Introduction Chemistry has made the world a more colorful place
1. D 2. D 3. D 4. B 5. D 6. D
7. C 8. A 9. B 10. C
11. (1) ② (2) ③ (3) ①
(4) ④
12. (1) ② ⑤ ( (2) ④ ⑥ ⑧ (3) ③ ⑦
(4) ①
13. (1) the development of clean energy that does not pollute the environment
(2) the development of biodegradable plastics (3) the use of chemical
principles to eliminate pollution at the source (any other reasonable answer will do)
14. (1) can save the resources of the metal (2) can
14.
Reducing the impact on the environment (any other reasonable answer)
Unit 1: Entering the World of Chemistry
Subject 1: Changes and Properties of Substances
1. B 2. A 3. B 4. D 5. B 6. D
7. C 8. A 9. B 10. C 11. C
12. (1) Chemical Changes (2) Physical Changes
13. (1) The light emitted by an electric lamp when it is energized is a physical change
(2) The heat generated by an electric lamp when it is energized is a physical change (or
the heat generated by an electric iron when it is energized, etc.) (3) Painting a wall with paint
is a physical change (4) The sublimation of dry ice produces gases which are
physical changes (5) The evaporation of saline water produces a solid
is a physical change.
Physical changes
14. (1) ① ② ③ (2) ④ ⑦ (3) ⑦
15. Let's take a look at the
chemistry around us from the following aspects: (1) Clothing: chemical fibers (man-made fibers or synthetic
fibers), polypropylene nonwoven fabrics, plastics, the production of rubber and so on,
Changing the people's clothing and improved the quality of life.
(2) Food: the development of chemical fertilizers and pesticides has led to the production of bumper crops of grain, vegetables, water
fruit, etc., which not only solved the problem of people's food and clothing
problems, but also changed the structure of the diet, so that people's diets have moved in the direction of
being conducive to health. (3) Housing: the mass production of iron and steel, aluminum,
cement, plastic steel doors and windows and other building materials, driving
the construction industry's booming development, so that people's living conditions have greatly improved
good. (4) Line: oil processing, highway construction, the production of synthetic
rubber, automobile manufacturing and cars into the home
Court, etc., so that people travel more convenient, fast. (5) Medical:
Medical equipment, drugs, health care equipment research, hospital equipment
updated, improved medical conditions, so that people's health
situation has been greatly improved. (6) Use: People's daily use of
computers, televisions, refrigerators, washing machines, cell phones, a variety of adhesive
combination, non-stick pans, pencils, rulers and so on, all reflecting all the changes brought to us by chemical
science.
2
Human Education Edition - Chemistry - Grade 9 (above)
Subject 2 Chemistry is a science based on experimentation
1.C 2.C 3.D 4.C 5.C 6.A
7.A 8.C 9.C 10.A
11.Oxygen Carbon Dioxide Left
12.Fill the cylinder with water and cover it with a glass. Fill the cylinder with water, cover it with a piece of glass, take it into the
cave, pour out the water, and then cover it with a piece of glass and take it out of the cave.
13. (1) The exhaled gas makes the clarified limewater more
cloudy
(2) The exhaled gas beads up on the glass
(3) A burning match burns shorter in the exhaled gas
14.
14. (1) ① Carbon dioxide produced by burning candles
makes clarified lime water cloudy (2) Water vapor
(3) ③ ① Carbon dioxide does not support combustion
Subject 3 Walking into a Chemistry Laboratory
1. C 2. C 3. B 4. C 5. A 6. D
7. C 8. C 9. D 10. D
11. (1) Measuring cylinder (2) Glue-tip burette (3) Gas-collecting
bottle (4) Test tube (5) Crucible tongs (6) Clamps of the iron stand (7) Asbestos mesh to make the beaker heated uniformly (8)
Tweezers, medicine spoon, paper trough
12. (1) Crush the container (2) Fire (3) Damage to
laboratory bench
13.
