27. Helium is an element with more content in the sun, and its element symbol is
A.he is a good example.
28. The kitchen materials can't form a solution if they are put into enough water and fully stirred.
A. edible oil B. white vinegar C. white sugar D. salt
29 belongs to the organic matter is
A.C60 B. CO C. H2CO3 D. C2H6O
30. A group of substances of allotrope is
A. Hydrogen and liquid hydrogen B. Mercury and silver C. Dry ice and ice D. Oxygen and ozone
3 1.Cr2O3 can be used as a catalyst for some chemical reactions, in which the valence state of chromium is
A.+2 B. +3 C. +5 D. +6
PH value is one of the important indicators of water quality monitoring. The following water samples are acidic.
A. industrial wastewater with pH =1.3 B. rainwater with pH = 4.5
C. distilled water with C.pH = 7.0. Mineral water with pH = 7.3
33. In the engine bottle full of oxygen combustion, produce bright blue-purple flame material is
A. Sulfur powder B. Iron wire C. Charcoal D. Red phosphorus
34. The common name of the substance corresponds to the chemical formula, which is correct.
A. natural gas: CO B. caustic soda: Na2CO3 C. slaked lime: Ca(OH)2 D. caustic soda: KOH.
35. The chemical equation of magnesium burning in carbon dioxide is 2 mg+CO2 = = = C+2 MgO. This reaction belongs to
A. Combination reaction B. Decomposition reaction C. Displacement reaction D. Double decomposition reaction
36. The principle of derusting with dilute sulfuric acid is
37. In the process of artificial purification of natural water in waterworks, it is usually not used.
A. electrolysis B. adsorption C. filtration D. disinfection
38. The picture on the right shows part of the contents of the commercially available hydrochloric acid label, of which 36.0%~38.0% represents hydrochloric acid.
A. Chlorine content B. Solute solubility
C. Solute mass fraction D. Solute quantity
39. The characteristics of a substance without chemical change are
A. Flammability B. Volatility C. Instability D. Reduction
40. In the process of heating the vitriol, the relevant experimental operation is correct.
4 1. A thin film containing Zn2(OH)2CO3 will be formed on the surface of zinc sheet left in the air for a long time. If this substance is produced by a combination reaction. In addition to Zn, there is 1. N2 2。 Oxygen 3. Carbon dioxide 4. H2O as reactant.
A. one b, two c, three d and four.
The following figure is a schematic diagram of a chemical reaction (O and O represent different elemental atoms respectively), which may be
A. Combustion of hydrogen B. Electrolysis of water
C. Methane combustion D. Carbon monoxide combustion
43.x can be reacted as follows: 1. X+ acid = = = salt+water; 2.X+ nonmetallic oxide = = = salt+water. X can be
A. copper oxide B. hydrochloric acid C. sodium hydroxide D. sodium carbonate
44. At room temperature, perform the following operations on 100mL saturated sodium chloride solution, and finally get the solutions in beakers A and B..
A. same solute mass B. same solute mass fraction C. all unsaturated solutions D. same solvent mass.
45. The description of molecules and atomic particles is correct.
A. matter can only be composed of molecules. The same atom may constitute different molecules.
C. the molecular mass must be greater than the atomic weight d. The number of molecules must change in chemical changes.
46. The calculation expression of water molecule mass (unit: gram) is
7. Fill in the blanks [Source: ZXX k.com] [Source: Subject Network]
47. Humans often obtain metallic materials from ores.
(1) Iron is the most easily smelted metal. The chemical equation of the main reaction in industrial ironmaking is: Fe2O3+3CO= high temperature =2Fe+3CO2, and the oxidant in the reaction is _ _ _ _ _ _ _ _. Among the substances involved in the reaction, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ refers to
(2) Copper is an early metal used by human beings. The chemical equation of carbon dioxide generated by the reaction of charcoal with copper oxide is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
(3) Aluminum is widely used in modern life. The main component of raw materials for aluminum smelting is Al(OH)3, which is composed of _ _ _ _ _ _ _ _, and 2 moles of Al(OH)3 contain _ _ _ _ g oxygen.
(4) Metal smelting usually transforms the metal elements in the ore into _ _ _ _ _ _ (fill in "combined" or "free") state.
