Early exam chemistry 1st option. Additional materials and equipment
Changes in KIM USE 2017 compared to 2016
Chemistry - significant changes. The structure of the examination paper has been optimized:
1. The structure of part 1 of the KIM has been fundamentally changed: tasks with a choice of one answer have been excluded; tasks are grouped into separate thematic blocks, each of which contains tasks of both basic and advanced levels of complexity.
2. Reduced the total number of tasks from 40 (in 2016) to 34.
3. Changed the assessment scale (from 1 to 2 points) for completing tasks basic level difficulties that test the assimilation of knowledge about the genetic relationship of inorganic and organic substances (9 and 17).
4. Maximum primary score for the performance of the work as a whole will be 60 points (instead of 64 points in 2016).
Structure of KIM USE 2017 in chemistry
Each version of the examination work is built according to a single plan: the work consists of two parts, including 34 tasks. Part 1 contains 29 tasks with a short answer, including 20 tasks of the basic level of complexity (in the version they are present under the numbers: 1–9, 12–17, 20–21, 27–29) and 9 tasks advanced level difficulty (their serial numbers: 10, 11, 18, 19, 22–26).
Part 2 contains 5 tasks of a high level of complexity, with a detailed answer. These are tasks numbered 30-34.
Total tasks - 34; of them according to the level of complexity: B - 20 P - 9; AT 5.
The maximum primary score for a job is 60.
The total time to complete the work is 210 minutes.
Early Unified State Examination in Chemistry 2017. Task 31
The gas obtained by calcining silver (I) nitrate was mixed with another gas obtained by the decomposition of potassium chlorate. The resulting mixture of gases was absorbed by water, and an acid was formed. Magnesium phosphide was treated with hydrochloric acid, and gas was released. This gas was carefully passed through a hot concentrated solution of the resulting acid. Write the equations for the five described reactions. In your answer, write the sum of the coefficients in all equations.
Early Unified State Examination in Chemistry 2017. Task 33
Potassium bicarbonate weighing 45 g was calcined to constant weight. The residue was dissolved in excess sulfuric acid. The resulting gas was passed through 200 g of a 5.6% potassium hydroxide solution. Determine the composition and mass of the formed salt, its mass fraction(%) in solution. When solving, write down the reaction equations that are indicated in the condition of the problem, and give all the necessary calculations (indicate the units of measurement of the required physical quantities). In your answer, write down the sum of the molar mass (g / mol) of the formed salt, its mass (g) and its mass fraction (%, rounded to the nearest whole number) in the final solution. Ignore the solubility of gases in water.
Early Unified State Examination in Chemistry 2017. Task 34
On combustion 12.24 g organic matter non-cyclic structure received 20.16 l (n.o.) of carbon dioxide and 12.96 g of water. It is known that 1 mol of this organic substance attaches only 1 mol of water and this substance does not react with an ammonia solution of silver oxide. Based on the given conditions of the problem: 1) make the calculations necessary to establish the molecular formula of an organic substance. 2) make a molecular formula of organic matter. 3) make a structural formula of an organic substance, which unambiguously reflects the order of bonding of atoms in its molecule. 4) make an equation for the reaction of hydration of organic matter. In your answer, write down the molar mass (g / mol) of the original organic matter.
Sodium nitride weighing 8.3 g reacted with sulfuric acid with a mass fraction of 20% and a mass of 490 g. Then crystalline soda weighing 57.2 g was added to the resulting solution. Find the mass fraction (%) of the acid in the final solution. Write down the reaction equations that are indicated in the condition of the problem, give all the necessary calculations (indicate the units of measurement of the required physical quantities). Round your answer to the nearest whole number.
Real USE 2017. Task 34.
The cyclic substance A (does not contain oxygen and substituents) is oxidized with a ring break to substance B weighing 20.8 g, the combustion products of which are carbon dioxide with a volume of 13.44 l and water with a mass of 7.2 g. Based on the given task conditions: 1) perform the calculations necessary to establish the molecular formula of organic substance B; 2) write down the molecular formulas of organic substances A and B; 3) compose structural formulas organic substances A and B, which unambiguously reflect the order of bonding of atoms in a molecule; 4) write the reaction equation for the oxidation of substance A with potassium permanganate sulfate solution to form substance B. In the answer for the site, indicate the sum of all atoms in one molecule of the original organic substance A.
The national examination in chemistry is one of the subjects that a graduate can choose on his own. This subject is necessary for those students who are going to continue their education in the field of medicine, chemistry and chemical technology, construction, biotechnology, Food Industry and similar industries.
