na2C03? Make up the names of the following complex substances according to their formulas: FeS, ZnO, ZnS, AlBr3, SiCl4, Cr2S3, CuCl2 , K3N, H20. Indicate which elements are included in the composition of calcium nitride, zinc sulfide, calcium iodide, sodium chloride, phosphorus oxide, gold chloride, magnesium silicide. Make up chemical formulas of substances according to the known ratio of atoms: iron oxide (per two atoms Fe - three O atoms), carbon sulfide (for one C atom - two S atoms), tin chloride (for one Sn atom - four C1 atoms), nitric oxide (for two N atoms - five O atoms).

The purpose of the lesson: continue the formation of the concept of substance, introduce students to complex substances, methods of proving their complexity - analysis and synthesis.

During the classes

1. Frontal survey.

Which substances are classified as simple: a) Diamond, b) Water, c) Table salt?

What two groups are simple substances divided into if there is a clear boundary between them?

What properties and structures do metals and non-metals have?

How to express the composition of a simple substance (molecular and non-molecular)?

Paperwork.

Make up chemical formulas of molecular simple substances, the models of which are shown in the textbook.

Write the formulas of simple substances formed by elements of the third period.

These exercises are of particular importance, as they help them connect the internal structure of a substance with its iconic model (formula).

2. Discussion of new material.

Questions:

1. Discussion of the elemental composition of substances using known examples;
2. Experimental proof of the complexity of matter - synthesis of a complex substance;
3. Substance analysis;
4. Discussion of the structures of complex substances.

We demonstrate a number of simple and complex substances: copper oxide, graphite, quartz (or river sand), basic copper carbonate (malachite), sulfur, hydrogen, carbon dioxide, water. Which of these substances consist of one element, and which of two or more? Students can name sulfur and hydrogen as consisting of one element, and water, based on previous experience, as consisting of two elements. At the same time, they can tell how to prove that water consists of two elements. We conclude that it is impossible to recognize simple and complex substances by their appearance. We need to explore them.

What do we call those substances that consist of one element?

What do we call substances that consist of two or more elements?

As a rule, children answer accurately – complex substances. Let's formulate the definition. Students need to be involved in this.

How to conduct an experiment to prove whether a substance is complex or simple? The substance needs to be decomposed.

By what signs do we know that a substance is complex? If new substances are obtained from it, then it is complex.

Here it is necessary to explain that determining the composition of a substance using decomposition is called analysis, and that decomposition is often carried out using heating. It is very helpful to have students carry out the experiments themselves. Decomposition devices (a test tube with a gas outlet tube mounted in a stand) should be prepared on the student tables. We pour malachite (on some tables) and potassium permanganate (on others) into a test tube. I tell students the names of substances not for memorization, although they remember them already in the first lessons. Students are tasked with proving that these substances are complex.

Before the experiments, I introduce the guys to the rules of working with an alcohol lamp. Students in the group studying malachite need to place a glass of lime water under the gas outlet tube. Another group studying potassium permanganate is a glass of clean water.

How many new substances did the students receive?

When malachite decomposes, three substances are clearly visible: gas, water droplets (on the walls of the test tube), and a black substance remaining in the test tube. Carbon dioxide is tested by the turbidity of lime water. The teacher reports that the black substance remaining in the test tube is copper oxide.

During the decomposition of potassium permanganate, observations are complicated by the masking of the resulting black oxide and almost the same color of manganate, which outwardly differ little from the potassium permanganate taken. Students name two substances as a result of the experiment - a gas and a black solid.

Students test the released gas in an empty glass by bringing a smoldering splinter, which lights up brightly.

I examine the isolated second substance myself. To do this, I dissolve the resulting substance as a result of decomposition and the starting substance – potassium permanganate – in two glasses of water. Potassium permanganate gives a crimson color, and the substance, as a result of decomposition, gives a green color.

Students see the difference between the two substances and conclude that the decomposition of potassium permanganate produces two different substances. Based on the research in groups, students fill out the table.

I bring students to a general conclusion: those substances that decompose into two or more new ones consist of several elements and belong to complex substances, and those that cannot be decomposed consist of one element and belong to simple ones.

Next I move on to the concept of synthesis. I demonstrate an experiment: I heat iron filings with sulfur powder. What substance is formed as a result - stable or complex? What elements does it consist of? The students answer - made of sulfur and iron. This means that we conclude that with the help of synthesis, complex substances can be obtained from simple substances. Based on experience, students give the concept of synthesis.

3. Consolidation.

To reinforce this, I show a poster with drawings of the structures of complex and simple substances. Where students isolate complex substances. Next, students answer the question - what are complex substances and give examples. Based on the material studied, we conclude: complex substances have molecular (carbon dioxide) and non-molecular structures (manganese oxide).

Homework: pp. 4-6, exercise 4.

MALACHITE– is a copper compound, the composition of natural malachite is simple: it is basic copper carbonate (CuOH) 2 CO 3, or CuCO 3 ·Cu(OH) 2. This compound is thermally unstable and easily decomposes when heated, even not very strongly. If you heat malachite above 200 o C, it will turn black and turn into black powder of copper oxide, and at the same time water vapor and carbon dioxide will be released: (CuOH) 2 CO 3 = 2CuO + CO 2 + H 2 O. However, getting malachite again is a very difficult task : This could not be done for many decades, even after the successful synthesis of diamond.
Video experiment: "Decomposition of malachite."

