Using research assignments in chemistry lessons. Production of ozone by electrical discharge in oxygen

Question No. 8 Is it possible to isolate table salt from a solution by filtration? Why?
Question No. 9 A mixture of table salt with sand and water is given. How to separate table salt and sand from it? What properties of the substances making up the mixture are taken into account?
Question No. 1 What does chemistry study? What are its most important tasks and significance? Name what chemical products you use in everyday life
Question No. 2 What is the difference between the concepts of “substance” and “body”? Give examples.
Question No. 3 From the following list, write down separately the names of substances and objects: iron, micrometer, copper, nylon, mercury, file, knife, sugar
Question No. 4 What similar and distinctive properties do the following substances have: a) table salt and sugar; b) acetic acid and water?
Question No. 5 Based on life experience and using additional literature, fill out the table below and compare the properties of copper and sulfur
Question No. 6 Describe the most important methods for separating mixtures and obtaining pure substances.
Question No. 7 Given a mixture of: a) alcohol and water; b) river sand and sugar; c) copper and iron filings; d) water and gasoline. How to separate these mixtures? Explain on what properties of the components of the mixture their separation is based.
Question No. 10 Make a table in your notebook and fill it with examples based on your life experience.
Question No. 11 Which of the following phenomena are physical and which are chemical: a) rusting of iron; b) freezing of water; c) combustion of gasoline; d) melting aluminum? Explain.
Question No. 6 Using the data in Table 3 (p. 30), create chemical formulas for compounds with oxygen of the following chemical elements: Zn, B, Be, Co, Pb, Ni. Name them.
Question No. 1 What is the valence of chemical elements? Explain this with specific examples.
Question No. 2 Why is the valence of hydrogen taken as unity?
Question No. 3 In the reaction of iron with hydrochloric acid, one metal atom displaces two hydrogen atoms. How can this be explained using the concept of valence?
Question No. 4 Determine the valence of elements using the formulas: HgO, K2S, B2O3, ZnO, MnO2, NiO, Cu2O, SnO2, Ni2O3, SO3, As2O5, Cl2O7.
Question No. 5 The chemical symbols of the elements are given and their valency is indicated. Make up the appropriate chemical formulas:
Question No. 7 Make up the formulas of the oxides: copper (I), iron (III), tungsten (VI), iron (II), carbon (IV), sulfur (VI), tin (IV), manganese (VII).
Question No. 8 Explain the essence of the main provisions of atomic-molecular teaching.
Question No. 9 What phenomena confirm: a) the movement of molecules; b) the presence of gaps between molecules?
Question No. 10 How does the movement of molecules differ in gases, liquids, and solids?
Question No. 11 How do solids with molecular and non-molecular structures differ in their physical properties?
Question No. 1 By whom, when and how was the law of conservation of mass discovered? Give the formulation of the law and explain it from the point of view of atomic-molecular science.
Question No. 4 Adhering to the sequence previously given (see pp. 35 or 39-40), and taking into account the valency of the elements, compose reaction equations according to the following schemes.
Question No. 8 Why is the physical quantity “amount of substance” used in chemistry and in what units is it measured? Explain your answer with examples.
Question No. 2 Zinc powder was poured into the retort (Fig. 35), the gas outlet tube was closed with a clamp, the retort was weighed and the contents were cursed. When the retort cooled down, it was weighed again. Has its mass changed and why? Then the clamp was opened. Are there any scales left in
Question No. 5 Write two reaction equations of each type known to you and explain their essence from the point of view of atomic molecular theory.
Question No. 6 Given metals: calcium Ca, aluminum Al, lithium Li. Make up equations for the chemical reactions of these metals with oxygen, chlorine and sulfur, if it is known that sulfur in compounds with metals and hydrogen is divalent.
Question No. 7 Rewrite the reaction equation diagrams below, instead of question marks, write the formulas of the corresponding substances, arrange the coefficients and explain what type each of the indicated reactions belongs to:
Question No. 9 Create 2-3 equations of chemical reactions known to you and explain in what mass and quantitative ratios the substances react.
Question No. 10 What does the physical quantity “molar mass” mean and how does it differ from the physical quantities “molecular mass”, “atomic mass”, “relative molecular mass” and “relative mass&r”
Question No. 11 What do the following entries mean: m(H2O) -18 amu; Mr(H2O)=18; M(H2O)=18 g/mol;
Question No. 12 The equation for the reaction 2Mg+O2 → 2MgO is given. According to this equation, make a table showing the relationship between the mass of reacting substances in grams, the number of atoms and the amount of substance, by analogy with the data in Table 5 (p. 39 textbook
Question No. 5 How does the theory of molecules explain physical phenomena? Give examples.
Question No. 7 Based on ideas about atoms and molecules, explain the process of decomposition of water.
Question No. 8 How to explain from the standpoint of atomic-molecular teaching: a) evaporation of water; b) decomposition of water under the influence of direct electric current?
Question No. 16 What is the mass of an atom called and in what units is it measured? Determine how many times the mass of a sulfur atom is greater than the mass of a hydrogen atom and the mass of an oxygen atom.
Question No. 17 Can any molecule contain the following masses of oxygen and sulfur: a) 8 amu; b) 16 amu; c) 64 amu; d) 24 amu? Give an explanation.
Question No. 1 Describe the role of M.V. Lomonosov and D. Dalton in the creation of atomic-molecular science
Question No. 2 What experiments do you know (from physics and chemistry courses) that confirm the following provisions: a) substances consist of molecules; b) are molecules formed by atoms?
Question No. 3 From your physics course, you know the phenomenon of diffusion. Give examples and explain this phenomenon in the light of the theory of molecules.
Question No. 4 What is the difference between the concepts “atom” and “molecule”?
Question No. 6 Why should the concept of not only molecules, but also atoms be used to explain chemical transformations?
Question No. 9 Give examples of substances with molecular and non-molecular structure. How do these substances differ in properties?
Question No. 10 One of the carbon oxides (carbon dioxide, which you know) turns into a solid state at a temperature of about -78°C, and one of the silicon oxides melts at a temperature of about 1610°C. What are the conclusions about the structure of these substances in the solid state?
Question No. 11 Which substances are called simple and which are called complex? From the names listed below, write down separately the names of simple and complex substances: oxygen, water, mercury, copper oxide, iron, hydrogen, iron sulfite, mercury oxide.
Question 12 How can you prove that oxygen, mercury and hydrogen are simple substances, water and mercury oxide are complex substances? How can one experimentally prove that iron sulfide is a complex substance? What are the conditions for the occurrence and course of reactions of sul formation
Question 13 How do mixtures differ in composition and properties from chemical compounds? Give examples.
Question No. 14 What is a chemical element called? Why is it impossible to identify the concepts of “chemical element”, “simple substance”, “atom”?
Question No. 15 When one complex substance decomposes, copper oxide and water are formed. What chemical elements are included in this substance?
Question No. 18 What does a chemical sign or symbol mean? What is a coefficient? Draw a table in your notebooks and enter the following entries into it according to the sample below: 5C, 5H, O, 2H, 3Cu, 4S, 3Fe.
Question No. 19 Write the chemical symbols for the following elements: aluminum, calcium, silicon and phosphorus. Explain what they mean.
Question No. 2 How is oxygen obtained in the laboratory and in industry? Write the equations for the corresponding reactions. How do these methods differ from each other?
Question No. 4 Describe the physical and chemical properties of oxygen. Write down equations for the corresponding chemical reactions. Under the formulas of the substances write their names, above the formulas write the valency of the elements in the compounds.
Question No. 1 Name the chemical element most common in the earth's crust. What compounds does this element contain and what is its content in nature?
Question No. 3 What are catalysts and what is their importance in chemical processes? What conclusions can you draw about the importance of catalysts in catalytic processes in the production of some chemical products?
Question No. 5 What processes are related to oxidation processes? What substances are called oxides? Write the equations of chemical reactions that result in the formation of oxides of the following chemical elements: a) silicon; b) zinc; c) barium; d) hydrogen; d) al
Question No. 6 When the basic copper carbonate (mineral malachite) Cu2CO3(OH2) decomposes, three oxides are formed. Write the reaction equations.
Question No. 7 Write down equations for the reactions that occur: a) during the combustion of phosphorus; b) aluminum.
Question No. 9 Using specific examples, explain how the oxygen cycle occurs in nature.
Question 12 What is the importance of oxygen in the life of plants and animals? In living organisms, during the oxidation of glucose C6H1206, the energy necessary for their life is released. Write the equations for this reaction if it is known that carbon oxide is eventually formed
Question No. 4 When opening a bottle of lemonade, a rapid release of gas is observed. How can this be explained?
Question No. 1 What are solutions and how do they differ from suspensions and emulsions? Support your answer with examples.
Problem No. 1 500 g of a solution saturated at 20°C contains 120 g of potassium nitrate. Determine the solubility of this salt.
Problem No. 2 27 g of salt were dissolved in 513 g of distilled water. Calculate the solute content in the resulting solution as a percentage.
Question No. 3 What is solubility? What is the relationship between temperature change and the solubility of solids and gases?
Problem No. 3 When evaporating 25 g of solution, 0.25 g of salt was obtained. Determine the mass fraction of the dissolved substance and express it as a percentage.
