I. Reaction of substances with oxygen:
(1) the reaction of simple substance with oxygen (combination reaction);
Magnesium burns in air: 2Mg+O22MgO.
Iron burns in oxygen: 3Fe+2O2Fe3O4.
Copper is heated in air: 2Cu+O22CuO.
Aluminum burns in air: 4Al+3O22Al2O3.
Hydrogen burns in air: 2H2+O22H2O.
Red phosphorus burns in air: 4P+5O22P2O5.
Sulfur powder burns in air: S+O2SO2.
Carbon burns in air: C+O2CO2.
Incomplete combustion of carbon in air: 2C+O22CO
(2) the reaction of compounds with oxygen:
Combustion of carbon monoxide in oxygen: 2CO+O22CO2 (combination reaction)
Methane burns in air: CH4+2O2CO2+2H2O.
Alcohol burns in air: C2H5OH+3O22CO2+3H2O.
2. Several decomposition reactions:
Water decomposes under the action of direct current: 2h2o 2h2 =+O2 =
Heating potassium permanganate: 2kmno4k2mno4+MnO2+O2 =
Unstable decomposition of carbonic acid: H2CO3 = = H2O+CO2 =
Heating mercury oxide: 2HgO2Hg+O2↑ =
Hydrogen peroxide decomposes to produce oxygen: 2h2o 22h2o+O2 =
Calcined limestone at high temperature: CaCO3CaO+CO2↑ =
Three. Several redox reactions:
Reduction of copper oxide by hydrogen: H2+CuOCu+H2O.
Reduction of copper oxide by charcoal: c+2cuo2cu+CO2 =
Reduction of iron oxide by coke: 3c+2fe2o34fe+3co2 =
Reduction of copper oxide by carbon monoxide: CO+CuOCu+CuO.
Reduction of iron oxide by carbon monoxide: 3CO+Fe2O32Fe+3CO2.
4. The relationship between acid, alkali and simple oxide salt:
(1) Elemental metal+acid = = salt+hydrogen (displacement reaction)
Reaction of zinc with dilute sulfuric acid: zinc+sulfuric acid = = zinc sulfate +H2 =
Reaction of iron with dilute sulfuric acid: Fe+H2SO4 = = FeSO4+H2 =
27 magnesium reacts with dilute sulfuric acid: mg+H2SO4 = = mgso4+H2 =
28 Reaction of aluminum with dilute sulfuric acid: 2al+3H2SO4 = = Al2 (SO4) 3+3H2 =
29 reaction of zinc with dilute hydrochloric acid: Zn+2hcl = = zncl2+H2 =
Reaction of 30 iron with dilute hydrochloric acid: Fe+2 HCl = = FeCl 2+H2 =
3 1 reaction of magnesium with dilute hydrochloric acid: mg+2hcl = = MgCl2+H2 =
Reaction of aluminum with dilute hydrochloric acid: 2al+6hcl = = 2alcl3+3h2 =
(2) Simple metal+salt (solution) = = another metal+another salt
The reaction between iron and copper sulfate solution: Fe+CuSO4==FeSO4+Cu.
The reaction between zinc and copper sulfate solution: Zn+CuSO4==ZnSO4+Cu.
The reaction between copper and mercury nitrate solution: Cu+Hg(NO3)2==Cu(NO3)2+Hg.
(3) Alkaline oxide+acid = = salt+water
Reaction of 36 iron oxide with dilute hydrochloric acid: Fe2O3+6HCl==2FeCl3+3H2O.
37 Reaction of iron oxide with dilute sulfuric acid: Fe2O3+3H2SO4==Fe2SO4+3H2O
The reaction of 38 copper oxide with dilute hydrochloric acid: CuO+2HCl==CuCl2+H2O.
Reaction of 39 copper oxide with dilute sulfuric acid: CuO+H2SO4==CuSO4+H2O.
40 MgO reacts with dilute sulfuric acid: MgO+H2SO4==MgSO4+H2O.
The reaction of 4 1 calcium oxide with dilute hydrochloric acid: CaO+2HCl==CaCl2+H2O.
