All-Russian chemistry Olympiad for schoolchildren. School stage. Chemistry Chemistry Olympiad

Electric 22.09.2020

Electric

in the 2017-2018 academic year

School stage

8th grade

Dear participant!

‒

We wish you success!

Task 1. (8 points)

TEST. Choose one correct answer

1... A carbon compound that plays a major role in its natural cycle:

A) carbon monoxide; B) soot; B) oil; D) methane; D) carbon dioxide.

2. The cleanest water listed in the list is:

A) plumbing; B) spring; C) rain;

D) well; D) mineral.

3. From the listed chemical and physical-chemical processes, select one that does not require high temperature:

A) firing; B) calcination; C) fermentation;

D) sintering; D) fusion.

4. Among the listed metal materials used for the manufacture of prize medals, tokens and coins, the alloy is

A) gold; B) silver; B) bronze; D) nickel; D) aluminum.

5. Which of the following operations is not used in a chemical laboratory for the separation and purification of substances?

A) recrystallization; B) hypothermia; B) distillation; D) sublimation; E) re-precipitation.

6. Starting from the top left cell and moving horizontally (left or right) or vertically (up or down), go through all the cells so that the letters in the cells form a rule on precautions when handling chemicals. Each cell can only be used once.

7. Solve the crossword puzzle by filling it in with the Russian names of chemical elements. The key word is the surname of the great Russian scientist, one of the founders of atomic-molecular science.

1) C, 2) O, 3) Al, 4) N, 5) Zn, 6) I, 7) P, 8) H, 9) Pb

Task 2. (8 points)

1) Complete the phrases: (a) The composition of an individual substance, in contrast to the composition of a mixture __________ and can be expressed chemically __________; (b) __________, unlike __________, boils with a constant __________.

2) Which of the two liquids - acetone and milk - is an individual substance, and which is a mixture?

3) You need to prove that the substance you have chosen (one of the two in item 2) is a mixture. Briefly describe your actions.

Task 3. (8 points)

Common substance “This complex substance is widespread in nature. Found across the globe. Odorless. At atmospheric pressure, a substance can only be in a gaseous and solid state. Many scientists believe that this substance has an effect on the rise in the temperature of our planet. It is used in various industries, including the food industry. Used to extinguish fires. However, in a chemical laboratory, they cannot extinguish burning metals such as magnesium. Children are very fond of drinks made with this substance. But the constant consumption of such drinks can irritate the walls of the stomach. "

1) Identify the substance based on its description.

2) What names of this substance do you know?

3) Give examples of application known to you and name the sources of this substance formation.

Task 4. (8 points)

In the process of breathing, a person consumes oxygen and exhales carbon dioxide. The contents of these gases in the inhaled and exhaled air are shown in the table.

	O 2 (% by volume)	CO 2 (% by volume)
Inhaled
Exhaled

The volume of inhalation-exhalation is 0.5 liters, the frequency of normal breathing is 15 breaths per minute.

1) How many liters of oxygen does a person consume per hour and how much does carbon dioxide emit?

2) There are 20 people in a class with a volume of 100 m 3. Windows and doors are closed. What is the volumetric CO 2 content in the air after a 45 minute lesson? (Absolutely safe content - up to 0.1%).

Task 5 (10 points)

Powders of the following substances were dispensed in five numbered glasses: copper, copper (II) oxide, charcoal, red phosphorus and sulfur.

The students investigated the properties of the given powdery substances, the results of their observations were presented in the table.

Glass number	Substance color		Changes observed when the test powder is heated in air
		floats on the surface of the water	starts to smolder
		drowning in water	does not change
		floats on the surface of the water	melts, burns with a bluish flame, when burning, a colorless gas with a pungent odor is formed
	dark red	4 sinks in water	burns with a bright white flame, when burning, a thick white smoke is formed
		drowning in water	gradually turns black

1) Determine which glass contains each of the substances issued for research. Justify the answer.

2) Write the equations of the reactions that occur with the participation of the substances given out when they are heated in air.

3) It is known that the density of substances in glasses No. 1 and No. 3 is greater than the density of water, that is, these substances must sink in water. However, powders of these substances float on the surface of the water. Suggest a possible explanation for this.

All-Russian chemistry Olympiad for schoolchildren

in the 2017-2018 academic year

School stage

Grade 9

Dear participant!

When completing tasks, you have to perform certain work, which is better organized as follows:

‒ read the assignment carefully;

‒ if you are answering a theoretical question or solving a situational problem, think over and formulate a specific answer (the answer should be short, write its content in the provided field, write clearly and legibly).

For each correct answer, you can receive the number of points determined by the jury members, but not higher than the specified maximum mark.

When performing tasks, you can use a calculator, periodic table and solubility table. Tasks are considered completed if you handed them over to the person in charge of the audience on time.

We wish you success!

Task 1. (6 points)

Which particle contains 11 protons, 10 electrons and 7 neutrons? Determine its composition, charge, relative molecular weight. Write the formulas for the two compounds that contain this particle.

Task 2. (10 points)

The following substances are given: copper (II) sulfate, barium chloride, iron (III) oxide, carbon (IV) oxide, sodium oxide, silver, iron, sodium carbonate, water. Which of these substances will react with each other directly or in aqueous solution at room temperature? Give the equations for five possible reactions. For each reaction, indicate what type it belongs to.

Task 3. (10 points)

Calcium chips weighing 4.0 g were calcined in air and then thrown into water. When the chips were dissolved in water, 560 ml of gas (n.a.) was released, which practically does not dissolve in water.

1) Write down the reaction equations.

2) Determine by how many grams the mass of the chips increased during ignition.

3) Calculate the composition of the calcined chips in mass percent.

Write the reaction equations, with the help of which, using simple substances calcium, phosphorus and oxygen, you can get calcium phosphate.

Task 4.(8 points)

To dissolve 7.8 g of metal, 40 ml of 20% hydrochloric acid (density 1.095 g / ml) is required, and a divalent metal salt is formed. The evolved hydrogen completely reacts with 6.4 g of trivalent metal oxide. Determine which metals were used in these reactions.

Task 5. (8 points)

Four numbered test tubes contain solutions of barium chloride, sodium carbonate, potassium sulfate, and hydrochloric acid. Suggest a way to recognize substances without using additional reagents. Write the reaction equations.

School stage

Grade 10

Dear participant!

When completing tasks, you have to perform certain work, which is better organized as follows:

‒ read the assignment carefully;

For each correct answer, you can receive the number of points determined by the jury members, but not higher than the specified maximum mark.