Question No. 4 Given 500 g of solution with a mass fraction of sodium hydroxide of 0.2. Calculate the mass of the substance that is obtained by evaporating this solution.
Question No. 5 How can you prepare a solution with a given mass fraction of solute? Explain with examples.
Question No. 6 What is the difference between the concepts of “saturated” and “concentrated” solution?
Question No. 3 In what form does hydrogen occur in nature and what is its prevalence? Calculate which substance contains more hydrogen: H20 or CH4 methane.
Question No. 4 Write down equations for the reactions that can result in hydrogen. Explain what type these reactions are.
Question No. 7 How to pour from one vessel to another: a) hydrogen; b) oxygen?
Question No. 9 Write down equations for the chemical reactions of hydrogen with the following oxides: a) mercury (II) oxide; b) iron scale Fe3O4; c) tungsten (VI) oxide. Explain what the role of hydrogen is in these reactions, what happens to the metal and hydrogen in the cut
Question No. 1 Give a general description of the element hydrogen. Give examples of compounds containing hydrogen and write their formulas.
Question No. 2 Explain what the entries mean: 5H, 2H2, 6H and 3H2.
Question No. 5 Hydrogen can be obtained by reacting aluminum with solutions of hydrochloric and sulfuric acids. Write down equations for these reactions. (When arranging coefficients, see p. 35 of the textbook).
Question No. 6 One cylinder is filled with hydrogen, the other with oxygen. How to determine which cylinder contains each gas?
Question No. 8 Write reaction equations characterizing the chemical properties of hydrogen.
Question No. 2 A mixture consisting of 1 ml of hydrogen and 6 ml of oxygen was exploded in the eudiometer. What gas and in what quantity was left after the explosion?
Problem 100 g of water was added to 200 g of a solution, the mass fraction of the substance in which is 0.3. Calculate the mass fraction of the solute in the resulting solution.
Question No. 5 Give examples of decomposition, combination and substitution reactions involving water. Make up equations for these reactions and write their names under the formulas of the substances.
Question No. 6 When water interacts with other substances, for example: a) acids can be formed; b) alkalis; c) alkalis and hydrogen. Give two examples for each case. Under the formulas of the substance, write their names.
Question No. 1 Describe the methods for obtaining halogens in a free state. Which halogens are more difficult and which are easier to isolate in the free state?
Question (task) Which gas is heavier - fluorine or chlorine - and by how much?
Question No. 2 Describe the change in the physical and chemical properties of halogens depending on the change in their relative atomic masses.
Question No. 4 Create reaction equations that can be used to carry out the following transformations: Cl → CuCl2 → Cu(OH)2 → CuO → CuCl2 → Cu.
Question No. 6 Create reaction equations for scheme 22 (page 151 of the textbook).
Problem No. 1 In a closed, durable vessel, 8 liters of chlorine were mixed with 12 liters of hydrogen and the mixture was exploded. What volume of hydrogen chloride was obtained? What gas and in what volume remained in excess?
Problem No. 2 What volume (mass and amount of substance) of chlorine under normal conditions will be released during the interaction of manganese (IV) oxide MnO2 weighing 17.4 g with hydrochloric acid taken in excess?
Question No. 6 Describe the chemical properties of chlorine. Make up chemical reaction equations showing: a) the interaction of lithium with chlorine; b) combustion of iron powder in chlorine; c) combustion of hydrogen in chlorine; d) interaction of chlorine with water. Please enter st.
Question No. 1 Draw diagrams of the distribution of electrons in halogen atoms according to energy levels. Explain which of them and why should be the strongest oxidizing agent.
Question No. 2 Draw the structure of fluorine and hydrogen fluoride molecules using their electronic formulas. Indicate the type of chemical bond in the molecules of these substances.
Question No. 3 How do the substances fluorine, hydrogen fluoride, and sodium fluoride differ: a) by the type of chemical bond; b) by the structure of the crystal lattice; c) by chemical properties?
Question No. 4 What are the most important compounds of chlorine found in nature? Why is chlorine not found in a free state in nature?
Question No. 5 Using two specific examples, explain the chemical essence of obtaining chlorine in a free state. Write down equations for the corresponding chemical reactions.
Question No. 8 For diagram 20 (p. 141 of the textbook), compose two or three examples of chemical reaction equations for each given case.
Question No. 9 What are the chemical properties of chlorine based on its use in practice? Write the equations for the corresponding reactions.
Question No. 3 How is hydrochloric acid obtained in laboratory conditions and in industry? Write down equations for the corresponding chemical reactions.
Problem No. 5 Calculate whether 140 ml of hydrochloric acid solution (p) = 1.1 g/cm3) is enough for 13 g of zinc to completely react with it.
Question No. 1 What are two ways to obtain hydrogen chloride? Write down equations for the corresponding chemical reactions.
Problem No. 1 100 ml of gas mixture intended for the synthesis of hydrogen chloride was passed through a solution of potassium iodide. As a result, 0.508 g of iodine was released. What was the composition of the gas mixture in percent (by volume)?
Question No. 2 Describe the physical and chemical properties of hydrogen chloride and explain for what purposes this gas is used.
Problem No. 2 Hydrogen chloride, which was obtained by reacting an excess of concentrated sulfuric acid with 58.5 g of sodium chloride, was dissolved in 146 g of water. Determine the mass fraction of hydrogen chloride as a percentage in the resulting solution.
Problem No. 3 Approximately 400 volumes of hydrogen chloride dissolve in one volume of water at room temperature. Calculate the mass fraction of hydrogen chloride as a percentage in the resulting solution.
Question No. 4 The formulas of the following substances are given: Zn, Cu, AL, CaO, SiO2, Fe2O3, NaOH, Al(OH)3, Fe2(SO4)3, CaCO3, Fe(NO3)3. Which of the following substances react with hydrochloric acid? Write down equations for the corresponding reactions.
Problem No. 4 What amount of aluminum will be required to react with hydrochloric acid, taken in excess, to obtain 5.6 liters of hydrogen (no.)?
Question No. 2 What substances are called bases and how are they classified? Write the base formulas and name them.
Task No. 3 Arrange the compounds whose formulas are given below in increasing order of their iron content: a) Fe3O4; b) Fe(0H)3; c) FeSO4; d) FeO; e) Fe2O3.
Question No. 6 Write the reaction equations with which you can carry out the transformations: Ca + Ca0 + Ca(OH)2 + CaCl2; Zn + ZnCl2 + Zn(OH)2 + ZnO;Cu + Cu + CuO + CuCl ₂+ Cu + CuS0 ₄
Question No. 1 Fill out the table by writing down 2-3 formulas of substances belonging to each class of substances.
Problem No. 1 Calculate the mass of sulfuric acid that will be required to neutralize a solution containing 10 g of sodium hydroxide.
Problem No. 2 A solution containing 240 g of sodium hydroxide was added to a solution containing excess iron (III) chloride. Determine the mass and amount of iron (III) hydroxide formed.
Question No. 3 Give three reaction equations with which you can obtain: a) soluble and b) practically insoluble bases. Write their names.
Question No. 4 Using table 13 (paragraphs 1, 4 and 5 of the textbook), compose three equations for the corresponding reactions in which alkalis participate.
Problem No. 4 In 1000 g of water at 20°C the following is dissolved: a) 1.56 calcium hydroxide; b) 38 g of barium hydroxide. Determine the mass fractions of substances in these solutions and express them as percentages.
Question No. 5 Which of the substances whose formulas are given react with a solution of sodium hydroxide:? Write equations for practically feasible reactions.
Question No. 7 Write the equations for the decomposition reactions when heated: a) copper (II) hydroxide; b) iron (III) hydroxide; c) aluminum hydroxide.
Question No. 3 Write the names of the salts whose formulas are given: NaCl, NaNO3, CaCl2, KHSO4, Al(NO3)3, K3PO4, Na2SO4, Ca(HS)2, FeSO4, Na2SO3, Cr2(SO4)3, Na2CO, AgNO3, Fe2 (SO4)3, NaHCO3, Ca(HCO3)2, Na2S.
Question No. 4 Write the formulas of the most important salts of the following acids: a) hydrochloric; b) sulfur; c) nitrogen; d) orthophosphoric; d) coal. Name these salts.
Question No. 5 List the methods for obtaining salts and write two equations for the corresponding chemical reactions. If necessary, use table 15 of the textbook.
Question No. 2 Write the chemical formulas of the following salts: magnesium carbonate, iron (II) bicarbonate, iron (III) sulfate, calcium hydrogen orthophosphate, basic magnesium chloride, calcium dihydrogen orthophosphate.
Task No. 2 Calculate in what mass ratios calcium hydroxide should be mixed with orthophosphoric acid for a neutralization reaction to occur.
Question No. 7 What substances do calcium chloride react with if it turns out: a) calcium sulfate; b) calcium carbonate; c) calcium orthophosphate; d) calcium hydroxide; d) hydrogen chloride? Write the reaction equations and explain why they go to completion.
Question No. 8 In what two ways can you obtain calcium oxide: a) calcium sulfate; b) calcium orthophosphate? Write down reaction equations.
Question No. 9 Write the equations for neutralization reactions that result in the formation of salts, the formulas of which are as follows: a) AlCl3; b) BaSO4; c) Ba(NO3)2 d) Na3PO4; e) NaNO; f) NaHSO4; g) KH2PO4; h) K2HPO4. Under the appropriate formulas of the substances, write them
Question No. 10 Create reaction equations, the diagrams of which are given below.
Question No. 1. What are oxides and how to classify them? Draw a table in your notebooks and write down the following oxide formulas in the appropriate columns: Na2O, N2O5, SiO2, CaO, CrO, CrO3, CuO, Mn2O7, FeO, SO2. Give them names.
Question No. 6 Write the equations of chemical reactions, the diagrams of which are given below: Ca + CaO + Ca(OH)2; SO3+... + K2SO4+...; Cu + CuO + CuSO4; N2O5+2LiOH + ...P + P2O5 + H3PO4; P2O5+... → ^t Ca3(P04)2+...
Task No. 1 Derive the chemical formula of the oxide if it is known that 2.3 parts by weight. sodium are combined with 0.8 parts by weight. oxygen.
Question No. 2 Create reaction equations, the diagrams of which are given below:
Task No. 2 Write the equation for the reaction of phosphorus oxide (V) with water flowing when heated, and calculate the ratio of the masses of the elements in the reacting substances.