It is better to start preparing for this subject in advance, since at cramming in this case will not be able to leave. In addition, it is necessary to clarify possible changes and the dates of the exam, in order to be able to correctly distribute the forces in preparation. To simplify this task for you as much as possible, we will analyze the features of the exam in chemistry in 2017.
Demo version of the USE-2017
USE dates in chemistry
You can take the chemistry exam on the following dates:
- Early period. The early date for the exam will be 03/16/2017, and 05/03/2017 is declared as a reserve.
- Main stage. The main date for the examination is June 2, 2017.
- Backup date. 06/19/2017 was chosen as a reserve day.
Several categories of persons can pass the exam before the main deadline, which include:
- students of evening schools;
- students who are called to serve in the ranks;
- schoolchildren leaving for a competition, competition or olympiad of federal or international significance,
- eleventh-graders who go abroad due to a change of place of residence or to study at a foreign university;
- students who are prescribed preventive, health-improving treatment or undergoing rehabilitation procedures on the main date for passing the exam;
- graduates of previous years;
- students who studied abroad.
Recall that an application for passing the exam in advance must be written and submitted before 03/01/2017.
Statistical information
Practice conducting the exam shows that chemistry is not very popular among graduates. This exam is not easy, so only one student out of ten chooses it. Difficulty is also confirmed by the percentage of students who pass this subject with an unsatisfactory grade - in different years this figure ranges from 6.1 to 11% of total mass students taking chemistry exams.
As for the average scores for the exam, recently they range from 67.8 (2013) to 56.3 (2015) points. On the one hand, one can notice a downward trend in this indicator, however, on the other hand, we hasten to reassure the students. These scores correspond to the level of the school "four", so do not be too afraid of chemistry.
Chemistry is considered one of the most difficult exams and requires serious preparation. What can be used on the exam in chemistry?
In the chemistry exam, students can use the periodic table, a table containing information on the solubility of salts, acids and bases, as well as reference materials with data on the electrochemical series of metal voltages. All necessary materials will be given to students along with the ticket. From the exam in chemistry, a non-programmable type calculator is also mentioned.
Any other items such as smartphones, tablets, players, reference books and programmable computers are prohibited and are a reason for removing a student from the classroom. If you need to go to the first-aid post or toilet, you should warn the observer about this, who will accompany you to the right place. Other activities (such as talking to neighbors or changing exam locations) are also prohibited.
Exam ticket structure
The chemistry ticket consists of 34 tasks divided into 2 parts:
- the first part includes 29 short answer tasks;
- the second part consists of 5 tasks, the solution of which will require a detailed answer.
When completing assignments in chemistry, students must meet the allotted 210 minutes for this.
State examination in chemistry in 2017 will last 3.5 hours Changes in KIM-2017 in chemistry
The national examination in chemistry has undergone a lot of changes, which are reflected in the optimization of the structure of the ticket. New KIM is focused on increasing objectivity in assessing the knowledge and practical skills of students. It is worth paying attention to such points:
- In the structure of the first part of the examination sheet, tasks were excluded that require the choice of one option from the proposed answers. New tasks give the choice of several correct answers from the proposed ones (for example, 2 out of 5 or 3 out of 6), require students to be able to establish a correspondence between individual positions from several sets, and also carry out calculations. In addition, the tasks were grouped into separate thematic blocks, each of which contains tasks related to the basic level of complexity and advanced. In separate blocks, tasks are arranged in order of increasing complexity, that is, from one to another, the number of actions that need to be performed to get an answer will increase. According to the FIPI representatives, these changes will bring the ticket in line with the program school course chemistry and will help students more effectively demonstrate knowledge of the terminology and patterns of chemical processes.
- In 2017, he reduced the total number of tasks - now there will be only 34, not 40. Tasks that provide for similar types of activities have been removed from the ticket: for example, aimed at identifying knowledge about salts, acids and bases and their chemical properties. These changes are explained by the fact that the new ticket is practical, so even basic tasks require students to systematically apply the acquired knowledge.
- Tasks of the basic level (numbers 9 and 17) test knowledge of the genetic relationships of substances of organic and inorganic nature. Now they are evaluated not at 1, but at 2 points.
- The initial score that is awarded for work has been changed - now it is not 64, but 60 points.
Grading system
Points for the exam are set based on a hundred maximum. Until 2017, they were not transferred to the grading system familiar to schoolchildren, but this can be done independently.
To get an A, pay attention to discipline and demo options - If the student scored from 0 to 35 points, his level of knowledge is assessed as unsatisfactory and corresponds to the mark "2";
- Points in the range from 36 to 55 are an indicator of a satisfactory level of knowledge and correspond to the mark "3";
- By scoring from 56 to 72 points, you can count on a score of "4";
- With scores of 73 and above, the score is considered excellent, that is, "5".