13. The 100-mL cylinder has a larger measuring range, so the error
difference in reading will be larger; the 100-mL cylinder has a larger surface area, so more liquid remains on the wall of the
14. (3)
White solid, with wick in the centerMelting point higher than room temperature; combustible
Burning, flaming, exothermic, with some
Partial melting of the candle
Candle is flammable, combustion is exothermic,
Flame suggests that it is the candle vapors that are burning
Burning, the candle melts with the heat
Mist on the wall of the cup produces water
Lime water turns cloudy and produces carbon dioxide
Bottom turns black, probably charcoal black
Candle flame goes out
Oxygen is gradually removed and oxygen is removed from the candle. p>
Oxygen is gradually consumed, and the carbon dioxide produced
does not support combustion
The result of condensation of the white smoke candle vapors
Unit 2: The Air Around Us
Subject 1: Air
1. B 2. C 3. A 4. D 5. B 6. D
7. B 8. D 9. D 10. C
11. p>
11. (1) Substances can burn in air (food
spoils easily in air, metals rust in air, etc.)
(2) Dry crackers become moist in air (water beads on the surface of things you take out of the refrigerator
, frost on windows in winter, etc.)
(3) Plants are able to photosynthesize (clarified lime water placed in the air is not a good choice)
(4) Plants are able to photosynthesize (clarified lime water placed in the air is not a good choice). p>
Grey water becomes cloudy when left in the air, etc.
(4) There is a lot of nitrogen in the air
12. Nitrogen Oxygen Nitrogen Oxygen
13. (1) Produces a lot of white smoke and lets out a lot of heat
Phosphorus + Oxygen? → ignite
phosphorus pentoxide (2) 15
(3) make sure
that the oxygen is consumed so that the results are accurate (4) not easily
dissolved in water does not support combustion (5) not enough red phosphorus; not enough water in the beaker; open the stopcock before it has cooled down (any other
reasonable answer is acceptable) (6) prevent leakage of gas from the collecting
cylinder when the burning spoon is extended; good sealing of the device
Subject 2 Oxygen
1. A 2. A 3. D 4. A 5. D 6. D
7. B 8. B 9. B 10. A
11. (1) Carbon + Oxygen? → ignition
Carbon dioxide
3
Answers and Hints
(2) Magnesium + oxygen? → ignite
Magnesium oxide (3) Alcohol + Oxygen
→ igniteWater + Carbon dioxide (4) Hydrogen + Oxygen? → ignite
water
(1) (2) (4)
12. Use a matchstick to ignite the wire to prevent the high
temperature solid from splashing on the bottom of the bottle, causing the cylinder to explode Avoiding
the matchstick from consuming too much oxygen The sparks shoot out, releasing heat
in quantities that produce a black solid
13. (1) (1) (1) are all chemical reactions. ) ① both are chemical reactions ② both are oxidation
reactions ③ both require ignition (2) liquid (3) sulfur +
oxygen? → ignition
Sulfur dioxide Phosphorus + oxygen? → ignite
Phosphorus pentoxide
Diphosphorus Iron + oxygen? → ignite
Triiron tetraoxide
14. (1) White phosphorus burns and the piston stops at "4"
(2) Oxygen makes up about 1
5 of the volume of the air
Subject 3: Oxygen Preparation
1. D 6. C
7. D 8. B 9. A
10. Manganese Dioxide as Catalyst Drainage Method
Manganese Dioxide as Catalyst, Heating and Drainage Method
11. (1) Potassium Chloride + Oxygen (2) Mercury + Oxygen
(3) Potassium Manganate + Manganese Dioxide + Oxygen
12. Potassium Chlorate Oxygen Potassium chloride Sulfur dioxide
Manganese dioxide
13. (1) Alcohol lamp Iron stand Long-necked funnel Cone
shaped flask Sink (2) D F Cotton Potassium permanganate
→ HeatingManganese dioxide + manganese dioxide + oxygen Decomposition
(3) Reach below the liquid level Any time to be able to control the progress of the reaction and end (4) Wrong method of collection, the leakage of gas, the reaction is not controlled. (4) wrong collection method, device leakage, etc.