Question No. 3 Write down reaction equations that can be used to obtain the following oxides: CO2, Al2O3, Li2O, CaO, MgO, P2O5, CuO.
Question No. 4 Which of the following oxides react with water: BaO, Li2O, CuO, SO3, CaO, SiO2, P2O5, Fe2O3, Al2O3, Na2O, Mn2O7? Write the reaction equations.
Question No. 5 Write the formulas of oxides whose hydrates are the following acids: H2SO4, H2SO3, H2CO3, H2SiO3, HMnO4, H3BO3.
Question No. 3 The chemical element gallium Ga is similar to the element aluminum Al, and selenium Se is similar to sulfur. Write the formulas of oxides, hydroxides and salts that contain these elements. Write down reaction equations that characterize the chemical properties...
Task. 4.05 g of zinc oxide was treated at elevated temperature with a solution of sodium hydroxide taken in excess. Determine the mass and amount of the substance formed - salt.
Question No. 2 Give examples that prove that chemical elements can be divided into separate groups.
Question No. 3 What are isotopes? Using specific examples, explain why the relative atomic masses of elements are expressed in fractional numbers.
Question No. 1 Give examples to prove that atoms have a complex structure.
Question No. 2 How do nuclear reactions differ from chemical reactions?
Question No. 4 Explain what is called the energy level and draw a diagram of the structure of the atom of sodium Na, nitrogen N, calcium Ca, phosphorus P and chlorine Cl.
Question No. 5 Based on the theory of atomic structure, explain the essence of the phenomenon of periodicity in changes in the chemical properties of elements.
Question No. 6 Chemical elements of short periods are divided into s- and p-elements. How can we explain this?
Question No. 2 What is the difference between the melting temperatures of substances with different crystal lattices: a) ionic; b) atomic; c) molecular? Give an explanation.
Question No. 1 How do amorphous substances differ from crystalline substances?
Problem No. 1 The interaction of hydrogen with copper (II) oxide produced 0.1 mol of copper. Calculate: a) the mass of copper formed; b) the mass and amount of copper (II) oxide that reacted.
Problem No. 2 The reaction produced 4 g of copper (II) oxide. Calculate: a) the mass and amount of the copper substance that reacted; b) mass and amount of substance consumed oxygen.
Question No. 3 What type of crystal lattice is characteristic of substances whose formulas are given: a) LiF; b) Na2SO4; c) NH3; d) H2; e) Ca3(PO4)2; e) H2S,
Question No. 5 What is oxidation number? What are its similarities and differences in comparison with the concept of “valence”?
Question No. 6 Determine the oxidation state of manganese in the compounds: K2MnO4, KMnO4.
Question No. 7 Make up equations for redox reactions: a) aluminum with oxygen; b) iron with chlorine; c) sodium with sulfur (for a sample entry, see p. 131 of the textbook).
No. 5. Familiarization with samples of simple and complex substances, minerals and rocks, metals and non-metals
No. 1 Consideration of substances with different physical properties
No. 2. Separation of mixtures
No. 3 Examples of physical phenomena
No. 4 Examples of chemical phenomena
No. 6. Decomposition of basic copper(II) carbonate
No. 7. Reaction of replacement of copper with iron
No. 8. Familiarization with oxide samples
No. 9. Production and properties of hydrogen
No. 10. Reaction of hydrogen with copper(III) oxide
No. 11. Effect of acids on indicators
No. 12. Ratio of acids to metals
No. 13. Interaction of acids with metal oxides
No. 14. Properties of soluble and insoluble bases
No. 15. Interaction of alkalis with acids
No. 16. Interaction of insoluble bases with acids
No. 17. Decomposition of copper(II) hydroxide when heated
Question No. 1 Explain the reaction of the compound of iron with sulfur in the light of the doctrine of atoms. Why do these elements come together in the 7:4 mass ratio?
Question No. 2 A substance is known in which there is 1 volume of sulfur for every 2 copper atoms. In what mass ratios do you need to take copper and sulfur so that both substances completely react?
Question No. 3 Who and when was the law of constancy of composition discovered? Give a definition and explain the essence of this law from the point of view of the doctrine of atoms.
Question No. 4 Hydrogen combines with sulfur in a mass ratio of 1:16. Using data on the relative atomic masses of these elements, derive the chemical formula of hydrogen sulfide. What is the significance of the law of constancy of the composition of a substance for the removal of chemicals?
Question No. 5 Using information about the relative atomic masses of chemical elements, compose the chemical formula of copper sulfate if the mass ratios of copper, sulfur and oxygen in it are respectively equal to 2:1:2.
Question No. 6 What practical significance does the law of constancy of the composition of matter have?
Question No. 7 What does the chemical formula show? Give examples.
Question No. 8 Is it possible to express the mass of iron sulfide (in amu) with the following numbers: a) 44; b) 176; c) 150; d) 264? Why?
Question No. 9 Write the chemical formulas of substances if it is known that they contain: a) an iron atom and three chlorine atoms; b) two aluminum atoms and three oxygen atoms; c) a calcium atom, a carbon atom and three oxygen atoms. Calculate relative molecular
Question No. 10 Calculate the mass fractions of elements in percent using the formulas: 1) CuSO4 - copper sulfate; 2) Fe2O3 - iron oxide; 3) HNO3 - nitric acid.
Question No. 11 According to the sample given on p. 25 of the textbook, explain what the chemical formulas mean: HgO, O2, H2, H2SO4, CuO.
Question No. 1 What is the content of gases in the air by volume and mass? Think about why there is more oxygen in the air by mass than by volume, while nitrogen has an inverse relationship.
Task No. 1 Calculate the amount of heat released when burning 100 liters of hydrogen taken under normal conditions. The thermochemical equation of the reaction: 2H2+O2=2H2O+572 kJ. (The mass of 1 liter of hydrogen is 0.09 g.)
Question No. 2 What experiments can be used to determine the content of oxygen and nitrogen in the air?
Question No. 3 How did A. Lavoisier experimentally prove the composition of air?
Question No. 4 What noble gases do you know? List the areas of their application.
Question No. 5 How does the combustion of substances in oxygen differ from their combustion in air?
Question No. 6 What are the similarities and differences between the combustion of simple and complex substances? Explain with examples.
Question No. 7 Using the above instructions (see p. 56 of the textbook), create equations for the combustion reactions of the following substances: a) barium; b) aluminum; c) lithium; d) phosphorus; e) hydrogen; f) hydrogen sulfide H2S; g) ethane C2H6; h) acetylene C2H2.
Question No. 8 What are the conditions for the occurrence and cessation of combustion? What fire extinguishing means should be used in the following cases: a) a person’s clothing caught fire; b) gasoline ignited; c) there was a fire in a timber warehouse; d) oil caught fire
Question No. 10 Give examples in which cases slow oxidation processes are beneficial and in which they are harmful.
Question No. 11 Give examples of exothermic and endothermic reactions. Write equations for the corresponding reactions and give explanations.
Question No. 12 How do chemical equations differ from thermochemical equations? Explain with specific examples.
Question No. 13 Give three examples of thermochemical reactions. Write the equations for these reactions.
Question No. 1 What substances are called acids? Draw the table below in your notebook and write down the chemical formulas of the acids you know in the appropriate columns, underline the acid residues and note their valency.
Task No. 1 Which acid is richer in phosphorus - orthophosphoric Н3Р04 or metaphosphoric НР03?
Question No. 2 Make up the structural formulas of the following acids: a) carbonic; b) hydrogen bromide; c) sulfurous; d) chlorine HClO4.
Task No. 2 Derive the chemical formula of a compound containing 3.95 parts by weight. chemical element selenium (Ar(Se)=79) and 0.1 parts by weight. hydrogen.
Question No. 3 How are acids produced? Write down reaction equations.
Question No. 4 In what two ways can one obtain: a) orthophosphoric acid; b) hydrosulfide acid? Write the equations for the corresponding reactions.
Question No. 5 Draw the table below in your notebook. Reactions of decomposition, connection, substitution, exchange.
Question No. 6 Give three equations of chemical reactions that characterize the chemical properties of acids. Note what type of reaction they are.
Question No. 7 Which of the substances whose formulas are given react with hydrochloric acid: a) CuO; b) Cu; c) Cu(OH)2; d) Ag; e) Al(OH)3.
Question No. 8 Write reaction equations that are feasible.
Question No. 1 What is a period called? What is common and how do large periods differ from small ones?
Question No. 3 How do the properties of chemical elements change in periods and main subgroups? Explain these patterns from the point of view of the theory of the structure of the volume.
Question #1 What is electronegativity? Using table 20 of the textbook and the periodic table, arrange the chemical symbols of the elements listed below in order of increasing electronegativity values: phosphorus, magnesium, boron, cesium, oxygen, cream
Question No. 2 Why do the numerical values of the electronegativity of atoms of elements allow us to judge the type of chemical bond that arises between atoms? Explain with specific examples.
Question No. 3 In your notebooks, write three formulas of compounds with: a) ionic; b) covalent; c) covalent nonpolar bond. Draw their electronic formulas.
Question No. 4 Given substances: CaF2, F2, H2S, LiCl, NH3, N2. Explain what type of bond exists between atoms in each individual compound. Why?
Question No. 5 Taking into account the electronegativity values of the elements (Table 20 of the textbook), create chemical formulas and indicate the shift of the common bonding electron pairs in the following compounds: a) calcium with hydrogen; b) lithium with nitrogen; c) oxygen with fluorine; G
Question No. 7 Which compound is more durable and why: a) sodium iodide or potassium iodide; b) sodium fluoride or sodium chloride; c) calcium fluoride or potassium chloride?
Problem No. 1 Determine the density and relative density of nitrogen (II) oxide in air.
Problem No. 2 When chlorine interacts with hydrogen, 0.25 mol of hydrogen chloride is formed. Calculate the volume of chlorine that entered the reaction (no.).
Problem No. 3 6 kg of coal C burned. Calculate the volume of carbon monoxide (IV) formed (no.).
Problem No. 4 Calculate what volume of oxygen is required to burn 10 m3 of ethane C2H6 (no.).