It is not easy to obtain even a compound of the same composition as malachite. If you merge solutions of copper sulfate and sodium carbonate, you will get a loose, voluminous blue precipitate, very similar to copper hydroxide Cu(OH) 2; At the same time, carbon dioxide will be released. But after about a week, the loose blue sediment will become very dense and take on a green color. Repeating the experiment with hot solutions of reagents will lead to the fact that the same changes in the sediment will occur within an hour.

The reaction of copper salts with alkali metal carbonates was studied by many chemists from different countries, but the results of the analysis of the resulting precipitates varied among different researchers, sometimes significantly. If you take too much carbonate, no precipitate will form at all, but you will get a beautiful blue solution containing copper in the form of complex anions, for example, 2–. If you take less carbonate, a voluminous jelly-like precipitate of light blue color falls out, foamed with bubbles of carbon dioxide. Further transformations depend on the ratio of reagents. With an excess of CuSO 4, even a small one, the precipitate does not change over time. With an excess of sodium carbonate, after 4 days the blue precipitate sharply (6 times) decreases in volume and turns into green crystals, which can be filtered, dried and ground into a fine powder, which is close in composition to malachite. If you increase the concentration of CuSO 4 from 0.067 to 1.073 mol/l (with a slight excess of Na 2 CO 3), then the time for the transition of the blue precipitate to green crystals decreases from 6 days to 18 hours. Obviously, in the blue jelly, over time, nuclei of the crystalline phase are formed, which gradually grow. And green crystals are much closer to malachite than shapeless jelly.

Thus, in order to obtain a precipitate of a certain composition corresponding to malachite, you need to take a 10% excess of Na 2 CO 3, a high concentration of reagents (about 1 mol/l) and keep the blue precipitate under the solution until it turns into green crystals. By the way, the mixture obtained by adding soda to copper sulfate has long been used against harmful insects in agriculture under the name “Burgundy mixture.”

Soluble copper compounds are known to be poisonous. Basic copper carbonate is insoluble, but in the stomach under the influence of hydrochloric acid it easily turns into soluble chloride: (CuOH) 2 CO 3 + 2HCl = 2CuCl 2 + CO 2 + H 2 O. Is malachite dangerous in this case? It was once considered very dangerous to prick yourself with a copper pin or hairpin, the tip of which turned green, indicating the formation of copper salts - mainly basic carbonate under the influence of carbon dioxide, oxygen and moisture in the air. In fact, the toxicity of basic copper carbonate, including that which forms in the form of a green patina on the surface of copper and bronze products, is somewhat exaggerated. As special studies have shown, the dose of basic copper carbonate that is lethal for half of the tested rats is 1.35 g per 1 kg of weight for males and 1.5 g for females. The maximum safe single dose is 0.67 g per 1 kg. Of course, a person is not a rat, but malachite is clearly not potassium cyanide. And it’s hard to imagine that anyone would eat half a glass of powdered malachite. The same can be said about basic copper acetate (historical name is verdigris), which is obtained by treating the basic carbonate with acetic acid and is used, in particular, as a pesticide. Much more dangerous is another pesticide known as “Paris green”, which is a mixture of basic copper acetate with its arsenate Cu(AsO 2) 2.

Chemists have long been interested in the question of whether there is not basic, but simple copper carbonate CuCO 3. In the table of salt solubility there is a dash in place of CuCO 3, which means one of two things: either this substance is completely decomposed by water, or it does not exist at all. Indeed, for a whole century no one managed to obtain this substance, and all textbooks wrote that copper carbonate does not exist. However, in 1959 this substance was obtained, albeit under special conditions: at 150 ° C in an atmosphere of carbon dioxide under a pressure of 60–80 atm.

Malachite as a mineral.

Natural malachite is always formed where there are deposits of copper ores, if these ores occur in carbonate rocks - limestones, dolomites, etc. Often these are sulfide ores, of which the most common are chalcocite (another name is chalcokite) Cu 2 S, chalcopyrite CuFeS 2, bornite Cu 5 FeS 4 or 2Cu 2 S·CuS·FeS, covellite CuS. When copper ore weathers under the influence of groundwater, in which oxygen and carbon dioxide are dissolved, copper goes into solution. This solution, containing copper ions, slowly seeps through the porous limestone and reacts with it to form the basic copper carbonate, malachite. Sometimes droplets of solution, evaporating in the voids, form deposits, something like stalactites and stalagmites, only not calcite, but malachite. All stages of the formation of this mineral are clearly visible on the walls of a huge copper ore quarry up to 300–400 m deep in the province of Katanga (Zaire). The copper ore at the bottom of the quarry is very rich - it contains up to 60% copper (mainly in the form of chalcocite). Chalcocite is a dark silver mineral, but in the upper part of the ore layer all its crystals turned green, and the voids between them were filled with a solid green mass - malachite. This was precisely in those places where surface water penetrated through rock containing a lot of carbonates. When they met chalcocite, they oxidized sulfur, and copper in the form of basic carbonate settled right there, next to the destroyed chalcocite crystal. If there was a void in the rock nearby, malachite stood out there in the form of beautiful deposits.