Unit 3 Water in Nature
Topic 1 Composition of Water
1. A 2. B 3. B 4. D 5. C 6. B
7. B 8. D 9. B 10. C
11. oxygen hydrogen 1:2 water? → energized
Oxygen +
hydrogen decomposition reaction hydroxide two elements molecules can be
divided, atoms can not be divided
12. (1) negative Oxygen (2) (①) water is composed of hydrogen and oxygen
two elements (2) water is energized, the decomposition reaction occurs
generation of hydrogen and oxygen (3) before and after the chemical reaction of the elements of the
Types remain the same (any other reasonable answer is acceptable)
13. ***Drops of 43,200mL of water can be used for 864 people to drink
for one day. Through calculations, strengthen our awareness of water conservation,
Doing our part for human and social development
14. (1) Oxygen is denser than air, and hydrogen is less dense
than air (2) Sharp pops Explosions Purity
Subject 2 Molecules and Atoms
1. D 2.C 3.C 4.A 5.B 6.D
7. B 8. A 9. C 10. B
11. (1) Molecules are in constant motion (2) Molecules move faster at higher temperatures (3) Molecules are very small
(4) Gas molecules are more widely spaced apart (5) Molecules are particles that maintain the chemical properties of a substance
12. From right to left, they become Red Constant motion
13. In the process of change, mercury atoms and oxygen atoms are
not changed, so the atom is the most
smallest particles in the chemical change, the atoms can be combined to form molecules
14. temperature increases, the rate of molecular motion accelerated
Topic 3 water purification
1. D 2. D 3. D 4. C 5. D 6. C
7. D 8. A 9. C 10. C
11. (1) filtration (2) so that impurities suspended in the water
coagulation and precipitation (3) adsorption of colored, smelly substances
(4) disinfection and sterilization (5) a greater number of soluble calcium, magnesium
compounds Boiling
12. (1) filtration (2) drainage (3) insoluble
4
Humanistic Edition-Chemistry-9th Grade (Upper)
distillation (4) fine gauze, chopsticks (5) (1) ① the filter paper is torn
(2) the instrument is not washed (3) the liquid level is higher than the edge of the filter paper
, etc. (6) (1) ① the mouth of the beaker is tightly pressed against the glass rod (2) the glass rod is
tightly pressed against the triple-layer filter paper (6) The mouth of the beaker is pressed against the glass rod. (7) The glass rod is pressed against the three layers of filter paper. (8) The lower end of the funnel is pressed against the inner wall of the beaker
13. (1) Adsorbs impurities and prevents the liquid from splashing
(2) The filter paper does not fit tightly against the wall of the funnel, and the air bubbles that are left in it slow down the filtration process. (3) It is not pure water, and it contains soluble impurities. Activated carbon (3) No
Topic 4 Caring for water resources
1. B 2. B 3. B 4. B 5. D 6. D
7. C 8. D
9. (1) Activated carbon (2) Filtration (3) Mop washing,
toilet flushing, etc. (4) Reducing sewage discharge and pollution;
water conservation, protect water resources, reduce water costs, etc.
