1. The following changes are physical changes ().
A. Gas explosion B. Milk turns sour
C. Iron rusts D. Neon lights glow red when electrified.
2. The following statements about "must" and "not necessarily" are incorrect.
A. A chemical reaction that produces only one substance must be a combination reaction.
B. the oxidation reaction is not necessarily a combination reaction.
C. The chemical reaction between substance and oxygen must be an oxidation reaction.
D. chemical reactions do not necessarily have obvious phenomena.
3. The description of candle burning experiment is wrong.
A. release a lot of heat B. emit yellow flame C. produce carbon dioxide and water D. the flame is divided into three layers.
4. Nobel Prize winner in chemistry, Israeli scientist Daniel? Sherman's outstanding contribution to the discovery of quasicrystals. Quasicrystals may have the following properties, among which the chemical properties are
A. low density B. wear resistance C. poor conductivity D. strong oxidation resistance
The following changes in the kitchen are all physical changes.
A. Rice turns sour B. Fruit juicing C. Iron pan rusts D. Gas burning
6. The use of the following substances mainly uses its chemical properties is ()
A. Natural gas is used as fuel B. "Dry ice" is used for artificial rainfall.
C. pig iron casting iron pot D. copper is used to make wires
7. In the following statements, all those that describe the physical properties of substances are ().
A. Iron rusts easily and carbon dioxide liquefies easily.
B. Oxygen is oxidizing and H2 is flammable.
C pure iron sheet is silvery white, and alcohol is volatile.
D metal can conduct electricity, and H2CO3 can turn purple litmus solution into red.
8. The main physical change of the properties and uses of the following substances is ()
A. industrial derusting with dilute sulfuric acid B. Sodium hydroxide deliquesces easily when exposed to air.
C. hydrochloric acid can turn purple litmus red. D. concentrated sulfuric acid can make paper black
9. Light a candle and put a cold dish (as shown below) above the candle flame. After a while, new carbon black will be collected at the bottom of the cold dish. This experiment shows that ()
A. Due to insufficient oxygen, the candle burns incompletely, resulting in carbon black.
B, the volatile candle condenses into carbon black after cooling.
C. candles can be burned without oxygen.
D. candles contain carbon black.
10. Among the following changes, slow oxidation does not include ().
A. Breathing of animals and plants B. Dissolution of sucrose C. Brewing of wine and vinegar D. Food decay
1 1. The fuel for the torch of Nanjing Youth Olympic Games is propane [C3H8]. In the following description about the properties of propane, the chemical properties of propane are
A. The boiling point is -42. 1℃, which is easy to liquefy.
B. Slightly soluble in water, soluble in alcohol.
C.[ Material] Flammability [Thermal] Flammability
D. Colorless gas
13. Gas can be collected by drainage method and downward exhaust method, so the physical properties of gas are as follows
A. Insoluble in water, with higher density than air; Insoluble in water, less dense than air.
C. Soluble in water with higher density than air.
14. The following are the self-introductions of some substances, among which the chemical properties are introduced.
A.copper: I can conduct electricity. B.oxygen: I am light blue when I am liquid.
C. nitrogen: I am a gas at room temperature. D.iron: I will rust.
15. From the point of view of material changes, the following allusions mainly reflect chemical changes.
A. Sima Guang smashed the cylinder B. Cutting the wall and stealing the light C. Burning Chibi D. Grinding the iron pestle into a needle
Second, fill in the blanks
16. Fill in the blanks with only one or more of the five elements of Ca, C, O, Cl and H as required:
(1) Write a chemical formula:
(1) oxide _ _ _ _ _ _ _ _; (2) acid _ _ _ _ _; (3) alkali _ _ _ _ _ _;
(4) salt _ _ _ _ _.
(2) Write a chemical equation:
① Decomposition reaction _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;
② The metathesis reaction _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
17. There are four substances A, B, C and D. A is a colorless and odorless gas, and black solid B burns more violently in A than in air, producing a colorless and odorless gas C, which can make clear limewater turbid; D. The filling gas of the bulb is colorless and odorless gas; Put burning B into D, and it will go out soon. Then:
(1) Names of four substances: a; b； c； d .
(2) Write the symbolic expression of the reaction in the above process;
18. Write the symbolic expressions of the following chemical reactions:
(1) litmus test solution turns red after introducing carbon dioxide.
② Using hydrogen peroxide solution to make oxygen in the laboratory.
③ Fine iron wire burns in oxygen.
