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Preparing for the future Tasks for working on the topic "3 VPR" Characteristic properties of substances

All-Russian test work

Chemistry, 11th grade

Explanations for the sample of the All-Russian test work

When familiarizing yourself with a sample test work, you should keep in mind that the tasks included in the sample do not reflect all the skills and content issues that will be tested as part of the all-Russian test work. A complete list of content elements and skills that can be tested in the work is given in the codifier of content elements and requirements for the level of training of graduates for the development of an all-Russian test in chemistry. The purpose of the sample test work is to give an idea of the structure of the all-Russian test work, the number and form of tasks, and their level of complexity.

Sample of all-Russian history test work

Instructions for performing the work

The test includes 15 tasks. 1 hour 30 minutes (90 minutes) is allotted to complete the history work.

Write down answers to assignments in the space provided for this in your work. If you write down an incorrect answer, cross it out and write a new one next to it.

When performing work, you are allowed to use the following additional materials:

Periodic table of chemical elements by D. I. Mendeleev;

Table of solubility of salts, acids and bases in water;

Electrochemical voltage series of metals;

Non-programmable calculator.

When completing assignments, you can use a draft. Entries in draft will not be reviewed or graded.

We advise you to complete the tasks in the order in which they are given. To save time, skip a task that you cannot complete immediately and move on to the next one. If you have time left after completing all the work, you can return to the missed tasks.

Points received for completed tasks are summed up. Try to complete as many tasks as possible and score the most points.

1. From your chemistry course, you know the following methods for separating mixtures: sedimentation, filtration, distillation (distillation), magnetic action, evaporation, crystallization. Figures 1-3 show examples of using some of the listed methods.

Which of the following methods for separating mixtures can be used for purification:

1. Steel buttons from sawdust;

2. Air from small drops of water-based paint sprayed in the room?

Write down the figure number and the name of the corresponding method of separating the mixture in the table.

Answer:

2. The figure shows a diagram of the distribution of electrons among the energy levels of an atom of a certain chemical element.

Based on the proposed scheme, complete the following tasks:

1. Identify the chemical element whose atom has such an electronic structure;

2. Indicate the period number and group number in D.I. Mendeleev’s Periodic Table of Chemical Elements in which this element is located;

3. Determine whether the simple substance that forms this chemical element is a metal or non-metal.

Write your answers in the table.

Answer:

3. D.I. Mendeleev’s periodic table of chemical elements is a rich repository of information about chemical elements, their properties and the properties of their compounds, the patterns of changes in these properties, methods for obtaining substances, as well as their location in nature. For example, it is known that with an increase in the atomic number of a chemical element in periods, the radii of atoms decrease, and in groups they increase.

Considering these patterns, arrange the following elements in order of decreasing atomic radius: N, Al, C, Si. Write down the designations of the elements in the required sequence.

Answer: Al - Si - C - N.

4. The table below lists the characteristic properties of substances with molecular and atomic crystal lattices.

Characteristic properties of substances

Using this information, determine what kind of crystal lattice it has:

1. Quartz (SiO2);

2. Carbon dioxide (CO2).

Write down your answer:

Quartz has ________________

Carbon dioxide has _________________

Answer: Quartz (SiO2) has an atomic crystal lattice; carbon dioxide (CO2) has a molecular crystal lattice.

Read the text and complete tasks 5-7.

Sulfur (IV) oxide is used in the food industry as a preservative (food additive E220). Since this gas kills microorganisms, it is used to fumigate vegetable stores and warehouses. This substance is also used to bleach straw, silk and wool, that is, materials that cannot be bleached with chlorine.

The industrial method for producing this substance is to burn sulfur or sulfides. In laboratory conditions, it is obtained by the action of strong acids on sulfites, for example, by reacting sulfuric acid with sodium sulfite.

When sulfur (IV) oxide reacts with calcium hydroxide, the salt calcium sulfite is formed. This substance is used in industry as a food additive E226, a preservative, for the preparation of jelly, marmalade, ice cream, drinks and fruit juices.

5. Complex inorganic substances can be conditionally distributed, that is, classified, into four groups, as shown in the diagram. In this diagram, for each of the four groups, write one chemical formula of the substances mentioned in the text above.

Complex substances:

oxide -

base -

acid -

salt -

Answer: oxide - SO2

base - Ca(OH)2

acid - H2SO4

salt - Na2SO3 or CaSO3.

6. 1. Write a molecular equation for the sulfur combustion reaction discussed in the text.

Answer: S + O2 = SO2

2. Indicate with what thermal effect (with absorption or release of heat) this reaction occurs.

Answer: the reaction proceeds with the release of energy (exothermic).

7. 1. Write a molecular equation for the reaction between sulfur(IV) oxide and calcium hydroxide mentioned in the text.

Answer: Ca(OH)2 + SO2 = CaSO3 + H2O

2. Describe the signs of the ongoing reaction between sulfur oxide (IV) and a solution of calcium hydroxide.

Answer: as a result of the reaction, an insoluble substance is formed - calcium sulfite; cloudiness of the original solution (precipitation) is observed.

8. When studying the mineralization of bottled water, the following metal cations were found in it: Ag2+, Na+, Mg2+. To carry out a qualitative analysis, a CaCl2 solution was added to this water.

1. What changes can be observed in the solution during this experiment (the concentration of the substance is sufficient for analysis)?

Answer: a white cheesy sediment is observed.

2. Write down the abbreviated ionic equation for the chemical reaction that occurred.

Answer: Ag+ + Cl- = AgCl↓

9. A diagram of the redox reaction is given.

HNO3 + Cu = Cu(NO3)2 + NO2 + H2O

1. Make an electronic balance for this reaction.

Answer: an electronic balance has been compiled.

2| N+5 +e → N+ 4

1| Cu0 -2e → Cu+2

2. Identify the oxidizing agent and reducing agent.

Answer: It is stated that copper in oxidation state 0 is a reducing agent, and HNO3 (or nitrogen in oxidation state +5) is an oxidizing agent.

3. Arrange the coefficients in the reaction equation.

Answer: the reaction equation has been compiled: 4HNO3 + Cu = Cu(NO3)2 + 2NO2 + 2H2O

10. The transformation scheme is given:

Na2S → H2S → SO2 → BaSO3

Write molecular reaction equations that can be used to carry out these transformations.

Answer:

1. Na2S + 2HCl = 2NaCl + H2S

2. 2H2S + 3O2 = 2SO2 + 2H2O

3.SO2 + Ba(OH)2 = BaSO3 + H2O

(Other reaction equations that do not contradict the conditions for specifying reaction equations are allowed.)

To complete tasks 11-13, use the substances listed in the list:

1. Ethane

2. Acetylene

3. Toluene

4. Methanol

5. Acetaldehyde

11. From the list above, select substances that correspond to the indicated classes/groups of organic compounds. Write down the numbers of the structural formulas of these substances in accordance with their names.