(4) Acid oxide+alkali = = salt+water
Caustic soda will deteriorate when exposed to air: 2NaOH+CO2==Na2CO3+H2O.
43 Soda absorbs sulfur dioxide gas: 2NaOH+SO2==Na2SO3+H2O
44 Soda absorbs sulfur trioxide gas: 2NaOH+SO3==Na2SO4+H2O.
45 The slaked lime deteriorates in air: Ca(OH)2+CO2==CaCO3↓+H2O.
46 slaked lime absorbs sulfur dioxide: Ca(OH)2+SO2==CaSO3↓+H2O.
(5) Acid+alkali = salt+water
Reaction of hydrochloric acid with caustic soda: HCl+NaOH==NaCl+H2O.
Reaction of hydrochloric acid and potassium hydroxide: HCl+KOH==KCl+H2O.
49 The reaction between hydrochloric acid and copper hydroxide: 2HCl+Cu(OH)2==CuCl2+2H2O
Reaction of 50 hydrochloric acid with calcium hydroxide: 2HCl+Ca(OH)2==CaCl2+2H2O.
5 1 The reaction of hydrochloric acid with ferric hydroxide: 3HCl+Fe(OH)3==FeCl3+3H2O.
52 kinds of aluminum hydroxide drugs were used to treat hyperacidity: 3HCl+Al(OH)3==AlCl3+3H2O.
The reaction between sulfuric acid and caustic soda: H2SO4+2NaOH==Na2SO4+2H2O.
The reaction between sulfuric acid and potassium hydroxide: H2SO4+2KOH==K2SO4+2H2O.
The reaction between sulfuric acid and copper hydroxide: H2SO4+Cu(OH)2==CuSO4+2H2O.
The reaction between sulfuric acid and iron hydroxide: 3H2SO4+2Fe (OH) 3 = = Fe2 (SO4) 3+6H2O.
Reaction between nitric acid and caustic soda: nitric acid+sodium hydroxide = = sodium nitrite +H2O.
(6) acid+salt = another acid+another salt
58 marble reacts with dilute hydrochloric acid: CaCO3+2hcl = = CaCl2+H2O+CO2 =
The reaction of sodium carbonate with dilute hydrochloric acid: Na2CO3+2HCl = = 2NaCl+H2O+CO2 =
60 magnesium carbonate reacts with dilute hydrochloric acid: mgco3+2hcl = = MgCl2+H2O+CO2 =
6 1 the reaction between hydrochloric acid and silver nitrate solution: HCl+AgNO3==AgCl↓+HNO3.
Reaction of sulfuric acid and sodium carbonate: Na2CO3+H2SO4 = = Na2SO4+H2O+CO2 =
The reaction between sulfuric acid and barium chloride solution: H2SO4+BaCl2==BaSO4↓+2HCl.
(7) alkali+salt = = another alkali+another salt
64 Sodium hydroxide and copper sulfate: 2NaOH+CuSO4==Cu(OH)2↓+Na2SO4
65 sodium hydroxide and ferric chloride: 3NaOH+FeCl3==Fe(OH)3↓+3NaCl
66 Sodium hydroxide and magnesium chloride: 2NaOH+MgCl2==Mg(OH)2↓+2NaCl
67 Sodium hydroxide and copper chloride: 2NaOH+CuCl2==Cu(OH)2↓+2NaCl
68 Calcium hydroxide and sodium carbonate: Ca(OH)2+Na2CO3==CaCO3↓+2NaOH
(8) Salt+Salt = = Two new salts
79 sodium chloride solution and silver nitrate solution: NaCl+AgNO3==AgCl↓+NaNO3
70 sodium sulfate and barium chloride: Na2SO4+BaCl2==BaSO4↓+2NaCl.
Verb (short for verb) Other reactions:
7 1 CO2 is soluble in water: CO2+H2O==H2CO3.
72 quicklime is soluble in water: CaO+H2O==Ca(OH)2.
73 Sodium oxide is soluble in water: Na2O+H2O==2NaOH
74 Sulfur trioxide is soluble in water: SO3+H2O==H2SO4.
Thermal decomposition of 75 copper sulfate crystal: cuso 4·5h2o cuso 4+5h2o.
