Municipal budgetary educational institution

"Average comprehensive school No. 4 Shebekino Belgorod region»

Features of solving and evaluating tasks 30-35 of the Unified State Exam in chemistry

Prepared by: Arnautova Natalya Zakharovna,

teacher of chemistry and biology

MBOU "Secondary school No. 4, Shebekino, Belgorod region"

2017

Methodology for assessing tasks with a detailed answer (main approaches to determining criteria and rating scales for completing tasks)

The basis of the methodology for assessing tasks with a detailed answer is a number of general provisions. The most important among them are the following:

Testing and evaluation of tasks with a detailed answer is carried out only through an independent examination based on the method of element-by-element analysis of the examinees' answers.

The use of the element-by-element analysis method makes it necessary to ensure that the wording of the task conditions clearly corresponds to the content elements being checked. The list of content elements tested by any assignment is consistent with the standard requirements for the level of preparation of high school graduates.

The criterion for assessing the completion of a task using the method of element-by-element analysis is to establish the presence in the answers of the examinees of the answer elements given
in the response model. However, another answer model proposed by the examinee may be accepted if it does not distort the essence of the chemical component of the task conditions.

The rating scale for task performance is established depending on the number of content elements included in the response model, and taking into account factors such as:

Level of complexity of the content being tested;

A specific sequence of actions that should be carried out when completing a task;

Unambiguous interpretation of the task conditions and possible options wording of the answer;

Compliance of the assignment conditions with the proposed assessment criteria for individual content elements;

Approximately the same level of difficulty for each of the content elements tested by the task.

When developing assessment criteria, the features of the content elements of all five long-answer tasks included in the examination paper are taken into account. It is also taken into account that the records of the examinees’ answers can be either very general, streamlined and not specific, or too brief
and insufficiently reasoned. Close attention is paid to highlighting the elements of the answer that are worth one point. This takes into account the inevitability of a gradual increase in the difficulty of obtaining each subsequent point
for a correctly formulated element of content.

When drawing up a scale for grading calculation problems (33 and 34), the possibility of different ways of solving them is taken into account, and therefore, the presence in the examinee’s answer of the main stages and results of completing the tasks indicated
in the evaluation criteria. Let us illustrate the methodology for assessing tasks with a detailed answer using specific examples.

2017-2018 academic year

Tasks

Maximum score

Job Level

Task 30

2016-2017

Tasks 30 are aimed at testing the ability to determine the degree of oxidation chemical elements, determine the oxidizing agent and the reducing agent, predict the products of redox reactions, establish the formulas of substances missed in the reaction scheme, draw up an electronic balance, and on its basis assign coefficients in reaction equations.

The scale for assessing the performance of such tasks includes the following elements:

 an electronic balance has been compiled – 1 point;

 the oxidizing agent and the reducing agent are indicated – 1 point.

 formulas of missing substances are determined and coefficients are assigned
in the equation of redox reaction – 1 point.

Example task:

Using the electron balance method, create an equation for the reaction

Na 2 SO 3 + … + KOH K 2 MnO 4 + … + H 2 O

Identify the oxidizing agent and the reducing agent.

Points

Possible answer

Mn +7 + ē → Mn +6

S +4 – 2ē → S +6

Sulfur in the +4 oxidation state (or sodium sulfite due to sulfur in the +4 oxidation state) is a reducing agent.

Manganese in oxidation state +7 (or potassium permanganate due to manganese
in the oxidation state +7) – oxidizing agent.

Na 2 SO 3 + 2KMnO 4 + 2KOH = Na 2 SO 4 + 2K 2 MnO 4 + H 2 O

The answer is correct and complete:

the degree of oxidation of elements that are, respectively, an oxidizing agent and a reducing agent in the reaction is determined;

oxidation and reduction processes were recorded, and an electronic (electron-ion) balance was compiled on their basis;

the missing substances in the reaction equation are determined, all the coefficients are placed

Maximum score

When assessing the examinee’s answer, it is necessary to take into account that there are no uniform requirements for the formatting of the answer to this task. As a result, the compilation of both electronic and electron-ion balances is accepted as the correct answer, and the indication of the oxidizing agent and reducing agent can be done in any clearly understandable way. However, if the answer contains elements of the answer that are mutually exclusive in meaning, then they cannot be considered correct.

2018 format tasks

1. Task 30 (2 points)

To complete the task, use the following list of substances: potassium permanganate, hydrogen chloride, sodium chloride, sodium carbonate, potassium chloride. It is permissible to use aqueous solutions of substances.

From the proposed list of substances, select substances between which an oxidation-reduction reaction is possible, and write down the equation for this reaction. Make an electronic balance, indicate the oxidizing agent and the reducing agent.

Explanation.

Let's write the reaction equation:

Let's create an electronic balance:

Chlorine in oxidation state −1 is a reducing agent. Manganese in the oxidation state +7 is an oxidizing agent.TOTAL 2 points

substances are selected, the equation of the redox reaction is written, and all the coefficients are set.

oxidation and reduction processes were recorded, and an electronic (electron-ion) balance was compiled on their basis; which are respectively the oxidizing agent and the reducing agent in the reaction;

There was an error in only one of the response elements listed above

There were errors in two of the above response elements

All elements of the answer are written incorrectly

Maximum score

2018 format tasks

1. Task 31 (2 points)

To complete the task, use the following list of substances: potassium permanganate, potassium bicarbonate, sodium sulfite, barium sulfate, potassium hydroxide. It is permissible to use aqueous solutions of substances.

