The season of state exams in Russian schools has started. From March 23 to May 7, early exams are held, and from May 25, the Unified State Examination in the Russian language opens the main wave, which will end with reserve retakes on June 26. Further - obtaining certificates, graduation balls, admission to a university!

KIM early exam in chemistry for review can be downloaded. I will post answers and solutions to this option soon.

Some results of the early exam in chemistry, which took place on April 4, 2015, can be summed up now. Examples of assignments with a written response received from colleagues and students who took exams:

Task 36.
1) KJ+KJO 3 +…=…+K 2 SO 4 +H 2 O
2) Fe(OH)3+…+Br2=K2FeO4+…+H2O
3) Cr(OH)3+J2+…=K2CrO4+…+H2O

Solution:

1) Based on the fact that potassium sulfate is formed on the right side, we add sulfuric acid on the left side. The oxidizing agent in this reaction is potassium iodate, and the reducing agent is potassium iodide. This reaction is an example of counter-disproportionation, when both atoms - both the oxidizing agent (J + 5) and the reducing agent (J -), pass into one atom - iodine with an oxidation state of 0.

5KJ + KJO 3 + 3H 2 SO 4 = 3I 2 + 3K 2 SO 4 + 3H 2 O

2J — — 2e = J 2 0

2J 5+ +10e = J 2 0

Oxidizing agent - KJO 3 (J +5)

Reducing agent - KJ (J -).

2) Bromine in an alkaline medium is very strong. Since on the right side is formed salt iron +6, the reaction medium is alkaline, on the left we add alkali - potassium hydroxide. Since bromine is an oxidizing agent in this reaction, it is reduced to an oxidation state of -1, and in an alkaline medium it is recorded as a salt - potassium bromide.

2Fe(OH) 3 + 10KOH + 3Br 2 = 2K 2 FeO 4 + 6KBr + 8H 2 O

Fe 3+ - 3e \u003d Fe 6+

Br 2 + 2e \u003d 2Br -

Oxidizing agent - Br 2 (Br 2)

The reducing agent is Fe (OH) 3 (Fe 3+).

3) According to the product on the right side - potassium chromate - we determine the alkaline medium in which the reaction is carried out, i.e. add alkali on the left - potassium hydroxide KOH. The oxidizing agent is molecular iodine in an alkaline medium, therefore, it is reduced to iodide ion and written as a salt KI:

2Cr(OH) 3 + 3J 2 + 10KOH=2K 2 CrO 4 + 6KI + 8H 2 O

Cr +3 - 3e = Cr +6

J 2 + 2e \u003d 2J -

Oxidizing agent - J 2

Reducing agent - Cr (OH) 3 (Cr +3).

Task 37. A solution of copper nitrate was subjected to electrolysis. The substance formed at the cathode reacted with CuO. The resulting substance was treated with concentrated sulfuric acid. A gas with a pungent odor was released. Sodium sulfide solution was added to this solution, and a black precipitate formed.

Let's take a closer look at the complex oxidation reaction of an aromatic hydrocarbon with an unsaturated alkyl substituent. Indeed, the reaction is ambiguous, and during the reaction, most likely, a mixture of various oxidation products is formed. organic matter. I’ll make a reservation right away that everything that is written below refers to the exam and the interpretation of this oxidation in the exam.

So, why does oxidation occur with the rupture of sigma and pi bonds? Because oxidation with a break of only pi-bonds (Wagner reaction) in the exam is drawn up as follows:

The oxidation of unsaturated hydrocarbons in an aqueous medium and when heated proceeds with the breaking of sigma and pi bonds (double bond). At the same time, we also know that the oxidation of benzene homologues produces benzoic acid (in an acidic environment) or metal benzoate (in a neutral environment). When permanagnate is reduced, an alkali is formed. The resulting alkali will neutralize the reaction products. How much it will neutralize them is a matter of stoichiometric ratios, i.e. the question of electronic balance, and it is possible to answer the question of the composition and quantity of the products of the oxidation reaction of complex organic molecules only in the process of compiling the balance.

In this case, the oxidation will most likely proceed according to the following mechanism: potassium benzoate is formed and the C-C connections marked in the figure. The detached carbon atoms are oxidized to carbon dioxide)

The following fragments from textbooks serve as proof of the correctness of this assumption:

Chemistry. Grade 10. profile level. Kuzmenko, Eremin. 2012, p. 421.

