Junior Grade 3 Chemistry Final Exam Paper

Article 1

Relative atomic mass that may be used: H-1C-12N-14O-16Ca-40Pb-207

1. Multiple choice questions (this article The big question consists of 16 small questions, each question is worth 2 points, max. 32 points) Each small question has only one option that meets the meaning of the question.

1. Which of the following changes is a chemical change ()

A. Carbonization of coal B. Fractionation of petroleum

C. A neon light filled with neon gas emits red light D. The pressure cooker exploded due to excessive pressure

2. Which of the following are pure substances ()

A. Clean air B. Stainless steel C. Petroleum D. Ice-water mixture

3. In chemical experiments, human facial features play an important role. In the picture below, the use of facial features that meets the experimental requirements is ()

A. Smell with the nose B. Blow with the mouth C. Listen with the ears D. Eyesight

4. On December 24, 2010, three children in Xinshan Community, Gaohe Town, Huaining County were tested at Anhui Provincial Children’s Hospital for excessive lead in their blood (that is, the lead content in their blood exceeded the standard). normal value). The "lead" here refers to ()

A. Molecule B. Atom C. Element D. Elemental substance

5. Which of the following handling of emergencies is incorrect ()

A. If there is a fire in the room and you are trapped, immediately cover your mouth and nose with a wet towel, crawl forward, and look for a safe exit

B. If concentrated lye splashes on the skin, apply dilute sulfuric acid immediately

C. If someone is found to be poisoned by gas, immediately open doors and windows, close valves, and move the poisoned person to a fresh air place

D. A car transporting sulfuric acid accidentally overturned into the river and leaked. Quicklime can be used to treat the river water

6. In 2014, many celebrities were imprisoned for drug abuse, and they were criticized by the public. Meth (C10H15N) is a common drug. Which of the following statements is correct ()

A. The relative molecular mass of methamphetamine is 149gB. Meth is composed of 26 atoms

C. The mass fraction of carbon element in methamphetamine D. Meth molecules are composed of three elements

7. Which of the following classifications of water pollution by Xiao Ming is incorrect ()

A. Sewage discharged from farmland - agricultural pollution B. Wastewater discharged from fertilizer plants - agricultural pollution

C. Sewage discharged from households - domestic pollution D. Sewage discharged from small paper mills - industrial pollution

8. The following groups of substances are arranged in the order of mixture, compound and element ()

A. Ice water, dry ice, nitrogen B. Petroleum, coal, mercury

C. Clean air, sodium chloride, liquid oxygen D. Iodized salt, alcohol, natural gas

9. The four candles in the picture below will all go out. The reason why one of them goes out is different from the other three: ()

10. The chemical equation of the reaction is: 2Cu(NO3)22CuO+O2↑+4X. From this, it can be inferred that the chemical formula of X is that fireworks are often set off during festivals. A kind of fireworks agent contains copper nitrate, which can produce green flames when set off ()

A. NO2B. N2C. N2O4D. 2NO

11. The correct statement for "2" in the following chemical terms is ()

　①2O3②2N③N2④2NO3-⑤Mg2+⑥Mg⑦H2O

A. Indicates the number of atoms in the molecule is ③⑦B. Indicates the number of charges carried by ions is ⑤⑥

C. Representing the number of ions is ④⑤D. Representing the number of molecules is ①②

12. The "gas-to-electricity" converter made of tin dioxide (SnO2) as a sensitive material can be used to monitor harmful gases.

The valence of Sn in SnO2 is ()

A, -4B, +4C, 4D, +2

13. The chemical equation of a certain reaction is: A+3B=2C+2D. If 8 grams of A and 24 grams of B react completely, the mass of D produced is 9 grams, and the mass of C produced at the same time is ()

A. 13 grams B. 23 grams C. 31 grams D. 67 grams

14. Which of the following statements is correct ()

A. When entering a coal mine, you must first do a light test B. "White pollution" refers to white garbage

C. The gas that can extinguish burning wood is not necessarily CO2D. "Green food" generally refers to green food

15. Among the following oxides, the mass fraction of oxygen element is ()

A.N2OB.NO2C.N2O4D.N2O5

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16． Xiao Ming uses the device on the right to measure the oxygen content in the air. The correct understanding of this experiment is ()

A. Using more or less red phosphorus will not affect the experimental results

B. Burning enough red phosphorus can make the water entering the container occupy 4/5 of the container

C. The combustion of red phosphorus consumes oxygen in the air, causing the pressure in the container to drop and the water level to rise

D. As soon as the red phosphorus is burned, observe it immediately and record the time when water enters the container

2. Fill-in-the-blank questions (this question includes 6 small questions, ***20 points)

< p>17． (4 points) Use the chemical symbols you know to represent:

　(1) 2 hydrogen molecules (2) 3 aluminum ions

(3) 4 phosphorus pentoxide molecules ; (4) n calcium atoms.