Explanation.

Possible answer:

2. Task 31

To complete the task, use the following list of substances: hydrogen chloride, silver(I) nitrate, potassium permanganate, water, Nitric acid. It is permissible to use aqueous solutions of substances.

From the proposed list of substances, select substances between which an ion exchange reaction is possible. Write down the molecular, complete and abbreviated ionic equations for this reaction.

Explanation.

Possible answer:

Task 32. 2018 format tasks

In the condition of task 32, testing knowledge of the genetic relationship of various classes of inorganic substances, a description of a specific chemical experiment is proposed, the progress of which the examinees will have to illustrate using the equations of the corresponding chemical reactions. The grading scale for the task remains, as in 2016, equal to 4 points: each correctly written reaction equation is scored 1 point.

Example task:

Iron was dissolved in hot concentrated sulfuric acid. The resulting salt was treated with an excess of sodium hydroxide solution. The brown precipitate that formed was filtered and calcined. The resulting substance was heated with iron.

Write equations for the four reactions described.

Contents of the correct answer and assessment instructions(other wording of the answer is allowed that does not distort its meaning)

Points

Possible answer

Four equations for the described reactions are written:

1) 2Fe + 6H 2 SO 4
Fe 2 (SO 4 ) 3 + 3SO 2 + 6H 2 O

2) Fe 2 (SO 4 ) 3 + 6NaOH = 2Fe(OH) 3 + 3Na 2 SO 4

3) 2Fe(OH) 3
Fe 2 O 3 + 3H 2 O

4) Fe 2 O 3 + Fe = 3FeO

All reaction equations are written incorrectly

Maximum score

It should be noted that the absence of coefficients (at least one) before the formulas of substances in reaction equations is considered an error. No points are awarded for such an equation.

Task 33. 2018 format tasks

Tasks 33 test the assimilation of knowledge about the relationship of organic substances and provide for checking five elements of content: the correctness of writing five reaction equations corresponding to the diagram - a “chain” of transformations. When writing reaction equations, examinees must use the structural formulas of organic substances. The presence of each checked content element in the answer is scored 1 point. Maximum amount points for completing such tasks - 5.

Example task:

Write the reaction equations that can be used to carry out the following transformations:

When writing reaction equations, use the structural formulas of organic substances.

Contents of the correct answer and assessment instructions
Other wording of the answer is allowed that does not distort its meaning)

Points

Possible answer

Five reaction equations have been written corresponding to the transformation scheme:

Five reaction equations written correctly

Four reaction equations written correctly

Three reaction equations written correctly

Two reaction equations written correctly

One reaction equation written correctly

All elements of the answer are written incorrectly

Maximum score

Please note that it is permissible to use structural formulas in the examinee’s answer. different types(expanded, contracted, skeletal), unambiguously reflecting the order of connection of atoms and mutual arrangement substituents and functional groups
in a molecule of organic matter.

Task 34. 2018 format tasks

Tasks 34 are calculation problems. Their implementation requires knowledge of the chemical properties of substances and involves the implementation of a certain set of actions to ensure that the correct answer is obtained. Among such actions we name the following:

– drawing up equations of chemical reactions (according to the data of the problem conditions) necessary to perform stoichiometric calculations;

– performing calculations necessary to find answers to questions
in the problem statement there are questions;

– formulating a logically substantiated answer to all questions posed in the task conditions (for example, establishing a molecular formula).

However, it should be borne in mind that not all of the named actions must necessarily be present when solving any calculation problem, and in some cases some of them can be used more than once.

The maximum score for completing the task is 4 points. When checking, you should first of all pay attention to the logical validity of the actions performed, since some tasks can be solved in several ways. At the same time, in order to objectively evaluate the proposed method for solving the problem, it is necessary to check the correctness of the intermediate results that were used to obtain the answer.

Example task:

Determine the mass fractions (in%) of iron(II) sulfate and aluminum sulfide
in a mixture if, when 25 g of this mixture is treated with water, a gas is released that completely reacts with 960 g of a 5% solution of copper sulfate.

In your answer, write down the reaction equations that are indicated in the problem statement,
and provide all the necessary calculations (indicate the units of measurement of the required physical quantities).

Points

Possible answer

The reaction equations were compiled:

The amount of hydrogen sulfide is calculated:

The amount of substance and mass of aluminum sulfide and iron(II) sulfate are calculated:

The mass fractions of iron(II) sulfate and aluminum sulfide in the initial mixture were determined:

ω(FeSO 4 ) = 10 / 25 = 0.4, or 40%

ω(Al 2 S 3 ) = 15 / 25 = 0.6, or 6 0%

The answer is correct and complete:

the answer correctly contains the reaction equations corresponding to the conditions of the task;

calculations have been carried out correctly using the necessary physical quantities specified in the task conditions;

a logically substantiated relationship between the physical quantities on the basis of which calculations are carried out is demonstrated;

in accordance with the task conditions, the required physical quantity is determined

There was an error in only one of the response elements listed above

All elements of the answer are written incorrectly

Maximum score

When checking the answer, the examinee must take into account the fact that if the answer contains an error in calculations in one of the three elements (second, third or fourth), which led to an incorrect answer, the mark for completing the task is reduced by only 1 point.