76 anhydrous copper sulfate as desiccant: cuso 4+5h2o = = cuso 4·5h2o.
JJ Lin (735979509) 65438
Chemistry examination questions for the senior high school entrance examination in 2006 (experimental area of curriculum reform) (with answers)
(Exam form: closed-book exam questions * * * 6 big questions and 28 small questions. Score: 100. Examination time limit: 90 minutes. )
I should pay attention to this point: this volume has 8 pages and is divided into one or two volumes. Among them, there are 2 multiple-choice questions in volume 1 and 6 non-multiple-choice questions in volume 2; Please fill in the answers to the first multiple-choice questions in the corresponding places in the second volume, and only hand in the second volume.
The first volume (multiple choice questions)
First of all, I will choose (this topic *** 16 small question. Only one option in each small question meets the meaning of the question. 1 ~ 12 questions, 2 points for each small question; 13 ~ 16 questions, 3 points for each question, 36 points)
1. Studies show that iodine deficiency can cause goiter, so iodine can be supplemented from kelp. "Iodine" here refers to
A. iodine atom B. iodine molecule C. iodine ion D. iodine element
2. The changes shown in the figure below belong to chemical changes.
A. exhale the slide B. light the candle C. dry the wet clothes D. energize the light bulb to glow.
3. Among the following food packaging measures, what can't effectively prevent food corruption is
A. charging air B. charging nitrogen C. charging carbon dioxide D. vacuumizing.
4. The following common substances in life can be mixed with water to form a solution after stirring.
A. Flour B. Soil C. Salt D. Vegetable oil
5. The following experimental operations are correct.
A. Do not check the purity before igniting the combustible gas.
B. When diluting concentrated sulfuric acid, slowly inject water into the concentrated sulfuric acid.
C. When filtering, the liquid level is always lower than the edge of the filter paper.
D. After heating, blow out the flame of the alcohol lamp with your mouth.
6. It is wrong to explain the following phenomena from the molecular point of view.
A. Volatilization of gasoline-molecular volume becomes larger
B.flowers are everywhere-molecules are constantly moving.
C. Hydrogen combustion-molecular change
D A drop of water has about 1.67× 102 1 water molecule-the molecule is very small.
7. The following substances belong to the oxide is
A. oxyboron H2O potassium chloride sodium hydroxide
8. The following practices in daily life are correct.
A. If the kitchen gas leaks, immediately turn on the power switch of the exhaust fan.
B. When you enter a cave with bad air, you can test it with candle lighting.
C use a coal stove for heating, and put a pot of water on the coal stove to prevent gas poisoning.
D. In order to prevent food waste, moldy peanuts and rice can be washed with water before eating.
9. Among the following common fertilizers, compound fertilizer is
A. Potassium sulfate (k2so4) urea
C. ammonium dihydrogen phosphate D. calcium phosphate
10. The valence of lead in lead dioxide (PbO2) is
A.-2 B.+ 1 C.+2 D. +4
1 1. Rational development and utilization of resources is the premise of human sustainable development. The following measures to protect resources are wrong.
A. Brush a layer of paint on the iron railing to protect metal resources.
B. The factory wastewater is recycled after treatment to save water resources.
C. Install tail gas purification devices on automobiles to save petroleum resources.
It is forbidden to use disposable wooden chopsticks to protect forest resources.
12. The following is to convert chemical energy into electrical energy.
A. Coal power generation B. Wind power generation C. Hydroelectric power generation D. Solar power generation
13. The following statement about fire fighting is wrong.
A. When cooking, cover the oil pan immediately when it catches fire-isolate combustible materials from the air.
B. The wood is splashed with water on the fire, which reduces the ignition point of combustible materials.
C. Put out forest fires and open up isolation zones-remove and isolate flammable materials.
D. Accidentally spilled alcohol on the desktop and burned it, and covered it with a wet cloth-oxygen insulation to cool down.