Saturated hydrocarbon -

Monohydric alcohol -

Answer:

Saturated hydrocarbon - ethane C2H6

Monohydric alcohol - methanol CH3OH.

12. In the proposed schemes of chemical reactions, enter the structural formulas of the missing substances, selecting them from the list above. Arrange the coefficients in the resulting diagrams to obtain the equation of the chemical reaction.

1. ....... + Cl2 = CH3CH2Cl + HCl

2. ....... + Cu(OH)2 = CH3COOH + Cu2O + H2O

Answer:

13. Toluene is a raw material for the production of components of motor fuels with a high octane number, for the production of explosives (trinitrotoluene), pharmaceuticals, dyes and solvents. Toluene can be obtained in accordance with the transformation scheme below.

Enter the structural formula of substance X into the given transformation scheme, selecting it from the list proposed above.

Write down the equations of two reactions that can be used to carry out these transformations. When writing reaction equations, use the structural formulas of substances.

Answer:

14. One of the important concepts in ecology and chemistry is “maximum permissible concentration” (MPC). MPC is the content of a harmful substance in the environment, in which the constant presence of this substance does not have a direct or indirect adverse effect on the present or future generation throughout life, does not reduce a person’s performance, does not worsen his well-being and living conditions.

The maximum permissible concentration of formaldehyde in the air is 0.003 mg/m3. In a room of 40 sq. m with a ceiling height of 2.5 m, 1.2 mg of formaldehyde evaporated from the surface of doors made of particle boards (chipboards) impregnated with phenol-formaldehyde resin. Determine whether the maximum permissible concentration of formaldehyde in the air of a given room is exceeded. Suggest a way to reduce the concentration of formaldehyde indoors.

Answer: 1. The volume of the room is determined, and the concentration of formaldehyde in it is determined:

V (rooms) = 40 x 2.5 = 100 cubic meters. m

2. A conclusion has been formulated that the maximum permissible concentration has been exceeded; the maximum permissible concentration of formaldehyde in the room exceeds 0.003 mg/cubic meter. m;

3. One proposal has been formulated to reduce the formaldehyde content in the room.

Possible options: replacing the doors with new ones made from a different material (for example, wood); covering the surface of the doors with film, a layer of varnish or paint; regular airing (ventilation) of premises.

15. To treat burned skin, use a 5% solution of potassium permanganate. Calculate the masses of potassium permanganate and water required to prepare 120 g of such a solution. Write down a detailed solution to the problem.

Answer: m(KMnO4) = 0.05 x 120 = 6 g

m(water) = 120-6 = 114 g

Tasks 7. Inorganic chemistry. Properties of bases, amphoteric hydroxides, acids, salts

1. Write a molecular equation for the reaction between calcium hydroxide and carbon dioxide that was mentioned in the text.

2. Explain what features of this reaction make it possible to use it to detect carbon dioxide in the air.

The food industry uses the food additive E526, which is calcium hydroxide Ca(OH)2. It is used in the production of: fruit juices, baby food, pickled cucumbers, table salt, confectionery and sweets.

It is possible to produce calcium hydroxide on an industrial scaleby mixing calcium oxide with water, this process is called quenching.

Calcium hydroxide is widely used in the production of building materials such as whitewash, plaster and gypsum mortars. This is due to his abilityinteract with carbon dioxideCO2 contained in the air. The same property of a calcium hydroxide solution is used to measure the quantitative content of carbon dioxide in the air.

A useful property of calcium hydroxide is its ability to act as a flocculant that purifies wastewater from suspended and colloidal particles (including iron salts). It is also used to increase the pH of water, since natural water contains substances (e.g. acids ), causing corrosion in plumbing pipes.

1. Write a molecular equation for the reaction between sodium sulfite and hydrochloric acid.

2. Explain what features of sulfurous acid allow this reaction to be used to produce sulfur dioxide.

Read the following text and complete the tasks.

Sulfur dioxide is a very common additive used in the food industry. On labels it can be found as E220, and the preservative itself is formed as a result of the combustion of sulfur. This substance can be found almost everywhere: fruits and vegetables (canned, dried, frozen). To get rid of mold and mildew for the purpose of disinfecting warehouses, cellars, greenhouses, fumigation of premises with sulfur dioxide (sulfur dioxide (IV)) is sometimes used. To do this, sulfur is set on fire in the room. However, sulfur dioxide for cellar treatment can be obtained by reacting sodium sulfite with a solution of sulfuric acid. Sometimes calcium sulfite is mixed with a solution of hydrochloric acid for these purposes.

1. Write a molecular equation for the reaction between a solution of silver nitrate and zinc.

2. Explain why such a reaction is possible.

Read the following text and complete the tasks.

At the end of the 18th century, alchemists discovered the healing anti-inflammatory properties of lapis (silver nitrate). They obtained it by dissolving metallic silver in concentrated nitric acid. Lapis is still found in pharmacies as an antiseptic in the form of ointments, solutions and a lapis pencil for cauterizing wounds from suppuration.

Silver nitrate is also used in the process of producing high-quality mirrors. In this case, to obtain silver nitrate purified from impurities, its solutions are treated with zinc shavings.

To detect silver nitrate and verify the authenticity of silver items, a solution of hydrochloric acid is used. Conversely, silver ions are reactive to chlorine ions.

1. Write a molecular equation for the reaction between solutions of baking soda and acetic acid.

2. Explain why soda “slaked” with vinegar is used when preparing dough.

Read the following text and complete the tasks.

Baking soda (sodium bicarbonate) is used in medicine, the confectionery industry, and in everyday life. Baking soda is formed when excess carbon dioxide is passed through a sodium hydroxide solution. At home, sodium bicarbonate, “quenched with vinegar,” is added to the dough to make the finished product soft and fluffy. In industry, baking soda is produced from sodium carbonate by exposing its solution to excess carbon monoxide (IV).

1. Write a molecular equation for the reaction between aluminum and a solution of potassium hydroxide.

2. Explain what properties of aluminum oxide make this reaction possible.

Read the following text and complete the tasks.

Aluminum cookware is a fairly common item even in modern kitchens. The main advantage of this metal is the formation of a thin but durable oxide film on the surface, which prevents the destruction of cookware and increases its useful life. Thanks to the protective layer, food retains its taste. At the same time, the disadvantages of aluminum cookware are quite obvious. This material is easily susceptible to both mechanical damage and destruction under the influence of acids and alkalis, and can react actively with acidic or alkaline products, releasing a fairly large amount of metal ions harmful to health. Therefore, it is strictly forbidden to use aluminum cookware for preparing dishes with vinegar, tomato, sour fruits and berries, dairy products and marinades. In addition, this container cannot be used for long-term storage of any food or dishes, including water.