Task 35. 2018 format tasks

Tasks 35 involve determining the molecular formula of a substance. Completing this task includes the following sequential operations: carrying out the calculations necessary to establish the molecular formula of an organic substance, writing the molecular formula of an organic substance, drawing up a structural formula of a substance that uniquely reflects the order of bonds of atoms in its molecule, writing a reaction equation that meets the conditions of the task.

The grading scale for task 35 in part 2 of the examination paper will be 3 points.

Tasks 35 use a combination of tested content elements - calculations, on the basis of which they come to determine the molecular formula of a substance, compile a general formula of a substance, and then determine the molecular and structural formula of a substance on its basis.

All these actions can be performed in different sequences. In other words, the examinee can come to the answer in any logical way available to him. Therefore, when assessing a task, the main attention is paid to the correctness of the chosen method for determining the molecular formula of a substance.

Example task:

When burning a sample of some organic compound weighing 14.8 g, 35.2 g are obtained carbon dioxide and 18.0 g of water.

It is known that the relative vapor density of this substance with respect to hydrogen is 37. During the study of the chemical properties of this substance, it was established that when this substance interacts with copper(II) oxide, a ketone is formed.

Based on the data of the task conditions:

1) make the calculations necessary to establish the molecular formula of an organic substance (indicate the units of measurement of the required physical quantities);

write down the molecular formula of the original organic substance;

2) draw up a structural formula of this substance, which unambiguously reflects the order of bonds of atoms in its molecule;

3) write the equation for the reaction of this substance with copper(II) oxide using the structural formula of the substance.

Contents of the correct answer and assessment instructions

(other wording of the answer is allowed that does not distort its meaning)

Points

Possible answer

The amount of combustion product substance found:

The general formula of the substance is C x H y O z

n(CO2) = 35.2 / 44 = 0.8 mol; n (C) = 0.8 mol

n(H 2 O) = 18.0 / 18 = 1.0 mol; n(H) = 1.0 ∙ 2 = 2.0 mol

m(O) = 14.8 – 0.8 ∙ 12 – 2 = 3.2 g; n(O) = 3.2 ⁄ 16 = 0.2 mol

The molecular formula of the substance was determined:

x:y:z = 0.8:2:0.2 = 4:10:1

The simplest formula is C 4 H 10 O

M simple (C 4 H 10 O) = 74 g/mol

M source (C x H y O z ) = 37 ∙ 2 = 74 g/mol

Molecular formula of the starting substance – C 4 H 10 O

The structural formula of the substance has been compiled:

The equation for the reaction of a substance with copper(II) oxide is written:

The answer is correct and complete:

the calculations necessary to establish the molecular formula of a substance have been correctly performed; the molecular formula of the substance is written down;

the structural formula of an organic substance is written down, which reflects the bond order and relative arrangement of substituents and functional groups in the molecule in accordance with the assignment conditions;

the equation of the reaction, which is indicated in the task conditions, is written using the structural formula of an organic substance

There was an error in only one of the response elements listed above

There were errors in two of the above response elements

There were errors in three of the above response elements

All elements of the answer are written incorrectly

All elements of the answer are written incorrectly

Maximum score

TOTAL part 2

2+2+ 4+5+4 +3=20 points

Bibliography

1. Methodological materials for chairmen and members subject commissions subjects Russian Federation to check the completion of tasks with detailed answers for the 2017 Unified State Examination papers. Article " Guidelines for assessing the completion of Unified State Examination tasks with a detailed question.” Moscow, 2017.

2. FIPI control project measuring materials Unified State Exam 2018.

3. Demos, specifications, Unified State Exam codifiers 2018. FIPI website.

4. Information about planned changes to the 2018 CMM. FIPI website.

5.Site “I will solve the Unified State Exam”: chemistry, for an expert.

To pass final exams at school. It will need to be taken for admission to universities in the following areas: chemistry and chemical technology, medicine, construction, biotechnology and others. In general, the exam is not very popular - only one student out of ten graduates chooses chemistry.

Check out general information about the exam and start preparing. The KIM Unified State Exam 2019 version has some differences from last year: 1) a task was added to part 2 high level difficulties with a detailed answer, 2) for four questions the level of difficulty and maximum primary score(the maximum score has not changed throughout the test), 3) for a clearer distribution of tasks into thematic blocks, the developers slightly changed their order in part 1.

Unified State Examination

Last year, to pass the Unified State Examination in chemistry with at least a C, it was enough to score 37 primary points. They were given, for example, for correctly completing the first 15 tasks of the test.

It is not yet known exactly what will happen in 2019: we need to wait for the official order from Rosobrnadzor on the correspondence of the primary and test scores. Most likely it will appear in December. Considering that the maximum primary score for the entire test remains the same, most likely the minimum score will not change either. Let's focus on these tables for now:

Structure of the Unified State Exam test

In 2019, the test consists of two parts, including 35 tasks.