(4) The ammonium bicarbonate stored in the warehouse disappeared in summer.
Which of the above reactions belongs to decomposition reaction and which belongs to oxidation reaction (fill in the blanks with serial numbers)
19.(5 points) Iron wire 1 root, 2 sulfur, 3 red phosphorus, 4 magnesium rods and 5 candles, and the five substances are burned in oxygen respectively. Answer the following questions with serial numbers: (1) What can't burn in air? (2) commonly used as a smoke bomb is; (3) commonly used as a signal flare; (4) Always put it in a light bulb to prevent the tungsten wire from being oxidized; (5) The generated gas will pollute the air.
20. Choose a suitable substance and fill in its serial number in the corresponding space: A, patina; B ammonium bicarbonate; C. oxygen; D. nitrogen; E. carbon dioxide; F. diamonds; G. potassium permanganate
(1) The most abundant gas in the air is _ _ _ _ _ _; (2) In nature, the hardest substance that can be used to scrape glass is _ _ _ _ _ _ _ _ _;
(3) a chemical fertilizer, easy to decompose _ _ _ _ _ _ when heated; (4) Violet-black solid, which is often used to make oxygen _ _ _ _ _ _;
(5) One of the raw materials for photosynthesis can be used as a greenhouse gas fertilizer _ _ _ _ _ _ _ _; (6) Green solid will turn black when heated.
2 1.(4 points) Physical properties of substances often include: ① color, ② state, ③ smell, ④ taste, ⑤ hardness, etc. According to the properties of substances, the following groups of substances can be easily distinguished. Please fill in the relevant serial number on the horizontal line.
(1) salt water and sugar water; (2) copper and aluminum;
(3) alcohol and white vinegar; (4) Mercury and silver.
Third, short answer questions
22. The picture on the right shows some labels of a health care product. Please read carefully and answer the following questions.
(1) The health care product has the following functions: among its main components, substances providing calcium are: participating in calcium metabolism and promoting its absorption; Zinc in minerals belongs to human body (choose "trace" or "constant").
(2) After taking this health care product, sometimes there will be abdominal distension and burping, and the reason for this reaction is (expressed by chemical equation).
Therefore, this health care product can also be used to treat diseases, but patients with severe gastric ulcer should use this medicine with caution and try to explain the reasons with what they have learned.
.
The mass of each piece of calcium is g.
23. When studying the chemical properties of oxygen, a research group found that there was no flame when the iron wire burned, but there was a bright flame when the candle burned. The students in this group made the following survey.
(1) Write the chemical equation of iron wire burning in oxygen.
(2) Inquiry 1: What is the cause of the flame produced by candle burning?
Light the candle, put one end of the metal tube into the internal flame, and draw out the contents. When the candle is lit at the other end, it also produces a flame (pictured). It can be seen that the flame produced by candle burning is formed by burning (full of "solid" or "gas") substances.
(3) Inquiry 2: What is the root cause of the flame produced by the burning of substances?
Find materials
Melting point/boiling point/temperature during combustion/℃
Paraffin 50∽70 300∽550 about 600
Iron 1535 2750 is about 1800.
Sodium 97.8 883 is about 1400.
As can be seen from the above table, whether a substance can produce flame when burning is related to its (fill in "melting point" or "boiling point") and the temperature when burning. It is inferred that when sodium burns, it will produce (fill in "Yes" or "No") flame.
(4) Charcoal has no flame when burned in oxygen, but it will produce flame when burned in life. The reason may be.
24.(4 points) Read the material and answer questions.
One kind of substance, chlorine (Cl2), is usually a yellow-green toxic gas.
Material Ⅱ Cl2 has strong chemical activity and oxidation, and can be directly combined with various metals and nonmetals. When the mixture of hydrogen and chlorine is ignited or illuminated by strong light, an explosion will occur.
The material ⅲ Cl2 can be used to prepare many disinfectants, such as ClO2, NaClO, Ca(ClO)2, etc.
(1) The correct way to smell chlorine in the laboratory is.
(2) The reactions of hydrogen and chlorine to generate hydrogen chloride gas are classified from the aspects of energy change ("endothermic reaction" or "exothermic reaction") and basic reaction types, which belong to.
(3) The following statement is incorrect (optional number of letters)
Combustion must involve chemical changes.
Oxygen is not necessary for combustion.
The reaction of substance C with oxygen belongs to oxidation reaction.