1. Write a molecular equation for the reaction of producing ammonia water (ammonium hydroxide) from ammonia.

2. Explain whether it is correct to call a 10% ammonia solution ammonia.

Read the following text and complete the tasks.

Ammonium hydroxide, or ammonia water, is used in the chemical industry in the process of producing ammonium salts used in agriculture as nitrogen fertilizers, for example, ammonium nitrate (ammonium nitrate). In the food industry, ammonium hydroxide is used as an acidity regulator and emulsifier E527.

Emulsifier E527 is most often used in food products containing cocoa powder or butter. This could be sweets, chocolates or caramels, pastries and other confectionery products.

1) Write a molecular equation for the reaction between calcium hydroxide and carbon dioxide discussed in the text.

2) Indicate the signs of this reaction.

Read the following text and complete the tasks.

Calcium hydroxide Ca(OH) 2 It is one of the most commonly used inorganic compounds in everyday life and industry. It is possible to produce calcium hydroxide on an industrial scale by mixing calcium oxide with water, a process called slaking.

Calcium hydroxide is widely used in the production of building materials such as whitewash, plaster and gypsum mortars. This is due to its ability to interact with carbon dioxide CO 2 contained in the air. The same property of a calcium hydroxide solution is used to measure the quantitative content of carbon dioxide in the air.

A useful property of calcium hydroxide is its ability to act as a flocculant that purifies wastewater from suspended and colloidal particles (including iron salts).

1) Write a molecular equation for the reaction of ammonia oxidation with oxygen specified in the text.

2) Indicate which processes - endothermic or exothermic - this reaction belongs to.

Read the following text and complete the tasks.

Ammonia (NN 3 ) is one of the most used inorganic substances in industry. To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used. Attention! When receiving ammonia, hold the receiver tube with the bottom up. The industrial method for producing ammonia is based on the direct interaction of hydrogen and nitrogen.

The ammonia molecule has the shape of a trigonal pyramid with a nitrogen atom at the apex. Three unpaired electrons of the nitrogen atom participate in the formation of covalent bonds with the 1s electrons of three hydrogen atoms (N-H bonds), the fourth pair of outer electrons is unshared. Under normal conditions, ammonia is a colorless gas with a sharp characteristic odor (the smell of ammonia), highly soluble in water, and poisonous. Ammonia vapors strongly irritate the mucous membranes of the eyes and respiratory organs, as well as the skin. This is what we perceive as a pungent odor.

1) Write a molecular equation for the reaction specified in the text between a solution of potassium carbonate and carbon monoxide (IV).

2) What is the volume (n.v.) of carbon monoxide (IV) released by the body per day?

Read the following text and complete the tasks.

Carbon monoxide (IV), or carbon dioxide (CO 2 ), is an odorless and colorless gas, heavier than air, when strongly cooled it crystallizes in the form of a white snow-like mass - “dry ice”. At atmospheric pressure it does not melt, but evaporates. Contained in the air and mineral springs, released during the respiration of animals and plants. Soluble in water (1 volume of carbon dioxide in one volume of water at 15 °C).

According to its chemical properties, carbon dioxide is classified as an acidic oxide. When dissolved in water it forms an acid. Reacts with alkalis to form carbonates and bicarbonates.

The human body produces approximately 1 kg of carbon dioxide per day. It is transported from tissues, where it is formed as one of the end products of metabolism, through the venous system and then excreted in exhaled air through the lungs.

Carbon(IV) monoxide is found in industrial quantities in flue gases. It is a by-product of chemical processes, for example during the decomposition of natural carbonates (limestone, dolomite), and the production of alcohol (alcoholic fermentation). The mixture of the resulting gases is washed with a solution of potassium carbonate, which absorbs carbon dioxide, converting it into bicarbonate. A solution of bicarbonate decomposes when heated or under reduced pressure, releasing carbon dioxide.

In laboratory conditions, small amounts of it are obtained by reacting carbonates and bicarbonates with acids, for example, marble or soda with hydrochloric acid in a Kipp apparatus. The use of sulfuric acid in this case is less desirable.

1) Write a molecular equation for the decomposition reaction of nitric acid specified in the text.

2) Why does concentrated nitric acid have a brown color?

Read the following text and complete the tasks.

Nitric acid (HNO 3 3 It usually has a brown color due to the decomposition process that occurs in the light or when heated. Nitric acid can be distilled without decomposition only under reduced pressure. Gold, some platinum group metals and tantalum are inert to nitric acid over the entire concentration range, other metals react with it, the course of the reaction being determined by its concentration. HNO 3 how a monobasic acid interacts with basic and amphoteric oxides, bases, and displaces weak acids from their salts. Nitric acid at any concentration exhibits the properties of an oxidizing acid due to nitrogen in the oxidation state +5. The depth of reduction depends primarily on the nature of the reducing agent and the concentration of nitric acid.

1) Write down the equation for the reaction of firing pyrite in air.

2) Why is a specially designed kiln called a fluidized bed kiln?

Read the following text and complete the tasks.

Sulfuric acid (H 2 SO 4

1) Write the equation for the interaction of sulfuric acid with iron(III) hydroxide.

2) Give the formulas for possible products of the reduction of concentrated sulfuric acid.

Read the following text and complete the tasks.

Sulfuric acid (H 2 SO 4 ) is one of the main products of large-scale chemistry. Without it, it is impossible to produce fertilizers, polymers, medicines, and dyes. Approximately 220 million tons of sulfuric acid are produced worldwide each year.

Dilute sulfuric acid has all the general properties of acids, reacting with bases, basic and amphoteric oxides, metal hydroxides, metals and salts. Concentrated sulfuric acid is a strong dehydrating agent. When dissolving, sulfuric acid is poured into water in a thin stream, but not vice versa! H 2 SO 4 exhibits fairly strong oxidizing properties and is capable of oxidizing nonmetals and some low-active metals that are in the series of standard redox potentials (“series of metal voltages”) after hydrogen. As a rule, when exposed to metals, hydrogen is not released from concentrated sulfuric acid.

In one of the methods for producing sulfuric acid, the first stage is the roasting of pyrite FeS 2 in the presence of atmospheric oxygen. Firing “in a fluidized bed” is carried out in specially designed furnaces. The resulting sulfur dioxide is thoroughly purified and oxidized to sulfur oxide (VI), which is absorbed with concentrated sulfuric acid. The absorption product, after dilution with water, turns into sulfuric acid of the required concentration.

1) Write down in molecular form the equation for the reaction of the formation of sodium bicarbonate specified in the text, which occurs when ammonia and carbon dioxide are passed through a solution of table salt.

2) What is the reaction of the medium in a solution of sodium carbonate?

Read the following text and complete the tasks.