• Part 1: 29 tasks (1–29) with a short answer (number or sequence of numbers);
• Part 2: 6 tasks (30–36) with detailed answers, complete solutions to the tasks are written down on answer sheet 2.

Preparation for the Unified State Exam

• Take the Unified State Exam tests online for free without registration or SMS. The tests presented are identical in complexity and structure to the actual exams conducted in the corresponding years.

• Download demo versions of the Unified State Examination in Chemistry, which will allow you to better prepare for the exam and pass it easier. All proposed tests have been developed and approved for preparation for the Unified State Exam. Federal Institute pedagogical measurements (FIPI). In the same FIPI all official Unified State Exam options.
  The tasks that you will see most likely will not appear on the exam, but will be similar to the demo ones, on the same topic or simply with different numbers.
• Familiarize yourself with the basic exam prep formulas to help refresh your memory before attempting the demos and test options.

General Unified State Examination figures

Year	Minimum Unified State Examination score	Average score	Number of participants	Failed, %	Qty 100 points	Duration- Exam length, min.
2009	33
2010	33	56,04	83 544	6,2	275	180
2011	32	57,75	77 806	8,6	331	160
2012	36	57,3	93 181	11	365	180
2013	36	67,8	93 802	7,3	3220	180
2014	36	55,3				180
2015	36	56,3				180
2016	36					180
2017	36					180
2018

The basis for changes in the 2016 examination model was the need to increase the objectivity of assessing the educational achievements of examinees in accordance with the requirements of the Federal State Educational Standard for the preparation of high school graduates.

The main emphasis was placed on strengthening the activity basis and practice-oriented orientation of KIM. The formulation of these tasks led to adjustments in approaches to the construction of individual tasks. As a result, some tasks were presented in the examination paper in a new format, due to which they were strengthened in their orientation towards testing the formation, first of all, of those skills ( educational activities), which are the most indicative in terms of completeness and success in mastering the subject. Special attention among them the skill deserves apply knowledge in the system, which involves the implementation of various actions in the process of mastering the subject: identification classification characteristics substances and reactions; explanation the essence of a particular process; establishment relationships between the composition, structure and properties of substances; self-assessment the correctness of the chosen method of completing the task, etc.

Let us illustrate how the described approach was implemented in relation to the construction of specific tasks.

In Part 1 of the 2016 exam paper, the format of six tasks has been changed basic level difficulties. These are the following tasks:

· No. 6, the implementation of which involves the use of generalized knowledge about the classification and nomenclature of inorganic substances. The result of completing this task is to identify three correct answers out of six proposed options;

· No. 11 and No. 18, their implementation involves the use of generalized knowledge about the genetic relationship of inorganic and organic substances. The result of completing the tasks is to establish two correct answers out of five proposed options;

· No. 24, No. 25, No. 26 are calculation problems. The answer to these tasks presented in new form, is a number with a specified degree of precision.

The main result of changing the format of these tasks was that their implementation provides for a more diverse sequence of educational actions than in the case of traditional tasks with a choice of answers. So, in particular, to select the correct answer, which is not given in the form ready-made options, but must be installed independently, it requires the mandatory use of generalized knowledge of key concepts and patterns in the interrelation. This is clearly illustrated by the examples below of changes to the assignment format for 2015.

Task No. 6

Among the listed substances:

Write down the numbers under which they are indicated.

The format of tasks with serial number 18, which are aimed at testing the content element “genetic relationship of organic substances,” has been similarly changed.

Task No. 24 (calculation problem)

The mass of potassium nitrate that should be dissolved in 150 g of a solution with a mass fraction of this salt of 10% to obtain a solution with a mass fraction of 12% is equal to

1)

0.3 g

2)

2.0 g

3)

3.0 g

4)

3.4 g

Answer:

The number of one of the proposed answer options is recorded.

Calculate the mass of potassium nitrate (in grams) that should be dissolved in 150 g of a solution with a mass fraction of this salt of 10% to obtain a solution with a mass fraction of 12%.

Answer: ___________________ d (Write the number to the nearest tenth.)

Tasks with serial numbers 25 and 26 are presented in a similar format.

Along with changing the format for presenting some tasks in the 2016 examination paper, an adjustment was made to the distribution of tasks according to difficulty levels and types of skills and methods of action being tested. The result of this adjustment was the following changes.

In Part 1 of the work, the format of two tasks has been changed higher level difficulties (their serial numbers are 34 and 35), which test the assimilation of knowledge of the characteristic chemical properties of hydrocarbons and oxygen-containing organic substances. In the 2015 paper, these were “multiple choice” tasks and, as USE practice has shown, they did not fully meet the criteria for tasks of an increased level of complexity. In the 2016 work, these tasks are presented in the format of tasks that are more complex and more information-rich - “to establish correspondence between the elements of two sets.” Thanks to this, the existing contradiction between the content of the task and the form of its presentation was eliminated. Below are examples of such typical tasks from 2015 and 2016.

An example of adjusting the difficulty level of tasks with serial numbers 34 and 35.

Phenol reacts with

Answer:

Establish a correspondence between the starting substances and the products that are predominantly formed during their interaction with bromine.