So, for the formation of malachite, the proximity of limestone and copper ore is necessary. Is it possible to use this process to artificially obtain malachite under natural conditions? Theoretically, this is not impossible. For example, it was proposed to use this technique: pour cheap limestone into old underground workings of copper ore. There will also be no shortage of copper, since even with the most advanced mining technology it is impossible to avoid losses. To speed up the process, water must be supplied to the production. How long can such a process last? Typically, the natural formation of minerals is an extremely slow process and takes thousands of years. But sometimes mineral crystals grow quickly. For example, gypsum crystals under natural conditions can grow at a rate of up to 8 microns per day, quartz - up to 300 microns (0.3 mm), and the iron mineral hematite (bloodstone) can grow by 5 cm in one day. Laboratory studies have shown that and malachite can grow at a rate of up to 10 microns per day. At this speed, in favorable conditions, a ten-centimeter crust of a magnificent gem will grow in about thirty years - this is not such a long time: even forest plantations are designed for 50, or even 100 years or even more.

However, there are cases when discoveries of malachite in nature do not please anyone. For example, as a result of many years of treatment of vineyard soils with Bordeaux mixture, real malachite grains are sometimes formed under the arable layer. This man-made malachite is obtained in the same way as natural one: Bordeaux mixture (a mixture of copper sulfate and milk of lime) seeps into the soil and meets with lime deposits underneath it. As a result, the copper content in the soil can reach 0.05%, and in the ash of grape leaves - more than 1%!

Malachite also forms on products made of copper and its alloys - brass, bronze. This process occurs especially quickly in large cities, where the air contains oxides of sulfur and nitrogen. These acidic agents, together with oxygen, carbon dioxide and moisture, promote corrosion of copper and its alloys. In this case, the color of the main copper carbonate formed on the surface has an earthy tint.

Malachite in nature is often accompanied by the blue mineral azurite - copper azure. This is also basic copper carbonate, but of a different composition - 2CuCO 3 ·Cu(OH) 2. Azurite and malachite are often found together; their banded intergrowths are called azuromalachite. Azurite is less stable and gradually turns green in humid air, turning into malachite. Thus, malachite is not at all rare in nature. It even covers ancient bronze things that are found during archaeological excavations. Moreover, malachite is often used as copper ore: it contains almost 56% copper. However, these tiny malachite grains are of no interest to stone seekers. More or less large crystals of this mineral are found very rarely. Typically, malachite crystals are very thin - from hundredths to tenths of a millimeter, and up to 10 mm in length, and only occasionally, under favorable conditions, can huge multi-ton deposits of a dense substance consisting of a mass of seemingly stuck together crystals form. It is these deposits that form jewelry malachite, which is very rare. Thus, in Katanga, to obtain 1 kg of jewelry malachite, about 100 tons of ore must be processed. There were once very rich deposits of malachite in the Urals; Unfortunately, at present they are practically depleted. Ural malachite was discovered back in 1635, and in the 19th century. Up to 80 tons of malachite of unsurpassed quality were mined there per year, and malachite was often found in the form of rather weighty blocks. The largest of them, weighing 250 tons, was discovered in 1835, and in 1913 a block weighing more than 100 tons was found. Solid masses of dense malachite were used for decoration, and individual grains distributed in the rock - the so-called earthy malachite, and small accumulations of pure malachite were used to produce high-quality green paint, “malachite green” (this paint should not be confused with “malachite green”, which is an organic dye, and the only thing it has in common with malachite is its color). Before the revolution in Yekaterinburg and Nizhny Tagil, the roofs of many mansions were painted with malachite in a beautiful bluish-green color. Malachite also attracted Ural copper smelters. But copper was mined only from a mineral that was of no interest to jewelers and artists. Solid pieces of dense malachite were used only for decoration.

Sources: Internet resources

http://www.krugosvet.ru/enc/nauka_i_tehnika/himiya/MALAHIT.html

I. Complex substances and mixtures

1. The composition is heterogeneous.
2. Consists of different substances.
3. They do not have permanent properties.
4. They have permanent properties.
5. Retains the properties of the original components.
6. They do not retain the properties of the original components.
7. Can be separated by physical methods.
8. Cannot be separated by physical methods.
9. The starting components are present in certain proportions.
10. The starting components are present in arbitrary ratios.
11. The rock granite consists of quartz, mica and feldspar.
12. The iron sulfide molecule consists of iron and sulfur atoms.
13. They can be homogeneous or heterogeneous.
14. composition is expressed by a chemical formula.

II. Atom and molecule

1. The smallest particle of a chemical element.
2. The smallest particle of a substance that retains its properties.
3. There are forces of mutual attraction and repulsion.
4. During physical phenomena they are preserved, during chemical phenomena they are destroyed.
5. Particles vary in size and properties.
6. Are in continuous motion.
7. Have a chemical symbol.
8. They have a chemical formula.
9. They have quantitative characteristics: mass, relative mass, valency, oxidation state.
10. Can connect with each other.
11. During chemical reactions they are not destroyed, but rearranged.

Key “+” if “yes”, key “–” if “no”.

III. Simple substance and chemical element

1. A collection of atoms of the same type.
2. Consists of atoms of the same type.
3. In chemical reactions it cannot decompose to form several other substances.
4. Oxygen is a gas that is slightly soluble in water.
5. Fish breathe oxygen dissolved in water.
6. Iron is a metal that is attracted by a magnet.
7. Iron is part of iron sulfide.
8. An oxygen molecule consists of two oxygen atoms.
9. There are currently 114 different types of atoms known.
10. Oxygen is part of water.