The explosion must be a violent oxidation reaction between combustible materials and oxygen.
Fourth, inference questions
25.(6 points) Among the seven elements A, B, C, D, E, F and G, the simple substance of element A can provide breathing for animals and plants; There are no neutrons in the atom of B; C is a metal element, which mainly exists in human bones and teeth; D is the element with the most kinds of compounds; E and f are two elements that make up salt; Lack of G element in human body can lead to anemia. The following substances consist of one or more of these seven elements. Please answer the following questions:
(1) If A is a simple substance composed of element B, the chemical reaction equation of its combustion is.
(2) If A is composed of four elements, the chemical reaction equation of A for treating hyperacidity is.
(3) If both substances A and B are exposed, they will deteriorate, and the two solutions prepared after deterioration will react to form A. Then the chemical equation of A deterioration is that the reaction chemical equation of A formation is.
(4) If A can react with two different substances to form B and C respectively, and B and C are composed of two identical elements, the chemical equations of the reaction are respectively.
Reference answer
1.D
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Test and analysis: A. Gas explosion is caused by gas combustion. When gas burns, it produces new substances, which belongs to chemical changes; B. The sour taste of milk is a sour substance produced by milk reaction. Changes produce new substances, which belong to chemical changes; C. Silver-white iron will become reddish-brown rust in the process of rust, producing new substances, which is a chemical change; D neon lights emit red light after being electrified, and no new substances are produced, which is a physical change.
Test sites: physical changes and chemical changes
2.B
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Analysis of test questions: A, the combination reaction is the reaction of two or more substances to produce another substance, that is, there are two or more reactants, so it is wrong; B, the oxidation reaction is the reaction between substance and oxygen, and the combination reaction emphasizes the kind of substance, which has nothing to do with whether it reacts with oxygen or not, so the oxidation reaction is not necessarily a combination reaction, such as candle burning, but it is an oxidation reaction, but it is not a combination reaction. Correct, C, substance and oxygen.
Test site: combination reaction and oxidation reaction.
3.C
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Analysis of test questions: the description of experimental phenomena includes direct perception through sensory organs such as eyes, mouth, nose and hands, and the conclusion inferred from the phenomenon is the experimental conclusion, so C is chosen.
Test Center: Description of Experimental Phenomena
4.D
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Analysis of test questions: physical properties: the properties of substances that do not need to undergo chemical changes. Including: color, state, smell, melting point, boiling point, density, hardness, solubility, volatility, ductility, conductivity, water absorption and adsorption. Chemical properties: the properties of substances in chemical changes. Combustibility, oxidation, reduction, activity, stability, corrosiveness, toxicity, metal activity, etc. , so choose D.
Test center: judgment of physical and chemical properties
5.B
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Test and analysis: the fundamental difference between physical change and chemical change lies in whether new substances are produced, and if new substances are produced, they belong to chemical change; On the contrary, it is a physical change. A, rice spoilage is the result of slow oxidation, which produces new substances and belongs to a chemical change; B. Fruit juicing is a change of material form, and no new material is generated, which belongs to physical change. Correct, C, iron pot rust is a chemical change in which iron reacts with oxygen and water in the air; D gas combustion is a chemical change in which carbon monoxide reacts with oxygen to generate new substances. So choose B.
Test center: the distinction between chemical change and physical change
6.A
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Analysis of test questions: physical properties: the properties of substances that do not need to undergo chemical changes. Including: color, state, smell, melting point, boiling point, density, hardness, solubility, volatility, ductility, conductivity, water absorption and adsorption. Chemical properties: the properties of substances in chemical changes. Flammability, oxidation, reducibility, activity, stability, corrosiveness, toxicity, metal activity, etc. A, natural gas as a fuel to use its flammability and chemical properties; B, "dry ice" is used for artificial rainfall, which uses dry ice to sublimate and absorb heat, so that the surrounding temperature is reduced, which is a physical property; C, pig iron is used for casting iron pots, which is a physical property; Copper is used in manufacturing.
Test center: judgment of physical and chemical properties
7.C
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Analysis of test questions: physical properties: the properties of substances that do not need to undergo chemical changes. Including: color, state, smell, melting point, boiling point, density, hardness, solubility, volatility, ductility, conductivity, water absorption and adsorption. Chemical properties: the properties of substances in chemical changes. Combustibility, oxidation, reduction, activity, stability, corrosiveness, toxicity, metal activity, etc. , so choose C.