Answer:	A	B	IN	G

Another example of adjusting the level of difficulty of tasks was a change in the form of presentation of the task, aimed at testing the assimilation of the content element “Chemical equilibrium; shift in chemical equilibrium." This is one of the key concepts in the structure of the “Chemical Reaction” content line, and therefore, testing its assimilation should be carried out taking into account the depth of study of this material in the chemistry course. Tasks of a basic level of complexity, which in the work of 2015 were focused on testing this element of content, did not adequately ensure the fulfillment of the above requirement. Therefore, based on an analysis of the results of completing such tasks, the feasibility of checking of this element content only with tasks of an increased level of complexity (their serial number in work - 31).

Task No. 31 (KIM Unified State Exam 2016)

Establish a correspondence between the equation of a chemical reaction
and the direction of shift in chemical equilibrium with increasing pressure in the system.

REACTION EQUATION		DIRECTION OF CHEMICAL EQUILIBRIUM SHIFT
A) N 2(g) + 3H 2(g) 2NH 3(g) B) 2H 2 (g) + O 2 (g) 2H 2 O (g) IN) H 2 (g) + Cl 2 (g) 2HCl (g) G) SO 2 (g) + Cl 2 (g) SO 2 Cl 2 (g)		1) shifts towards reaction products 2) shifts towards the starting substances 3) practically does not move
Answer:	A	B	IN	G

Let us note that this approach to improving the CMM provides opportunities for a more objective and differentiated assessment of the educational achievements of examinees. different levels. Namely:

· at the level of mastering the conceptual apparatus of a chemistry course, general patterns and methods of studying substances and reactions;

· at the level of application of knowledge in chemistry in the context Everyday life;

· at the level of development of intellectual skills that allow one to comprehend real situations, use one’s experience to gain new knowledge, find and explain the necessary solutions.

Demonstration version of control measuring materials
single state exam

The demo is a sample CMM built to specification. Using his example, any future exam participant and the general public can become familiar with what tasks and in what quantities are included in the examination paper, what rules must be followed when completing tasks, and what requirements are imposed on recording answers to tasks. The demo version gives you the opportunity to familiarize yourself with the assignment assessment system. Its structure contains instructions for checking and assessing multiple-choice, short- and long-answer tasks. Answers to all tasks in the demo version are attached to it.

When familiarizing yourself with demo version It is important to keep in mind that a CMM is not an exact copy any version of the 2015 exam paper, but includes only standard tasks, and only those that have already been used in the exam of previous years and successfully completed by graduates.

Materials from the FIPI website (http://www.fipi.ru)

The FIPI website contains the following regulatory, analytical, educational and methodological and information materials, which can be used in organizing educational process and preparing students for the Unified State Exam.

– documents defining the structure and content of the KIM Unified State Examination in Chemistry 2016;

– educational teaching materials for members and chairmen of regional subject commissions for checking the completion of tasks with a detailed answer;

– methodological letters previous years;

– educational computer program"Expert Unified State Exam";

– training tasks from the open segment of the federal bank of test materials;

2. Tasks with detailed answers in the system of control measuring materials for the unified state exam
in chemistry

In the Unified State Exam KIM system in chemistry, an important role is assigned to tasks with a detailed answer, which provide for a comprehensive test of mastery at a high level of complexity of several (two or more) content elements from various content blocks of the course in general, inorganic and organic chemistry.

Verification of the completion of such tasks can only be carried out through an independent examination and on the basis of a specially developed standardized assessment system, which makes it possible to minimize differences in the opinions of experts in assessing the performance of the same work.

The creation of a standardized system for assessing the completion of tasks with a detailed answer within the framework of the unified state exam in chemistry assumed:

– determination of the basic requirements for tasks of this type;

– identification of the typology of the main elements of content and educational activities tested by these tasks;

– determination of criteria and scales for assessing the performance of tasks of this type;

– development of a methodology for training experts who check the completion of tasks with a detailed answer.

Description of the methodology for standardized assessment of tasks of this type, necessary to ensure objectivity assessment procedures The Unified State Exam is the main goal of the proposed methodological recommendations.

Purpose and features of tasks with a detailed answer

In the exam paper, tasks with a detailed answer are the fewest (there are only 5 of them in each version of the paper). Along with the fact that they comprehensively test the assimilation of the most complex content elements from the content blocks: “ Theoretical basis chemistry" (content line "Chemical reaction"), "Methods of knowledge in chemistry. Chemistry and Life", these tasks are aimed at testing skills that meet the requirements of the educational standard profile level:

– explain the dependence of the properties and use of substances on their composition and structure; the nature of the mutual influence of atoms in molecules organic compounds; relationship between inorganic and organic substances; the essence and pattern of the studied types of reactions;

– conduct combined calculations using chemical equations.

The combination of tested content elements in tasks with a detailed answer is carried out in such a way that their condition already shows the need for: sequential implementation of several interrelated actions, identifying cause-and-effect relationships between content elements, formulating an answer in a certain logic and with the argumentation of individual provisions. From here it becomes obvious that completing tasks with a detailed answer requires the graduate to have solid theoretical knowledge, as well as developed skills to apply this knowledge in various educational situations, consistently and logically build an answer, draw conclusions and conclusions, give arguments in favor of the expressed point of view, etc. P.