Key “+” if “yes”, key “–” if “no”.

IV. Coefficient and index

1. Shows the number of atoms in a molecule.
2. The number before the chemical formula or symbol of a chemical element.
3. In the molecules of most simple gaseous substances it is equal to 2.
4. Place in accordance with the valence in the formula of the complex substance.
5. Placed when the number of atoms on the left and right sides of a chemical equation is equalized.
6. 7H, 5O.
7. There are two hydrogen atoms and one oxygen atom in a water molecule.
8. In the chemical formulas of metals it is equal to 1.
9. In a molecule of iron sulfide the sum is 2.
10. 5FeS.

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Job number
Coefficient

V. Simple substance and complex substance

1. Molecules consist of atoms of the same type.
2. Molecules are made up of different types of atoms.
3. They do not decompose during chemical reactions to form other substances.
4. They decompose during chemical reactions to form other substances.
5. Characterized by constant physical properties: melting point, boiling point, color, density, etc.
6. Destroyed during chemical reactions, but preserved during physical phenomena.
7. The composition is constant.
8. The composition varies over a fairly wide range.
9. Does not have permanent properties.
10. The molecule consists of two oxygen atoms and one hydrogen atom.
11. Can exist in three states of aggregation: gaseous, liquid, solid.

Key “+” if “yes”, key “–” if “no”.

VI. Chemical phenomena and physical phenomena

1. Molecules are preserved.
2. Molecules are destroyed.
3. Change in state of aggregation.
4. Change color and odor, heat is released, and sediment forms.
5. Atoms are not destroyed, but regrouped.
6. Can be expressed using a chemical equation.
7. Melting of glass when water freezes.
8. Combustion of fuel, rotting of organic substances.
9. Grinding chalk.
10. Rusting of iron, souring of milk.
11. Release of copper on an iron nail in a solution of copper chloride.
12. Burning alcohol.

Key “+” if “yes”, key “–” if “no”.

VII. Types of chemical reactions

1. The starting substance is one complex one.
2. The starting substance is two or more simple ones.
3. The starting substance is one simple and one complex.
4. Reaction products are two or more simple substances.
5. Reaction products are two or more complex substances.
6. The reaction products are one complex substance.
7. Reaction products – simple and complex substances.
8. Reaction products are two or more simple or complex substances.
9. The reaction products are two complex substances.
10. The reaction products are two simple substances.
11. Decomposition of malachite.
12. Combustion of sulfur.
13. Interaction of zinc with hydrochloric acid.

Key “+” if “yes”, key “–” if “no”.

VIII. Hydrogen and oxygen

1. Dissolves in water.
2. Poorly soluble in water.
3. Light gas.
4. Heavy gas.
5. Flammable gas.
6. Gas that supports combustion.
7. Burns in chlorine.
8. Is a reducing agent.
9. When mixed with oxygen, it forms an explosive mixture.
10. Collected by air displacement.
11. Collect in a vessel turned upside down.
12. Collect in a vessel placed at the bottom.
13. Collected by displacing water.
14. Interact with copper oxide when heated.
15. Used as environmentally friendly fuel.
16. Used in rocket engines.

Key “+” if “yes”, key “–” if “no”.

IX. Metals and non-metals

1. Simple substances have a metallic luster, are good conductors of heat and electricity, and are malleable.
2. Simple substances - solid, liquid or gaseous, mostly do not have a metallic luster and do not conduct electric current well.
3. The highest oxygen valence is I–II.
4. Higher oxides have basic properties.
5. Form volatile hydrogen compounds.
6. The highest oxygen valency is IV –VII.
7. Higher oxides have acidic properties.
8. Do not form volatile hydrogen compounds.
9. Form hydroxides with basic properties.
10. Form hydroxides with acidic properties.

Key “+” if “yes”, key “–” if “no”.

X. Group and period

(In a group, changes are considered from top to bottom, in a period – from left to right)

1. Non-metallic properties are enhanced.
2. Non-metallic properties weaken.
3. Metallic properties are enhanced.
4. Metallic properties weaken.
5. Elements contain the same number of electrons in their outermost electronic level.
6. Elements contain the same number of electronic levels.
7. The number of electronic levels increases.
8. The radius of atoms decreases.
9. The radius of atoms increases.
10. Gradual increase in the number of electrons at the external level.
11. Identical structure of the external electronic level.
12. The attraction of outer electrons to the nucleus increases.

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Job number

XI. Alkali metals. (lithium, sodium, potassium, rubidium, cesium)

1. The metal is silvery-white.
2. Metals with a density less than 1.
3. Metals with a density greater than 1.
4. The lightest metal.
5. The heaviest metal.
6. A metal with a melting point below human body temperature.
7. Metals that form basic oxides during oxidation.
8. Metals with oxygen valency equal to 1.
9. Metals that ignite at normal temperatures.
10. Metals that ignite only when heated.
11. Metals that react with water to form alkali.
12. The most active metal.