Test center: judgment of physical and chemical properties
8.B
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Test and analysis: the fundamental difference between physical change and chemical change lies in whether new substances are produced, and if new substances are produced, they belong to chemical change; On the contrary, it is a physical change. A, industrial dilute sulfuric acid derusting is a chemical change in which sulfuric acid reacts with iron oxide to generate new substances; B, sodium hydroxide is easy to deliquesce in air, absorbing moisture in the air, but not generating new substances, which is a physical change. Correct, C, hydrochloric acid can make purple litmus turn red, reflecting the acidity of hydrochloric acid and generating new substances, which belongs to chemical changes; D, concentrated sulfuric acid makes the paper black, which is the corrosiveness of concentrated sulfuric acid. So choose B.
Test center: the distinction between chemical change and physical change
9.A
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Test and analysis: light a candle and put a cold plate above the candle flame (as shown in the figure below). After a while, new carbon black will be collected at the bottom of the cold plate. This experiment shows that due to insufficient oxygen, the candle burns incompletely and produces carbon black, so choose A.
Test center: exploration of candle burning experiment
10.B
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Analysis of test questions: slow oxidation is the reaction between substances and oxygen, which is slow and difficult to be found; Belonging to chemical changes; A the respiration of animals and plants belongs to slow oxidation; B the dissolution of sucrose does not produce new substances, which is not a chemical change; C the brewing of wine and vinegar belongs to slow oxidation; D food decay belongs to slow oxidation; So choose B.
Test site: classification of oxidation reaction
1 1.C
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Test analysis: physical properties refer to the properties of substances without chemical changes. Chemical properties refer to the properties of substances in chemical changes. The essential feature of chemical change is that new substances are produced in the process of change. The boiling point of A is -42. 1℃, and it is easy to liquefy without chemical change. B is slightly soluble in water, but does not change chemically when dissolved in alcohol; C. Flammability needs to be manifested through chemical changes; D colorless gas does not need to be expressed by chemical changes, so choose C.
Test center: determination of physical and chemical properties
12.C
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Test analysis: chemical change refers to the change with new substances, and physical change refers to the change without new substances. The essential difference between chemical change and physical change lies in whether new substances are produced; First, the explosion and combustion of fireworks will produce substances such as carbon dioxide, which belongs to chemical changes. Wrong; B, charcoal combustion can produce carbon dioxide, which belongs to chemical change. Wrong; C, no new substances are produced in the process of casting molten steel into steel ingots, which belongs to physical changes. Correct; D, the process of wine can produce alcohol, which is a chemical change. Wrong. So I chose C.
Test center: determination of physical and chemical changes.
13.B
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Test analysis: a gas can be collected by drainage method, indicating that it is insoluble in water or insoluble in water; It can also be collected by downward deflation, indicating that the density is less than air, so the gas has the physical properties of being insoluble in water and the density is less than air, so B is selected.
Test site: gas collection method
14.D
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Test analysis: physical properties are properties that do not need to be expressed through chemical changes, while chemical properties need to be expressed through chemical changes. The essential difference between the two is whether it is expressed by chemical changes, and the conduction of option A does not need to be expressed by chemical changes. The color of option b does not need to be represented by chemical changes; The state of option C does not need to be represented by chemical changes; D option rust needs to be manifested through chemical changes, so choose D.
Test center: determination of physical and chemical properties
15.C
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Test analysis: chemical changes are changes with new substances, while physical changes are changes without new substances. The essential difference between them lies in whether new substances are produced; A. Sima Guang smashed the jar and no new substance was produced; B. Cutting the wall and stealing light will not produce new substances; C. Red Cliff produces new substances when it burns. D. no new substance is produced when the iron pestle is ground into a needle; So choose C.
Test center: determination of physical and chemical changes.
16. (1)1cao2hlc3ca (oh) 24calcl2 (reasonable)
(2)①2 H2O 2 H2 ↑+ O2↑②CaCO3+2 HCl = = = CaCl 2+H2O+CO2↑
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Analysis of test questions: ① Oxide refers to a compound composed of two elements, one of which is oxygen. According to the elements in the title, the oxide can be calcium oxide, carbon dioxide, carbon monoxide, water, etc. ② Acids consist of acid radical ions and hydrogen ions. According to the elements in the title, the acid can be hydrochloric acid or carbonic acid. (3) Alkali refers to a compound composed of metal ions and hydroxide ions. According to the elements in the title, the alkali can be calcium hydroxide. ④ Salt refers to a compound composed of metal ions and acid radical ions. According to the elements in the topic, the salt can be calcium chloride, calcium carbonate, etc.