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§ 14. Law of conservation of mass of substances
Substances enter into chemical reactions that result in the formation of other substances. Do any changes occur to the mass of the substance as a result of the reaction? Scientists have made various assumptions on this issue.
The famous English chemist R. Boyle, calcining various metals in an open retort and weighing them before and after heating, discovered that the mass of metals became larger. Based on these experiments, he did not take into account the role of air and made the incorrect conclusion that the mass of substances changes as a result of chemical reactions. R. Boyle argued that there is some kind of “fiery matter”, which, when the metal is heated, combines with the metal, increasing its mass.

M.V. Lomonosov, unlike R. Boyle, calcined metals not in the open air, but in sealed retorts and weighed them before and after calcination. (A retort with a brazier is shown in Fig. 35, see p. 54.) He proved that the mass of substances before and after the reaction remains unchanged and that during calcination some part of the air is added to the metal. (Oxygen had not yet been discovered at that time.) He formulated the results of these experiments in the form of a law: “All changes that occur in nature are such states that as much as is taken from one body, so much will be added to another.” Currently this law is formulated as follows:
The mass of substances that entered into a chemical reaction is equal to the mass of the formed substances.
Much later (1789), the law of conservation of mass was established independently of M.V. Lomonosov by the French chemist A. Lavoisier (p. 55).