Organic chemistry. Traven V.F., Volume 1, 2004, p. 474:

So, we have decided on the products, now we are drawing up a reaction scheme:

The reaction products - carbon dioxide and potassium hydroxide - interact with each other. Since the alkali is in excess, 6 molecules of potassium carbonate are formed and 1 molecule of unreacted potassium hydroxide remains.

Thank you very much, colleagues and readers, for your questions. I will be happy to answer new questions and comments on the materials.

Task 39. 2.3 g of sodium was dissolved in 100 ml of water. 100 ml of 30% nitric acid (p=1.18 g/ml) was added to the resulting solution. Find mass fraction salt in the final solution.

Task 40. When burning 20 g of acyclic organic matter, 66 g of carbon dioxide and 18 ml of water were formed. This substance reacts with an ammonia solution of silver oxide, 1 mol of this substance can attach only 1 mol of water. Determine the formula and write the reaction with an ammonia solution of silver oxide.

Demo Options USE in chemistry for grade 11 consist of two parts. The first part includes tasks to which you need to give a short answer. To the tasks from the second part it is necessary to give a detailed answer.

All demonstration USE options in chemistry contain correct answers to all tasks and assessment criteria for tasks with a detailed answer.

AT demo version of the USE 2020 in chemistry compared with demo 2019 in chemistry no changes.

Demonstration options for the exam in chemistry

Note that chemistry demos are presented in pdf format, and to view them you need to have installed, for example, the freely distributed software package Adobe Reader on your computer.

	Demonstration version of the exam in chemistry for 2002
	Demonstration version of the exam in chemistry for 2004
	Demonstration version of the exam in chemistry for 2005
	Demonstration version of the exam in chemistry for 2006
Demonstration version of the exam in chemistry for 2007
	Demonstration version of the exam in chemistry for 2008
	Demonstration version of the exam in chemistry for 2009
	Demonstration version of the exam in chemistry for 2010
	Demonstration version of the exam in chemistry for 2011
	Demonstration version of the exam in chemistry for 2012
	Demonstration version of the exam in chemistry for 2013
	Demonstration version of the exam in chemistry for 2014
	Demonstration version of the exam in chemistry for 2015
	Demonstration version of the exam in chemistry for 2016
	Demonstration version of the exam in chemistry for 2017
	Demonstration version of the exam in chemistry for 2018
	Demonstration version of the exam in chemistry for 2019
	Demonstration version of the exam in chemistry for 2020

Changes in the demonstration versions of the exam in chemistry

Demonstration versions of the exam in chemistry for grade 11 for 2002 - 2014 consisted of three parts. The first part included tasks in which you need to choose one of the proposed answers. The tasks from the second part were required to give a short answer. To the tasks from the third part it was necessary to give a detailed answer.

In 2014 in demonstration version of the exam in chemistry the following changes:

• all calculation tasks, the performance of which was estimated at 1 point, were placed in part 1 of the work (A26-A28),
• topic "Redox Reactions" tested with assignments IN 2 and C1;
• topic "Hydrolysis of salts" checked only with the task AT 4;
• a new task has been included(in position AT 6) to check the topics "qualitative reactions to inorganic substances and ions", "qualitative reactions of organic compounds"
• total number of jobs in each variant was 42 (instead of 43 in the work of 2013).

In 2015, there were fundamental changes have been made:

Option became be in two parts(part 1 - short answer questions, part 2 - open-ended questions).

Numbering assignments has become through throughout the variant without letter designations A, B, C.

Was the form of recording the answer in tasks with a choice of answers has been changed: the answer has become necessary to write down the number with the number of the correct answer (and not mark with a cross).

It was the number of tasks of the basic level of complexity has been reduced from 28 to 26 tasks.

Maximum score for completing all the tasks of the examination paper in 2015 became 64 (instead of 65 points in 2014).

• The grading system has been changed. tasks for finding the molecular formula of a substance. The maximum score for its implementation - 4 (instead of 3 points in 2014).

AT 2016 year in demo in chemistrysignificant changes have been made compared to the previous year 2015 :

Part 1 changed the format of tasks 6, 11, 18, 24, 25 and 26 basic level of difficulty with a short answer.

Changed the format of tasks 34 and 35advanced level difficulties : these tasks now require you to match instead of selecting multiple correct answers from a suggested list.

The distribution of tasks by difficulty level and types of skills being tested has been changed.