10. (1) (1) ① (2) ② (3) ⑤ (4) ④
(5) ③
11. (1) watering the flowers with rice-washing water; mopping the floors and flushing toilets with bathing, washing clothes
or washing water, etc. (2) (1) Do not throw away the waste electricity
ponds, especially not to the water, and
to family members and surrounding leaders to do publicity; ② waste batteries
into the designated garbage cans, centralized treatment; ③ explore ways to manage
waste batteries
12. (1) write mercury, phosphorus, hydrogen, oxygen, three of the four kinds of
kinds can be (2) B (3) industrial wastewater or sewage
to be treated to standard discharge; chemical and biological waste. (3) industrial wastewater or sewage
to be treated and discharged; fertilizers or pesticides should be used reasonably
; promote the use of farmyard manure; do not use phosphorus-containing detergents (other
other reasonable answers can be) (4) 鈪 ② (3) ①
② ① (3) ②
expansion topic the lightest gas
1. D 2. 7．C
8．Zinc grains Dilute sulfuric acid Zinc + Dilute sulfuric acid → Sulfuric acid
Zinc + Hydrogen gas
9．(1) Potassium permanganate? → heating
Potassium manganate + manganese dioxide
Manganese + oxygen A D or F (2) B filtration Leakage
Doublet, beaker, glass rod (3) B, C, G E or F
(4) state of the reactants Reaction conditions Water solubility
density (5) water surface is stable and no longer falling
10. Hypothesis 1: Manganese dioxide (or MnO2) bis
oxygenated water (or H2O2) Stick a sparking wooden stick into the test tube
The sparking stick rekindles Oxygen (or O2) B
Hypothesis 2: Iron powder (or Fe) Dilute sulfuric acid (or dilute
H2SO4) Move the sparking stick closer to the mouth of the test tube The gas
burns and the flame is light blue Hydrogen gas (or H2) A or B
Unit IV The Mystery of the Composition of Matter
Subject 1 The Composition of Atoms
1. C 2. D 3. D 4. A 5. A 6. D
7. C 8. D 9. B 10. B
11. (1) Molecules, atoms, ions (2) Protons, protons
Nuclei (3) Electrons (4) Molecules, atom, neutron
(5) atom (6) molecule (7) nucleus (or proton
and neutron) (8) electron (9) proton and electron
(10) electron
12. (1) 40 (2) 12ac
bd
13. (1) C A B (2) B H2O energy
(3) Water? → Energized
Hydrogen + Oxygen
14.
5
Reference Answers and Hints
Topic 2 Elements
1. D 2. C 3. A 4. D 5. C 6. D
7. B 8. C 9. A 10. A
11. (1) Cu (2) 4Mg (3) Na (4) He
(5) Al (6) O (7) N (8) Fe (9) Hg
(10) H2
12. (1) Mendeleev (2) 200.6 Ar
(3) A (4) 118
13. (1) D (2) B (3) C (4) A
(5) E
14. (1) D (2) B (3) C (4) A
(5) E
16.
14. (1) The outermost layers have all reached a relatively stable structure (or the outermost
layer is filled with electrons) (2) The number of electrons in the outermost layer (or
the number of protons, the number of nuclear charges) increases in turn (3) From metallic elements
to non-metallic elements, and finally rare gases elements
Topic 3 Ions
1. D 2. D 3. C 4. C 5. A 6. D
7. D 8. D 9. A 10. C
11. 11 ②
12. (1) A (2) 3 2
13. C B, D A A A, C
14. 3Mg2+ nCl- SO2 -
4NH+
4
15. 1 atom of argon (or elemental argon or argon gas)
2Si 3 ferrous ions 4Al3+
16.(1) number of nuclear charges (or protons) Number of electrons on the first
layer (2) 8 Ne (3) 8 Al3+< /p>
Topic 4 Chemical formula and valency
1. A 2. B 3. B 4. B 5. A 6. B
7. D 8. A 9. C 10. C
11. (1) (1) ① Nitrogen element, 1 nitrogen atom ② 2