48. The experimental group conducted the following experiments on the dissolution of potassium nitrate under different conditions.
Put 20g of potassium nitrate crystal into three beakers A, B and C, then add 50.0g of cold water, hot water and alcohol respectively, and fully stir (keep their respective temperatures unchanged). The results are shown in the following figure.
(1) The solution in the beaker is a (saturated or unsaturated) solution.
(2) From the above experiments, it can be concluded that there are _ _ _ _ _ _ _ _ _ _ _.
(3) Cool the solution in the second beaker to t2. C, the solubility of potassium nitrate is _ _ _ _ _ g/100g of water. Add 10g of water to beaker B. When the temperature changes to T2°C, the solution just reaches saturation, and then t1_ _ T2 (fill in ">", "<" or "=".
(4) The solubility data of potassium nitrate at different temperatures were obtained through experimental determination.
Temperature solubility (g/100g water)
203 1.6
4063.9
50 14 5
60 1 10
70 140
80 169
Analysis of the above data shows that there may be a big error in the solubility data of potassium nitrate at a certain temperature, and the error is _ _ _ _ _. C.
According to the data in the table, please trace points in the coordinate diagram and draw a curve that conforms to the change law of potassium nitrate solubility.
49. Carry out the experiment as shown in the figure below, and quickly inject all the liquid in the needle tube into the container. The experimental contents are shown in the following table. [Source: Z#xx#k.Com]
Before the experiment began, the liquid level at the left and right ends of the red ink remained stable. Container I and container II have the same volume, and the device has good air tightness.
(1) In experiment A, the phenomenon in container I is _ _ _ _ _. The reason why the liquid level of red ink changes is _ _ _ _ _ _ _ _ _ _ _ _ _ _ (expressed by chemical equation).
(2) In Experiment B, the container with sufficient hydrochloric acid in syringes I and II and the same solute mass fraction is _ _ _ _ (fill in "I" or "II"), and the position of red ink changes to _ _ _ _ _.
Eight. Short Answer Questions
50. A marble sample (containing impurities that are insoluble in water and do not react with acid) fully reacts with enough hydrochloric acid, filters green leaves, dries, cools, and weighs the obtained calcium chloride solid. Relevant experimental data are shown in the following figure (no loss):
(1) The mass of calcium chloride is _ _ _ _ _ _ _ _ _ grams.
(2) Calculate the content of calcium carbonate in the marble sample (calculated according to the chemical equation).
[Source: Xue Ke. com]
5 1. gas extraction is an important chemical experiment activity.
(1) Hydrogen peroxide and manganese dioxide are used to produce oxygen in the laboratory. The chemical equation of oxygen production by this method is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. The device that can collect oxygen is _ _ _ _ _ _ _ _ _ _ (fill in the number)
In order to get dry oxygen, the prepared gas can pass through a drying device filled with oxide, which is _ _ _ _ _.
(2) When preparing carbon dioxide in the laboratory, it is required to control the reaction at any time. The following generators that meet this condition are _ _ _ _ _ _ _ (fill in the number).
Use the selected device to prepare carbon dioxide, and the name of the instrument that can be used for adding liquid is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
52. The solution may contain one or more of sodium carbonate, sodium sulfate, potassium chloride and hydrochloric acid. In order to determine its composition, the following experiments were carried out.
Step 1: sampling, flame reaction, and observing purple flame through blue cobalt glass.
Step 2: Take another sample and add barium chloride solution and dilute nitric acid drop by drop. The relationship between the amount of precipitated substances and time is shown in the following figure.
(1) According to the above experiments, the stock solution must contain sodium carbonate, sodium sulfate and _ _ _ _ _ _.
(2) In the second experiment, the solute in the solution corresponding to the image between AB must be _ _ _ _ _.
The reduced sediment in BC section is _ _ _ _ _ _ _ _ _ _ _.
(3) The amount of substance precipitated at point C is one third of that precipitated at point B. The relationship between the amount of sodium carbonate (m 1) and the amount of sodium sulfate (n2) in the original solution is N2 = _ _ _ _ _ _ _ _ _ _ _ _ _ _
[Source: Zxxk.Com]
Answer part
Multiple choice questions: baddabaaccd acbbcbdcabad