You can see the final result on the USE portal by identifying yourself using your passport data. Recall also that minimum score, which you need to score for the exam in chemistry - 36. It is also worth saying that, according to the latest news, the scores for the exam in chemistry will affect the grade in the certificate. You should certainly take this chance to correct the mark in the report card that does not suit you.
Answers and solution - early version in chemistry 2017
For tasks 1-3, use the following row chemical elements. The answer in tasks 1-3 is a sequence of numbers, under which the chemical elements in this row are indicated. 1) S 2) Na 3) Al 4) Si 5) Mg
1) Determine the atoms of which of the elements indicated in the series in the ground state contain one unpaired electron. Write down the numbers of the selected elements in the answer field
Let's write down the electronic configurations of these elements
S: 1s 2 2s 2 2p 6 3s 2 3p 4
Na: 1s 2 2s 2 2p 6 3s 1
Al:s 2 2s 2 2p 6 3s 2 3p 1
Si:1s 2 2s 2 2p 6 3s 2 3p 2
Mg: 1s 2 2s 2 2p 6 3s 2
We see that the elements Na and Al have one unpaired electron each
In a given scheme of transformations X Y Cu CuCl CuI ⎯⎯→ ⎯⎯ 2 → substances X and Y are: 1) AgI 2) I2 3) Cl2 4) HCl 5) KI Write in the table the numbers of the selected substances under the corresponding letters
2 ) From the chemical elements indicated in the series, select three metal elements. Arrange the selected elements in ascending order of restorative properties. Write in the answer field the numbers of the selected elements in the desired sequence
Restorative properties increase from right to left in groups and from top to bottom in periods, therefore, we will arrange the three metal elements Na, Mg, Al Al, Mg, Na
3) From among the elements indicated in the row, select two elements that, in combination with oxygen, exhibit an oxidation state of +4. Write down the numbers of the selected elements in the answer field.
write possible compounds with oxygen
4) From the proposed list of substances, select two substances in which an ionic chemical bond is present.
1) KCl 2) KNO3 3) H3BO3 4) H2SO4 5) PCl3
5) Establish a correspondence between the formula of a substance and the class / group to which this substance belongs: for each position indicated by a letter, select the corresponding position indicated by a number.
6) From the proposed list of substances, select two substances, with each of which zinc interacts.
1) nitric acid (solution)
2) iron(II) hydroxide
3) magnesium sulfate (solution)
4) sodium hydroxide (solution)
5) aluminum chloride (solution)
3Zn + 8HNO3= 3Zn(NO3)2 + 4H2O + 2NO
Zn+ 2NaOH + 2H2O = Na2 + H2
7 ) From the proposed list of substances, select two oxides that react with water.
Write down the numbers of the selected substances in the answer field.
BaO+H2O= Ba(OH)2
8) A solution of substance Y was added to a test tube with a solution of salt X. As a result of the reaction, the formation of a white precipitate was observed. From the proposed list of substances, select substances X and Y that can enter into the described reaction.
1) hydrogen bromide
3) sodium nitrate
4) sulfur oxide (IV)
5) aluminum chloride
Write in the table the selected numbers under the corresponding letters.
AlCl3 + 3NH4OH = Al(OH)3+ 3NH4Cl
solution of substance NH3 -> NH3*H2O
9) In a given transformation scheme
Cu—X—CuCl2—Y——CuI
substances X and Y are:
Write in the table the numbers of the selected substances under the corresponding letters
2CuCl2 + 4KI = 2CuI + I2 + 2KCl
10) Establish a correspondence between the reaction equation and the oxidizing substance in this reaction: for each position indicated by a letter, select the corresponding position indicated by a number.
| REACTION EQUATION | OXIDIZING AGENT |
| A) H2 + 2Li = 2LiH | 1) H2 |
| B) N2H4 + H2 = 2NH3 | 2) N2 |
| C) N2O + H2 = N2 + H2O | 3) N2O |
| D) N2H4 + 2N2O = 3N2 + 2H2O | 4) N2H4 |
| 5) Li |
Answer: 1433
11) 1215
30) KI + KIO 3 + H 2 SO 4 = I 2 + K 2 SO 4 + H 2 O
| 2I -1 - 2e = I 2 0 | 5 | |
| 10 | ||
| 2I +5 + 10e =I 2 0 | 1 |
KI due to I -1 reducing agent
KIO 3 due to I +5 oxidizer
5KI + KIO 3 + 3H 2 SO 4 = 3I 2 + 3K 2 SO 4 + 3H 2 O
1) 2Cu(NO 3) 2- → 2CuO + 4NO 2 + O 2