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Job number

XII. Halogens (fluorine, chlorine, bromine, iodine)

1. Gaseous substance.
2. Liquid substance.
3. Solid matter.
4. Boiling point below 0o C.
5. Boiling point above 0o C.
6. Halogen is dark gray in color.
7. Halogen is red-brown in color.
8. Reacts with hydrogen to form volatile hydrogen compounds.
9. Reacts with metals to form salts.
10. The valency of hydrogen is 1.
11. Valence of oxygen is 7.
12. Possible valence

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Job number

XIII. Chlorine and hydrogen chloride

1. Colorless gas

2. The gas is yellow-green in color.

1. Gaseous under normal conditions.
2. Odorless.
3. Has a pungent odor.
4. has no color.
5. Slightly soluble in water.
6. Well soluble in water.
7. Easily liquefied.
8. The oxidation state of nitrogen is – 3.
9. The oxidation state of nitrogen is 0.
10. In a molecule there are covalent polar bonds between atoms.
11. In a molecule, there are covalent nonpolar bonds between atoms.
12. Does not burn in air.
13. Reacts with hydrogen in the presence of a catalyst.
14. Burns in oxygen.
15. Interacts with water.
16. Reacts with acids to form salts.

Key “+” if “yes”, key “–” if “no”.

Job number

XV. Carbon(II) monoxide and carbon(IV) monoxide

1. Gas, practically insoluble in water.
2. The gas is noticeably soluble in water.
3. Gaseous under normal conditions.
4. Odorless.
5. Does not liquefy.
6. It liquefies and hardens easily.
7. Poisonous gas.
8. Non-toxic gas.
9. The oxidation state of carbon is +2.
10. The oxidation state of carbon is +4.
11. Flammable.
12. Doesn't light up.
13. In a molecule, there are covalent polar bonds between atoms.
14. Gas is lighter than air.
15. Gas is heavier than air.
16. Non-salt-forming oxide.
17. Acid oxide.
18. Reacts with metal oxides to form carbon monoxide (IV).
19. When passed through lime water, cloudiness is observed.

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XVI. Carbon(IV) monoxide and silicon(IV) oxide

1. Colorless gas, 1.5 times heavier than air.
2. Solid crystalline substance.
3. Substance with a molecular crystal lattice.
4. Substance with an atomic crystal lattice.
5. Dissolves in water.
6. Practically insoluble in water.
7. Is an acidic oxide.
8. Odorless.
9. It liquefies and hardens easily.
10. The oxidation state of the element is +4.
11. Has a low melting point.
12. Has a high melting point.
13. Reacts with basic oxides.
14. Reacts with alkalis.
15. Does not react chemically with water.
16. At elevated temperatures, it displaces other, more volatile acid oxides from salts.

Key “+” if “yes”, key “–” if “no”.

XVII. Hydrochloric acid and sulfuric acid

1. Oily, viscous liquid.
2. Colorless liquid.
3. “Smoke” in humid air.
4. It is hygroscopic.
5. Concentrated. Irritating to the respiratory tract and mucous membranes.
6. At normal temperatures it is non-volatile and odorless.
7. Carbonizes sugar, paper, wood, fibers.
8. Forms hydrates when dissolved in water.
9. Used for drying gases.
10. Can be stored in iron containers and transported in steel tanks.
11. Stored and transported in rubberized tanks and barrels.
12. Used in batteries

Key “+” if “yes”, key “–” if “no”.

1. We write an invitation on paper with salt solutions of iron (III), copper (II), bismuth, iron (II) sulfate. Then we wipe the colorless record with a swab moistened with a solution of yellow blood salt. Blue, dark brown, yellow, green entries appear.

We thoroughly moisten a handkerchief made of cotton or linen fabric with water so that there are no dry places left. Then moisten with acetone or alcohol. After each operation, lightly wring out the fabric. We set the moistened handkerchief on fire with a burning torch and hold it with crucible tongs at arm's length. Place a porcelain cup with 0.3 g of potassium permanganate, to which a few drops of concentrated sulfuric acid has been added, on a tray. Place shavings around the cup. Unbeknownst to the audience, we pick up a cotton swab soaked in ethyl alcohol and squeeze it onto the mixture. The shavings burst into flames. Aluminum metal powder and dry iodine are mixed in a mortar. Iodine is taken about 10 g, aluminum is two or three times more. The mixture is thoroughly ground and transferred to a porcelain crucible, which is placed on an iron tray. The dry powder mixture can be stored at room temperature without any modification. If you add 2-3 drops of water to it, then after a while (from a few seconds to 2-3 minutes) a violent reaction begins to form aluminum iodide. The reaction is accompanied by a violent outbreak. Powdered sugar in the amount of 75 g is placed in a tall glass glass, moistened with 5-7 ml of water and stirred with a long glass rod. 30–40 ml of concentrated sulfuric acid is poured over the stick. Then quickly mix with a glass rod, which is left in a glass filled with the mixture. After one or two minutes, the contents of the glass begin to turn black, swell and rise in the form of a voluminous, loose and spongy mass, carrying the glass rod upward. The mixture in the glass becomes very hot and even smokes. She slowly crawls out of the glass. A bright blue solution of CoCl2 or Co(NO3)2 in ethyl alcohol or acetone is poured into a glass. Pour water into another clean glass and add it to the glass with the blue solution. The color instantly turns pale pink. Add alcohol or acetone to a glass with a pale pink solution. In this case, the solution again turns bright blue. Pour 3-4 teaspoons of dry sifted river sand into a plate and make a slide out of it with a depression at the top. Then prepare a reaction mixture consisting of 1 teaspoon of powdered sugar and 1/4 teaspoon of sodium bicarbonate. The sand is soaked in 96% ethanol and the prepared mixture is poured into the depression of the slide, and then the alcohol is set on fire. After 3-4 minutes, black balls appear on the surface of the mixture, and black liquid appears at the base of the slide. When all the alcohol burns, the mixture turns black and a wriggling, thick black “viper” slowly crawls out of the sand. At the base it is surrounded by a “collar” of burning alcohol. To conduct this experiment, you can use a smoker for aromatic oils, into which you pour a few drops of a 25% ammonia solution or disguise a bottle of ammonia solution with colored paper, giving it a fancy shape. Immerse the tube in concentrated hydrochloric acid, and then bring it to the ammonia fumes. White ammonium chloride smoke is produced. The presenter pours lightly ground crystals of potassium permanganate onto cotton wool in a Petri dish, pours glycerin and then drops a few drops of concentrated sulfuric acid from a pipette. A fire occurs. First pour a 25% ammonia solution into a bottle or flask with a volume of 2-10 liters, wet the walls, and pour the excess liquid into a bottle to drain the solutions. Close the bottle with a stopper. The presenter places the newly obtained chromium oxide in a spoon for burning substances and heats it in the flame of an alcohol lamp, and then adds it to a bottle with an ammonia-air mixture and dumps the powder. A sheaf of sparks is formed, swirling in the bottle. The bottle should not be tightly closed. The presenter places 4-5 tablets of sulfadimethoxine in a pile of crushed 2-3 tablets of dry alcohol and sets the alcohol on fire with a torch. After some time of burning, black snakes begin to crawl out of the hill.