18. (3 points) Write a chemical equation that meets the requirements:

(1) Electrolysis of water

(2) Potassium chlorate to produce oxygen

(3) Carbon monoxide reduces iron oxide

19. (4 points) my country's "Haiyang Shiyou 981" drilling platform started drilling in Xisha, marking a new level of my country's energy development.

(1) At present, most of the fuels used by humans come from fossil fuels, such as coal, oil and so on.

(2) The Chang'e-3 probe was successfully launched from the Xichang Satellite Launch Center in December 2013. The third sub-stage of the Chang'e 3B rocket responsible for the launch mission used liquid hydrogen and liquid oxygen as propellant. , the chemical equation of liquid hydrogen burning in liquid oxygen is, the basic type of this reaction is, according to the information provided by the equation, one of the basis for judging that hydrogen is an ideal energy source is (fill in the serial number)

A. Hydrogen is easy to store and transport B. Hydrogen resources are abundant

C. Hydrogen combustion products do not pollute the air D. The cost of obtaining hydrogen is low

20. (4 points) ① and ② in the figure below are the information of fluorine and calcium in the periodic table of elements. A, B, C, and D are schematic structural diagrams of the four particles.

Answer based on the above information:

(1) The nuclear charge number of fluorine element is, and the relative atomic mass of calcium element is.

(2) Which of A, B, C, and D belongs to the same element (fill in the serial number);

(3) The chemical properties of A particle are the same as those of B, C, and D Which of the particles have similar chemical properties (fill in the serial number).

21． (5 points) There are five substances in the laboratory: ①O2②H2③CO④CO2⑤CH4 Please fill in the serial numbers of the five substances into the corresponding blanks according to the following requirements, and write the chemical equation of the reaction.

(1) What can make wooden sticks with sparks rekindle is.

(2) The main component of the "West-East Gas Transmission" gas is, and the chemical equation of its combustion is

(3) The gas that can make clear lime water turn turbid is, The chemical equation of the reaction is

.

3. Experimental questions: (This big question includes 2 small questions, ***11 points)

22. (7 points) The following are common instruments and devices in chemical experiments Schematic diagram:

(1) Write the name of the instrument marked with numbers in the diagram: ①; ②.

(2) The name of the experimental operation in Figure B is; the role of the glass rod.

(3) The oxygen generating device should be selected in the laboratory, and the oxygen collecting device should be selected. The operations that must be performed before heating to produce oxygen are:

23. (4 points) A certain class of students went to the laboratory to conduct experiments on the production and properties of carbon dioxide and found that the following instruments were already placed on the experimental table for selection (the iron stand was omitted).

(1) Assemble a CO2 generating device. The instrument you choose is (fill in the letter).

(2) The drug that should be used to produce CO2 is (fill in the chemical formula).

(3) Use a test tube to collect CO2. The method for checking the fullness is:. Invert the test tube filled with CO2 gas in the water and gently shake the test tube. The observed phenomenon is

.

IV. Calculation questions (this major question includes 1 small question, ***7 points)

24. A limestone factory has a batch of limestone raw materials. In order to measure the purity of the limestone, the factory laboratory technician weighed 62.5g

of crushed limestone powder, calcined it at high temperature four times (no change in impurities), cooled, and weighed Repeat the operation of the remaining solid mass

and record the data as follows: (Hint: Calcium carbonate decomposes at high temperatures to generate calcium oxide and carbon dioxide gas)

The operation sequence is the first time and the second time. Three times and the fourth time

The remaining solid mass is 55.5g43.5g40.5g40.5g

Trial calculation: (1) After complete reaction, _____________g of carbon dioxide is generated; (1 point)

⑵The mass of calcium carbonate in limestone samples. (4 points)

(3) The mass fraction of calcium carbonate in the limestone sample. (2 points)

Part 2

Possible relative atomic mass: O—16S—32Fe—56Cu—64

1. Multiple choice question (this question There are 12 questions, and each question has only one option that matches the meaning of the question. Each question from 1 to 8 is worth 2 points, and each question is worth 16 points. ． The uses of the following substances mainly utilize chemical properties

A. Copper-made wires B. Tungsten filament

C. Oxygen supplies breathing D. Fill the balloon with hydrogen

2. The World Health Organization lists C1O2 as a Class A highly efficient and safe sterilizing disinfectant. It is widely used in food preservation, drinking water disinfection, etc. The valence of chlorine element in C1O2 is