(2)① Water can be decomposed to produce hydrogen and oxygen when it is electrified. The chemical equation is: 2H2O2H2↑+O2↑;
② Calcium carbonate can react with hydrochloric acid to generate calcium chloride, water and carbon dioxide gas. The chemical equation is: CaCO3+2hcl = = CaCl2+H2O+CO2 =
Test sites: classification of substances, types of reactions, writing of chemical equations.
17.( 1)A, oxygen b, charcoal or carbon c, carbon dioxide d, nitrogen.
(2) Carbon+oxygen = carbon dioxide+calcium hydroxide = calcium carbonate +H2O
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Analysis of test questions: (1) Inference questions capture some special reaction phenomena. According to the fact that black solid B burns more violently in A than in air, it produces colorless and odorless gas C, which can make clear limewater turbid. It can be inferred that black solid B should be charcoal or carbon, while gas A should be oxygen, and gas C is naturally carbon dioxide. According to D, the filling gas of the bulb is a colorless and odorless gas. Put burning B into D, it will go out quickly, which means it is nitrogen.
(2) There are always two reactions in the above process. One is that black solid B burns in A, and the symbolic expression is: C+O2=CO2. The other is that C can make clear limewater turbid, and the symbolic expression is: CO2+Ca(OH) 2=CaCO3+H2O.
Test Center: A Solution to Reasoning Problem
18.①CO2+H2O = h2co 3②H2O 2 = H2O+O2③Fe+O2 = fe3o 4
④NH4HCO3 = NH3 + CO2 + H2O ②④ ③
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Analysis of test questions: ① litmus test solution turns red when it meets acid. The reason why litmus test solution turns red after introducing carbon dioxide is that carbon dioxide reacts with water to generate carbonic acid. The symbolic expression is: CO2+H2O = H2CO3.
② Hydrogen peroxide solution is used to produce oxygen and water in the laboratory, and the symbolic expression is: H2O2 = H2O+O2.
(3) The fine iron wire burns in oxygen to generate Fe3O4, and the symbolic expression is: Fe+O2 = Fe3O4.
(4) ammonium bicarbonate is unstable and will be decomposed into ammonia, water and carbon dioxide when heated. The symbolic expression is: nh4hco3 = NH3+CO2+H2O; Decomposition reaction: a reaction that produces two or more substances from one substance, so it belongs to decomposition reaction. Oxidation reaction is the reaction between substance and oxygen, so it belongs to oxidation reaction.
Test sites: writing of symbolic expressions, decomposition reaction, oxidation reaction.
19.( 1) ① ; (2) ③ ; (3) ④ ; (4) ③ ; (5) ②
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Test and analysis: (1) What can't burn in air is ① iron wire; (2) Red phosphorus is often used as a smoke bomb; (3) Magnesium rods are often used as flares; (4) Red phosphorus is often put in the bulb to prevent the tungsten wire from being oxidized; (5) The gas produced will pollute the air, that is, sulfur.
Testing center: properties and uses of substances.
20.d； f； b； g； e； A.
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Test and analysis: (1) The most abundant gas in the air is D nitrogen; (2) The hardest substance in nature, which can be used to scratch glass, is F diamond; (3) Fertilizer A is easy to decompose ammonium bicarbonate B when heated; ④ Violet-black solid, commonly used for oxygen production is potassium permanganate; (5) One of the raw materials of photosynthesis can be used as greenhouse gas fertilizer _E carbon dioxide; (6) Green solid, which will turn black and turn into rust when heated.
Testing center: properties and uses of substances.
2 1.( 1)④ (2)① (3)③ (4)②
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Test and analysis: (1) Salt is salty and sucrose is sweet. It can be distinguished according to taste, so choose 4; (2) Aluminum is silvery white and copper is red, which can be distinguished according to color. (3) Alcohol has a special smell, while white vinegar has a pungent smell. According to the smell, it can be distinguished, so fill in ③; (4). Mercury and silver are in different states, so fill in: ③.
Testing Center: Material Identification
22.( 1) calcium supplementation or prevention and treatment of osteoporosis and rickets CaCO3 vitamin D3 trace.
(2)CaCO3+2HCl==CaCl2+H2O+CO2↑ Overacidity produces carbon dioxide gas, which will cause gastric perforation.