In 2017 compared to demo version of 2016 in chemistrythere have been significant changes. The structure of the examination paper has been optimized:

Was changed the structure of the first part demo version: tasks with a choice of one answer were excluded from it; tasks were grouped into separate thematic blocks, each of which began to contain tasks of both basic and advanced levels of complexity.

It was reduced the total number of tasks up to 34.

Was grading scale changed(from 1 to 2 points) completing tasks of the basic level of complexity, which test the assimilation of knowledge about the genetic relationship of inorganic and organic substances (9 and 17).

Maximum score for the completion of all tasks of the examination paper was reduced to 60 points.

In 2018 in demo version of the exam in chemistry compared with demo version of 2017 in chemistry the following changes:

It was task 30 added high level of complexity with a detailed answer,

Maximum score for the completion of all tasks of the examination work remained without change by changing the scale for grading tasks in part 1.

AT demonstration versions of the Unified State Exam 2019 - 2020 in chemistry compared with demo version of 2018 in chemistry there were no changes.

It is not at all necessary to pass the unified state exam in chemistry if the graduate is not going to be a doctor or a chemist. Therefore, this subject is rarely chosen by schoolchildren. The level of difficulty in the exam is growing, but the preparation for the exam sometimes leaves much to be desired. Therefore, the FIPI website (Federal Institute for Pedagogical Measurements) posted a demo version of KIMs in 2015. The portal has the ability to download online tests USE. We will answer point by point a few questions of graduates and their parents who decided to take online testing on the FIPI website.

Demo materials 2015: what is the structure?

The demo has three parts. The first is a demo. It is an opportunity to pass a trial exam in chemistry. The second is a codifier that allows you to determine which topic a particular question belongs to. The third is the specification, i.e. information about materials and demo versions.

How is the demo version different from the offline exam?

Pre-testing has a lot of undoubted advantages. The main one is that you can do it indefinitely. In fact, on a real, even trial exam, only three hours are given for all tasks. To pass it , just click on the appropriate button. By the way, in the demo there are also those KIMs that, indeed, will meet in a real exam.

What is a theme coder?

Sometimes during the test delivery, the question arises, to which topic does this or that question belong? The encoder will easily determine this. Thanks to him, you can "pull up" this or that chemical topic.

Why is a specification needed?

The third section is for neophytes, graduates or people who first learned what KIMs are, that is, control and measuring materials. The specification details the procedures passing the exam and the procedure for completing checklists.

What does the exam consist of?

In 2015, 11% of all examinees (75,600 people) passed the exam in chemistry.

507 people received 100 points.

12.8% of graduates did not score the minimum number of points, which is five times more than in the previous one. Still, it is surprising how, with such poor knowledge, they chose chemistry for the exam, and even more so, apparently, they were going to study it at the university!

With the basic level, as shown by the results of the exam, the graduates coped relatively well. Even the poorly prepared category of children demonstrated the presence of general knowledge of these topics. It can be said that the elementary foundations of chemistry have been mastered: both the periodic system of elements of D.I. Mendeleev, and the structure of the atom, and the classification of chemical reactions, the compilation of simple chemical equations.

Schoolchildren know how the properties of elements and their compounds change depending on the position in periodic system chemical elements D.I. Mendeleev. Moreover, these tasks did not require a detailed answer - a simple choice and recording the number of the correct answer.

But a deep understanding of the dependence of the course of a chemical reaction on chemical properties most graduates did not demonstrate interacting substances.

The tasks of the advanced level turned out to be practically impossible even for well-prepared participants. Perhaps because such tasks came as a surprise to them, they did not prepare for them.

Particularly difficult was the task of establishing the molecular formula of an organic substance and writing it down, as well as writing down the molecular formula of the original substance,

The topic “Interrelation of different classes of inorganic substances” is also difficult for graduates. Only a few were able to fully describe the successive series of chemical transformations of a substance that reacts with other substances. Basically, they either didn’t even take on this task, or wrote one or two first reactions.

In the "Organic Chemistry" section, difficulties arose with how to identify the indicated substance from a number of proposed ones, since they do not know which substances react with each other (for example, which of the proposed reagents must be taken to determine that the available chemical substance - acetic acid).

The tasks of the block "Methods of cognition of substances and chemical reactions" showed good results, including calculations on chemical equations.

However, complex complex tasks (numbers 39 and 40), which require knowledge of the interaction of substances and the recording of a sequential chain of equations with subsequent calculations, puzzled the graduates.

For both poorly prepared graduates and strong ones, the task of industrial production of a substance (for example, ammonia, menthol, sulfuric acid) caused difficulty. As well as finding a correspondence (for example, between the interacting substances indicated in two columns).