2 CO 3 ) is used in glass production, soap making and the production of washing and cleaning powders, enamels, and for the production of ultramarine. It is also used to soften the water of steam boilers and generally to reduce water hardness. In the food industry, sodium carbonates are registered as a food additive E500 - an acidity regulator, a leavening agent, and an anti-caking agent.

Theoretically, sodium carbonate can be obtained by the interaction of the corresponding oxides - acidic and basic. In 1861, Belgian chemical engineer Ernest Solvay patented a method for producing soda that is still used today. Equal amounts of ammonia and carbon dioxide gases are passed into a saturated sodium chloride solution. The precipitated residue of slightly soluble sodium bicarbonate is filtered off and calcined (calcined) by heating to 140-160 °C, during which it turns into sodium carbonate.

3 COOH and sulfuric H 2 SO 4.

1) Write down in molecular form the equation specified in the text for the decomposition of sodium bicarbonate, leading to the formation of soda ash.

2) What is “water hardness”?

Read the following text and complete the tasks.

Sodium carbonate (soda ash, Na 2 CO 3 ) is used in glass production, soap making and the production of washing and cleaning powders, enamels, to obtain ultramarine dye. It is also used to soften the water of steam boilers and generally to reduce water hardness. In the food industry, sodium carbonates are registered as a food additive E500 - an acidity regulator, a leavening agent, and an anti-caking agent.

Sodium carbonate can be obtained by reacting alkali and carbon dioxide. In 1861, Belgian chemical engineer Ernest Solvay patented a method for producing soda that is still used today. Equimolar amounts of ammonia and carbon dioxide gases are passed into a saturated sodium chloride solution. The precipitated residue of slightly soluble sodium bicarbonate is filtered off and calcined (calcined) by heating to 140-160 °C, during which it turns into sodium carbonate.

The Roman physician Dioscorides Pedanius wrote about soda as a substance that hissed with the release of gas when exposed to acids known by that time - acetic CH 3 COOH and sulfuric H 2 SO 4.

1) Write a molecular equation for the reaction specified in the text for the industrial production of carbon monoxide (IV) from limestone.

2) Without giving the reaction equation, explain what the use of dolomite is based onin agriculture for soil deoxidation.

Read the following text and complete the tasks.

Carbon dioxide (CO 2 ) - an odorless and colorless gas, heavier than air, upon strong cooling it crystallizes in the form of a white snow-like mass - “dry ice”. At atmospheric pressure it does not melt, but evaporates. Contained in the air and water of mineral springs, it is released during the respiration of animals and plants. Soluble in water (1 volume of carbon monoxide in one volume of water at 15 °C). The +4 oxidation state for carbon is stable, however, carbon dioxide can exhibit oxidizing properties by interacting, for example, with magnesium. According to its chemical properties, carbon dioxide is classified as an acidic oxide. When dissolved in water it forms an acid. Reacts with alkalis to form carbonates and bicarbonates. The human body emits approximately 1 kg of carbon dioxide per day. It is transported from tissues, where it is formed as one of the end products of metabolism, through the venous system and then excreted in exhaled air through the lungs. In industrial quantities, carbon monoxide (IV) is released from flue gases or as a by-product of chemical processes, for example during the decomposition of natural carbonates (limestone, dolomite) or during the production of alcohol (alcoholic fermentation). The mixture of the resulting gases is washed with a solution of potassium carbonate, which absorbs carbon monoxide (IV), converting it into bicarbonate. A solution of bicarbonate decomposes when heated or under reduced pressure, releasing carbon dioxide. In laboratory conditions, small amounts of it are obtained by reacting carbonates and bicarbonates with acids, for example, marble or soda with hydrochloric acid in a Kipp apparatus. The use of sulfuric acid in this case is less desirable.

1) Write a molecular equation for the reaction specified in the text that occurs without changing the oxidation state of nitrogen.

2) Name the resulting product.

Read the following text and complete the tasks.

Ammonia (NN 3

The ammonia molecule has the shape of a trigonal pyramid with a nitrogen atom at the apex. Three unpaired electrons of the nitrogen atom participate in the formation of covalent bonds with the 1s electrons of three hydrogen atoms (N-H bonds), the fourth pair of outer electrons is unshared. Under normal conditions, ammonia is a colorless gas, lighter than air, with a sharp characteristic odor (the smell of ammonia), highly soluble in water, and poisonous. Ammonia vapors strongly irritate the mucous membranes of the eyes and respiratory organs, as well as the skin. This is what we perceive as a pungent odor.

1) Write a molecular equation for the reaction of iron and nitric acid.

2) How does alloying with other metals improve the chemical resistance of iron?

Read the following text and complete the tasks.

Iron is one of the most used metals by humans. It is used in both heavy and light industries, such as construction, defense, agriculture, etc.

Industrial iron is obtained from iron ore, which mainly consists of hematite (Fe 2 O 3 ). To do this, ore, coke (C), which turns into carbon monoxide when heated, and additional additives that allow you to get rid of unwanted impurities are placed in a blast furnace.

The iron obtained in this way is not often used in its pure form, since it is chemically unstable and is usually alloyed with various additives, such as nickel, during the production process. If this is not done, steel can oxidize in air at high humidity or temperature, and it also reacts well with acids.

Also, to protect the metal surface, electrochemical or chemical passivation techniques are often used. Iron, for example, can be passivated with concentrated nitric or sulfuric acid, but dilute acids react well with the metal.

1) Write a molecular equation for the reaction of aluminum oxide and sodium hydroxide.

2) How will increasing temperature affect the reaction?

Read the following text and complete the tasks.

Aluminum is a soft, light and very convenient metal for the production of tableware, metal decorative elements, as well as light metal structural products. Since this metal is the most common on the surface of the earth, it is accordingly relatively cheap. However, you can hardly find it in its pure form in nature. Aluminum is usually produced electrochemically from alumina and aluminum fluoride.

Aluminum is often used for decorative purposes, but over time, due to atmospheric oxygen, a gray oxide film forms on the surface, which spoils the aesthetic appearance.

Such a film can be removed, for example, by etching in an alkaline solution of NaOH, resulting in a clean metal surface. Also, pure metal reacts well with acids, especially hydrochloric acid.

1) Write a molecular equation for the reaction of silicon dioxide and hydrofluoric acid.

2) What else is not advisable to store in silica glass?

Read the following text and complete the tasks.

Silicon is one of the most common elements on earth. Typically, in industry, it is obtained in its pure form by strongly heating flint sand and coke. In the laboratory, it is usually prepared by reacting silicon dioxide with magnesium. Silicon is currently actively used in solar energy and micro- and nanoelectronics.