(3)0.6
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Test analysis: (1) The main component of this health care product is calcium carbonate, which can provide you with the calcium you need for heating, so its function is to supplement calcium or prevent osteoporosis and rickets, participate in calcium metabolism and promote its absorption, and zinc is a trace element.
(2) After taking this health care product, the main component calcium carbonate reacts with hydrochloric acid in human gastric juice to generate carbon dioxide: CaCO3+2HCl = = CaCl2+H2O+CO2 =, so sometimes symptoms such as abdominal distension and burping occur, so this health care product can also be used to treat hyperacidity. However, due to the reaction to generate carbon dioxide gas, it may cause gastric perforation, so patients with severe gastric ulcer should use this medicine with caution.
(3) According to the label, each calcium tablet contains calcium carbonate 1.5g, so the mass of each calcium tablet =1.5× 40/100×100% = 0.6g..
Test center: chemical elements and human health, can read labels and calculate according to the contents of labels.
23. (1) 3fe+2o2f3o4 (2) The boiling point of gaseous state (3) is
(4) Combustible gases such as CO generated in the process of charcoal combustion continue to burn, resulting in flames.
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Test and analysis: (1) Chemical equation of iron wire burning in oxygen: 3fe+2o2f3o4.
(2) As one end of the metal conduit is put into the internal flame, the substance inside is led out and ignited at the nozzle at the other end, which shows that the gas is led out from the metal conduit, so the flame generated by candle burning is formed by the combustion of gaseous substances.
(3) According to the data in the table, candles burn with flame, and the temperature required for combustion is about 600℃ higher than the boiling point of paraffin wax 300∽550, while iron burns without flame, and the combustion temperature is about 1800, which is higher than the melting point 1535, but lower than the boiling point 2750. Therefore, whether the substance can produce flame is related to the boiling point, and the combustion temperature when it is combined with sodium is about 65438+.
(4) Combined with the above conclusions, the flame produced by burning substances is due to gas combustion, so it will be produced when burning charcoal in life: combustible gases such as CO produced during charcoal combustion continue to burn to produce flames.
Test Center: Exploration of Material Burning Phenomenon
24.( 1) Gently fan the bottle mouth by hand, so that only a very small amount of gas floats into the nostrils, and air is sucked into the nose (2) for exothermic reaction; Combination reaction (3)D
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Analysis of test questions: (1) The correct way to smell chlorine in the laboratory is to gently fan the bottle mouth with your hands, so that only a small amount of gas floats into your nostrils. Therefore, filling: gently fan the bottle mouth with your hands, so that only a small amount of gas floats into your nostrils. (2) When hydrogen burns in chlorine, it releases heat, which belongs to chemical combination reaction. So fill in: exothermic reaction, compound reaction. (3) Combustion must include chemical changes. Some explosions are chemical changes, such as gas explosions; Some are physical changes, such as tire inflation and explosion.
Test site: the method of smelling gas, the type of chemical reaction, the conditions and phenomena of combustion.
25.( 1)2 H2+O2 = = = 2H2O(2)nah co 3+HCl = = = NaCl+H2O+CO2 ↑( 3)2 NaOH+CO2 = = = na2co 3+H2O，na2co 3+Ca(OH)2 = = = CaCO3 ↓+ 2 NaOH(4)Fe+2 HCl = = = FeCl 2+H2↑、6HCl + Fe2O3 ===2FeCl3 +3H2O
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Test analysis: According to the description in the question, A is oxygen, B is hydrogen, C is calcium, D is carbon, EF is sodium and chlorine, and G is iron, so (1) if A is a simple substance composed of B, the chemical reaction equation of its combustion is 2h2+O2 = = 2h2o; (2) If A is composed of four elements, the chemical reaction equation of A for treating hyperacidity is nahco3+HCl = = NaCl+H2O+CO2 ↑; (3) If both substances A and B are exposed, they will deteriorate, and the two solutions prepared after deterioration will react to form a ... Then the chemical equation of nail deterioration is:) 2 NaOH+CO2 = = Na2CO3+H2O; The chemical equation of reaction to form A is Na2CO3+Ca (OH) 2 = = CaCO3 ↓+2NaOH; (4) If A can react with two different substances to form B and C respectively, and B and C are composed of two identical elements, the chemical equations of the reaction are Fe+2HCl = = FeCl 2+H2 ↑, 6HCl+Fe2O3 = = 2FeCl 3+3H2O respectively.
Test center: composition and properties of matter, inference of elements.