Real options for the exam in chemistry fipi. Preparing for the exam in chemistry

Documents are presented that regulate the structure and content of control measuring materials of the unified state exam in chemistry in 2015: a codifier of content elements and requirements for the level of training of graduates of general education institutions for the unified state exam in 2015; specification of control measuring materials for the Unified State Exam in 2015; demonstration version of control measurement materials of the unified state exam 2015. Document in PDF format.

General changes in the KIM Unified State Exam 2015:

1. The structure of the CMM option has been changed: each option consists of two parts (part 1 - tasks with a short answer, part 2 - tasks with a detailed answer).

2. Tasks in the CMM version are presented in continuous numbering mode without letter designations A, B, C.

3. The form of recording the answer in tasks with a choice of one answer has been changed: as in tasks with a short answer, the number of the correct answer is written in a number (not a cross).

4. For most academic subjects, the number of multiple-choice tasks has been reduced.

5. Based on the analysis of statistical data on the exam results and the quality of the CMM, in a number of subjects, some lines of tasks were excluded, and the form of a number of tasks was changed.

6. Work is ongoing on an ongoing basis to improve the evaluation criteria for tasks with a detailed answer.

There are no fundamental changes in the planned KIM Unified State Exam 2014 in chemistry.

1. The number of tasks at the basic difficulty level has been reduced from 28 to 26 tasks.

2. The form for recording the answer to each of tasks 1-26 has been changed: in KIM 2015 it is required to write down the number corresponding to the number of the correct answer.

3. The maximum score for completing all tasks of the 2015 examination paper is 64 (instead of 65 points in 2014).

4. The assessment system for the task of finding the molecular formula of a substance has been changed. The maximum score for its implementation is 4 (instead of 3 points in 2014).

Download:

On the topic: methodological developments, presentations and notes

Features of the Unified State Exam and State Examination in Chemistry in 2014

According to the project, some changes may be made to the KIM Unified State Examination and State Academy of Chemistry in 2014. The presentation shows the differences in the structure of the KIM Unified State Examination and State Examination in Chemistry compared to 2013....

Unified State Examination in Biology in 2015

Biology is the fourth most popular subject. About 20% of students choose it annually. It is noteworthy that more than 80% of those who choose biology usually receive more than 40 points in the exam. Also t...

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 in reserve retakes on June 26. Next - receiving certificates, graduations, entering a university!

The KIM of the early Unified State Examination in Chemistry can be downloaded for review. I will post answers and solutions to this option soon.

Some results of the early Unified State Examination in Chemistry, which took place on April 4, 2015, can be summed up now. Examples of written response tasks 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, the reducing agent is potassium iodide. This reaction is an example of counter-disproportionation, when both atoms - the oxidizing agent (J +5) and the reducing agent (J -) - transform 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)

Reductant - KJ (J -).

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

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

Fe 3+ - 3e = Fe 6+

Br 2 +2e = 2Br -

Oxidizing agent - Br 2 (Br 2)

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

3) Based on the product on the right side - potassium chromate - we determine the alkaline medium in which the reaction is carried out, i.e. add alkali to 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 salt KI:

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

Cr +3 - 3e = Cr +6

J 2 +2e = 2J —

Oxidizing agent - J 2

The reducing agent is 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. A solution of sodium sulfide was added to this solution, and a black precipitate formed.

Task 38.

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 of organic matter is formed. I’ll immediately make a reservation that everything that is written below relates to the Unified State Exam and the interpretation of this oxidation in the Unified State Exam.

So, why does oxidation occur with the breaking of the sigma and pi bonds? Because oxidation with breaking of only the pi bond (Wagner reaction) in the Unified State Examination is formalized as follows:

The oxidation of unsaturated hydrocarbons in an aqueous environment and upon heating occurs with the rupture of sigma and pi bonds (double bonds). 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 permanganate is reduced, an alkali is formed. The resulting alkali will neutralize the reaction products. How much it will neutralize them is a question of stoichiometric ratios, i.e. the question of electronic balance, and it is possible to answer the question about the composition and quantity of the products of the oxidation reaction of complex organic molecules only in the process of drawing up a balance.

In this case, oxidation will most likely proceed according to the following mechanism: potassium benzoate is formed and the C-C bonds marked in the figure are broken. 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:

Electronic balance:

Having received the balance coefficients, we arrange them and equalize them in order - balance coefficients, metal atoms, non-metal atoms, hydrogen, oxygen:

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 glad 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 the mass fraction of salt in the final solution.

Task 40. The combustion of 20 g of acyclic organic matter produced 66 g of carbon dioxide and 18 ml of water. This substance reacts with an ammonia solution of silver oxide; 1 mole of this substance can add only 1 mole of water. Determine the formula and write the reaction with an ammonia solution of silver oxide.