1. If you inhale green gas, you will be poisoned now. (chlorine).

2. It belongs to the eighth group and is named after Russia. (ruthenium).

3. He is your little soldier, but he suffers from the “plague.” (tin).

4. We find that element in the chimney in the form of soot, and we even find it in a simple pencil. (carbon).

5. He is called lifeless, but life cannot be created without him. (nitrogen).

6. In alloy technology, it has found application as a durable and lightweight metal. And it took an important place in aircraft manufacturing. (aluminum).

7. It has long been known to man: it is viscous and red, and from the Bronze Age it is familiar to everyone in alloys. (copper).

8. A guest came from outer space and found shelter in the water. (hydrogen)

9. He has been the cause of many troubles for many years. (gold)

“Find the mistake”

In which chemical reaction equations are the coefficients incorrectly placed?

3CO + Fe2O3 –> 2Fe + 3CO2;
5HCl + HClO –> 5Cl2 + 3H2O;
4NH3 + O2 –> 4NO + 3H2O;
NH3 + 3O2 –> 4N2 + H2O.

“Chemical Mathematics”

A chemical calculation must be performed. The number obtained during the calculation in the square coincides with the serial number of the letter in the alphabet. You need to write letters in a circle. After reading the riddle, you need to guess it. (The metal was silvery-white, when combined it became chalk. (calcium)

Execution of work" href="/text/category/vipolnenie_rabot/" rel="bookmark">performs work to obtain smokeless gunpowder, which is extremely necessary for the Russian army)

6. Name a substance that disinfects water. (Ozone)

7. Name the crystal hydrate necessary both in construction and in medicine (Gypsum)

Questions for specialized classes

Mirror

Everyone knows what a mirror is. In addition to household mirrors, used since ancient times, technical mirrors are known: concave, convex, flat, used in various devices. Reflective films for household mirrors are prepared from tin amalgam; for technical mirrors, films are made from silver, gold, platinum, palladium, chromium, nickel and other metals. In chemistry, reactions are used whose names are associated with the term “mirror”: “silver mirror reaction”, “arsenic mirror”. What are these reactions, what are they for? are they used?

Bath

Russian, Turkish, Finnish and other baths are popular among the people.

In chemical practice, baths as laboratory equipment have been known since the alchemical period and are described in detail by Geber.

What are baths used for - in the laboratory and what types of them do you know?

Coal

The coal that is used to heat the stove and is used in technology is known to everyone: it is hard coal, brown coal and anthracite. Coal is not always used as a fuel or energy raw material, but figurative expressions with the term “coal” are used in the literature, for example, “white coal,” meaning the driving force of water.

What do we mean by the expressions: “colorless coal”, “yellow coal”, “green coal”, “blue coal”, “blue coal”, “red coal”? What is “retort coal”?

Fire

In literature, the word “fire” is used in the literal and figurative sense. For example, “the eyes burn with fire”, “the fire of desires”, etc. The entire history of mankind is connected with fire, therefore the terms “fire”, “fiery” have been preserved since ancient times in literature and technology. What do the terms “flint”, “Greek fire”, “swamp fires”, “Dobereiner’s flint”, “will-o’-the-wisp”, “fireknife”, “sparklers”, “Elmo’s fire” mean?

Wool

After cotton, wool is the second most important textile fiber. It has low thermal conductivity and high moisture permeability, so we can breathe easily and stay warm in winter in woolen clothes. But there is “wool” from which nothing is knitted or sewn - “philosophical wool”. The name came from to us from distant alchemical times. What chemical product are we talking about?

Closet

A wardrobe is a common piece of household furniture. In institutions, we come across a fireproof wardrobe - a metal box for storing securities.

What kind of cabinets do chemists use and for what?