The correctness of the law of conservation of mass of substances can be confirmed by simple experiment. A little red phosphorus is placed in the flask (Fig. 16), closed with a stopper and weighed on a scale (a). Then the flask with phosphorus (b) is carefully heated. The fact that a chemical reaction has occurred is judged by the appearance in the flask of white smoke consisting of particles of phosphorus (V) oxide. During secondary weighing, make sure that the mass of substances has not changed as a result of the reaction (c).

From the point of view of atomic-molecular science, the law of conservation of mass is explained as follows: As a result of chemical reactions, atoms do not disappear or appear, but they are rearranged. Since the number of atoms before and after the reaction remains unchanged, their total mass also does not change.
The meaning of the law of conservation of mass of substances.

1. The discovery of the law of conservation of mass of substances contributed to the further development of chemistry as a science.

2. Based on the law of conservation of mass of substances, practically important calculations are made. For example, you can calculate how many starting materials are required to obtain iron (II) sulfide weighing 44 kg if iron and sulfur react in a mass ratio of 7:4. According to the law of conservation of mass of substances, the interaction of iron weighing 7 kg and sulfur weighing 4 kg produces iron (II) sulfide weighing 11 kg. And since it is necessary to obtain iron (II) sulfide weighing 44 kg, i.e. 4 times more, then the starting materials will also be required 4 times more: 28 kg of iron (7-4) and 16 kg of sulfur (4-4 ).

3. Based on the law of conservation of mass of substances, equations of chemical reactions are drawn up.
Answer questions 1-3 (p. 42).
§15. Chemical equations
A chemical equation is a conventional representation of a chemical reaction using chemical symbols and formulas.
Using the chemical equation of reactions, one can judge which substances react and which are formed. When composing reaction equations proceed as follows:

1. On the left side of the equation, write the formulas of the substances that react, and then put an arrow. It must be remembered that the molecules of simple gaseous substances almost always consist of two atoms (O 2, H 2, C1 2, etc.):

2. On the right side (after the arrow) write the formulas of the substances formed as a result of the reaction:

3. The reaction equation is drawn up based on the law of conservation of mass of substances, i.e. there must be the same number of atoms on the left and right. This is achieved by placing coefficients in front of the formulas of substances. First, the number of atoms that are contained in the reacting substances is equalized. In our examples these are oxygen atoms. Find the smallest common multiple of the numbers of oxygen atoms on the left and right sides of the notation from the arrow. In the reaction of magnesium with oxygen, the least common multiple is the number 2, and in the example with phosphorus, the number is 10. When dividing the least common multiple by the number of corresponding atoms (in the given examples, by the number of oxygen atoms), the entries from the arrow are found on the left and right sides the corresponding coefficients as shown in the following diagram:

The number of atoms of other chemical elements is equalized. In our examples, we should equalize the number of magnesium and phosphorus atoms:

In cases where the thermal effects of reactions are not indicated when drawing up chemical equations, an arrow is used instead of the equal sign.
§ 16. Types of chemical reactions
Chemical reactions can be divided into four main types: 1) decomposition; 2) connections; 3) substitution; 4) exchange (p. 82).
You became familiar with the decomposition reaction using the example of the decomposition of water (p. 13). You know the reaction of the compound from the example of the interaction of sulfur with iron (p. 15).