When performing tasks, you can use a calculator, periodic table and solubility table. Tasks are considered completed if you handed them over to the person in charge of the audience on time.

We wish you success!

Task 1. (10 points)

In ten numbered glasses, powders of the following substances were given: copper, copper (II) oxide, charcoal, red phosphorus, sulfur, iron, sodium chloride, sugar, chalk, malachite (basic copper (II) carbonate). The students investigated the properties of the given powdery substances, the results of their observations were presented in the table.

Glass number	Test substance color	"Behavior" of the powder when placed in a glass of water	Changes observed when the test powder is heated in a spoon with an alcohol lamp
			practically does not change
		sinks in water, gradually dissolves	melts, darkens, gradually charred
		sinks in water, does not dissolve	practically does not change
			melts, burns with a bluish flame
		sinks in water, does not dissolve	gradually turns black
	dark red	sinks in water, does not dissolve	burns with a bright white flame
		sinks in water, does not dissolve	gradually turns black
	dark grey	sinks in water, does not dissolve	darkens, particles in the flame glow
		particles float on the surface of the water, do not dissolve	starts to smolder
		sinks in water, does not dissolve	practically does not change

1. Determine which glass contains each of the substances issued for research. Justify the answer.

2. Which of the dispensed substances react with hydrochloric acid to produce gas? Write the appropriate reaction equations.

3. It is known that the density of substances in glasses No. 4 and No. 9 is greater than the density of water, that is, these substances must sink in water. However, powders of these substances float on the surface of the water. Suggest a possible explanation for this fact.

4. The three dispensed substances are known to conduct electric current. What are these substances? What solution of a substance conducts an electric current?

Task 2. (7 points)

Make up all isomers of dichloroalkene composition C 3 H 4 Cl 2

Task 3. (10 points)

Organic compound A contains 39.73% carbon and 7.28% hydrogen by weight. Determine the molecular formula of substance A and establish its structural formula if it is known that it contains a quaternary carbon atom, and the vapor density in air is 5.2. Name organic compound A according to the systematic nomenclature. Suggest a way to get A.

Assignment 4 (10 points)

Rebuild the left side of the equations:

…. +…. +…. \u003d Na 2 SO 4 + 2Ag ↓ + 2HNO 3

…. \u003d Na 2 S + 3Na 2 SO 4

…. +…. +…. \u003d 3Na 2 SO 4 + 2MnO 2 ↓ + 2KOH

…. +…. \u003d POCl 3 + SOCl 2

…. +…. +…. → 2H 2 SO 4

Task 5. (10 points)

While disassembling reagents in the laboratory, the young chemist found an unsigned can of odorless white powder. To study its properties, the young chemist carefully weighed 10.00 grams and divided them into exactly 5 parts, with each part he carried out the following experiments:

Experience number	Experiment progress	Observations
		Let's well dissolve in water. The solution turns red
		Vigorous gas evolution
	Carefully brought part of the sample into the burner flame	The burner flame turns purple
		Dropped 3.43 g of white precipitate, insoluble in acids and alkalis
		The tube is hot. No visible signs of reaction were observed

1. Determine the composition of the white powder. Confirm the answer by calculation.

2. For experiments 2, 4, 5, give the corresponding reaction equation.

3. What happens when white powder is heated? Give the equation for the impact reaction.

All-Russian chemistry Olympiad for schoolchildren in 2017-2018 academic year year

School stage

Grade 11

Dear participant!

When completing tasks, you have to perform certain work, which is better organized as follows:

‒ read the assignment carefully;

For each correct answer, you can receive the number of points determined by the jury members, but not higher than the specified maximum mark.

When performing tasks, you can use a calculator, periodic table and solubility table. Tasks are considered completed if you handed them over to the person in charge of the audience on time.

We wish you success!

Task 1. (10 points)

Two elements that are in the same period and in the same group of the periodic table (in its short version) form with each other a single stable binary compound with a mass fraction of one of the elements of 25.6%. This compound is readily soluble in water, and when gaseous ammonia is passed into its solution, a white precipitate forms, gradually darkening in air. Name the elements, determine the formula of the substance and write the reaction equations.

Task 2. (10 points)

How to obtain C 6 H 5 COOC 2 H 5 benzoic ethyl ester from natural limestone according to the following scheme:

CaCO 3 → CaC 2 → C 2 H 2 →… → C 6 H 5 C 2 H 5 → C 6 H 5 COOH → C 6 H 5 COOC 2 H 5

Write the reaction equations, indicate the reaction conditions.

Task 3. (10 points)

A white solid, self-decomposing at room temperature or under mechanical action, has the following elemental composition: ω (N) \u003d 45.16%, ω (O) \u003d 51.61%, ω (H) \u003d 3.23%. The substance is highly soluble in water and is a weak diacid.

A. Establish the formula of the substance, name it, write the acid dissociation equation.

B. Draw the structural formula of the acid.

C. Write down the reaction equations: a) thermal decomposition of a given acid, b) its interaction with atmospheric oxygen, c) its interaction with alkali

Task 4. (8 points)

The young chemist Vasya decided to investigate a certain alloy that he inherited from his grandmother. To begin with, Vasya tried to dissolve the alloy in hydrochloric acid, but found that no dissolution took place. Then he tried to dissolve it in hot concentrated nitric acid. At the same time, the alloy collapsed, the solution turned blue, but a colored precipitate remained at the bottom, which did not dissolve even after prolonged heating in nitric acid. Vasya filtered the precipitate and dried it. By placing the powder in a crucible and heating it until melting, and then cooling it down, Vasya immediately realized which substance was an insoluble precipitate.

1. What two metals is the alloy that Vasya studied?

2. How to dissolve the precipitate formed when the alloy is heated in nitric acid? Give the reaction equation.

3. How to isolate the second component of the alloy from the blue solution obtained after the reaction with nitric acid? Give the required reaction equations

Task 5. (10 points)

A student of the 8th grade, while carrying out practical work "Obtaining oxygen and studying its properties", assembled a device for obtaining oxygen by displacing water. At the same time, he violated one of the requirements of the instructions - he did not place a piece of cotton wool in a test tube near the gas outlet tube. When potassium permanganate was heated, the water in the crystallizer turned red-violet. While collecting oxygen, part of the colored solution got into the bottle with gas. The disciple burned sulfur in it. In this case, the red-violet color of the solution disappeared, and a colorless solution was formed. Having decided to investigate the resulting solution, the student poured into it a part of the colored solution from the crystallizer. And again the color changed - a dark brown precipitate of an unknown substance fell out.

