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1、初三化学推断题技巧Chemistry deduction questions in junior middle school First, junior high school chemistry common material color (1) the color of solid 1. Red solid: copper, iron oxide 2, green solid: aerugo 3, Blue Solid: copper hydroxide, copper sulfate crystal 4, purple black solid: Potassium Permanganat
2、e 5, pale yellow solid: sulfur 6 colorless solid: ice, dry ice, diamond 7 、 silver white, solid: silver, iron, magnesium, aluminum, mercury and other metals 8, black solid: iron powder, charcoal, copper oxide, manganese dioxide, iron oxide oxide (carbon black, activated carbon) 9, red brown solid ir
3、on 10, the white solid sodium chloride, sodium carbonate, sodium hydroxide, calcium hydroxide, calcium carbonate, calcium oxide, copper sulfate, phosphorus pentoxide, Magnesium Oxide (two) the color of the liquid 11, colorless liquid: water, hydrogen peroxide 12, a blue solution: copper sulfate, cop
4、per chloride, copper nitrate solution 13. Light green solution: ferrous sulfate solution, ferrous chloride solution, ferrous nitrate solution 14. Yellow solution: ferric sulfate solution, ferric chloride solution, ferric nitrate solution 15, purple solution: Potassium Permanganate solution Solution:
5、 16, purple litmus solution (three) the color of gas 17, reddish brown gas: nitrogen dioxide 18, yellow green gas: chlorine gas 19, colorless gas: oxygen, nitrogen, hydrogen, carbon dioxide, carbon monoxide, sulfur dioxide, hydrogen chloride gas, and most other gases Two, the acidity and basicity of
6、 chemical solution in junior high school 1, acidic solution, acid solution and some salt solution (sodium potassium bisulfate, etc.) 2, alkaline solution: alkaline solution and some salt solution (sodium carbonate, sodium bicarbonate and so on) 3. A neutral solution: water and most of the salt solut
7、ion Three, junior high school chemical exposure, placed in the air quality changes (I) increasing quality 1. Increased by water absorption: sodium hydroxide solid, calcium chloride, magnesium chloride, concentrated sulfuric acid 2, due to the increased water reaction of calcium oxide, barium oxide,
8、potassium oxide, sodium oxide, copper sulfate 3 because of the reaction with carbon dioxide: sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide (two) reduced in quality 1. Reduced by volatilization: concentrated hydrochloric acid, concentrated nitric acid, alcohol, gasoline,
9、concentrated ammonia water 2. Reduced by weathering: sodium carbonate crystals Four, the examination of chemical substances in junior high school (I) inspection of gases 1, oxygen with Mars, sticks into the bottle, if the wood is oxygen again. 2, hydrogen: Ignite the gas in the glass cover a small b
10、eak, dry beaker, observe whether the cup wall is water, to burn clear lime water poured into the cup, if the same turbidity is hydrogen. 3 carbon dioxide: pass into clear lime water, if muddy, it is carbon dioxide. 4, ammonia: Purple litmus paper wet, if litmus blue, is ammonia. 5, water vapor: thro
11、ugh anhydrous copper sulfate, if the white solid blue, then water vapor. (two) ion test; 6, hydrogen ions: adding purple litmus test solution / adding zinc particle 7, the hydroxyl ion / copper sulfate solution: phenolphthalein solution 8, carbonate ions: dilute hydrochloric acid and lime water clar
12、ification 9, chlorine ion: silver nitrate solution and dilute nitric acid, if produce white precipitation, then is chlorine ion 10, sulfate ion: barium nitrate solution and dilute nitric acid / drip first and then drops with dilute hydrochloric acid barium chloride 11, ammonium ion, sodium hydroxide
13、 solution and heating, the red litmus paper wet on the tube 12, copper ion: drip with sodium hydroxide solution, if produce blue precipitation is copper ion 13, iron ion: drip with sodium hydroxide solution, if produce reddish brown precipitation, it is iron ion (three) relevant examples 14, how to
14、test whether the deterioration of NaOH: drip with dilute hydrochloric acid, if the bubble is bad 15, test whether the lime contains Limestone: add dilute hydrochloric acid, if the bubble is generated, it contains limestone 16, test whether NaOH contains NaCl: first drip with sufficient dilute nitric
15、 acid, and then drip AgNO3 solution, if produce white precipitate, it contains NaCl. 17, check three bottles of solution were diluted HNO3, HCl dilute, dilute H2SO4? Add (NO3) 2 solution to the three test tubes respectively. If white precipitate is produced, it is dilute H2SO4; then AgNO3 solution i
16、s added, if white precipitate is produced, it is dilute HCl, and the remaining is dilute HNO3 18: Starch: add iodine solution, if turn blue, it contains starch. 19, to join the new system of glucose: copper hydroxide, if the generated brick red precipitate of cuprous oxide, containing glucose. Five.