The extended-answer tasks offered in the examination work have varying degrees of difficulty and involve checking from 3 to 5 elements of the answer. Each individual response element is scored
1 point, so the maximum score for a correctly completed task is from 3 to 5 points (depending on the degree of complexity of the task). Testing of tasks is carried out by an expert based on an analysis of the test taker’s performance of the task and its comparison with the elements of the answer proposed in the criteria for assessing the task.

It is important to take into account that the content of tasks with a detailed answer in many cases can direct examinees to use in various ways their implementation. This applies, first of all, to methods for solving calculation problems. Therefore, instructions for assessing assignments should be considered in relation to the answer option proposed by the examinee.

All of the above features of tasks with a detailed answer allow us to conclude that they are intended to test proficiency in skills that meet the highest requirements for the level of training of graduates and can serve effective means differentiated assessment of the achievements of each of them.

Key content elements tested by long-response tasks

When selecting content for tasks with a detailed answer, it is taken into account, first of all, which elements of content and skills are the most important and meet the requirements of the educational standard of the profile level for the preparation of secondary (complete) school graduates. These content elements included, in particular: redox reactions, structure of substances, mutual influence of atoms in molecules, mechanisms of reactions in organic chemistry, genetic relationships between classes of inorganic and organic compounds, calculations by chemical formulas and reaction equations.

When completing tasks, the examinee must demonstrate an understanding of the essence of the unity of the world of substances, the mechanisms of reactions, the ability to draw up reaction equations, apply knowledge about the properties of substances of various classes, structural features of substances, etc. A large role is assigned to calculation problems in chemistry. This is explained by the fact that when solving them it is necessary to rely on knowledge of the chemical properties of compounds, use the ability to draw up equations of chemical reactions, i.e. use a theoretical framework and specific operational, logical and computational skills.

The examination paper uses tasks related to the implementation of all types chemical calculations, which are presented in educational programs not only for secondary (complete) school, but also for basic school (see Appendix 1).

An approach to selecting the content of tasks with a detailed answer, which has proven itself positively in the process conducting the Unified State Exam, retained in relation to the content of the 2016 examination paper.

In 2018, during the main period, more than 84.5 thousand people took part in the Unified State Examination in Chemistry, which is more than 11 thousand people more than in 2017. The average score for the examination work remained virtually unchanged and amounted to 55.1 points (in 2017 - 55.2). Proportion of graduates who did not pass minimum score, amounted to 15.9%, which is slightly higher than in 2017 (15.2%). For the second year, there has been an increase in the number of high-scoring students (81-100 points): in 2018, the increase was 1.9% compared to 2017 (in 2017 - 2.6% compared to 2016). A certain increase in 100-point scores was also noted: in 2018 it amounted to 0.25%. The results obtained may be due to more targeted preparation of high school students for certain models of tasks, primarily those of a high level of complexity, included in part 2 exam version. Another reason is the participation of Olympiad winners in the Unified State Examination in Chemistry, which gives the right to non-competitive admission provided they complete the examination work with more than 70 points. Placement in open jar tasks of a larger number of sample tasks included in the exam options. Thus, one of the main tasks for 2018 was to strengthen the differentiating ability of individual tasks and the exam version as a whole.

More detailed analytical and methodological Unified State Exam materials 2018 are available at the link.

Our website contains about 3,000 tasks to prepare for the Unified State Exam in Chemistry in 2018. The general outline of the examination work is presented below.

EXAMINATION PLAN FOR THE USE OF CHEMISTRY 2019

Designation of the level of difficulty of the task: B - basic, P - advanced, V - high.