1. Write down the reaction equation for the decomposition of potassium permanganate.

2. What substance got into the crystallizer with water?

3. Why did the solution become discolored when burning sulfur? Write down the reaction equation.

4. Name the substance that precipitated. Write down the reaction equation.

Keys

All-Russian chemistry Olympiad for schoolchildren in 2017-2018 academic year year

School stage

Grade 8 (max. 42 points)

Task 1. (8 points)

Test 2.5 score (0.5 point for each task)

6. Rule -Chemicals cannot be tasted. - 1 point

7. Crossword 4.5 points(0.5 point for each element)

1 - Carbon, 2- oxygen, 3-aluminum, 4-nitrogen, 5-zinc, 6 - iodine, 7- phosphorus, 8- hydrogen, 9 - lead.

Task 2. (8 points)

1) (a) The composition of an individual substance, in contrast to the composition of a mixture, is constant and can be expressed by a chemical formula; (b) an individual substance, unlike a mixture of substances, boils at a constant temperature. (4 points)

2) Acetone is an individual substance, milk is a mixture. (2 points)

3) Place the drops of both liquids in the microscope. The milk will be uneven under the microscope. This is a mixture. The acetone will be homogeneous under the microscope.

Another possible solution: acetone boils at a constant temperature. During boiling water evaporates from milk, a film forms on the milk surface - foam. Other reasonable evidence is also accepted. (2 points)

Task 3. (8 points)

1. Named substance - carbon dioxide (carbon monoxide (IV)) (2 points ). A possible answer - water - is wrong. Water does not irritate the stomach.

2. Dry ice, carbon dioxide, carbonic anhydride (3 points: 1 point for each answer).

3. Carbon dioxide is used in the production of carbonated drinks, sugar production, when extinguishing fires as a refrigerant, etc. It is formed during the respiration of animal organisms, fermentation, decay of organic residues, in the production of quicklime, combustion of organic substances (peat, wood, natural gas, kerosene , gasoline, etc.) . (One point per example, but no more than 3 points).

Task 4. (8 points)

1) In an hour, a person takes 900 breaths and 450 liters of air pass through the lungs. (1 point) Not all of the inhaled oxygen is consumed, but only 21% - 16.5% \u003d 4.5% of the air volume, that is, approximately 20 liters. (1 point )

The same amount of carbon dioxide is released as oxygen consumed, 20 liters. (1 point)

2) In 45 minutes (3/4 hours), 1 person emits 15 liters of CO2. (1 point)

20 people emit 300 liters of CO2 . (1 point)

Initially, the air contained 0.03% of 100 m3, 30 liters of CO2, (1 point)

after the lesson it became 330 liters. CO2 content: 330 l / (100,000 l) 100% \u003d 0.33% (2 points ) This content exceeds the safe threshold, so the class must be ventilated.

Note. The calculation in the second question uses the answer to the first question. If in the first question the wrong number was received, but then the correct actions were performed with it in the second paragraph, the maximum score is given for this point, despite the incorrect answer.

Task 5. (10 points)

1) Glass # 1 contains coal powder. Black in color, smolders in air when heated.

No. 2 - copper (II) oxide; has a black color, does not change when heated.

No. 3 - sulfur; yellow color, characteristic combustion with the formation of sulfur dioxide.

No. 4 - red phosphorus; dark red color, characteristic combustion with the formation of phosphorus (V) oxide.

No. 5 - copper; Red color; the appearance of a black color on heating due to the formation of copper (II) oxide.

(0.5 points for each correct definition and another 0.5 points for reasonable justification.Total - 5 points)

2) C + O2 \u003d CO 2 S + O2 \u003d SO 2 4P + 5O 2 \u003d 2P 2 O 5 2Cu + O 2 \u003d 2CuO (1 point for each equation Total - 4 points)

3) The glasses No. 1 and No. 3 contain, respectively, powders of charcoal and sulfur. Charcoal particles are penetrated by capillaries filled with air, so their average density is less than 1 g / ml. In addition, the surface of coal, like the surface of sulfur, is not wetted by water, that is, it is hydrophobic. Small particles of these substances are held on the surface of the water by the force of surface tension. (1 point)

Keys

All-Russian chemistry Olympiad for schoolchildren in 2017-2018 academic year year

School stage

Grade 9 (max. 42 points)

Task 1. (6 points)

1. There are 1 more protons than electrons. Therefore, the particle has a charge of +1. There are fewer neutrons than protons, therefore, the particle contains hydrogen atoms, in which there are no neutrons at all. 11 - 7 \u003d 4 - this is the minimum number of H atoms. Without hydrogen there will be 7 protons and 7 neutrons - this is a nitrogen atom-14: 14N. Particle composition: 14NH4 + - ammonium ion ( 2 points )

Charge: 11 - 10 \u003d +1 (1 point)

Relative molecular weight: 11 + 7 \u003d 18 or 14 + 4 \u003d 18 (1 point)

Formulas: NH4Cl, (NH4) 2CO3 or other ammonium salts (2 points)

Task 2 (10 points)

Possible reactions:

Na 2 O + H 2 O \u003d 2NaOH compounds

Na 2 O + CO 2 \u003d Na 2 CO 3 compounds

BaCl 2 + CuSO 4 \u003d BaSO 4 + CuCl 2 exchange

2CuSO 4 + 2Na 2 CO 3 + H 2 O \u003d Cu 2 (OH) 2 CO 3 + CO 2 + 2Na 2 SO 4 exchange

Fe + CuSO 4 \u003d Cu + FeSO 4 substitution

Na 2 CO 3 + CO 2 + H 2 O \u003d 2NaHCO 3 compounds

Na 2 O + H 2 O + CuSO 4 \u003d Cu (OH) 2 + Na 2 SO 4 compounds and exchange

2NaOH + CO 2 \u003d Na 2 CO 3 + H 2 O exchange

BaCl 2 + Na 2 CO 3 \u003d BaCO 3 + 2NaCl exchange

For each of the five equations - 2 points (1 point for substances, 0.5 points for the coefficients, 0.5 points for the type of reaction).

(other formulations of the answer are allowed that do not distort its meaning)

Task 3 (10 points)

When calcined chips are calcined, the reaction occurs: 2Ca + O 2 \u003d 2CaO (The condition that the gas is practically insoluble in water excludes the reaction of calcium with nitrogen, which can lead to calcium nitride hydrolyzing to form NH 3.) Since calcium melts at high temperatures, and the reaction product is also refractory, metal oxidation initially occurs only from the surface. Calcined shavings are metal coated with an oxide layer on the outside. When placed in water, both metal and oxide react with it: CaO + H 2 O \u003d Ca (OH) 2; Ca + 2H 2 O \u003d Ca (OH) 2 + H 2.