To get acquainted with the substitution reaction, you can perform the following experiment. A cleaned iron nail (or iron filings) is dipped into a blue solution of copper (II) chloride CuCl 2 . The nail (sawdust) is immediately covered with a coating of copper, and the solution turns from blue to greenish, since instead of copper (II) chloride CuC1 2, iron (II) chloride FeCl 2 is formed. The chemical reaction that occurs is expressed by the chemical equation

Fe + CuCl 2 -> Cu + FeCl 2

By comparing the chemical reactions discussed above, we can give them definitions and identify their features (Scheme 6).

1 You will become familiar with exchange reactions in a further chemistry course (p. 82).

2 In many cases, heat is required for the reaction to begin. Then in the reaction equations the sign t is placed above the arrow.

3 If a gas is released as a result of a reaction, an arrow Beepx is placed next to its formula, and if a substance precipitates, then a down arrow is placed next to the formula of this substance.
Complete exercises 5-7 (p. 42-43).

1. Who, when and how was the law of conservation of mass discovered? Give the formulation of the law and explain it from the point of view of atomic-molecular science.

2. Zinc powder was poured into the retort (Fig. 35), the gas outlet tube was closed with a clamp, the retort was weighed and the contents were calcined. When the retort cooled down, it was weighed again. Has its mass changed and why? Then the clamp was opened. Did the scales remain balanced and why?

3. What is the theoretical and practical significance of the law of conservation of mass of substances? Give examples.

4. Adhering to the sequence previously given (see p. 35), and taking into account the valency of the elements, compose reaction equations according to the following schemes:

5. Write two reaction equations of each type known to you and explain their essence from the point of view of atomic-molecular science.

6. Given metals: calcium Ca, aluminumA.I., lithiumLi. Make up equations for the chemical reactions of these metals with oxygen, chlorine and sulfur, if it is known that sulfur in compounds with metals and hydrogen is divalent.

7. Rewrite the reaction equation diagrams below, instead of question marks, write the formulas of the corresponding substances, arrange the coefficients and explain what type each of the indicated reactions belongs to:

USING RESEARCH ACTIVITIES IN CHEMISTRY LESSONS

One of the famous philosophers once noted that education is what remains in the mind of the student when everything he has learned is forgotten. What should remain in a student’s head when the laws of physics, chemistry, theorems of geometry and the rules of biology are forgotten? Absolutely right - creative skills necessary for independent cognitive and practical activity, and the conviction that any activity must meet moral standards.

Teaching in general is “a joint study conducted by teacher and student” (S.L. Rubinstein). It is the teacher who gives the forms and conditions for research activity, thanks to which the student develops internal motivation to approach any problem that arises in front of him from a research, creative position. When teaching children research skills, I first use problematic questions and situations. When using problem-based learning, you need to understand that only then can we talk about the development of thinking when problem situations are used regularly, replacing one another. The use of problem situations in chemistry lessons contributes to the formation of dialectical thinking in schoolchildren and the development of skills to find and resolve contradictions.

Ways to create a problem situation can be very diverse.

These include:

1. Demonstration or communication of some facts , which are unknown to students and require additional information to explain. They encourage the search for new knowledge. For example,teacher demonstrates allotropic modifications of elementsand offers to explain why they are possible, or, for example, students do not yet know that ammonium chloride can sublimate, but they are asked the question of how to separate a mixture of ammonium chloride and potassium chloride.

2. Using the contradiction between existing knowledge and the facts being studied, when, based on known knowledge, students make incorrect judgments. For example, the teacher asks the question:“Can carbon(IV) monoxide be passed through limewater to produce a clear solution?”Based on previous experience, students answer negatively, and the teacher shows a demonstration experiment with the formation of calcium bicarbonate.

3. Explanation of facts based on a known theory. For example, Why does the electrolysis of sodium sulfate produce hydrogen at the cathode and oxygen at the anode?Students must answer the question using reference tables: a series of metal voltages, a series of anions arranged in descending order of oxidation ability, and information about the redox nature of electrolysis.

4. Constructing a hypothesis based on a known theory, and then checking it. For example,Will acetic acid, as an organic acid, exhibit the general properties of acids?Students make a guess, the teacher sets up an experiment or lab, and then gives a theoretical explanation.

5. Finding a rational solution, when the conditions are set and the final goal is given. For example, the teacher offers an experimental task:three test tubes with substances are given; determine these substances in the shortest way, with the smallest number of samples.

6. Finding an independent solution under given conditions . This is already a creative task, for which a lesson is not enough, so to solve the problem it is necessary to use additional literature and reference books outside the lesson. For example,select conditions for a certain reaction, knowing the properties of the substances involved in it, make suggestions for optimizing the production process under study.

7. The principle of historicism also creates conditions for problem-based learning. For example, the search for ways to systematize chemical elements, which ultimately led D.I. Mendeleev, to the discovery of the periodic law.Numerous problems associated with providingmutual influence of atoms in molecules of organic substancesbased on the electronic structure, are also a reflection of issues that arose in the history of the development of organic chemistry.

The most successfully found problem situation should be considered one in which the problem is formulated by the students themselves. Research activity, in my opinion, can also be classified as a personally oriented technology, provided that the teacher shows interest in the student’s personal growth, the formation of his value guidelines, and personal qualities. This is possible thanks to the content of the work that the student performs and thanks to the communication between an adult and a child during research activities.

When carrying out research activities based on an experiment, the following stages of general scientific activity are assumed:

Setting the goal of the experiment, the goal determines what result the experimenter intends to obtain during the study.

Formulation and justification of a hypothesis that can be used as the basis for an experiment. A hypothesis is a set of theoretical propositions, the truth of which is subject to verification.

The planning of the experiment is carried out in the following sequence: 1) selection of laboratory equipment and reagents; 2) drawing up a plan for conducting an experiment, and, if necessary, depicting the design of the device; 3) thinking through the work after the end of the experiment (disposal of reagents, features of washing dishes, etc.); 4) identification of the source of danger (description of precautions when performing the experiment); 5) choosing a form for recording the results of the experiment.

Carrying out the experiment, recording observations and measurements.

Analysis, processing and explanation of the experimental results include: 1) mathematical processing of the experimental results (if necessary); 2) comparison of the experimental results with the hypothesis; 3) explanation of the ongoing processes in the experiment; 4) the formulation of the conclusion.

Reflection is awareness and evaluation of an experiment based on a comparison of goals and results. It is necessary to find out whether all operations to perform the experiment were successful.