Content elements and activities tested	Task difficulty level	Maximum score for completing the task	Estimated task completion time (min.)
Exercise 1. Structure electronic shells atoms of elements of the first four periods: s-, p- and d-elements. Electronic configuration of an atom. Ground and excited states of atoms.
Task 2. Patterns of changes in the chemical properties of elements and their compounds by periods and groups. General characteristics of metals of groups IA–IIIA in connection with their position in Periodic table chemical elements D.I. Mendeleev and the structural features of their atoms. Characteristics of transition elements - copper, zinc, chromium, iron - according to their position in the Periodic Table of Chemical Elements D.I. Mendeleev and the structural features of their atoms. General characteristics of non-metals of groups IVA–VIIA in connection with their position in the Periodic Table of Chemical Elements D.I. Mendeleev and the structural features of their atoms
Task 3. Electronegativity. Oxidation state and valence of chemical elements
Task 4. Covalent chemical bond, its varieties and mechanisms of formation. Characteristics of covalent bonds (polarity and bond energy). Ionic bond. Metal connection. Hydrogen bond. Substances of molecular and non-molecular structure. Type crystal lattice. Dependence of the properties of substances on their composition and structure
Task 5. Classification of inorganic substances. Nomenclature of inorganic substances (trivial and international)
Task 6. Characteristic Chemical properties simple substances - metals: alkaline, alkaline earth, aluminum; transition metals: copper, zinc, chromium, iron. Characteristic chemical properties of simple nonmetallic substances: hydrogen, halogens, oxygen, sulfur, nitrogen, phosphorus, carbon, silicon. Characteristic chemical properties of oxides: basic, amphoteric, acidic
Task 7. Characteristic chemical properties of bases and amphoteric hydroxides. Characteristic chemical properties of acids. Characteristic chemical properties of salts: medium, acidic, basic; complex (using the example of hydroxo compounds of aluminum and zinc). Electrolytic dissociation of electrolytes in aqueous solutions. Strong and weak electrolytes. Ion exchange reactions
Task 8. Characteristic chemical properties of inorganic substances: - simple substances-metals: alkali, alkaline earth, magnesium, aluminum, transition metals (copper, zinc, chromium, iron); - acids;
Task 9. Characteristic chemical properties of inorganic substances: – simple metal substances: alkali, alkaline earth, magnesium, aluminum, transition metals (copper, zinc, chromium, iron); - simple non-metal substances: hydrogen, halogens, oxygen, sulfur, nitrogen, phosphorus, carbon, silicon; - oxides: basic, amphoteric, acidic; - bases and amphoteric hydroxides; - acids; - salts: medium, acidic, basic; complex (using the example of hydroxo compounds of aluminum and zinc)
Task 10. Interrelation of inorganic substances
Task 11. Classification of organic substances. Nomenclature of organic substances (trivial and international)
Task 12. Theory of the structure of organic compounds: homology and isomerism (structural and spatial). Mutual influence of atoms in molecules. Types of bonds in molecules of organic substances. Hybridization of carbon atomic orbitals. Radical. Functional group
Task 13. Characteristic chemical properties of hydrocarbons: alkanes, cycloalkanes, alkenes, dienes, alkynes, aromatic hydrocarbons(benzene and homologues of benzene, styrene). Main methods of producing hydrocarbons (in the laboratory)
Task 14. Characteristic chemical properties of saturated monohydric and polyhydric alcohols, phenol. Characteristic chemical properties of aldehydes, saturated carboxylic acids, esters. The main methods for obtaining oxygen-containing organic compounds (in the laboratory).
Task 15. Characteristic chemical properties of nitrogen-containing organic compounds: amines and amino acids. The most important ways obtaining amines and amino acids. Biologically important substances: fats, carbohydrates (monosaccharides, disaccharides, polysaccharides), proteins
Task 16. Characteristic chemical properties of hydrocarbons: alkanes, cycloalkanes, alkenes, dienes, alkynes, aromatic hydrocarbons (benzene and homologues of benzene, styrene). The most important methods for producing hydrocarbons. Ionic (V.V. Markovnikov’s rule) and radical reaction mechanisms in organic chemistry
Task 17. Characteristic chemical properties of saturated monohydric and polyhydric alcohols, phenol, aldehydes, carboxylic acids, esters. The most important methods for obtaining oxygen-containing organic compounds
Task 18. The relationship between hydrocarbons, oxygen-containing and nitrogen-containing organic compounds
Task 19. Classification of chemical reactions in inorganic and organic chemistry
Task 20. Reaction speed, its dependence on various factors
Task 21. Redox reactions.
Task 22. Electrolysis of melts and solutions (salts, alkalis, acids)
Task 23. Hydrolysis of salts. Aqueous solution environment: acidic, neutral, alkaline
Task 24. Reversible and irreversible chemical reactions. Chemical balance. Shift of equilibrium under the influence of various factors
Task 25. Qualitative reactions to inorganic substances and ions. Qualitative reactions of organic compounds
Task 26. Rules for working in the laboratory. Laboratory glassware and equipment. Safety rules when working with caustic, flammable and toxic substances, household chemicals. Scientific research methods chemical substances and transformations. Methods for separating mixtures and purifying substances. Concept of metallurgy: general methods obtaining metals. General scientific principles chemical production(using the example of industrial production of ammonia, sulfuric acid, methanol). Chemical pollution environment and its consequences. Natural sources of hydrocarbons, their processing. High molecular weight compounds. Polymerization and polycondensation reactions. Polymers. Plastics, fibers, rubbers
Task 27. Calculations using the concept of “mass fraction of a substance in solution”
Task 28. Calculations of volumetric ratios of gases at chemical reactions. Calculations using thermochemical equations
Task 29. Calculation of the mass of a substance or volume of gases based on a known amount of a substance, mass or volume of one of the substances participating in the reaction
Task 30 (C1). Redox reactions
Task 31 (C2). Electrolytic dissociation of electrolytes in aqueous solutions. Strong and weak electrolytes. Ion exchange reactions.
Task 32 (C3). Reactions confirming the relationship between various classes of inorganic substances
Task 33 (C4). Reactions confirming the relationship of organic compounds
Task 34 (C5). Calculations using the concepts of “solubility”, “mass fraction of a substance in solution”. Calculations of the mass (volume, amount of substance) of reaction products, if one of the substances is given in excess (has impurities), if one of the substances is given in the form of a solution with a certain mass fraction of the dissolved substance. Calculations of mass or volume fraction the yield of the reaction product from the theoretically possible. Calculations mass fraction(masses) chemical compound in the mixture
Task 35 (C6). Establishing the molecular and structural formula of a substance

APPROXIMATE 2019 SCALE

Correspondence between minimum primary scores and minimum test scores 2019. Order on amendments to Appendix No. 1 to the order Federal service on supervision in the field of education and science.