What conclusions arise from the results of the USE in chemistry in 2015?

First of all, it is more critical to the choice of a subject for passing the exam. If knowledge is weak, then it is probably more reasonable to help the child find an educational institution to continue his education that does not require high scores in chemistry.

If you still stopped at the exam in this difficult subject, then you need to gather all your willpower, finances and begin systematic, targeted training.

The study of theory should go in parallel with the solution of many tests on the passed part of the subject, variants of the Unified State Examination of past years, and a demo version of the exam.

Each element of the table of D. I. Mendeleev should become dear and beloved for the child. He must be able at any time of the day or night to tell the characteristics of any element, its features, the ability to interact with other substances and which ones; it is great to reflect this in formulas and equations and be able to do calculations on them.

Before starting targeted preparation for the successful passing of the exam in chemistry, it is necessary to study the recommendations given in the following documents: Specification of control and measuring materials, Codifier of content elements and requirements for the level of training, Guidelines for teachers, prepared on the basis of an analysis of typical mistakes of USE participants in 2015 in chemistry (or you can also study a similar document for past years for safety reasons). And be guided by them when preparing. All of these documents can be found on the FIPI website.

USE 2015. Chemistry. Typical test tasks. Medvedev Yu.N.

M.: 2015. - 112 p.

Typical test tasks in chemistry contain 10 options for sets of tasks, compiled taking into account all the features and requirements of the Unified State Exam in 2015. The purpose of the manual is to provide readers with information about the structure and content of KIM 2015 in chemistry, the degree of difficulty of tasks. The collection contains answers to all test options and provides solutions to all tasks of one of the options. In addition, examples of forms used in the exam for recording answers and decisions are given. The author of the tasks is a leading scientist, teacher and methodologist, who is directly involved in the development of control measuring instruments. USE materials. The manual is intended for teachers to prepare students for the exam in chemistry, as well as for high school students and applicants - for self-training and self-control.

Format: pdf

The size: 2.7 MB

Watch, download: yandex.disk

CONTENT
Preface 4
Work instructions 5
OPTION 1 8
Part 1 8
Part 2 14
OPTION 2 16
Part 1 16
Part 2 22
OPTION 3 24
Part 1 24
Part 2 30
OPTION 4 32
Part 1 32
Part 2 38
OPTION 5 40
Part 1 40
Part 2 46
OPTION 6 48
Part 1 48
Part 2 54
OPTION 7 56
Part 1 56
Part 2 62
OPTION 8 64
Part 1 64
Part 2 70
OPTION 9 72
Part 1 72
Part 2 78
OPTION 10 80
Part 1 80
Part 2 86
ANSWERS AND SOLUTIONS 88
Part 1 88
Part 2 89
SOLUTIONS AND ANSWERS TO THE TASKS OF PART 2 90
SOLUTIONS OF TASKS OF OPTION 10 96
Part 1 96
Part 2 108

Dear graduates and applicants!
The present tutorial is a collection of tasks to prepare for the Unified State Examination (USE) in chemistry, which is both a final exam for a high school course and an entrance exam to a university. The structure of the manual reflects the modern requirements for the procedure for passing the exam in chemistry, which will allow you to better prepare for new forms of final certification and for admission to universities.
The manual consists of 10 options for tasks, which in form and content are close to USE demos and do not go beyond the content of the chemistry course, which is normatively determined by the Federal component of the state standard general education. Chemistry (Order of the Ministry of Education No. 1089 dated March 5, 2004).
The level of presentation of the content of the educational material in the assignments is correlated with the requirements of the state standard for the preparation of graduates of a secondary (complete) school in chemistry.
Three types of tasks are used in the control measuring materials of the Unified State Exam:
- tasks of a basic level of complexity with a choice of answers (in previous years, type A),
- tasks of an increased level of complexity with a short answer (in past years, type B),
- tasks of a high level of complexity with a detailed answer (in past years, type C). For each task of the first type (1-26) 4 answers are offered, of which only one
loyal. The task is considered completed correctly if the examinee indicated the correct answer.
In tasks of the second type (27-35) in the answer you need to write down a number or a sequence of numbers (the text of the solution does not need to be written). The answer is written in a special form.
In tasks of the third type (36-40), you need to write the text of the solution. The text of the decision is recorded on a special form. Tasks of this type make up the bulk of the written work in chemistry at the entrance exams to universities.