The assessment is given both for general scientific skills, such as the ability to set a goal, put forward a hypothesis, plan, carry out an experiment, analyze the results obtained, draw conclusions, but also for the special skills provided for by this work.

When organizing such classes, students find themselves in conditions that require them to be able to plan an experiment, competently make observations, record and describe its results, generalize and draw conclusions, as well as master scientific methods of cognition.

Of particular importance in the formation of research skills are tasks involving thought experiment, promoting the development of reasoning skills. These are tasks in which you need to obtain a specific substance from those offered; obtain the substance in several ways; carry out all the characteristic and qualitative reactions characteristic of this class of substances; identify genetic relationships between classes of inorganic substances.

For example, when studying the topic “Electrolytic dissociation,” the traditional experimental determination of the electrical conductivity of substances using a device begins with a thought experiment. After this we conduct a demonstration experiment. Students compare and analyze the results, complete drawings and diagrams in their notebooks, and write down equations for the electrolytic dissociation reaction.

Let's give examples thought experiment tasks.

1. Zinc powder was poured into the retort, the gas outlet tube was closed with a clamp, the retort was weighed and the contents were calcined. When the retort cooled down, it was weighed again. Has the mass changed and why? Then the clamp was opened. Has the mass changed and why?

2. Cups containing solutions of sodium hydroxide and sodium chloride are balanced on the scales. Will the pointer of the scale change its position after some time and why?

Based on the results of completing assignments, the teacher can judge the student’s readiness for practical work.

When studying qualitative reactions to ions, students acquire the ability to draw up a plan for recognizing substances. The class is divided into groups; each group is given the task of drawing up a plan for determining solutions of sulfate, carbonate and sodium chloride in three numbered test tubes. Mandatory conditions: clarity, desired conditions: speed and minimum reagents spent. Each group defends its plan, using previously acquired knowledge, writing down molecular and ionic reaction equations. Finally, students conduct a laboratory experiment, putting their plan into practice.

A special group consists of tasks heuristic and exploratory in nature. By performing them, students use reasoning as a means to gain subjectively new knowledge about substances and chemical reactions. At the same time, schoolchildren carry out theoretical research, on the basis of which they form definitions, find relationships between structure and properties, the genetic relationship of substances, systematize facts and establish patterns, conduct an experiment in order to solve a problem formed by the teacher or posed independently . For example, When studying amphoteric hydroxides, the following task can be proposed:

Will the result of the interaction of solutions of sodium hydroxide and aluminum chloride be the same when adding 1 to 2 and vice versa?

When studying the topic “Generalization of the main classes of inorganic substances,” we suggest answering the question: what happens if you add a solution of sodium hydroxide to a solution of copper (II) sulfate, and potassium hydroxide to a solution of sodium carbonate. On the topic of “Halogens” the following questions are of interest:

1.What color will the indicator paper be in a freshly prepared solution of chlorine in water?

2. What color will the indicator paper be in a chlorine solution that has been exposed to light for some time?

The answers to these questions are confirmed empirically.

Practice shows that the use creative tasks predicting the properties of substances contributes to the formation of research skills, stimulates interest, allows students to become acquainted with the achievements of scientists, and see beautiful, elegant, striking examples of the work of creative thought.

When studying the topic “Carbohydrates”, students are asked the following questions:

1. German chemist Christian Schönbein accidentally spilled a mixture of sulfuric and nitric acids on the floor. He mechanically wiped the floor with his wife's cotton apron. “Acid can set the apron on fire,” thought Shenbein, rinsed the apron in water and hung it over the stove to dry. The apron dried out, but then there was a quiet explosion and... the apron disappeared. Why did the explosion happen? ( It turned out that nitric acid mixed with cotton - actually the same cellulose - forms an explosive substance, which Shenbein called pyroxylin - “combustible wood”. In those years, pyroxylin could not replace gunpowder, since it was very explosive).

Thus, educational research is a way of creative learning, which, designed in accordance with the model of scientific research, allows you to build an educational process on an activity basis, and is possible when designing chemistry lessons.

Analysis of our own experience and familiarity with work experience in this direction allows us to draw some pedagogical conclusions:

1. Students of different levels of preparedness and different ages are involved in research activities with pleasure and interest, i.e. It is incorrect to say that this is the area of interests and capabilities of high school students and that only gifted children can do this type of activity. Teachers who involve students of different levels of preparedness in research activities must take into account the child’s capabilities, predict the level of results, and the pace of implementation of the research program.

2. During research activities, the development of the child’s abilities occurs under certain conditions:

If the topic and subject of the research activity correspond to the needs of the child;

Learning takes place in the “zone of proximal development and at a fairly high level of difficulty”;

If the content of the activity is based on the “subjective experience of the child”;

If learning methods of activity are taking place.

3. Teaching research skills begins with a lesson that is based on the laws of scientific research. The technology of research activities is focused on the development of skills:

Determine the goals and objectives of the study, its subject;

Independent literature search and note-taking;

Analysis and systematization of information;

Annotate the studied sources;

Put forward a hypothesis, conduct practical research in accordance with it, classifying the material;

Describe the results of the study, draw conclusions and generalizations.

An educated person in modern society is not only and not so much a person armed with knowledge, but who knows how to obtain, acquire knowledge and apply it in any situation. A school graduate must adapt to changing life situations, think critically independently, be sociable, and communicative in various social groups.

We are talking about the formation of modern key competencies in students: general scientific, informational, cognitive, communicative, value-semantic, social.

Chemistry is one of the most humanistically oriented natural sciences: its successes have always been aimed at meeting the needs of humanity.

Studying chemistry at school contributes to the formation of students' worldview and a holistic scientific picture of the world, understanding the need for chemical education to solve everyday life problems, and fostering moral behavior in the environment.

The postulate that the development of a moral and creative personality is the goal of the pedagogical process at school is scientifically substantiated.

What should be changed in the structure, content of lessons and educational work of the teacher to achieve the goal of education? How to create an effective model for activating mental activity and developing teaching techniques. In the context of modern theories of intellectual development, areas related to “qualitative” changes in learning acquire particular importance. Among the most significant learning strategies at the present stage, a number of authors highlight “research learning”, which gives cognitive activity a creative character and is at the same time one of the options for individualizing learning.

Teaching in general is “a joint study conducted by teacher and student” (S.L. Rubinstein). The teacher’s task is to create a hypothetical-projective model for creating a developmental environment for students. It is the teacher who gives the forms and conditions for research activity, thanks to which the student develops internal motivation to approach any problem that arises in front of him from a research, creative position.

Of course, there are various forms of extracurricular work with schoolchildren to develop the intellectual abilities of students (Olympic reserve school, Olympiads themselves, competitions, conferences, etc.), but scientific research work (R&D) of schoolchildren is of particular importance.