Silicon dioxide is the main part of most glasses. However, these glasses react with hydrofluoric acid, so it is usually stored in plastic containers. It is also used to create abrasives, ceramics and building materials. Due to its piezoelectric effects it is used in radio and high-precision electronics. When heating SiO 2 displaces the more volatile acid oxide from the salts, forming a silicate. When silicate reacts with acids, silicic acid is formed.

1) Write a molecular equation for the reaction of copper and nitric acid described in the text.

2) What color will the resulting solution be?

Read the following text and complete the tasks.

Nitrogen is a stable gas that makes up the bulk of the atmosphere. Because of its properties, it is often used for purging systems, pipes and to create an inert environment, since noble gases are more expensive. Nitrogen is also used as a refrigerant for freezing or maintaining low temperatures. Nitrogen is mainly used to produce ammonia. Ammonia is oxidized, first producing nitric oxide, and then nitrogen dioxide, and in the presence of water, nitric acid. Nitric acid reacts well with many metals. It is used to produce fertilizers, in nitration reactions to produce nitro compounds, as well as in the metal industry. Nitric acid is used in laboratory conditions to produce nitrogen dioxide by reaction with copper, without producing by-product gases.

1) Write a molecular equation for the reaction of hydrogen peroxide and sodium sulfite described in the text.

2) What kind of medium will be obtained in the final solution if we took reagents in a ratio of 1 to 1 mole?

Read the following text and complete the tasks.

Hydrogen peroxide is a very useful substance both in the chemical industry and medicine, and in everyday life. It is used, for example, as a bleaching agent in textile production and paper making. It is used as rocket fuel and as an oxidizer. Hydrogen peroxide can be obtained in laboratory conditions by reacting barium peroxide with sulfuric acid. Hydrogen peroxide is characterized by both oxidizing and reducing properties. For example, hydrogen peroxide can oxidize sodium sulfite to sulfate. The action of hydrogen peroxide on some hydroxides can produce metal peroxides, thus reacting with sodium hydroxide produces sodium peroxide

Hydrogen peroxide is very useful in medicine as an antiseptic, and when it comes into contact with a wound, it softens the tissue, making it easier to wash.

Hydrogen peroxide is unstable and decomposes into water and oxygen.

1) Write a molecular equation for calcium carbonate and hydrochloric acid.

2) Why is acid rain undesirable for ancient marble sculptures and buildings?

Read the following text and complete the tasks.

Carbon monoxide is one of the combustion products of organics and carbon-containing substances in the absence of oxygen. It is poisonous and fire hazardous. Burns with a blue flame and oxidizes to carbon dioxide. Carbon(II) monoxide reacts with halogens. The reaction with chlorine has received the greatest practical application; as a result of this reaction, phosgene is obtained, a substance that is widely used in various branches of chemistry, and also as a chemical warfare agent. Phosgene reacts well with ammonia to form urea.

Carbon monoxide reduces sulfur dioxide to sulfur, producing carbon dioxide.

When carbon dioxide gas is passed through calcium oxide, calcium carbonate is produced. Calcium carbonate is widely used in construction, in the food industry, as well as in the field of household chemicals. Calcium carbonate reacts well with acids, especially hydrochloric acid, releasing carbon dioxide.

1) Write a molecular equation for the reaction of lead oxide and nitric acid.

Read the following text and complete the tasks.

Lead has been used for thousands of years because it is widespread and easy to mine and process. It is very malleable and melts easily. Lead smelting was the first metallurgical process known to man. Due to its dense crystalline packing and large atomic mass, it serves as protection against radioactive radiation. Oxidation of lead produces lead oxide, which is used to produce lead glass. Lead oxide is an amphoteric oxide; when reacted with nitric acid, lead nitrate is obtained. This substance is very toxic and its scope of use is severely limited by safety precautions.

1) Write a molecular equation for the reaction of chromium oxide and sodium hydroxide.

2) How to determine whether the reaction has passed?

Read the following text and complete the tasks.

Chromium is an important component in many alloy steels (in particular stainless steels), as well as in a number of other alloys. The addition of chromium significantly increases the hardness and corrosion resistance of alloys. Used as wear-resistant and beautiful electroplated coatings. At high temperatures it burns, forming chromium(III) oxide, which is the main pigment for paint, as well as an abrasive. When chromium oxide is fused with sodium carbonate in an oxygen atmosphere, sodium dichromate is obtained. Sodium dichromate with sulfuric acid gives chromium(VI) oxide. Chromium(VI) oxide reacts with sodium hydroxide to produce sodium chromate.

1) Compose the molecular equation for the reaction of nitric acid with zinc(II) oxide as specified in the text.

2) Which reactions include the interaction of zinc oxide with nitric acid - exothermic or endothermic?

Read the following text and complete the tasks.

Nitric acid (HNO 3 ) is a monobasic acid, which was previously obtained by reacting concentrated sulfuric acid when heated with dry potassium nitrate. Nitric acid mixes with water in any ratio. In aqueous solutions, it almost completely dissociates into ions. Nitric acid is a colorless liquid that fumes in air, melting point 41.6 °C, boiling point +82.6 °C. Highly concentrated HNO 3 It usually has a brown color due to the decomposition process that occurs in the light or when heated. Nitric acid can be distilled without decomposition only under reduced pressure. Gold, some platinum group metals and tantalum are inert to nitric acid over the entire concentration range, other metals react with it, the course of the reaction being determined by its concentration. HNO3, as a monobasic acid, interacts with basic and amphoteric oxides and bases, and displaces weak acids from their salts. Nitric acid at any concentration exhibits the properties of an oxidizing acid due to nitrogen in the oxidation state +5. The depth of reduction depends primarily on the nature of the reducing agent and the concentration of nitric acid.

1) Compose the molecular equation for the reaction of sulfuric acid with iron as specified in the text.

2) What is the trivial name for the resulting iron compound?

Read the following text and complete the tasks.

Dilute sulfuric acid has all the general properties of acids, reacting with bases, basic and amphoteric oxides, metal hydroxides, metals and salts. Concentrated sulfuric acid is a strong dehydrating agent, exhibits fairly strong oxidizing properties and is capable of dissolving some low-active metals that are in the series of standard redox potentials (“series of metal voltages”) after hydrogen.

1) Write down the molecular equation of calcium hydroxide and carbon dioxide as specified in the text.

2) Why does the calcium hydroxide solution become cloudy during this reaction?

Read the following text and complete the tasks.

Diamond is the hardest natural substance on our planet. It is pure carbon with cubic system. Diamond, due to its mechanical and optical properties, is used as an abrasive or diamond knife, in watch mechanisms, optics, and also as decoration. Diamond burns to form carbon dioxide.

Carbon dioxide is used in the food industry as a preservative and leavening agent, and as a fire extinguishing agent. When calcium hydroxide reacts with carbon dioxide, the output is calcium carbonate, which is used in construction and the food industry with the appropriate E170 marking. Reacting calcium carbonate with sodium sulfide produces baking soda and calcium sulfide.