nitrogen atoms ③ 2 nitrogen molecules ④ Nitrogen, Nitrogen consists of the element nitrogen
, 1 nitrogen molecule, 1 nitrogen molecule, 1 nitrogen molecule, 1 nitrogen molecule. nitrogen molecule consists of 2 nitrogen
atoms ⑤ Calcium ion ⑥ Copper element, 1 copper atom
son, copper metal (2) ①CO2-
3 ②Mg ＋2O ③3SO2-
4
④NH4Cl ⑤5NO
3 ⑥Ca(OH)2
12. (1) KIO3 (2) 39:127:48
(3) Easily decomposed (4) 59.3% (5) 0.03kg
13. (1) Elemental (2) Mixture (3) +4
14. (1) 3:7 ∶(2) 89 15.7%
(3) Failed
Unit 5 Chemical Equations
Subject 1 Law of Conservation of Mass
1. C 2. B 3. C 4. A 5. B 6. B
7. A 8. B 9. D
10. (1) The sum of the masses of the copper and the oxygen taking part in the reaction
is equal to the mass of oxides produced.and is equal to the mass of copper oxide produced, so the
mass of copper oxide is greater than the mass of copper (2) The mass of decomposed potassium permanganate
is equal to the sum of the mass of the residual solids and the mass of oxygen released
, so the mass of the residual solids is less than the mass of the original potassium permanganate
11. (1) 0 (2) oxidation
12. a-4b
Topic 2 How to Write a Chemical Equation Correctly
1. D 2. A 3. B 4. C 5. D 6. C
7. A 8. D 9. A 10. B
11. (1) 2KMnO4?△ K2MnO4 + MnO2 + O2↑
< (1) 3Fe + 2O2 ignite Fe3O46
Human Education Edition - Chemistry - Grade 9 (above)
(2) S + O2 ignite SO2
(3) H2CO3 = CO2 ↑ ＋ H2O
(4) 2KClO3
M?n?O2 △ 2KCl + 3O2?(5) Fe2O3 ① ① ① ① ① ① ① ① ① ① ① ③
13. >(5) Fe2O3 + 3CO High temperature 2Fe + 3CO2↑
(Other reasonable answers are acceptable)
Subject 3 Simple Calculations Using Chemical Equations
1. B 2. A 3. D 4. A 5. A 6. D
7. C 8. D
9. 48 6 Can 32 No Oxygen elements in the water
Element All of the oxygen in the water becomes oxygen, and the product of the decomposition of potassium permanganate
Both potassium manganate and manganese dioxide contain the element oxygen
10.152g
11. O2: 2.4g MnO2: 1.9g
12.5 10 10 10 10
(1) 2g of O2 can react with only 3g of Mg
( (2) 6g of Mg reacts to give at most 10g of MgO
Unit 6 Carbon and Carbon Oxides
Subject 1 Diamond, Graphite, and C60
1. B 2. D 3. C 4. C 5. A 6. C
7. A 8. C 9. A
10. (1) Slippery (2) Electrically conductive (3) Temperature-resistant
11. p>
11. charcoal adsorption of nitrogen dioxide gas leads to a decrease in the
air pressure inside the flask
12. (1) carbon atoms are arranged differently in space
(2) inactivity soccer alkene and nanocarbon nanotubes are made of carbon
atoms of the composition of the monomaterials, carbon monomaterials are chemically
stable at room temperature (3) carbon dioxide is greater than
13. (1) 2H (2) can be used as an electrodeSubject 2: Study of Carbon Dioxide Production
1. D 2. C 3. D 4. D 5. C 6. A 7. C
8. (1) The spout of a long-necked funnel is not extended below the liquid level
(2) The tube in a conical flask should not be extended below the liquid level
(3) The mouth of the cylinder should not be tilted downward
(3) The cylinder should not be tilted downward
(4) The tube should not be tilted downward
. The mouth should not be tilted downwards
9. (1) 2.2 (2) 91%
10. 20L
11. (1) Block is better because the reaction speed
is moderate and easy to collect (2) Powder is better because
for the large area of contact, the reaction speed is fast, and it can be made in a shorter period of time
. (1) a large amount of carbon dioxide