14. The schematic diagram of the atomic structure of the element is shown on the right. Xiaohong understands that its mistake lies in
A. There are 12 protons in the nucleus.
There are three electron shells outside the nucleus.
C. this element belongs to metallic elements.
D. atoms are negatively charged after losing electrons.
15. When distinguishing the following common substance groups, the method used is wrong.
A. Hard water and soft water-add soapy water and shake.
B. wool and cotton fabrics. smell after burning
C carbon monoxide and methane-observe the flame color after ignition.
D salt and baking soda (NaHCO3)-add acetic acid drop by drop.
16. Xiaojun summed up the knowledge he learned in the form of the right picture, in which A includes B, C, D ... Among the following relationships, the wrong group is
A, B, C, D ... A, B, C, D ... ...
AA ordinary desiccant ordinary desiccant limestone, concentrated sulfuric acid, quicklime limestone, concentrated sulfuric acid, quicklime ordinary desiccant limestone, concentrated sulfuric acid, quicklime
Common alloy stainless steel, solder, pig iron stainless steel, solder, pig iron B common alloy stainless steel, solder, pig iron
CC Common Nutrients Common Nutrients protein, Inorganic Salts, Vitamin protein, Inorganic Salts, Vitamin C Common Nutrients protein, Inorganic Salts and Vitamins.
DD table salt, soda ash, potassium permanganate, soda ash, potassium permanganate D table salt, soda ash, potassium permanganate.
Volume 2 (non-multiple choice questions)
I want to pay attention to: 1. Carefully examine the questions and check them carefully; The handwriting is neat, and the writing standard of chemical symbols.
The answer can be expressed in words, tables or charts.
3. Data and information that may be used in the answer:
(1) Relative atomic mass: h ~1c ~12o ~16n ~14.
(2) Solubility of some acids, bases and salts at 20℃:
OH-OH-NO3-NO3-Cl-Cl-SO42-SO42-CO32-CO32-OH-NO3-Cl-SO42-CO32-
H+H+- Dissolve, volatilize, volatilize, volatilize, volatilize, volatilize H+- dissolve, volatilize, volatilize, dissolve, volatilize.
Sodium+sodium+soluble, soluble, soluble, soluble.
Ca2+Ca2+ slightly soluble slightly insoluble Ca2+ slightly soluble slightly insoluble.
Ba2+Ba2+ dissolve, dissolve, dissolve, dissolve, dissolve, dissolve, dissolve, dissolve, dissolve, dissolve, dissolve.
Cu2+Cu2+ insoluble soluble insoluble Cu2+ insoluble soluble insoluble.
Second, let me fill in the blanks (***4 small questions, 3 points for each empty chemical equation, and the rest 1 point, that is, 18 points).
17.(6 points) Fill in the following form:
( 1)( 1) (2)(2) ( 1) (2)
Chemical symbol chemical symbol HH 2P2O52P2O5 Al3+Al3+ chemical symbol H 2P2O5 Al3+
Name or meaning (write only one) Name or meaning (write only one) 2 iron atoms, 2 iron atoms, 3 oxygen atoms, 1 ozone molecule, 3 oxygen atoms, 2 valence carbon monoxide, 2 valence name or meaning (write only one) 2 iron atoms, 3 oxygen atoms, 1 ozone molecule.
18.(4 points) The figure on the right is the curve of the solubility of solid substances A and B with temperature change, so I can answer the following questions:
(1) At 40℃, the solubility of substance A is g. ..
⑵ The substances whose solubility changes greatly with temperature are.
(3) At 30℃, add 30g of substance B into 100g of water, and after fully dissolving, the obtained solution is a solution (filled with "saturated" or "unsaturated"), and the mass fraction of solute in the obtained solution is.
19.(5 points) Chemical knowledge is widely used in production and life.
(1) At the end of 2005, a chemical plant in Jilin exploded, and a large amount of toxic substances flowed into Songhua River. The environmental protection department put activated carbon into the water in time to reduce pollution, which is to use the characteristics of activated carbon.