How many points are given for each Unified State Examination task in chemistry? Evaluation criteria for the Unified State Exam in Chemistry 2019: points and grades, conversion table, as well as the structure of the exam, testing methodology and main changes in the new year. In 2019, tasks for the Unified State Exam in chemistry began to contain large quantity mathematical elements, calculations of physical quantities, and the testing of the basic theoretical course of chemistry became deeper. At the same time, the number of tasks has decreased, now instead of 40 questions, the student will have to solve 35 (according to other sources, 34). Accordingly, the rating scale has changed; for the Unified State Examination in Chemistry 2019, the primary score has become lower – by 4 units.

All tasks are scored differently, and you can earn up to 5 points for difficult tasks. Therefore, to enter specialized universities, it is necessary to study the subject as deeply as possible.

Table of criteria for assessing USE 2019 tasks in chemistry, taking into account the new requirements:

Job number	Maximum score
35	3

Assessment of tasks is carried out according to an established methodology, while for complex tasks where logic is required, points are assigned using special analytical tables. If the answer best meets the requirements of the analysis, you can get up to 5 points for it. If the student has only partially developed the topic, the number of points is reduced. For an uncompleted task, 0 points are awarded.

Complex assignments are checked by two experts. If there is a strong discrepancy in scores, then a third specialist is involved. This ensures the most effective and objective assessment of graduates’ knowledge.

Conversion table for the Unified State Exam 2019 in chemistry from points to grades:

Number of points	Grade

The structure of the Unified State Examination tasks in chemistry in 2019 includes 29 questions with a short answer, as well as 5 with an extended answer.

The duration of the exam is 210 minutes, according to the standard for simple questions should take about 3 minutes, for complex ones - up to 15. As for the minimum score for admission to specialized universities, each higher educational institution sets its own requirements. For example, to enter the Faculty of Chemistry of Moscow State University or the prestigious Moscow Medical University, you must score at least 50 points.

But usually the overall passing score is prestigious universities is 400-470 (at least less for the chemistry department, more for the medical department), and admission to Moscow State University does not depend on chemistry alone, so if you don’t have enough points, you can get it in mathematics, biology, Russian and internal entrance exams.

Significant changes in the Unified State Exam are also observed in other subjects.

For successful completion Chemistry is recommended to spend most of your time solving problems and equations. During the test, you can use a calculator, periodic table and salt solubility. The electrochemical voltage series of metals is also allowed.

The evaluation criteria for the Unified State Examination in Chemistry 2019 are described quite clearly in the regulations, but each graduate has the right to appeal.

Table of conversion of points to OGE-2019 grades in chemistry

Graduates of 9th grade have their own assessment criteria. According to all KIM and GIA, the maximum you can score is 34 points. But if a graduate wants to go to a medical college, a specialized class, or some other specialized secondary education related to chemistry, pharmacy and medicine, he needs to score 23 points or higher.

Chemistry score conversion table for OGE-2019

Despite its apparent simplicity, scoring 9 points for the minimum passing grade is not so easy. You need to be able to solve problems, navigate formulas, and have at least a minimal knowledge of theory. Those who pass with a bad mark will remain for the second year if they fail the retake.

Scoring table for assignments:

Job number
	2 (1 – if partially resolved)
	2 (1 – if partially resolved)
	2 (1 – if 2/3 correct)
	2 (1 – if 2/3 correct)

Many schoolchildren, to play it safe, start solving difficult tasks right away. If you solve them all without errors, you can score 19 points at once, that is, a “four”. However, this implies a complete solution to the task, otherwise it will be scored 1 point, or even not at all.

The assessment criteria for chemistry tests change every year, the rules become stricter, since there is an idea among the government that education is not of sufficient quality. This, of course, has no basis, because schoolchildren study worse not because of the program, but mostly because of overload.

What will go into the certificate? What to do if the Unified State Examination in chemistry is written as a bad mark?

If the Unified State Exam in chemistry is not passed, but the grades in mathematics and Russian are normal, the student will simply be given a certificate. And they will also give you a Unified State Exam certificate, where chemistry simply won’t be included. However, the exam can be retaken after a year. There is only one minus here - the overall score may not be enough for admission, and if the university requires chemistry without fail, then they will not accept documents at all. Accordingly, the student loses time, and young men may even be drafted into the army, after which it will be even more difficult to retake the test.

If the grade for the year is 4 or 5, and the Unified State Exam in Chemistry is passed with a 3 or 4 (that is, a decrease in the score), what will go into the certificate? The one year mark will be reached. If the Unified State Exam is passed with a 5, and in a year 3, then it also does not affect the certificate. But every specific school where they are required to calculate the arithmetic mean.

Why is this happening? Because no one checks this calculation later. Based on this, it is better to resolve the issue in advance with the chemistry teacher and class teacher, usually in normal schools teachers try to meet the graduates halfway. If a child has a 4, but he pushed himself and passed the Unified State Exam with a 5, why not help him?

But! We must remember that no one needs grades on the admission certificate, especially in chemistry. Today in 99% of cases they look only at the Unified State Examination certificate.