Quiz answers

Mirror

“Silver mirror reaction” is a characteristic reaction of an aldehyde with an ammonia solution of silver (I) oxide, as a result of which a precipitate of metallic silver is released on the walls of the test tube in the form of a shiny mirror film. The Marsh reaction, or “arsenic mirror,” is the release of metallic arsenic in the form of a black shiny coating on the walls of a tube through which, when heated to 300-400°, arsenic hydrogen - arsine - is passed, decomposing into arsenic and hydrogen. This reaction is used in analytical chemistry and in forensic medicine when arsenic poisoning is suspected.

Bath

Since the times of alchemy, water and sand baths have been known, i.e., a saucepan or frying pan with water or sand that provides uniform heating at a certain constant temperature. The following liquids are used as a coolant: oil (oil bath), glycerin (glycerin bath), molten paraffin (paraffin bath).

Coal

Colorless coal" is gas, "yellow coal" is solar energy, "green coal" is vegetable fuel, "blue coal" is the energy of the tides of the seas, "blue coal" is the driving force of the wind, "red coal" is the energy of volcanoes. .

Fire

A flint is a piece of stone or steel used to strike fire from flint. “Dobereiner flint,” or chemical flint, is a mixture of berthollet salt and sulfur applied to wood, which ignites when added to concentrated sulfuric acid.

“Greek fire” is a mixture of saltpeter, coal and sulfur, with the help of which in ancient times the defenders of Constantinople (Greeks) burned the Arab fleet.

“Swamp fires,” or wandering lights, appear in swamps or cemeteries, where the decay of organic matter releases flammable gases based on silane or phosphines.

“Fire Knife” is a mixture of aluminum and iron powders, burned under pressure in a stream of oxygen. Using such a knife, the temperature of which reaches 3500 ° C, you can cut concrete blocks up to 3 m thick.

“Sparklers” are a pyrotechnic composition that burns with a bright colored flame, which includes Berthollet salt, sugar, strontium salts (red color), barium or copper salts (green color), lithium salts (scarlet color). “Elmo's Lights” are luminous electrical discharges on the sharp ends of any objects that occur during thunderstorms or snowstorms. The name originated in the Middle Ages in Italy, when such a glow was observed on the towers of the Church of St. Elmo.

Wool

“Philosopher's wool” - zinc oxide. This substance was obtained in ancient times by burning zinc; Zinc oxide formed in the form of white fluffy flakes, reminiscent of wool. “Philosophical wool” was used in medicine.

Closet

In chemical laboratory equipment, electric drying cabinets or ovens with a low heating temperature of up to 100-200 ° C are used to dry substances. To work with toxic substances, fume hoods with forced ventilation are used.

Quiz

1. The names of which chemical elements include the names of animals?

2. By discarding the first and last letters in the name of the element of the eighth group, you get the name of mowed and dried grass.

3. Add one letter to the name of the element of the sixth group and get the name of the artiodactyl animal.

4. By replacing one letter in the name of a chemical element of the actinide family with another, you get the name of a bat with big ears.

5. The name of which chemical element does not correspond to its role in living nature?

6. The name of which chemical element includes the name of the tree?

7. Name a chemical element whose name coincides with the name of a pine forest?

8. Rearrange the letters in the name of the element of the eighth group so that you get the name of the forest of young fir trees.

9. The name of which edible includes the name of a chemical element?

10. By replacing the first letter in the name of the element of the first group, you will get the name of an excessively moistened area of ​​land overgrown with plants.

11. The name of which chemical element, the most important compound for plant life that determines their green color, includes the name of a chemical element?

12. Change only the letter in the name of an element of the fourth group and get the name of a representative of the most important class of organic compounds, widespread in nature and the main source of energy in organisms.

13. The names of which structural elements of the cell nucleus containing DNA include the name of a chemical element?

14. Discard the first two letters in the name of the chemical element of the first group and get the name of the arched bone that is part of the chest.

15. By replacing the last letter in the name of the chemical element of the fourth period with another, get the name of human and animal organs that produce specific substances involved in various biochemical processes.

16. By changing only one letter in the name of an element of the halogen family, you will get the name of the famous German zoologist and traveler, author of the multi-volume work “Animal Life”.

17. By discarding the first three letters in the name of a chemical element of the lanthanide family, you get the name of a strong drug used in medicine as a painkiller.