1) Write down the molecular equation for the addition of hydrogen chloride to ammonia as specified in the text.

2) How to understand that the reaction has started?

Read the following text and complete the tasks.

12. Ammonia (NН 3 ) is one of the most used inorganic substances in industry. To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used. The industrial method for producing ammonia is based on the direct interaction of hydrogen and nitrogen.

The ammonia molecule has the shape of a trigonal pyramid with a nitrogen atom at the apex. Three unpaired electrons of the nitrogen atom participate in the formation of covalent bonds with the 1s electrons of three hydrogen atoms (N-H bonds), the fourth pair of outer electrons is unshared. Under normal conditions, ammonia is a colorless gas, lighter than air, with a sharp characteristic odor (the smell of ammonia), highly soluble in water, and poisonous. Ammonia vapors strongly irritate the mucous membranes of the eyes and respiratory organs, as well as the skin. This is what we perceive as a pungent odor.

Ammonia is characterized by reactions both with a change in the oxidation state of the nitrogen atom (oxidation reactions) and without a change in the oxidation state of the nitrogen atom (for example, the addition of hydrogen chloride). When ammonia is burned, the output is pure nitrogen, and ammonium chloride obtained by reaction with hydrogen chloride can purify metals, such as copper, from oxide.

1) Compose the molecular equation for the reaction of sulfurous acid with potassium hydroxide specified in the text.

2) What kind of environment does the solution have after the reaction?

Read the following text and complete the tasks.

Sulfur dioxide is a very common additive used in the food industry. On labels it can be found as E220, and the preservative itself is formed as a result of the combustion of sulfur. This substance can be found almost everywhere: fruits and vegetables (canned, dried, frozen). However, sulfur oxide produced by burning petroleum products is a major environmental problem. When released into water, for example through precipitation, it forms sulfurous acid, which acidifies water bodies and soil. This acid also reacts with strong alkalis such as potassium hydroxide.

When carbon monoxide comes into contact with sulfur dioxide, pure sulfur precipitates and carbon dioxide is released, this reaction is used in the outlet pipes of the metallurgical industry.

1) Write down the molecular equation for the reaction of sodium oxide and carbon dioxide as specified in the text.

2) What will we observe if barium chloride is added to the solution of the resulting carbonate?

Read the following text and complete the tasks.

Sodium is a very active alkali metal that reacts explosively with water. It undergoes oxidation in air to form sodium oxide, and when burned, sodium peroxide is formed. When carbon dioxide is passed through sodium oxide, the output is sodium carbonate. Sodium carbonate reacts well with acids to form salt, carbon dioxide and water.

In industry, baking soda is produced from sodium carbonate by exposing its solution to excess carbon monoxide (IV). Baking soda (sodium bicarbonate) is used in medicine, the confectionery industry, and in everyday life. Baking soda is formed when excess carbon dioxide is passed through a sodium hydroxide solution. At home, sodium bicarbonate, “quenched with vinegar,” is added to the dough to make the finished product soft and fluffy.

1) Write down the molecular equation for the formation of phosphoric acid as specified in the text.

2) Which acid is stronger, hydrochloric or phosphoric?

Read the following text and complete the tasks.

Phosphorus is the most important biogenic element and at the same time finds very wide application in industry. Phosphorus burns well and is oxidized by oxygen.

Red phosphorus is used in the production of matches. The most chemically active, toxic and flammable is white (“yellow”) phosphorus, which is why it is very often used in explosives. When burned, phosphorus oxide is formed which, upon contact with water, forms phosphoric acid.

Phosphoric acid is used in the food industry as a food additive E338, in agriculture and medicine. In reaction with ammonia, phosphoric acid produces ammophos fertilizer. When reacted with calcium hydroxide, calcium phosphate is obtained.

1. Write a molecular equation for the reaction between sulfur(IV) oxide and calcium hydroxide mentioned in the text.

2. Describe the signs of the ongoing reaction between sulfur(IV) oxide and a solution of calcium hydroxide.

Read the following text and complete the tasks.

Sulfur(IV) oxide is used in the food industry as a preservative (food additive E220). Since this gas kills microorganisms, it is used to fumigate vegetable stores and warehouses. This substance is also used to bleach straw, silk and wool, that is, materials that cannot be bleached with chlorine.

The industrial method for producing this substance is to burn sulfur or sulfides. In laboratory conditions, it is obtained by the action of strong acids on sulfites, for example by reacting sulfuric acid with sodium sulfite.

When sulfur(IV) oxide reacts with calcium hydroxide, the salt calcium sulfite is formed. This substance is used in industry as a food additive E226, a preservative, for the preparation of jelly, marmalade, ice cream, drinks and fruit juices.

1. Write a molecular equation for the reaction between phosphoric acid and sodium hydroxide.

2. Indicate what type of reaction (compound, decomposition, substitution, exchange) the interaction of phosphoric acid with sodium hydroxide is.

Read the following text and complete the tasks.

Phosphorus(V) oxide (P 2 O 5 ) is formed when phosphorus is burned in air and is a white powder. This substance is very active and reacts with water, releasing a large amount of heat, so it is used as a desiccant for gases and liquids, and a water-removing agent in organic syntheses.

The product of the reaction of phosphorus(V) oxide with water is phosphoric acid (H 3PO 4 ). This acid exhibits all the general properties of acids, for example, it interacts with bases. Such reactions are called neutralization reactions.

Phosphoric acid salts, such as sodium phosphate (Na 3PO 4 ), are widely used. They are included in detergents and washing powders and are used to reduce water hardness. At the same time, excess

the amount of phosphates with wastewater into water bodies contributes to the rapid development of algae (water blooms), which makes it necessary to carefully monitor the phosphate content in wastewater and natural waters. The reaction with silver nitrate (AgNO) can be used to detect phosphate ion 3 ), which is accompanied by the formation of a yellow precipitate of silver phosphate (Ag 3PO4).

The test includes 15 tasks. 1 hour 30 minutes (90 minutes) is allotted to complete the chemistry work.

Formulate your answers in the text of the work according to the instructions for the assignments. If you write down an incorrect answer, cross it out and write a new one next to it.

When performing work, you are allowed to use the following additional materials:

– Periodic table of chemical elements;

– table of solubility of salts, acids and bases in water;

– electrochemical series of metal voltages;

– non-programmable calculator.

When completing assignments, you can use a draft. Entries in draft will not be reviewed or graded.

The points you receive for completed tasks are summed up. Try to complete as many tasks as possible and score the most points.

1. A dispersed system is a system in which one substance in the form of small particles is distributed in the volume of another.

The dispersed phase is a substance that is present in a dispersion system in smaller quantities. It can also consist of several substances.

A dispersion medium is a substance that is present in a dispersion system in larger quantities, and in the volume of which the dispersed phase is distributed.