2) The amount of the metal substance that has not reacted with oxygen is equal to the amount of the substance of the released gas (hydrogen): n (Ca) \u003d n (H 2) \u003d 0.56 / 22.4 \u003d 0.025 mol. In total, n (Ca) \u003d 4/40 \u003d 0.1 mol in the original shavings. Thus, 0.1 - 0.025 \u003d 0.075 mol of calcium entered into a reaction with oxygen, which is m (Ca) \u003d 0.075 * 40 \u003d 3 g. The increase in the chip mass is associated with the addition of oxygen. The mass of oxygen reacted with calcium is m (O 2) \u003d 32 * 0.0375 \u003d 1.2 g. So, the mass of the chips after calcination increased by 1.2 g.

3. Calcined shavings consist of calcium (0.025 mol) weighing 1 g and calcium oxide (0.075 mol) weighing 4.2 g. Composition in weight percent: Ca - 19.2%; CaO - 80.8%. Grading system:

1. For each reaction equation, 1 point - 3 points

2. By calculating the amount of substance hydrogen - 1 point

For the correct answer - 3 points

3. For the correct answer - 3 points

Task 4 (8 points)

1) Determine the amount of hydrogen substance

m (HCl) \u003d w ρ v \u003d 0.2 1.095 40 \u003d 8.76 g

ν (HCl) \u003d m in-islands / M in-islands \u003d 8.76 / 36.5 \u003d 0.24 mol (2 points)

2) Me + 2HCl \u003d MeCl 2 + H2

a) ν (Me) \u003d ν (H 2) \u003d 0.5ν (HCl) \u003d 0.5 0.24 \u003d 0.12 mol

b) M (Me) \u003d m in-va / ν \u003d 7.8 / 0.12 \u003d 65 g / mol (2 points)

Metal - zinc (1 point)

3) Me 2 O 3 + 3 H 2 \u003d 2Me + H 2 O

a) ν (Ме 2 О 3) \u003d 1 / 3ν (H 2) \u003d 0.12 / 3 \u003d 0.04 mol

b) M (Me 2 O 3) \u003d m in-va / ν \u003d 6.4 / 0.04 \u003d 160 g / mol

160 \u003d 2Ame + 3 16 Ame \u003d 56 (2 points)

Metal - iron (1 point)

Assignment 5 (8 points)

Thought experiment table compiled


	a white precipitate forms	a white precipitate forms	without changes
a white precipitate forms		Without changes	colorless and odorless gas is released
a white precipitate forms	Without changes		Without changes
Without changes	A colorless and odorless gas is released	Without changes

The reaction equations are given in molecular and ionic form:

BaCl 2 + Na 2 CO 3 → BaCO 3 ↓ + 2NaCl;

Na 2 CO 3 + 2HCl → 2NaCl + CO 2 + H 2 O

BaCl 2 + K 2 SO 4 \u003d BaSO 4 ↓ + 2KCl;

Evaluation guidelines

For compiling a table - 1 point

For the thought experiment table - 4 points

For each correctly composed molecular equation, 1 point (3 equations) - 3 score

Keys

All-Russian chemistry Olympiad for schoolchildren in 2017-2018 academic year year

School stage

Grade 10 (max. 47 points)

Task 1. (10 points)

1. Glass No. 1 contains sodium chloride. White color, soluble in water, practically does not change in air when heated.

No. 2 - sugar; white, soluble in water, melts and gradually charred when heated.

No. 3 - chalk; white, insoluble in water.

No. 4 - sulfur; yellow color, characteristic burning.

No. 5 - copper; Red color; the appearance of a black color when heated in air due to the formation of copper (II) oxide.

No. 6 - red phosphorus; dark red color; characteristic burning.

No. 7 - malachite; green color; the appearance of a black color during thermal decomposition due to the formation of copper (II) oxide.

No. 8 - iron; dark gray color; darkening when heated.

No. 9 - charcoal; black color; smolders when heated in air.

No. 10 - copper (II) oxide; black color; no change when heated.

0.5 points for each correct definition and reasonable justification. The maximum is 5 points.

2. Gaseous substances are released during the interaction of hydrochloric acid with chalk, malachite and iron:

CaCO 3 + 2HCl \u003d CaCl 2 + CO 2 + H 2 O

(CuOH) 2 CO 3 + 4HCl \u003d 2CuCl 2 + CO 2 + 3H 2 O

Fe + 2HCl \u003d FeCl 2 + H 2

3 points - 1 point for each equation

3. The glasses No. 4 and No. 9 contain, respectively, powders of sulfur and charcoal. Charcoal particles are penetrated by capillaries filled with air, so their average density is less than 1 g / ml. In addition, the surface of coal, like the surface of sulfur, is not wetted by water, that is, it is hydrophobic. Small particles of these substances are held on the surface of the water by the force of surface tension. 1 point

4. Copper, iron and coal conduct electric current. Sodium chloride solution conducts electric current because NaCl is an electrolyte. 1 point

Task 2. (7 points)

Trans-1,2-dichloropropene

Cis-1,2-dichloropropene

1,1-dichloropropene

2,3 - dichloropropene

Trans-1,3-dichloropropene

Cis-1,3-dichloropropene

3,3-dichloropropene

7 points: 0.5 points for each structure, 0.5 points for each name.

Task 3. (10 points)

1) Because the sum of the mass fractions is not 100%, therefore, there is still some residue in the molecule, the content of which is equal to:

100 – 39,73 – 7,28 = 52,99 %.

Molar mass of a substance: M (A) \u003d D air * M air \u003d 5.2 * 29 \u003d 151 g / mol.

The number of hydrogen atoms in a molecule A: 151 * 0.0728 / 1 \u003d 11.

The number of carbon atoms in a molecule A: 151 * 0.3973 / 12 \u003d 5.

The molar mass of the residue is 151 × 0.5299 \u003d 80 g / mol, which corresponds to one bromine atom, therefore, the molecular formula of the substance A - C 5 H 11 Br.