Demonstration versions of the Unified State Exam in chemistry for grade 11 consist of two parts. The first part includes tasks for which you need to give a short answer. For the tasks from the second part, you must give a detailed answer.

All demo versions of the Unified State Exam in chemistry contain correct answers to all tasks and assessment criteria for tasks with a detailed answer.

There are no changes compared to.

Demo versions of the Unified State Examination in Chemistry

Note that demonstration options in chemistry are presented in pdf format, and to view them you must have, for example, the free Adobe Reader software package installed on your computer.

Changes in demo versions of the Unified State Examination in Chemistry

Demonstration versions of the Unified State 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 required a short answer. For the tasks from the third part it was necessary to give a detailed answer.

In 2014 in demo version of the Unified State Exam in chemistry the following were introduced changes:

• all calculation tasks, the implementation of which was estimated at 1 point, were placed in part 1 of the work (A26–A28),
• subject "Redox reactions" tested using assignments AT 2 And C1;
• subject "Hydrolysis of salts" was checked only with the help of the task AT 4;
• a new task has been included(at position AT 6) to check the topics “qualitative reactions to inorganic substances and ions”, “qualitative reactions of organic compounds”
• total number of tasks in each version it became 42 (instead of 43 in the 2013 work).

In 2015 there were fundamental changes have been made:

The option became consist of two parts(part 1 - short answer assignments, part 2 - long-answer assignments).

Numbering tasks became through throughout the entire version 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 now needs to be written down in a number with the number of the correct answer (rather than marked with a cross).

Was the number of tasks at the basic difficulty level has been reduced from 28 to 26 tasks.

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

• The assessment system has been changed tasks to find the molecular formula of a substance. The maximum score for completing it is 4 (instead of 3 points in 2014).

IN 2016 year in demonstration version in chemistrysignificant changes have been made compared to the previous year 2015 :

In 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 35 increased level of difficulty : these tasks now require matching instead of selecting multiple correct answers from a given list.

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

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

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

Was the total number of tasks has been reduced up to 34.

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

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

In 2018 in demo version of the Unified State Exam in chemistry compared with demo version 2017 in chemistry the following occurred changes:

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

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

IN demo version of the 2019 Unified State Exam in chemistry compared with demo version 2018 in chemistry there were no changes.

On our website you can also get acquainted with educational materials for preparing for the Unified State Exam in mathematics prepared by teachers of our training center "Resolventa".

For schoolchildren in grades 10 and 11 who want to prepare well and pass Unified State Examination in mathematics or Russian language for a high score, the Resolventa training center conducts

We also organize for schoolchildren

In 2015, 11% of all examinees (75,600 people) took the Unified State 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 year. Still, it’s surprising how, with such poor knowledge, they chose chemistry to take the Unified State Exam, and even more so, apparently, they were going to study it at a university!

As the exam results showed, the graduates coped relatively successfully with the basic level. Even the poorly prepared category of children demonstrated their general knowledge of these topics. We can say that the elementary fundamentals of chemistry have been mastered: the periodic system of elements by D.I. Mendeleev, the structure of the atom, the classification of chemical reactions, and the preparation of simple chemical equations.

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

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

Advanced level tasks 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 the molecular formula of the original substance,

The topic “Interrelation of various 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 they wrote only one or two first reactions.

In the “Organic Chemistry” section, difficulties arose with how to identify the specified substance from a number of those offered to choose from, since they do not know which substances react with each other (for example, which of the proposed reagents should be taken to determine what is available) chemical substance - acetic acid).

Completing the tasks in the block “Methods of understanding substances and chemical reactions” showed good results, including calculations using chemical equations.

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

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

What conclusions emerge from the results of the Unified State Exam in Chemistry 2015?

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

If you still decide to take the exam in this difficult subject, then you need to gather all your willpower and finances and begin systematic, targeted preparation.

Studying the theory should go in parallel with solving many tests on the passed part of the subject, versions of the Unified State Exam of previous years, and a demo version of the exam.

Each element of D.I. Mendeleev’s table should become dear and loved to the child. He must be able to tell the characteristics of any element, its features, ability to interact with other substances and which ones at any time of the day or night; perfectly reflect this in formulas and equations and be able to make calculations using them.

Before starting targeted preparation for successfully passing the Unified State Exam in Chemistry, it is necessary to study the recommendations given in the following documents: Specification of test 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 Unified State Examination 2015 participants in chemistry (and you can also study a similar document for previous years to be on the safe side). And be guided by them when preparing. All listed documents can be found on the FIPI website.