12. (1) iron stand (2) ③ (3) Ⅱ error,
the stopper is not inverted Ⅳ error, the burning match is not placed in the bottle
mouth (4) 2H2O2
MnO 22H2O + O2 ↑ alcohol lamp
Topic 3 Carbon Dioxide and Carbon Monoxide
1. D 2. C 3. D 4. B 5. B 6. C
7. D 8. D 9. D 10. B 11. D
12. CO2 Cannot be burned CO Toxic CH4
Organic matter
13. C CO2 CO CaCO3
14. (1) The amount of carbon dioxide will increase It will lead to
the greenhouse effect (2) C6H12O6 + 6O2 = 6CO2
+ 6H2O
Unit 7 Fuels and Their Utilization
Topic 1 Combustion and Fire Extinguishing
1. C 2. B 3. D 4. B 5. C 6. C
7. B 8. A
9. (1) Insulate the oxygen Extinguish the alcohol lamp with a cap
Flame (2) Cool down to below the ignition point of combustible materials
House fires are extinguished with a high-pressure water hose
10. (1) Oxygen is consumed in the teacups (2) Carbon dioxide gas produced
rises and collects at the top Carbon dioxide
is denser than air (3) A, C
7
Reference Answers and Hints
11. Improvement and Experimentation (1) The temperature did not reach the ignition point of red phosphorus
(2) The white phosphorus in the hot water did not come into contact with oxygen
(or air)
Reflection and Evaluation (1) It can prevent the escape of phosphorus pentoxide produced by the combustion of white phosphorus
, which is hazardous to human health (2) It avoids
The rubber stopper is loosened by the thermal expansion of the gas in the test tube
Expansion and Relocation a Oxygen accounts for about
1 5 of the volume of air, and the above experiments white phosphorus in sufficient quantities, airtightness is good, so the volume of the liquid that enters the a test tube should be close to the volume of the test tube1
Subject 2 Fuels and Heat
1．B 2．C 3．B 4．C 5．D 6. B
7. C 8. C 9. C
10. CH4 ＋2O2 Ignition of CO2 ＋2H2O Ensure
Ventilation, no fireworks
11. (1) Coal, oil, natural gas, and combustible ice
(2) Natural gas (3) Combustible ice (4) Wind and tidal energy
12. (1) Motion (2) chemical (3) reduce volatility
, easy to store, safe and convenient to use, etc.
13. Method (1): one day it will be feasible to vigorously develop hydropower
stations, solar power stations and nuclear power stations, etc., when the supply of electricity is ten
minute
Method (5): solar energy is an inexhaustible source of inexpensive
Method (6): Catalysts can greatly speed up the decomposition of water
Topic 3: Environmental Impacts of Fuel Use
1. C 2. A 3. D 4. B 5. A 6. C
7. C 8. D 9. B
10. (1) Destruction of Vegetation, Reduction of Crop Yield (2) Corrosion
Building, Corrosion of Roads and Pavement
1. (2) decay
10. (1) destruction of vegetation, reduction of crop production (2) decay
10. (2) decay
10. (3) destruction of vegetation, reduction of crop production (2) decay
10. (2) decay
10. (2) decay
10. (2) corrosion
10. (2) corrosion
10. (2) decay
11. (3) decay
11. (4) decay
11. (5) decay
11. (6) decay
11. Effect reforestation, etc. (other reasonable answers are acceptable)
2CO2 + 6H2? Certain conditions C2H4 + 4H2O (4) hydrogen
energy (other reasonable answers are acceptable)
Expansion of the subject of comprehensive utilization of petroleum and coal
1.D 2.D 3.C 4.D 5.D 6.A
7.D 8.A
9. (1) ① liquid nitrogen vaporization heat absorption, play a role in cooling
② can play a role in isolation of oxygen
(2) C + H2O (water vapor) = CO + H2 replacement