2) A contains a quaternary carbon atom, so A has the following structure:

CH 3 - C - CH 2 Br 1-bromo-2,2-dimethylpropane

3) Method of obtaining A:

CH 3 -C (CH 3) 2 -CH 3 + Br 2 \u003d CH 3 -C (CH 3) 2 –CH 2 Br + HBr

Grading system:

1) Determination of the number of carbon atoms 1 point

Determination of the number of hydrogen atoms 1 point

Determination of bromine 2 points

Molecular Formula 1 point

2) Structure 2 points

Name 1 point

3) The equation of the reaction of obtaining 2 points.

Task 4. (10 points)

Na 2 SO 3 + H 2 O + 2AgNO 3 \u003d Na 2 SO 4 + 2Ag ↓ + 2HNO 3

4Na 2 SO 3 \u003d Na 2 S + 3Na 2 SO 4

3Na 2 SO 3 + H 2 O + 2KMnO 4 \u003d 3Na 2 SO 4 + 2MnO 2 ↓ + 2KOH

SO 2 + PCl 5 \u003d POCl 3 + SOCl 2

2SO 2 + 2H 2 O + O2 \u003d 2H 2 SO 4

For each equation - 2 points

Task 5. (10 points)

1. Violet coloring of the burner flame indicates that the required powder is a potassium salt. The precipitation of a white precipitate with an excess of barium chloride is a qualitative reaction to the sulfate ion. But potassium sulfate (K 2 SO 4) has a neutral medium (the salt is formed by a strong base and a strong acid), and according to experiment No. 1 litmus colors the salt solution red, which indicates an acidic reaction. Therefore, the sought salt is potassium hydrogen sulfate, KHSO 4. Let's check it by calculation: KHSO 4 + BaCl 2 → BaSO 4 ↓ + HCl + KCl

since the young chemist divided the initial sample of 10.00 g into five equal parts, it means that 2.00 g of salt entered the reaction:

n (KHSO 4) \u003d n (BaSO 4) \u003d 2g / 136g / mol \u003d 0.0147mol;

m (BaSO 4) \u003d 0.0147 mol * 233 g / mol \u003d 3.43 g.

The resulting mass of barium sulfate coincides with the results of the experiment, therefore the white powder is really KHSO 4.

2. Reaction equations:

2KHSO 4 + K 2 CO 3 → 2K 2 SO 4 + CO 2 + H 2 O

KHSO 4 + BaCl 2 → BaSO 4 ↓ + HCl + KCl

KHSO 4 + KOH → K 2 SO 4 + H 2 O

3. The equation of the decomposition reaction: 2KHSO 4 \u003d K 2 S 2 O 7 + H 2 O

Grading system:

1) Conclusion about the presence of potassium ions - 1 point

Conclusion on the presence of sulfate ions - 1 point

Payment - 2 points

Salt Formula - 1 point

2) 3 equations by 1 point - 3 points

3) The equation of the decomposition reaction - 2 points

Keys

All-Russian chemistry Olympiad for schoolchildren in 2017-2018 academic year year

School stage

Grade 11 (max. 48 points)

Task 1. (10 points)

Since the elements are in the same period and in the same group of the periodic system, one of them is in the main subgroup, and the other is in the side, that is, it is a d-metal. Judging by the solubility in water, the substance is a halide, which means that the metal is in a side subgroup of the seventh group of the periodic system. Judging by the properties, it is manganese and the substance is MnBr 2.

Indeed, the mass fraction of manganese in it is 55: 215 ≈ 0.256 \u003d 25.6%. Elements - Mn and Br, substance - MnBr 2 (6 points: 2 points for each element, 2 points for the substance).

Reaction equations:

MnBr 2 + 2NH 3 + 2H 2 O \u003d Mn (OH) 2 ↓ + 2NH 4 Br;

2Mn (OH) 2 + O 2 \u003d 2MnO 2 ↓ + 2H 2 O (4 points: 2 points per equation).

Task 2. (10 points)

CaCO 3 + 4C \u003d CaC 2 + 3CO (calcination);

CaC 2 + 2H 2 O \u003d Ca (OH) 2 + C 2 H 2;

3C 2 H 2 \u003d C 6 H 6 (heating, catalyst - coal);

C 2 H 2 + 2H 2 \u003d C 2 H 6 (when heated, the catalyst is platinum);

C 2 H 6 + Cl 2 \u003d C 2 H 5 Cl (under lighting);

C 6 H 6 + C 2 H 5 Cl \u003d C 6 H 5 C 2 H 5 + HCl (catalyst - aluminum chloride);

C 6 H 5 C 2 H 5 + 2K 2 Cr 2 O 7 + 8H 2 SO 4 \u003d C 6 H 5 COOH + CO 2 + 2K 2 SO 4 + 2Cr 2 (SO 4) 3 + 10H 2 O; C 2 H 5 Cl + NaOH \u003d C 2 H 5 OH + NaCl;

C 6 H 5 COOH + C 2 H 5 OH \u003d C 6 H 5 COOC 2 H 5 + H 2 O (when heated, the catalyst is H 2 SO 4). Grading Scheme:

for the correct transition from limestone to acetylene - 3 points;

for obtaining benzene from acetylene - 1 point;

for the production of benzoic acid from benzene - 2 points;

for obtaining ester in one way or another from benzoic acid - 4 points .

Task 3. (10 points)

A. Establishing the formula of a substance

We denote the formula H x N y O z - x: y: z \u003d 3.23 / 1: 45.16 / 14: 51.61 / 16 \u003d 1: 1: 1;

the simplest formula is HNO, but according to the condition it is a dibasic acid, so it is logical to assume that its formula H 2 N 2 O 2 is nitrous acid. Dissociation equation H 2 N 2 O 2 ↔ H + + HN 2 O 2 - ↔ 2H + + N 2 O 2 -2 (5 points)

B. Structural formula H-O- N \u003d N - O-H (2 points)

B. Decomposition: H 2 N 2 O 2 → H 2 O + N 2 O

Oxidation with air oxygen: 2H 2 N 2 O 2 + 3O 2 (air) \u003d 2HNO 2 + 2HNO 3 Neutralization with alkali: H 2 N 2 O 2 + 2NaOH \u003d Na 2 N 2 O 2 + 2 H 2 O (3 points)

(other formulations of the answer are allowed that do not distort its meaning)

Task 4. (8 points)

1. Copper (by the color of the solution) and gold (insolubility in nitric acid and a characteristic form of a compact metal) (4 points: 2 points per element)

2. Dissolving in aqua regia (1 point)

Reaction equation:

Au + HNO 3 (conc.) + 4HCl (conc.) \u003d H + NO + 2H 2 O (2 points) (Options with hydrochloric acid and chlorine, selenic acid, a mixture of nitric and hydrofluoric acids, etc. are also suitable - evaluate with full score.)

