Early exam in chemistry real options. Additional materials and equipment
Tasks 33 and 34 with solutions.
No. 33: A mixture of copper and copper (II) oxide was treated with concentrated sulfuric acid. The volume of released gas was 4.48 liters. This formed a solution weighing 300 g with a mass fraction of salt 16%. Determine the mass fraction of copper (II) oxide in the initial mixture.
No. 34: A non-cyclic hydrocarbon was burned in oxygen, with the release of carbon dioxide weighing 70.4 g and water weighing 21.6 g. When interacting with HCl, this hydrocarbon adds chlorine to the primary carbon atom. Based on the given conditions of the problem: 1) make the calculations necessary to establish the molecular formula of an organic substance; 2) write down the molecular formula of the organic substance; 3) make a structural formula of the starting substance, which unambiguously reflects the order of bonding of atoms in its molecule; 4) write the reaction equation with HCl.
No. 34: When burning organic matter of a non-cyclic structure with a mass of 16.2 g, 26.88 liters (n.a.) were released carbon dioxide, 16.2 g of water. 1 mole of a substance completely reacts with 1 mole of water. It is known that this substance does not react with OH. Based on the given conditions of the problem: 1) make the calculations necessary to establish the molecular formula of an organic substance; 2) write down the molecular formula of the organic substance; 3) make a structural formula of the starting substance, which unambiguously reflects the order of bonding of atoms in its molecule; 4) write the equation for the reaction of this substance with water.
Answers and solution - early option 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 sign electronic configurations element data
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 items in ascending order reducing 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 there is an ionic chemical bond.
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(rr)
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 oxidant
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
Early USE options in chemistry 2016-2015
| Chemistry | Download option |
| 2016 | variant ege 2016 |
| 2015 | variant ege 2015 |
Changes in KIM USE 2017 compared to 2016
Chemistry - significant changes. Optimized structure examination work:
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 genetic connection inorganic and organic matter(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 high level 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.