Fill in the table of aggregative states of the dispersion medium and phase

2. The figure shows a model of the electronic structure of an atom of a certain chemical element.

Based on the analysis of the proposed model, complete the following tasks:

1) identify the chemical element whose atom has such an electronic structure;

2) indicate the number of protons this element contains;

3) indicate the number of filled energy levels;

4) determine the maximum valence of this element

Write your answers in the table.

3. With an increase in the charge of the nucleus of atoms, a gradual natural change in the properties of elements and their compounds from metallic to typically non-metallic is observed, which is associated with an increase in the number of electrons at the external energy level.

Considering these patterns, arrange in order of increasing non-metallic properties the following elements: Na, Cl, Al, Si. Write down the designations of the elements in the required sequence.

Answer: ____________________________

4. A hydrogen atom connected to a fluorine, oxygen or nitrogen atom (less commonly, chlorine, sulfur or other non-metals) can form another additional bond. A hydrogen bond is caused by the electrostatic attraction of a hydrogen atom (carrying a positive charge δ+) to an atom of an electronegative element having a negative charge δ−. In most cases, it is weaker than covalent, but is significantly stronger than the usual attraction of molecules to each other in solid and liquid substances.

From the proposed compounds, select 2 compounds whose molecules form hydrogen bonds: ethanal, ethanol, hydrogen, ammonia, oxygen.

Write your answer in the space provided:

1) _________________________

2) _________________________

5. Salt-forming oxides are classified into three groups, as shown in the diagram. In this diagram, fill in the missing group names and give two examples of chemical formulas of substances belonging to this group.

Read the following text and complete tasks 6–8.

Barium sulfate is often used in X-ray studies of the gastrointestinal tract as a radiocontrast agent, since heavy barium atoms absorb X-rays well. Although all soluble barium salts are poisonous, barium sulfate is practically insoluble in water (and in hydrochloric acid, which is found in gastric juice), so it is non-toxic. For an X-ray examination of the digestive organs, the patient takes orally a suspension of barium sulfate (“barite porridge”) with a barium content of 58.7%.

Barium sulfate is prepared by reacting soluble barium salts, oxide, peroxide or hydroxide with sulfuric acid or soluble sulfates. In analytical chemistry, barium sulfate is used as a good gravimetric form for the determination of sulfate ions and barium ions in gravimetric analysis.

In addition, barium sulfate is used as a color component for pyrotechnics, since barium ions contribute to the color of the flame green. Currently, barium nitrate is mainly used for these purposes, due to the fact that it is a strong oxidizing agent and promotes vigorous combustion of the pyrotechnic mixture.

6. 1) Write a molecular equation for the reaction of producing barium sulfate from barium peroxide, which was mentioned in the text.

Answer: _____________________________________________________

2) Explain why barium sulfate does not have a toxic effect on the body.

Answer: ________________________________________________________________ ________________________________________________________________________

7. 1) Write a molecular equation for the reaction between barium chloride and sodium sulfate.

Answer: _________________________________________________________________

2) Explain what features of this reaction make it possible to use barium chloride in analytical chemistry.

Answer: ________________________________________________________________

______________________________________________________________________

8. 1) Write a shortened ionic equation for the reaction between barium chloride and sodium sulfate.

Answer: _____________________________________________________________

2) Explain why barium nitrate is preferable to barium sulfate as a color component for pyrotechnics.

9. A scheme of the redox reaction is given

PH3 + KMnO4 + H2SO4 → MnSO4 + H3PO4 + K2SO4 + H2O

1) Make an electronic balance for this reaction

______________________________________________________________________

2) Specify the oxidizing agent and reducing agent

______________________________________________________________________________________________________________________________________________

3) Arrange the coefficients in the reaction equation

______________________________________________________________________

10. The transformation scheme is given: Al → Na → AlCl3 → Al(OH)3

Write molecular reaction equations that can be used to carry out these transformations

1) ________________________________________________________________

2) ________________________________________________________________

3) _________________________________________________________________

11. Establish a correspondence between the name of an organic substance and the class/group to which this substance belongs: for each position indicated by a letter, select the corresponding position indicated by a number.

NAME OF SUBSTANCE CLASS/GROUP

A) Toluene 1) alcohols

B) Acetylene 2) alkenes

B) Ethanol 3) arenas

Write down the selected numbers in the table under the corresponding letters.

12. Insert the formulas of the missing substances into the proposed schemes of chemical reactions and arrange the coefficients

1) CaC2 + H2O → …….. + ……………….

2) CH3NH2 + ……….. → ……….. + N2 + H2O

13. The raw materials for the production of sulfuric acid are native sulfur and sulfide ores. Among them, the most important is iron pyrite – pyrite FeS2. In nature, it occurs in massive, dense layers, from which it is extracted in the form of pieces, which are crushed and ground. In the production of sulfuric acid from pyrite, sulfur dioxide is produced by burning iron pyrites.

What mass of pyrite is needed to produce 67.2 liters of sulfur dioxide (s.c.)? Write down a detailed solution to the problem.

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

14. Acetone is a popular solvent, used as a raw material for the synthesis of many important chemical products, such as acetic anhydride, methyl methacrylate. Acetone is a natural metabolite produced by mammalian organisms, including the human body. In accordance with the diagram below, create reaction equations for the production of acetone. When writing reaction equations, use the structural formulas of organic substances.

1) _________________________________________________________

2) _________________________________________________________

3) _________________________________________________________

Glauber's salt Na2SO4.10H2O is used in the treatment of gastrointestinal diseases as a laxative. How many (g) Na2SO4.10H2O is needed to prepare 250 g of solution, with a mass fraction of Na2SO4 equal to 5%. Write down a detailed solution to the problem.

Answers

4. 1) ethanol 2) ammonia

(other wording of the answer is allowed that does not distort its meaning)
Response elements: 1) An electronic balance has been compiled: P-3 -8 ē → P+5 5 Mn+7 + 5 ē → Mn+2 8 2) It is indicated that PH3, due to P-3, is a reducing agent, and KMnO4 due to Mn+7 is an oxidizing agent; 3) The reaction equation has been drawn up: 5PH3 + 8KMnO4 +12 H2SO4 →8 MnSO4 +5 H3PO4 +4 K2SO4 + 12H2O
The answer is correct and complete, contains all the elements mentioned above
Two of the above response elements are written correctly
One of the above response elements is correctly written
All elements of the answer are written incorrectly

Catalog of tasks.
Tasks 3. Periodic table

Sorting Basic First simple First complex Popularity First new First old
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Solution.

The atomic radius increases down the group and to the left through the period. Nitrogen has the smallest atomic radius of the chemical elements presented, since it belongs to the second period of the fifth group. Next comes carbon, it belongs to the second period of the fourth group, then silicon - the third period of the fourth group and aluminum - the third period of the third group.