3. Any reasonable method, for example: Fe + Cu (NO 3) 2 \u003d Cu + Fe (NO 3) 2 (1 point).

Assignment 5. (10 points)

1.2KMnO 4 \u003d K 2 MnO 4 + MnO 2 + O 2 (2 points)

2.Potassium permanganate particles got into the crystallizer with oxygen flow (1 point) 3. S + O 2 \u003d SO 2 (1 score )

2KMnO 4 + 5 SO 2 + 2H 2 O \u003d K 2 SO 4 + 2MnSO 4 + 2H 2 SO 4 (2 score )

4. Sediment - manganese dioxide MnO 2 (2 points)

2KMnO 4 + 3MnSO 4 + 2H 2 O \u003d 5MnO 2 ↓ + K 2 SO 4 + 2H 2 SO 4 (2 score )

The final stage in chemistry 2018–2019 academic year of the year
will take place on February 23 Of 2019

The main

The Olympiad starts at 10:00 local time. List of venues.

The winners and prize-winners of the last year's Olympics, as well as the winners and prize-winners of the qualifying rounds of the current year's Olympiad are invited to participate in the Olympiad (list of invitees).

The duration of the Olympiad is 4 astronomical hours.

On the day of the Olympics

On-site registration starts at 9:30 am.

Participants must have with them:

passport (or other identity document)
APPLICATION FOR THE Final stage (formed from the Personal Account), signed by parents and you
pen, pencil, ruler, calculator (not on your phone or tablet!)

Am I not on the list? Or another problem?

Write a message to the Chemistry Jury (http: // website / vsesib / → Feedback → Chemistry Jury) with the following content:
“I am not invited to the Final Stage, but I am the winner / awardee of such and such a stage. My data: full name, ID in your personal account, class, status (prize-winner / winner, stage), region, locality. Please include me in the list of invited participants. "

After receiving the letter, we will do our best to help you solve the problem.

Prohibited!

At the Olympics, it is FORBIDDEN to use telephones and other means of communication and Internet access, any other electronic devices and gadgets, except for a conventional or engineering calculator.

It is forbidden to use any books, cheat sheets and other records.

It is forbidden to use the paper and reference information brought with you, including your own copies of D.I. Mendeleev, solubility, etc.

Appeals

For participants in the Olympics at the site in Magnitogorsk, an in-person appeal will take place on the day of the Olympiad.

The time and place of the face-to-face appeal in Novosibirsk will be announced additionally on the website of the Olympiad after the Final stage.

For participants from other sites an external appeal will be organized - instructions will be published on the Olympiad website after the Final Stage.

Summarizing

The results of the Olympiad will be published as the work is checked. Works from all sites are checked by a single jury in Novosibirsk. Summing up and determining the winners and prize-winners will be carried out according to a single rating of all participants after the end of the in-person and correspondence appeal. The final results will be published no later than April 1, 2019.

Tasks

8th grade

2017-2018 academic year

Prepared by:

chemistry teacher of the Semyonovsk branch

MBOU "Kuibyshevskaya secondary school"

Apalkov Andrey Dmitrievich

Tasks

school stage of the All-Russian Olympiad for schoolchildren in chemistry

8th grade

Total (maximum) number of points - 24

1. Define the names of pure substances and mixtures: toothpaste, citric acid, ozone, steel, iodine alcohol solution, sea water, iodine. (2 points)

2. Write down chemical phenomena from the proposed series. Indicate the signs that confirm your choice.

(2 points)

3. Three vessels of the same volume under normal conditions are filled with three different substances: nitrogen, hydrogen chloride and water. Arrange the vessels in ascending order of the number of molecules in them. Justify the answer.(2 points)

4. The shell of eggs consists mainly of calcium carbonate CaCO 3. (4 points).

5 .

H 2 OP 2 O 5 AlO 2 NaH 2 O 3 CO 2 Na 3 NCFeCl 3 N 2 TO 2 SiO 3

(4 points)

6. The main vitamin contained in tea is vitamin P. Its formula is C 36 H 28 O 15 (4 points)

7. In the combination of iron with oxygen, the mass ratio of the elements is 7: 3. Establish the formula of this compound.(6 points)

Olympiad in chemistry school stage 8th grade

Answers

Exercise 1. Identify the names of pure substances and mixtures: toothpaste, citric acid, ozone, steel, iodine alcohol solution, sea water, iodine.

Pure substances: citric acid, ozone, iodine

Mixtures: toothpaste, iodine alcohol solution, steel, sea water

Task 2. Write down chemical phenomena from the proposed series. Indicate the signs that confirm your choice.

Melting paraffin; burning a candle; sour milk; baking pancakes; scale formation.

Chemical phenomena and their signs:

– Burning a candle, as heat is released, new substances are formed - soot and water.Or the release of warmth and light.

– Souring milk, as there is a smell and sediment.

– Pancake baking as color change occurs.

– Scale build-up as a sludge forms.

Melting wax is not a chemical process.

0,25

The melting of wax is not a chemical process, it is a physical phenomenon. Sign - a change in the state of aggregation.

Maximum points

Task 3. Under normal conditions, three vessels of the same volume are filled with three different substances: nitrogen, hydrogen chloride and water. Arrange the vessels in ascending order of the number of molecules in them. Justify the answer.

The number of molecules is proportional to the amount of the substance. Under equal conditions, equal volumes of gases contain equal amounts of substances, therefore, an equal number of molecules. Under normal conditions, nitrogen and hydrogen are gases, and water is liquid.

Therefore, the location will be as follows:

n (N 2 ) \u003d n (HCL)< n(H 2 O)

Maximum points

Task 4.Egg shells are predominantly calcium carbonate CaCO 3. Calculate how much calcium the hen's body loses with each egg laid if the shell mass is on average 10 g.(4 points)

M (CaCO 3) \u003d 100 g / mol. w (Ca) \u003d 40%,

10g of the shell contains 4g of calcium.

Answer. With each egg, the chicken loses 4 g of calcium.

Maximum points

Task 5. The student received a task in which the names of the substances had to be compiled into their chemical formulas. In carrying out this task, he did not leave gaps between the formulas of the substances, as a result of which he got the following record:H 2 OP 2 O 5 AlO 2 NaH 2 O 3 CO 2 Na 3 NCFeCl 3 N 2 TO 2 SiO 3

Select formulas for individual substances from this entry, emphasize simple substances.