⑵ Since June 5438+February 2005 1, the use of ethanol gasoline has been widely promoted in our province, that is, adding a proper amount of ethanol to gasoline. The advantage of using ethanol gasoline is that the chemical equation of complete combustion of ethanol (C2H5OH) in oxygen is as follows.
20.(3 points) Dry ice is solid carbon dioxide, which is easy to sublimate at room temperature. The picture below shows the sublimation of dry ice. According to the information in the picture, the properties and uses of dry ice are analyzed from the point of view.
(1) When dry ice sublimes (fill in "absorption" or "release"), it generates a lot of heat, so it can be used as a refrigerant or for artificial rainfall.
⑵ Dry ice can participate in the photosynthesis of green plants after being converted into carbon dioxide gas, so it is used for greenhouse vegetable cultivation.
⑶ 。
Third, let me explain (***3 small questions, 3 points for each empty chemical equation, and the rest 1 point, that is, 17 points).
2 1.(4 points) Nitric acid can be reacted as follows: 4 HNO34 NO2↑+ ↑+ 2H2O. Based on this, I can answer:
The chemical formula of the substance in (1) is.
(2) I can also analyze from different angles and get the following understanding of HNO3:
Look from the composition,;
In nature,;
In terms of storage, ...
22.(7 points) We often use the following devices for experiments:
A B C D E
(1) Device B in the laboratory can prepare a variety of gases, and I can write the chemical equation for preparing one of them:, and the gas collection device is (fill in the letter number, the same below).
(2) The mixture of solid A and solid B is often heated in the laboratory to prepare gas C, so the generator used to prepare gas C is; If only E device can be used when collecting gas C, it can be inferred that the nature of C may be, ...
23.(6 points) Put the four substances A, B, C and D into a closed container and react under certain conditions. After a period of time, the relevant data are measured as follows:
Material AA BB CC DD material A B C D
Mass before reaction (g) Mass before reaction (g) 99 22 2222 1 1 Mass before reaction (g) 9 2 22 1
Mass after reaction (g) mass after reaction (g) xx 22 66 2 12 1 mass after reaction (g) x 2 6 2 1
(1) This type of reaction is a reaction; x= g .
According to the analysis of the data in the table, B may not participate in the chemical reaction, or it may be the agent of the reaction.
(2) Write an example of the same chemical equation as the above reaction type.
Fourth, let me analyze (***2 small questions, the chemical equation is 3 points each, and the rest are 1 minute,1minute).
24.(6 points) A factory has copper scrap containing a small amount of iron filings. Xiaojun wanted to recover copper from it, and he designed two schemes according to the idea of "green chemistry":
Experimental operation steps Experimental operation steps Scheme evaluation Scheme evaluation Experimental operation steps Scheme evaluation
Scheme I (physical method) Scheme I (physical method) respectively recovers copper and iron in magnets in contact with iron filings and copper filings mixture ... Scheme I (physical method) respectively recovers copper and iron in magnets in contact with iron filings and copper filings mixture. ...
Scheme 2 (chemical method) Scheme 2 (chemical method) embodies the idea of green chemistry: copper is recycled, and Scheme 2 (chemical method) embodies the idea of green chemistry: copper is recycled.
Write the chemical reaction equation involved in scheme 2.
25.(5 points) On May 18, 2006, a major traffic accident occurred in a expressway, and a tanker full of highly toxic chemicals-dimethyl sulfate (C2H6O4S) leaked. Firefighters diluted the dimethyl sulfate leaked from the driveway with a spray gun, but some drugs still flowed into the roadside farmland.
Dimethyl sulfate is an oily flammable liquid with a slight onion smell. It burns completely to produce carbon dioxide, sulfur dioxide and water; It reacts rapidly with water to produce sulfuric acid and methanol (CH3OH).
Use what you have learned to answer the following questions:
(1) Xiaojun thinks that cars and people can be evacuated, and then the leaked toxic dimethyl sulfate can be burned by burning. My views and reasons are as follows.
.
(2) A week later, Xiaojun measured the pH value of farmland soil on the roadside and found that the pH value was 7 (fill in ""). At his suggestion, the farmer sprinkled a proper amount of white solid into the soil to improve the pH value of the soil.