18. The name of which aquarium fish is identical to the name of a chemical element.

19. What chemical element was discovered in the leaching products of seaweed ash?

20. What metal can “suffer from the plague”?

21. The lack of which element in the human body leads to dental caries?

22. What chemical element was used to poison Napoleon?

23. What chemical element is seaweed - kelp - rich in?

24. Which metal has bactericidal properties?

25. For what diseases does the doctor prescribe bromine?

26. What acid is in the human stomach?

27. Which animal is involved in the discovery of iodine?

28. Which organ contains the most bromine?

29. What halogen is concentrated in the thyroid gland?

Quiz answers

1. Arsenic – mouse, yak.

2. Xenon - hay.

3. Sulfur – chamois.

4. Uranus – ushan.

5. Nitrogen – “lifeless”.

6. Nickel - spruce.

8. Nickel - spruce forest

9. Boron - boletus.

10. Gold is a swamp.

11. Chlorine – chlorophyll.

12. Carbon is a carbohydrate.

13. Chromium - chromosomes.

14. Silver - rib.

15. Iron - iron.

16. Bromine - Brem.

17. Europium - opium.

22. Arsenic.

24. Silver.

25. Nervous.

26. Solyanaya

The world of metals is rich and interesting, among which are man’s old friends: copper, iron, lead, mercury, gold, silver, tin. This friendship goes back thousands of years. But there are also metals that have only become known in recent decades. The properties of metals are wonderful and varied. MERCURY, for example, does not freeze even in the cold (melting point -39 ° C), and TUNGSTEN is not afraid of the hottest embraces (the most refractory and can withstand temperatures over 3000 ° C). LITHIUM can be an excellent swimmer: it is twice as light as water and, even if it wants to, cannot drown, but OSMIUM, the champion among heavy metals, will sink like a stone. SILVER “happily” conducts electric current, but TITANIUM clearly “has no soul” for this activity: its electrical conductivity is 300 times lower than that of silver. We meet IRON at every step, and HOLMIUM is contained in the earth's crust in such minute quantities that even grains of this metal are incredibly expensive: pure holmium is several times more expensive than gold.

Why did HEAVY METALS attract attention?

There are more than 50 elements that can be classified as heavy metals, 17 of them are considered very toxic, but quite widespread. The toxic concentration depends on the type of metal, its biological role and the type of organism that is exposed to it.

The toxicity of heavy metals is related to the physicochemical properties of the metals. Thus, the high electronegativity of mercury gives it the opportunity, first of all, to interact with the active centers of enzymes and reduce their activity, and in plants, to suppress photosynthesis in chloroplasts.

Metals of secondary subgroups of large periods are contained in the human body in small quantities, but when moving from light metals to heavy metals, their toxicity increases. Analyzing the chemical composition of the human body, scientists came to the conclusion that heavy metals affect not only the physiological, but also the mental state of a person. For example, it is known that under stress, the content of ZINC in the blood increases, and an increased content of NICKEL and MANGANESE in the blood occurs shortly before a heart attack. Using mass spectroscopy, it was discovered that aggressive people have increased levels of LEAD, IRON, CADMIUM, COPPER and decreased levels of ZINC and COBALT in their hair. Thus, the content of metals in the human body, even in very small quantities, is vital, and a drop in concentration below the permissible level leads to severe disorders. This is because many metals serve primarily as catalysts.

Young people are more susceptible to the toxic effects of heavy metals. The unfavorable results of their exposure are weakened growth and development, disruption of the nervous system, and can also cause the development of autoimmunity, in which the immune system destroys its own cells. This can lead to joint diseases, damage to the kidneys, circulatory system and nervous system.

Based on the above, today we will talk about heavy metals, which are most often associated with human poisoning. Such metals are: LEAD, MERCURY, CADIMATE, COPPER.

1. Pour 2 ml of protein solution into 4 test tubes.

2. Add 1 ml of lead acetate solution to the first test tube, 1 ml of iron (III) chloride solution to the second, 1 ml of copper (II) chloride solution to the third, and 1 ml of sodium chloride solution to the fourth.

3. Observations.

4. Conclusions.

Observations: The protein coagulated in test tubes to which heavy metal salts were added, i.e. in test tubes Nos. 1, 2, 3.

This is interesting! In 1692, shortly before his fiftieth birthday, Newton became seriously ill. The illness, which lasted more than a year, was serious and incomprehensible. She undermined the scientist’s physical strength and disrupted his mental balance. It was a “black year” in Newton’s life, as biographers call it. He lost sleep and appetite, was in a state of deep depression, and avoided contact even with friends. At times he experienced something like persecution mania, and at other times his memory began to fail him. Who turned out to be the culprit of Newton's disease?

It turned out that the culprit of Newton's disease was MERCURY and its salts. For 18 years, Newton often turned to chemistry. From Newton's notes it follows that he worked with large quantities of mercury, heated mercury salts for a long time to obtain volatile substances, and often tasted what he came up with. In the workbooks, notes such as “sweetish taste,” “tasteless,” “salty,” “very caustic” appear 108 times. All the symptoms of Newton's disease resembled those of mercury poisoning. An analysis of the great scientist’s hair showed that the concentrations of highly toxic metals in them significantly exceed the normal level. This is interesting! In Russia, under Tsar Alexei Mikhailovich, everyone who was found with tobacco was ordered to be beaten with a whip until the smoker confessed where the tobacco came from. The rule prohibiting smoking on the streets was in effect for many decades in the city on the Neva. A person who has smoked 22 thousand cigarettes is equivalent to a uranium mine worker. When smoking 1 pack of cigarettes with a total tobacco weight of 20 g, carcinogenic resins are formed, which contain heavy metals (CADMIUM, nickel). Over the course of a year, about 1 kg of tobacco tar accumulates in the body of a smoker, which can cause malignant tissue growth, i.e. cancer. He is already disabled. So is this “pleasure” worth all the consequences? This is interesting! A professor at one of the universities gave a lecture to students about mercury compounds; On the lectern in front of him stood two glasses: one with sweetened water, which the professor liked to drink during lectures, the other with a solution of sublimate for experiments. By mistake, the lecturer took a sip from the second glass. Sublime is a strong poison, and the professor knew about it. But he also knew the antidote. He ordered raw eggs to be mixed with water and drank the mixture. Severe vomiting began, the poison left the body, and subsequently no signs of poisoning appeared.