H 2 O; P 2 O 5; Al; O 2; Na; H 2; O 3; CO 2; Na 3 N; C; FeCl 3; N 2; TO 2 SiO 3

Al; O 2; Na; H 2 ; C; N 2 ;

Maximum points

Task 6. The main vitamin found in tea is vitamin P. Its formula is C 36 H 28 O 15 ... Determine the mass of one vitamin P molecule (in grams).

We find the mass of one caffeine molecule by the formulam( C 6 H 12 O 2 N 4 )=
whereN A - Avogadro's number

M( C 6 H 12 O 2 N 4 ) \u003d 6 12 + 12 1 + 4 14 \u003d 172 g / mol;

m(C 6 H 12 O 2 N 4) \u003d 1 · 172: 6.02 · 10 23 \u003d 28.57 · 10 -23 (g)

Maximum points

Task 7.In the combination of iron with oxygen, the mass ratio of the elements is 7: 3. Establish the formula for this compound.(6 points)

The mass fraction of the element in the compound is calculated by the formula

Answer: Fe 2 O 3 .

Maximum points

Winner - from 14 points.

Prize-winners - from 8 to 14 points.

From March 30 to April 5 in Saransk at the National Research Mordovian State University named after N.P. Ogarev passed the final stage of the All-Russian Olympiad for schoolchildren in chemistry. Students of grades 9, 10 and 11 came to the Olympiad from 54 constituent entities of the Russian Federation: Astrakhan Region, Khabarovsk Territory, Yamalo-Nenets Autonomous District, Moscow, St. Petersburg, Sverdlovsk, Novosibirsk Regions and other regions of the country - a total of 245 schoolchildren.

The grand opening of the Olympiad took place on March 30. Galina Alekseevna Lotvanova, Deputy Chairman of the Government of the Republic of Mordovia in charge of social issues, delivered a parting speech for the participants of the Olympiad , rector of the National Research Mordovian State University named after N.P. Ogaryova Sergei Mikhailovich Vdovin and Dean of the Faculty of Chemistry of Moscow State University named after M.V. Lomonosov, Academician of the Russian Academy of Sciences, chairman of the jury of the final stage of the All-Russian Olympiad for Schoolchildren in Chemistry Valery Vasilyevich Lunin.

On March 31 and April 1, theoretical tours were held in the classrooms of the National Research Mordovian State University named after N.P. Ogarev, and on April 2 - a practical round of the Olympiad. On April 3, a demonstration of works took place, where the students got acquainted with their results and had the opportunity to discuss with the jury the progress of solving problems and clarify their questions. On April 4, the participants of the Olympiad visited industrial enterprises of Saransk.

The closing ceremony was held on April 5. The participants and organizers of the Olympiad were greeted by the Head of the Republic of Mordovia Vladimir Dmitrievich Volkov. He also congratulated and presented gifts to the participants and teachers, whose birthdays fell on the period of the final stage of the All-Russian Olympiad of Schoolchildren in Chemistry.

The jury of the Olympiad determined 19 strongest guys from Borovichi, Vologda, Dmitrovgrad, Izhevsk, Kazan, Lipetsk, Moscow, Nizhnekamsk, Novosibirsk, St. Pereburg, Saransk and Tyumen, who became winners. Another 91 schoolchildren from different cities of Russia won the Olympics. The prize-winners' diplomas were presented by members of the jury Olga Valentinovna Arkhangelskaya and Vladimir Ilyich Terenin, as well as the rector of the National Research Mordovian State University named after N.P. Ogareva Sergei Mikhailovich Vdovin. The winners' diplomas were presented by the dean of the Faculty of Chemistry of Moscow State University named after M.V. Lomonosov, Academician of the Russian Academy of Sciences Valery Vasilievich Lunin.

It should be noted the absolute winner from the 9th grade, Alexei Shishkin from Samara, who scored a total of 248 points out of 250, and the 8th grade student Terlyakov Stanislav from Moscow, who became the prize-winner among the participants from the 10th grade and the 8th grade student Timur Davletbaev from Ufa, which became the winner among ninth-graders.

From among the winners, the jury of the Olympiad selected children to participate in the 51st International Mendeleev Olympiad, which will be held on April 23-29 in Astana (Kazakhstan). The winners and prize-winners also formed teams for summer and winter camps for the International (World) Olympiad.

Olympiad winners

Tasks and solutions

I THEORETICAL TOUR

Tasks

Solutions

II THEORETICAL TOUR

Tasks

Solutions

EXPERIMENTAL TOUR

Tasks and solutions

Brief photo report

This Olympiad is available to everyone!

For everyone who is interested in studying chemistry, we are launching a new international Olympiad. We invite pupils of grades 8-11 and students of I-II courses of secondary educational institutions to test their knowledge and receive well-deserved awards for their efforts and theoretical base.

How chemistry is taught at the Mega-Talent center: for participants of different age categories, separate sets of tasks have been prepared, including theoretical questions, tasks and tasks with diagrams, illustrations.

What themes are we repeating this season:

History of chemistry and chemical discoveries
Chemical properties of metals and non-metals
Hydrocarbons
Dispersed media and other topics

Participants will have 15 test questions of various types:

Questions with one or more correct answers.
Tasks for the correlation of two data series and comparison.
Tasks requiring work with illustrative sources.
Tasks with the solution of the problem with the initial data series.

The tasks of the Olympiad correspond to the Federal State Educational Standard and help:

Master the conceptual apparatus and the symbolic language of chemistry.
To form an initial systematic understanding of substances, their transformations and practical application.
To realize the objective significance of the foundations of chemical science as a field of modern natural science.

Separate awards await the organizer and parents

We will also send a separate thank you
admission to your educational institution

Also you will get

Gifts for all participants All participants receive a special “Table of Achievements” in which you can enter information about the results of participation in our events and personal achievements.

Infographics Teachers applying for 10 or more participants will be able to receive personalized class ratings in the form of infographics

Info poster ad With the help of the information poster, you can easily start organizing our event in your educational institution Download info poster

Register on the site site.
Apply for participation indicating the number of participants.
Confirm the application by paying for it in a convenient way for you.
Only one name of the Olympiad curator and one name of the educational institution can be indicated in one application, which will be reflected in the award materials of the participants and the curator. You can submit multiple applications for the event if required.
Use the received teaching materials for the Olympiad (methodological recommendations, tasks for each category of participants, answer forms).
Upload student papers prior to debriefing.
Download reward materials from your completed application after the day the results are posted.