(3) Write down any chemical equations involved in the problem:
.
Five, let me explore (*** 1 small question, chemical equation every empty 3 points, the rest every empty 1 point,1point)
26.( 10) Xiaojun made the following series of exploratory experiments with battens as the basic raw materials:
(1) Explore the composition of battens;
Experimental operation, experimental operation, experimental phenomenon, experimental conclusion, experimental conclusion method, experimental operation, experimental phenomenon, experimental conclusion method.
Ignite the dried battens, cover a dry cold beaker above the flame to ignite the dried battens, and cover a dry cold beaker above the flame for a while to generate water mist on the inner wall of the beaker. After a while, there was water mist on the inner wall of the beaker. There must be elements in the wood. According to the experiment, we can infer the experimental conclusion. According to the experiment, we can infer the experimental conclusion. Light the dry wood strips and cover a dry cold beaker above the flame for a while, and the inner wall of the beaker will produce water mist. There must be elements in the wood. According to the experiment, we can infer the experimental conclusion.
Keep the flame near the bottom of the beaker. Keep the flame near the bottom of the beaker. A layer of black substance will appear at the bottom of the beaker. A layer of black substance will appear at the bottom of the beaker. There must be elements in the wood. Keep the flame near the bottom of the beaker. A layer of black substance will appear at the bottom of the beaker. There must be elements in the wood.
⑵ According to the experimental principle of measuring the oxygen content in the air by burning red phosphorus, Xiaojun thinks that charcoal produced by burning wood strips can replace red phosphorus to measure the oxygen content in the air, and carries out experiments according to the device on the right.
(1) According to the experimental principle.
After checking the air tightness of the device, Xiaojun quickly inserted the burning spoon with enough red-hot charcoal into the gas container, plugged it, and opened the spring clip after the red-hot charcoal was extinguished and cooled to room temperature. No back suction was found.
After careful analysis, Xiaojun found that the reason for the failure of the experiment was (answer 1)
.
② Xiaojun replaced the fine sand in the gas cylinder with solution and repeated the above experiment. There is reverse absorption, and a chemical equation is written, which can reflect the action of the solution. Xiaojun also found that the amount of water sucked back did not reach 1/5 of the original remaining volume in the gas container. The reason may be (Answer 1).
(3) After reflecting on the inquiry process of the above experiment, Xiaojun thinks that when measuring the oxygen content in the air by combustion method, the choice of drugs or the requirements for products should be considered (answer 1).
Six, I can calculate (***2 small questions, 27 small questions 2 points, 28 small questions 6 points, 8 points)
27.(2 points) Teenagers should "cherish life and stay away from drugs". "Ice" refers to the synthetic drug methamphetamine (C 10H 15N), and it is also the main component of the drug "ecstasy", which has strong exciting and hallucinogenic effects, rapid action and easy addiction.
The relative molecular weight of (1) methamphetamine is:
⑵ The mass fraction of hydrogen in methamphetamine is.
28.(6 points) A chemical group is trying to determine the mass fraction of basic copper carbonate [Cu2(OH)2CO3] in a copper mine. Weigh 30g copper ore sample into a beaker, add 10% dilute hydrochloric acid dropwise until the reaction is complete, and use 146g dilute hydrochloric acid. (Assuming that impurities in copper ore do not react with dilute hydrochloric acid and are insoluble in water) Try to find out:
(1) What is the mass of HCl in dilute hydrochloric acid?
⑵ What is the quality of basic copper carbonate in copper mine? What's its mass fraction?
⑶ What is the mass fraction of solute in the copper chloride solution obtained after the reaction?
(The chemical equation of the reaction is: Cu2 (OH) 2co3+4hcl = = 2cucl2+CO2 ↑+3H2O.
The relative molecular weight of each substance in the reaction: Cu2 (OH) 2co3 ~ 222hcl ~ 36.5cucl2 ~135.