replacement reaction
10. (1) CH4 ＋ O2O2 ignition of CO2 ＋ 2H2O
(2) ① ② ④ (3) not enough oxygen, not enough combustion
10. Insufficient combustion
11. blood of industry chemistry physics mixtures
12. 308kg
13. fossil fuels such as coal, oil and their refined products produce harmful gases such as SO2, CO, NO2 and dust in the process of
combustion, which pollute the air
Midterm Comprehensive Exercises
1. A 2. A 3. B 4. D 5. B 6. D 7. B
8. (1) 2H H2O (2) 2SO2-
4Cl ＋4O2
9. (1) 2P2O5 (2) ZnO (3) KMnO4
(4) 2 atoms of potassium (5) two molecules of ozone<
(6) 2 hydroxide ions
10. liquid air Boiling point Not a part of
11. red phosphorus Iron wire Sulfur Charcoal Phosphorus + Oxygen
8
HUMAN EDITION - CHEMISTRY - 9TH GRADE (UPPER)
→ IgnitionPhosphorus pentoxide Carbon + Oxygen? → ignite
Carbon dioxide
Iron + oxygen? → ignition
Triiron tetraoxide Compound reaction
Oxygen oxidation reaction
12. (1) light blue gas, strong oxidizing, etc.
(2) the molecules that make them up are different (or the number of oxygen atoms in the molecule is different
) Ozone? → △
Oxygen
(3) Oxygen supports combustion (or supplies respiration)
makes metals rusty (or other reasonable answer)
13. (1) MnO2 Cu Zn (2) filter glass
glass rod Drainage Prevents droplets from splashing
14. (1) B A (2) Prevents potassium permanganate from entering
the catheter and blocking it. (2) prevent potassium permanganate from entering the tube and clogging it Move the tube out of the water Extinguish the alcohol lamp Extinguish the alcohol lamp Water is sucked backward to make the test tube explode (3) E D
15. (1) 80 (2) 7∶1∶12 (3) 17.5kg
16. (1) 1∶1∶3 (2) 59.3% (3) 0.059g
Final Comprehensive Exercises
1． D 2. B 3. D 4. C 5. C 6. C 7. C
8. (1) H2 (2) N2 (3) NaCl (4) SO2
(5) CH4 (6) H2O2 (7) CaCO3
(8) H2O
9. (1) Smaller (2) Unchanged
10. (1) 2Mg + CO2 Ignition 2MgO CO2 ignition 2MgO + C
(2) ① combustion does not necessarily require oxygen ② magnesium combustion does not
can be extinguished with carbon dioxide, etc. (other reasonable answers can be)
11. (1) oxygen (O2) carbon dioxide (CO2)
(2) chemically stable and non-toxic at room temperature
12. (1) CO C (2) C + H2O? (2) C + H2O?△?CO
+ H2 displacement reaction (3) 2H2 + O2 ignition of 2H2O
(4) clarified lime water clarified lime water becomes cloudy
13. (1) the lower end of a long-necked funnel does not extend below the surface of the liquid
the gas escapes from the long-necked funnel (2) carbon dioxide (CO2) is more dense than air (3) the density of CO2 is greater than that of air (3) the density of CO2 gas is greater than that of air (4) the density of CO2 gas is higher than that of air (5) the density of CO2 gas is greater than that of air (7) the density of CO2 gas is greater than that of CO2 (CO2) (3) 2H2O2
MnO 22H2O + O2↑, put a sparking stick of wood at the mouth of the collection
cylinder
14. (1) (1) (a) test-tube (2) long-necked funnel (2) C
D to prevent the backflow of the generated water from blowing up the test-tube (3) test
pure to expel the air in the test-tube to prevent
explosion when heated. p>
Explosion to prevent the burning copper from being oxidized by oxygen in the air
15. (1) soluble in water (2) calculated
The nitrogen content of the sample is 14%, which is less than 16%, and it cannot be classified
as a "good faith commodity
.