Students must solve all tasks on their own, without assistance.
Be responsible for filling out the answer table - the result of the participant may depend on it!
Please fill in all required fields correctly. The time to change the entered data is limited.
Remember that registration fee will not be refunded for the entries not added in time!

Who can win the Olympiad?

Our methodologists prepare assignments that correspond to the school curriculum. They are simpler than at regional olympiads, but more interesting and more diverse than at school tests. Our tasks are handled by excellent students and students who know the material at a sufficient level. However, the experience of participating in the Olympiads is also interesting for students with a satisfactory level of knowledge.

We participated in the last season's Olympiad. Are the tasks the same in this Olympiad?

No, we are preparing new tasks for each season. Assignments for different seasons are based on different sections of the curriculum. You can take part in the Olympiad again.

What does the set of tasks for the Olympiad look like?

On the day the assignments are issued, all teachers who have paid for participation can download a set of materials for the Olympiad, which includes:

Methodical recommendations for the Olympiad.
Motivation letter to the participant from the director of the MDG "Mega-Talent".
A set of 15 tasks of various types.
Calendar of upcoming events.

How are the results of the Olympiad evaluated?

After you enter the answers in a special table on the site, they will be submitted for verification. For each correct answer, the student receives 2 points. If there are two options for an answer to a test question and the student has correctly indicated only one option, he will receive 1 point.

How are rewards distributed?

The participant of the Olympiad who received 30 points is awarded the highest award - the winner's diploma.
Participants who received 26-29 points are awarded 2nd and 3rd places and awarded with diplomas of prize-winners.
All other participants receive personalized certificates.

The awards can be downloaded on the day of summing up.

How to pay for participation in the Olympiad?

To pay, use one of the proposed methods:

Bank card VISA / MasterCard / Maestro
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In order not to pay for each event separately and not to fill in all the data for payment every time, you can top up your personal balance.

How can you save on paying for participation in the Olympiads?

We will compensate for the costs of the Olympiad. The more students are listed in the application, the higher the percentage of compensation for teacher expenses.

You can also save money by replenishing the balance on the site. When replenishing your balance, you will receive a bonus of 7-20%, depending on the amount of replenishment.

Why do teachers choose Mega-Talent Olympiads?

Simple application form
Convenient access to teaching materials and awards
Self-entry of answers and work on errors
Compensation for the cost of printing assignments and reward materials
Unique and varied tasks

Photos of participants

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MAOU "Secondary School No. 56"

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FSKOU "Secondary School No. 140"

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MAOU "Secondary school No. 24, named after the Hero of the Soviet Union MV Vodopyanov". Krasnoyarsk.

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FKOU "SOSH GUFSIN of Russia in the Sverdlovsk region"

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KOGOBU VSSh village Lesnoy, Verkhnekamsk region

We conduct all-Russian and international Olympiads in which schoolchildren and students participate. Olympiads "Mega-Talent" in chemistry are held for students of grades 8-11 and students of I-II courses of secondary educational institutions. We reward all participants by presenting them with diplomas and certificates. Teachers receive from us certificates and gratitude for organizing the Olympiad.

MDG "Mega-Talent" through the eyes of statistics:

We have organized more than 400 Olympiads and expanded the list of subjects to 47 disciplines.
11,000 schoolchildren from 12 countries took part in the Chemistry Olympiads.
We paid the teachers 2,500,000 rubles to compensate for organizational expenses.
98% of teachers who took part in the Olympiad once become permanent organizers.

5 steps towards the teacher

It is convenient and profitable to cooperate with us, because we always follow 5 steps, thought out with the thought of each teacher and his concerns.

We open access to assignments for all classes at once and prepare methodological recommendations for the Olympiad.
We change the design of certificates and commendations every season to diversify your portfolio.
We save your money by offsetting the costs of printing tasks and awards.
Every month we give gifts and send the most active teacher to an advanced training course for free.
We will promptly respond to your questions in the online chat, mail and skype.

Students love the Mega-Talent Olympiads in Chemistry

Distance Olympiads are held in conditions familiar and comfortable for students - within the walls of their native school. The familiar environment helps them to get rid of unnecessary anxiety and focus on the main thing - on completing tasks. Therefore, Olympiads "Mega-Talent" often become an opportunity to declare themselves for students who are not confident in their abilities.

We create conditions for everyone to take part in the Olympiads, regardless of their level of progress. The tasks of our Olympiads are drawn up in accordance with the school curriculum and meet the requirements of the Federal State Educational Standard. We include only those topics that students managed to complete by the time of the Olympiad.

The assignments for each class consist of 15 different types of questions:

Questions with one or more correct answers.
Tasks for correlating two data series.
Tasks requiring work with illustrative sources.
Tasks for solving a problem with an initial data series.

The cost of participation in the Olympiad and the amount of compensation

To receive the materials of the Olympiad, you need to pay the registration fee. The amount of registration fee for one participant is indicated on the Olympiad page. We return up to 30% of this amount to the teacher for printing assignments and reward materials.The amount of compensation depends on the number of participants in the Olympiad. You will learn more about the terms of compensation after registration on the site.

The organizers of the Olympiads automatically go toteacher rating which is updated every month. The leaders of the rating receive valuable gifts.

During the academic year, we hold 7 Chemistry Olympiads

Every year, our center hosts 3 All-Russian and 4 International Olympiads. The schedule of the Olympiads is built in such a way as to avoid pauses between events.

Whenever you visit the site, you can always apply for one of our Olympiads. We prepare new tasks for each Olympiad, therefore 2-3 and sometimes 7 times a year participate in our Olympiads.

Automatic verification of works and publication of results

Test assignments are graded automatically immediately after you enter the answers of your students in a special plate by entering your personal account. On the day of publication of the results, you can download awards for yourself and all students who took part in the Olympiad.

Still not sure how to become a Chemistry Olympiad organizer?

Register on the site.
Go to the schedule and choose an olympiad in chemistry.
Submit your application and indicate the number of participants in the Olympiad.
Confirm the application to download assignments and guidelines.
Print the received materials and hold the Olympiad.
Add participants' answers in your personal account.
On the day of summing up, check out the results and download the well-deserved awards

How to pay for participation in the Chemistry Olympiad?

You can make the registration fee in one of the following ways:

Payment by credit card (online);
Payment according to the receipt, at the Russian Post office;
Payment using electronic payment systems (online).

Can schoolchildren and students not from Russia take part in the Olympiad?

Pupils and students from any country in the world can participate in all our Olympiads. The only requirement for students is fluency in Russian, since all assignments are written in Russian. Answers to other questions that we are often asked, we have collected .