A. -4B． +2C. +4D. +5

3. Which of the following symbols has only microscopic meaning

A. Cl2B. N2C. CuD. 2CO2

4. Iron nails are most likely to rust under the following circumstances:

A. In humid air B. In dry air

C. Immersed in tap water D. Immerse in vegetable oil

5. The following experimental operation methods are correct and can achieve the purpose of the experiment itself

A. Add liquid B. Heating liquid C. Weigh a certain mass of table salt D. Check the air tightness of the device

6. Which of the following understandings of molecules, atoms, and ions is correct

A. Atoms are the smallest particles and cannot be subdivided B. The higher the temperature, the faster the molecular motion rate

C. Ions cannot directly constitute matter D. Solids are difficult to compress, indicating that there is no space between solid molecules

7. In November 2014, the Anshan area often encountered severe haze weather. The following are not atmospheric pollutants

A. SO2B． CO2C. NO2D. Inhalable particulate matter (PM2.5)

8. The device on the right is commonly used to measure the oxygen content in the air. Which of the following understandings of this experiment is correct

A. Red phosphorus burns to produce a large amount of white smoke

B. The red phosphorus in the burning spoon can be replaced with thin iron wire

C. This experiment can show that N2 is difficult to dissolve in water

D. Insufficient amount of red phosphorus will cause the volume of water entering the gas collecting bottle to be greater than 1/5

9. The purification of tap water mainly includes the following processes, among which chemical changes occur

A. Natural precipitation B. Sand filter C. Activated carbon adsorption D. Sterilization

10. "Carbon sponge" is the lightest solid material known. Its main components are graphene and carbon nanotubes (both are carbon elements) and has a loose porous structure. Which of the following speculations about the properties of "carbon sponge" must be wrong

A. Carbon sponge is easily soluble in water B. Carbon sponge is a gray-black solid

C. Carbon sponge has adsorption effect D. Burning carbon sponge will produce carbon dioxide

11. Add a certain mass of aluminum powder to the CuSO4 solution, filter it after the reaction stops, and obtain the filter residue and blue filtrate. Which of the following statements is correct

A. Add dilute hydrochloric acid dropwise to the filter residue without generating bubbles B. There must be Cu in the filter residue, and there may be Al

C. There is only Al2(SO4)3D in the filtrate. There is only CuSO4 in the filtrate

12. Geological investigators discovered a threaded ore. During research, they found that the ore can burn in oxygen, and the main reaction is 4X+11O22Fe2O3+8SO2. Which of the following statements is incorrect

A. The chemical formula of X is FeS2B. The number ratio of sulfur and oxygen elements in SO2 is 1:2

C. The valence of oxygen element changes before and after the reaction D. The mass fraction of iron element in Fe2O3 is 70%

2. Fill in the blanks (this question includes 4 questions, 1 point for each blank, ***16 points)

13. Fill in the chemical symbols:

(1) Elemental sulfur; (2) Hydroxide ions;

(3) Water molecules; (4) The valence of the iron element in iron oxide.

14. In the figure below, A, B, C, and D are schematic structural diagrams of the four particles.

ABCD

Please answer the following questions:

(1) A, B, C, and D in the picture belong to particles of _______ elements;

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(2) Among the three types of particles A, B, and C, the one that does not have a stable structure is _________ (fill in the letter number);

(3) x in D=________;

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(4) The chemical formula of the compound formed by A and C is ___________.

15. Chemistry is all around us. Please choose the corresponding serial number from the following substances to fill in the blanks ① graphite ② activated carbon ③ titanium alloy ④ alcohol (fill in the serial number of the corresponding substance above, do not reuse):

(1) Laboratory Commonly used fuels are; (2) can be used to make pencil leads;

(3) can be used to make artificial bones; (4) can be used to absorb refrigerator odors.

16． Energy and environment are issues of common concern to all countries in the world.

(1) Coal and natural gas are common fossil fuels. Coal combustion produces gases such as carbon dioxide, sulfur dioxide, and carbon monoxide. Among these gases, those that dissolve in water can form acid rain.

(2) Human beings are developing and using new energy sources, such as tidal energy, hydrogen energy, etc. Tests of hydrogen storage alloys for hydrogen-powered vehicles have been successful. The advantages of hydrogen as fuel include.

3. Short answer and inference questions (this question includes 4 questions, ***20 points)

17. (4 points) Explain the scientific principles of the following words or sayings

(1) Draw fire from the bottom of the cauldron; (2) Make fire by drilling wood; (3) True Gold is not afraid of fire;

(4) Without diamonds, there is no porcelain job.