Research work allows students to experience, test, identify and actualize at least some of their talents and gifts. Participation in research activities develops:

cognitive functions of the student;
the ability to critically evaluate approaches to solving research problems;
Creative skills;
ability to competently and competently present research results.

I would like to note that the project method is being widely introduced at the First Temirtau Classical Lyceum as one of the elements of the educational process. This method, being one of the most promising, allows solving numerous problems of teaching, upbringing and development of a student. It is this that makes it possible to most actively develop research skills and create situations of success for schoolchildren of different levels of preparedness.

But it should be recognized that the lesson has remained the leading form of the pedagogical process for 350 years. Yu.A. Konarzhevsky said that “the UVP begins with the lesson, and it ends with the lesson. Everything else in school, although important, plays a supporting role, complementing and developing everything that is laid down during the lessons. Each new lesson is a step in the student’s knowledge and development, a new contribution to the formation of his mental and moral culture.”

The basis of the teacher’s work is an individual-personal and activity-based approach: all the student’s work in the lesson is aimed at finding a solution to the assigned cognitive task, at developing the skills to reason, prove, think, analyze, explain and compare.

Research activities, in our opinion, can also be classified as technologies of a personality-oriented nature, provided that the teacher shows interest in the student’s personal growth, the formation of his value guidelines, and personal qualities. This is possible thanks to the content of the work that the student performs and thanks to the communication between an adult and a child during research activities.

The use of the research method in teaching practice represents the highest stage of the student’s learning process and involves the development of creative thinking. Acquiring creative thinking skills is possible, first of all, through activities that simulate scientific ones.

Conducting such classes radically changes the students' view of natural processes: the need to delve into the essence of things. They themselves try to formulate creative tasks and think through the course of their experimental research. What is an experiment?

Experiment is one of those methods of scientific knowledge that a student must master when studying chemistry. Based on sensations, a more meaningful perception is created - an important condition for achieving conscious and lasting knowledge.

A chemical experiment is one of the most effective methods of stimulating educational and cognitive activity and must meet the following requirements: clarity, ease of implementation, safety, reliability, explainability.

In the practice of our work, we use an original chemical experiment that meets all these requirements, based on the Diana Epp method, seven transformations in one test tube.

When carrying out research activities based on an experiment, the following stages of general scientific activity are assumed:

Setting the goal of the experiment, the goal determines what result the experimenter intends to obtain during the study.
Formulation and justification of a hypothesis that can be used as the basis for an experiment. A hypothesis is a set of theoretical propositions, the truth of which is subject to verification.
The planning of the experiment is carried out in the following sequence: 1) selection of laboratory equipment and reagents; 2) drawing up a plan for conducting an experiment, and, if necessary, depicting the design of the device; thinking through the work after the end of the experiment (disposal of reagents, features of washing dishes, etc.); 3) identification of the source of danger (description of precautions when performing the experiment); 4) choosing a form for recording the experimental results.
Carrying out the experiment, recording observations and measurements.
Analysis, processing and explanation of the experimental results include: 1) mathematical processing of the experimental results (if necessary); 2) comparison of the experimental results with the hypothesis; 3) explanation of the ongoing processes in the experiment; 4) the formulation of the conclusion.
Reflection is awareness and evaluation of an experiment based on a comparison of goals and results. It is necessary to find out whether all operations to perform the experiment were successful.

An important stage of this work is the implementation of self-diagnosis by the experimenter. After all, without the ability to reflect, further self-development is impossible.

The assessment is given both for general scientific skills, such as the ability to set a goal, put forward a hypothesis, plan, carry out an experiment, analyze the results, draw conclusions, but also for the special skills provided for by this work.

Let's give examples thought experiment tasks.

2. Cups containing solutions of sodium hydroxide and sodium chloride are balanced on the scales. Will the pointer of the scale change its position after some time and why?

Based on the results of completing assignments, the teacher can judge the student’s readiness for practical work.

When studying qualitative reactions to ions, students acquire the ability to draw up a plan for recognizing substances. The class is divided into groups of four and each group is given the task of drawing up a plan for determining solutions of sodium sulfate, carbonate and sodium chloride in three numbered test tubes. Mandatory conditions: clarity, desired conditions: speed and minimum reagents spent. Each group defends its plan, using previously acquired knowledge, writing down molecular and ionic reaction equations. Finally, students conduct a laboratory experiment, putting their plan into practice.

Will the result of the interaction of solutions of sodium hydroxide and aluminum chloride be the same when adding 1 to 2 and vice versa?

1.What color will the indicator paper be in a freshly prepared solution of chlorine in water?

2. What color will the indicator paper be in a chlorine solution that has been exposed to light for some time?

The answers to these questions are confirmed empirically.

Practice shows that the use creative tasks to predict the properties of substances. Such tasks contribute to the formation of research skills, stimulate interest, allow students to become acquainted with the achievements of scientists, and see beautiful, elegant, striking examples of the work of creative thought.

When studying the topic “Carbohydrates”, students are asked the following questions:

2.What happens if you chew bread crumb for a long time?

Physics and chemistry are becoming popular among teachers research lessons. Such lessons require a lot of preparation, which, as practice shows, justifies itself. Such lessons are structured in accordance with the logic of the activity approach and include the following stages: motivational-orientative, operational-executive (analysis, forecasting and experiment), evaluative-reflective.

Analysis of our own experience and familiarity with work experience in this direction allows us to draw some pedagogical conclusions:

2. During research activities, the development of the child’s abilities occurs under certain conditions:

If the topic and subject of the research activity correspond to the needs of the child;

Learning takes place in the “zone of proximal development and at a fairly high level of difficulty”;

If learning methods of activity are taking place.

3. Teaching research skills begins with a lesson that is based on the laws of scientific research. The technology of research activities is focused on the development of skills:

Determine the goals and objectives of the study, its subject;

Independent literature search and note-taking;

Analysis and systematization of information;

Annotate the studied sources;

Put forward a hypothesis, conduct practical research in accordance with it, classifying the material;

Describe the results of the study, draw conclusions and generalizations.

Used Books

Bataeva E.N. Formation of research skills. J, Chemistry: teaching methods. 8.2003-1.2004

Emelyanova E.O., Iodko A.G. Organization of cognitive activity of students in chemistry lessons in grades 8-9. M.: School Press, 2002.

Dmitrov E.N. Cognitive problems in organic chemistry and their solutions. Tula: “Arktous”, 1996.

The fascinating world of chemical transformations: Original problems with solutions / A.S. Suvorov et al. Chemistry, 1998

Stepin B.D. Entertaining tasks and effective experiments in chemistry. M.: Bustard, 2002.

Ryagin S.N. Laboratory workshop “Identification of organic compounds” 10th grade: Educational and practical guide for students of specialized classes and modular groups. – Omsk: OOIPKPO, 2003.