Carbon dioxide ~44 H2O~ 18)
Reference answer
First of all, I will choose (this topic *** 16 small question. Only one option in each small question meets the meaning of the question. 1 ~ 12 questions, 2 points for each small question; 13 ~ 16, 3 points for each small question, 36 points. The answers are numbered in letters, and only one answer is selected for each small question and scored correctly. Other situations are not scored.)
Title Title Title1122 33 44 55 66 77 88 9910111112/. 438+05 16 16 Title12345678910121314/kloc-.
Answer answer answer answer answer answer answer answer answer answer answer answer answer answer answer answer answer.
2. Let me fill in the blanks (***4 small questions, 3 points for each empty chemical equation, and the rest 1 point is 18 point. When writing a chemical equation, as long as the chemical formula is wrong, the blank does not score; If the chemical formula is correct, or the reaction conditions are not balanced or the state symbols are not marked, deduct 1 minute. The same below)
17.
Chemical symbol chemical symbol 2 Fe 2 Fe 3 o 00 chemical symbol 2 FeO 3 o 00
Name and meaning (write only one) Name and meaning (write only one) Hydrogen element; Or hydrogen element with 1 hydrogen atom; Or 1 hydrogen atom, 2 molecules of phosphorus pentoxide and 2 molecules of aluminum ions of phosphorus pentoxide; Or 1 aluminum ion; Or 1 aluminum ion and 3 units of positively charged aluminum ion; Or 1 aluminum ion; Or 1 aluminum ion (write only one kind) hydrogen element with three unit positive charge names and meanings; Or 1 hydrogen atom and 2 molecular aluminum ions of phosphorus pentoxide; Or 1 aluminum ion; Or 1 aluminum ion with 3 unit positive charges.
18.( 1) 35 (2) A (3) saturated by 20%
19.( 1) adsorption description: words are misspelled and spaces are not scored.
(2) It can save petroleum resources (or effectively reduce the pollution of automobile exhaust; Or ethanol is a renewable energy source; Or it can promote agricultural production; Or ethanol is cheap, which reduces the cost ...) C2H5OH+3O22CO2+3H2O
20.( 1) Absorb (2) gas fertilizer
(3) Carbon dioxide can't burn, does not support combustion, and its density is higher than that of air, so it can be used to put out fires (carbon dioxide can also be dissolved in water to make carbonated drinks, such as soda or beer). ); Or carbon dioxide is dissolved in water to make carbonated water, which can improve alkaline soil; Or carbon dioxide can react with calcium hydroxide to make the lime slurry wall brush hard ...)
Note: The answers to the above open questions can be scored as long as they meet the requirements of the questions. Also in the following
Third, let me explain (***3 small questions, 3 points for each empty chemical equation, and the rest 1 point, that is, 17 points).
2 1.⑴ O2
(2) HNO3 is composed of hydrogen, nitrogen and oxygen (or 1 nitric acid molecule is composed of 1 hydrogen atom, 1 nitrogen atom and 3 oxygen atoms); Nitric acid is unstable to heat or light and easy to decompose; Should be stored at low temperature (or protected from light; Or in a brown reagent bottle ...)
22.( 1) 2H2O22H2O+O2 write (or CaCO3+2HCl = = CaCl2+H2O+CO2 write;
Or Zn+H2SO4 = = ZnSO4+H2 = ...) If O2 is prepared, select C (or D, or C and D); If CO2 is generated, select D; If H2 is ready, choose C (or E, or C and E).
Note: The second space above should match the 1 space. If the chemical equation of space 1 is written incorrectly, but it can be seen what gas is produced, and the second space matches it, the second space will be given points; If the space 1 is left blank, space 2 will not be scored.
(2) A is soluble in water and its density is less than that of air (or can react with water; Or does not react with components in the air at room temperature ...)
23.( 1) Combination 5 catalysis
(2) c+o2co2 or 2Mg+O22MgO or CO2+H2O = = H2CO3;
Or Cao+H2O = = Ca (OH) 2. ...
Fourth, let me analyze (***2 small questions, 3 points for each empty chemical equation, 1 minute for the rest, 1 1 minute).
24. Use sulfuric acid (or hydrochloric acid, or copper sulfate, or copper chloride, or copper nitrate) to filter waste.