Answer: N&C&Si&Al

Source: Demo version of VPR in chemistry, grade 11, 2017.

It is known that with an increase in the atomic number of an element in periods, the metallic properties of atoms decrease, and in groups they increase. Arrange in order of increasing metallic properties the following elements:

Write down the designations of the elements in the required sequence.

In your answer, indicate the designations of the elements, separating them with &. For example, 11&22.

Solution.

Carbon will have the least metallic property of the chemical elements presented, since it belongs to the second period of the fourth group. Next comes boron, it belongs to the second period of the third group, then aluminum - the third period of the third group and calcium - the fourth period of the second group.

Answer: C, B, Al, Ca.

Answer: C&B&Al&Ca.

Source: SOLVE VLOOKUP

The periodic system of chemical elements by D.I. Mendeleev is a rich repository of information about chemical elements, their properties and the properties of their compounds, the patterns of changes in these properties, the methods of obtaining substances, as well as their location in nature. For example, it is known that with an increase in the atomic number of a chemical element in periods, the radii of atoms decrease, and in groups they increase.

Considering these patterns, arrange the following elements in order of increasing atomic radii: Write down the designations of the elements in the desired sequence.

In your answer, indicate the designations of the elements, separating them with &. For example, 11&22.

Solution.

Oxygen has the smallest atomic radius of the chemical elements presented, since it belongs to the second period of the sixth group. Next comes sulfur, which belongs to the third period of the sixth group, then phosphorus, the third period of the fifth group, and gallium, the fourth period of the third group.

Answer: O, S, P, Ga.

Answer: O&S&P&Ga

OPTION 1 - No. 1, 2, 5, 7, 9

OPTION 2 - No. 3, 4, 6,8, 10

1. It is known that with an increase in the atomic number of an element in periods, the metallic properties of atoms decrease, and in groups they increase. Arrange the following elements in order: C, Ca, B, A1

2. It is known that with an increase in the atomic number of a chemical element in periods, the radii of atoms decrease, and in groups they increase.

arrange in order increasing atomic radii the following elements: O, Ga, P, S.

3. It is known that with an increase in the atomic number of an element in periods, the metallic properties of atoms decrease, and in groups they increase. Arrange in order increasing metallic properties, the following elements: F, He, Si, S.

4. It is known that with an increase in the atomic number of a chemical element in periods, the radii of atoms decrease, and in groups they increase.

increasing atomic radii the following elements: Cl, P, Ba, A1.

5. It is known that for elements of the main subgroups the reducing properties of elements in a period from left to right decrease, in groups from top to bottom they increase.

increasing restorative properties the following elements: Sn, C, Ge, Si.

6. It is known that for elements of the main subgroups the oxidizing properties of elements in the period from left to right increase, in groups from top to bottom they weaken.

Considering these patterns, arrange in order increasing oxidative properties the following elements: S, Al, P, C1.

7. It is known that with an increase in the atomic number of a chemical element in periods, the electronegativity of atoms increases, and in groups it decreases.

Considering these patterns, arrange in order increasing electronegativity the following elements: C, N, Si, Ge.

8. It is known that with an increase in the ordinal number of a chemical element in periods, the electronegativity of atoms increases, and in groups it decreases.

Considering these patterns, arrange in order decreasing electronegativity

9. It is known that the acidic nature of higher oxides of elements increases in periods with increasing nuclear charge, and decreases in groups.

Considering these patterns, arrange in order enhancing the acidic properties of higher oxides the following elements: B, C, N, A1.

10. It is known that the acidic nature of higher oxides of elements increases in periods with increasing nuclear charge, and decreases in groups.

Considering these patterns, arrange in order weakening the acidic properties of higher oxides the following elements: P, As, S, Cl.

TEST 2. Atomic structure

OPTION 1 - No. 1, 3

OPTION 2 - No. 2, 4

2) indicate the period number and group number in D. I. Mendeleev’s Periodic Table of Chemical Elements in which this element is located;

3 .The figure shows a model of the electronic structure of an atom of a certain chemical element.

Based on the analysis of the proposed model, complete the following tasks:

1) identify the chemical element whose atom has such an electronic structure;

4 .The figure shows a model of the electronic structure of an atom of a certain chemical element.

Based on the analysis of the proposed model, complete the following tasks:

1) identify the chemical element whose atom has such an electronic structure;

2) indicate the period number and group number in D.I. Mendeleev’s Periodic Table of Chemical Elements in which this element is located;

3) determine whether the simple substance that forms this chemical element is a metal or non-metal.

TEST 3. STRUCTURE OF SUBSTANCES, CLASSIFICATION

OPTION 1 No. 1, 3, 5, 7

OPTION 2 No. 2, 4, 6, 8

1. The table below lists the characteristic properties of substances that have a molecular and ionic structure.

Using this information, determine what structure the substances nitrogen N2 and table salt NaCl have. Write your answer in the space provided:

1) nitrogen N 2 - .... 2) table salt NaCl-...

2 .The table below lists the characteristic properties of substances that have a molecular and ionic structure.

Using this information, determine what structure the substances hydrogen H2 and potassium nitrate salt KNO3 have. Write your answer in the space provided:

1) hydrogen H 2 -…. 2) potassium nitrate salt KNO 3 - ...

3 .The table below lists the characteristic properties of substances that have a molecular and atomic structure.

Using this information, determine what structure the substances water (H 2 O) and graphite (C) have. Write your answer in the space provided:

1) water H 2 0 - … 2) graphite (C) - …..

4. The table below lists the characteristic properties of substances that have a molecular and atomic structure.

Using this information, determine what structure the substances chlorine CI 2 and silicon (Si) have. Write your answer in the space provided.

1) chlorine CI 2 - ... 2) silicon Si - ...

Mg(OH) 2 Fe(NOs) 3 PbO HNO 3

6 .Establish to which class/group the inorganic substances whose formulas are indicated in the table belong. In the empty cells of the table, enter the names of the groups/classes to which this substance belongs.

CaНР0 4 H 2 SO 3 N0 2 Fe(OH) 2

7 . Read the text carefully:

Sulfur dioxide is a very common additive used in the food industry. On labels it can be found as E220, and the preservative itself is formed as a result of the combustion of sulfur. This substance can be found almost everywhere: fruits and vegetables (canned, dried, frozen). However, sulfur oxide produced by burning petroleum products is a major environmental problem. When released into water, for example through precipitation, it forms sulfurous acid, which acidifies water bodies and soil. When carbon monoxide comes into contact with sulfur dioxide, pure sulfur precipitates and carbon dioxide is released, this reaction is used in the outlet pipes of the metallurgical industry.

Preparing for the future Tasks for working on the topic "3 VPR" Characteristic properties of substances

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