18. (5 points) Water is an important natural resource.

(1) As shown in the picture on the right, the gas obtained in test tube 2 is,

This experiment can prove that water is composed of elements.

(2) It is usually possible to distinguish between hard water and soft water.

There are ways to reduce the hardness of water in daily life.

(3) Among the following practices, which one is conducive to protecting water resources (fill in the alphabetical number, it is indefinite).

A. Use water-saving toilet B. Use pesticides and fertilizers rationally C. Random discharge of domestic sewage

19. (5 points) Metals are closely related to us.

(1) The main reason why aluminum is not easy to rust is ________ (fill in the alphabetical number).

A. Aluminum does not react with acid

B. Aluminum does not react with oxygen in the air

C. The oxide film on the surface of aluminum has a protective effect

(2) The principle of iron powder can be used for food preservation: when iron rusts, it can absorb ________ and ________, keeping food dry and preventing oxidation and deterioration. When elemental iron with particle sizes reaching the nanoscale is impacted in the air, it burns to form ferric iron oxide. The chemical equation of the reaction is ____________________________.

20． (6 points) The industrial process flow for producing circuit boards and treating waste liquid is as follows:

(1) From step 1, it can be determined that the two products generated by the reaction of FeCl3 and copper are ________ and ________.

(2) Step ② Adding excess iron powder can not only react with FeCl3 in the waste liquid, but also the chemical reaction equation that can occur is ____________________________________________________________.

(3) Step ③ Add dilute hydrochloric acid and stir thoroughly. When __________________ is observed, it means that only copper remains in the filter residue.

(4) The FeCl2 obtained in steps ②③ can react with a simple substance to form FeCl3, which can be recycled. According to the law of conservation of mass, it can be inferred that the chemical formula of this element is ___________.

IV. Experimental and inquiry questions (this question includes 3 questions, ***20 points)

21. (4 points) Briefly explain the possible consequences of the operation or the possible reasons for these consequences on the horizontal line after the question.

(1) When pouring the medicine in the reagent bottle, the label did not face the palm;

(2) When doing the experiment of sulfur burning in oxygen, there was no layer of water left at the bottom of the gas collection bottle ;

(3) The oxygen collected by the drainage method contains a small amount of nitrogen;

(4) During the oxygen combustion experiment using thin wire, the gas collecting bottle burst.

22. (8 points) Please answer according to the device in the picture below:

(1) Write the name of the instrument of a;

(2) Write the corresponding method for preparing O2 with device A in the laboratory Chemical equation:;

(3) The method to check the air tightness of device B is;

(4) Hydrogen is a colorless, odorless, and poorly soluble gas. Its density is smaller than that of air, and it is commonly produced in the laboratory by reacting zinc particles with dilute sulfuric acid.

①The device for preparing and collecting H2 in the laboratory is (fill in the alphabetical number);

②Hydrogen and oxygen may explode when mixed and ignited, so it must be first ignited.

23． (8 points) A student in an interest group read extracurricular materials and learned that many substances can affect the decomposition speed of hydrogen peroxide. Therefore, the students explored the effect of catalysts on the decomposition rate of hydrogen peroxide. Add different masses of MnO2 to hydrogen peroxide solutions of the same mass and concentration, and measure the volume of oxygen collected in the same time.

The experimental data of the experimental process are recorded as follows:

Mass measurement data of MnO2

Ⅰ0.1g9mL

Ⅱ0.2g16mL

　Ⅲ0.4g31mL

Experimental analysis

(1) Chemical equation for the decomposition of hydrogen peroxide_____________________________.

(2) In this experiment, the device for measuring the volume of O2 is ________ (fill in the number).

The experimental conclusion is __________________________________ when other conditions are the same.

Communication and evaluation

Some students suggested that measuring ______________ in the above experiment can also lead to the same conclusion.

Experiment reflection

In addition to the quality of the catalyst that will affect the decomposition rate of hydrogen peroxide, the _________ (write one) of the catalyst will also affect the decomposition rate of hydrogen peroxide. Your experiment The plan is ____________________________.

5. Calculation questions (this question includes 1 small question, ***8 points)

24. (8 points) Hydrometallurgy is the crystallization of the wisdom of the working people in ancient my country. Add a certain mass of copper sulfate solution (containing 16g of copper sulfate) to a certain mass of iron powder containing impurities (assuming that the impurities are insoluble in water and do not react with other substances). After the iron and copper sulfate react completely, filter and dry to obtain 6.8g solid. Find the mass fraction of raw iron powder.