17、 Chemistry in junior middle school three 1. The three ancient chemical processes in China: papermaking, making gunpowder and burning porcelain. 2. The three types of oxidation reactions are explosion, combustion, and slow oxidation. 3. The three particles of a substance: molecules, atoms, ions. 4, u
18、ncharged three kinds of particles: molecules, atoms, neutrons. 5, substance composition and composition of the three statements: (1) carbon dioxide is made up of carbon and oxygen. (2) carbon dioxide is made up of carbon dioxide molecules. (3) a carbon dioxide molecule is made up of one carbon atom
19、and one oxygen atom. 6. The three particles of an atom: protons, neutrons, electrons. 7, water pollution caused by three reasons: (1) industrial three wastes arbitrary discharge; (2) domestic sewage arbitrary discharge (3) pesticides, fertilizers, arbitrary release. 8, collect three methods: Drainag
20、e (water that is not allowed to water), to the upper air (denser air than gas), down the exhaust air method (density than air, small gas). 9, the three laws of conservation of mass do not change: the type of atom remains the same, the number of atoms remains unchanged, and the mass of the atom remai
21、ns constant. 10, three methods of converting unsaturated solutions into saturated solutions: Increase solute, reduce solvent, change temperature (increase or decrease). 11. The three conditions that the double decomposition reaction can take place is to produce water, gas or precipitation 12, three
22、major chemical fertilizers: N, P, K 13, the three kinds of pollutants discharged into the air: carbon monoxide, nitrogen oxides, sulfur oxides 14. The substance that burns white light: magnesium bars, charcoal, candles (carbon dioxide and water) 15, flammable, reducing substances: hydrogen, carbon m
23、onoxide, carbon monoxide. 16, flammable three kinds of gas are: hydrogen (ideal), carbon monoxide (toxic), methane (commonly used) 17, CO three chemical properties: flammability, reducibility, toxicity 18, three major fossil fuels: coal, oil, and natural gas (all mixtures) 19, three ferrous metals:
24、iron, manganese, chromium Three: 20, iron oxide FeO, Fe2O3, Fe3O4 21, iron smelting of three kinds of oxides: iron ore, coke, limestone 22, common three strong acids: hydrochloric acid, sulfuric acid, nitric acid 23, concentrated sulfuric acid of three characteristics: water absorption, dehydration,
25、 strong oxidation Three, commonly known as the 24 sodium hydroxide: caustic soda, caustic soda, caustic soda 25, three kinds of oxide copper subcarbonate heat decomposition: copper oxide, carbon dioxide, water (hydrogen peroxide) 26, laboratory preparation of CO2 can not use three substances: nitric
26、 acid, concentrated sulfuric acid, sodium carbonate Three, 27 alcohol lamp flame: flame, flame, flame 28, the use of alcohol lamp: the prohibition of alcohol to add into the burning lamp, prohibit the use of alcohol lamp to ignite another alcohol lamp, prohibited by mouth blow out of alcohol lamp 29
27、, the glass rod in salt in the purification of three roles: stirring, drainage, transfer 30. The three points in the liquid filtration operation: (1) when pouring the filtrate, the beaker mouth is close to the glass rod; (2) the glass rod is lightly supported at one end of the three layer filter pap
28、er; (3) the lower end of the funnel is close to the inner wall of the beaker. 31, solid solution of three steps: calculation, weighing, dissolution 32, dense with dilute the three steps: calculation, measurement, dissolution Three instrument 33, concentrated dilution: a beaker, glass rod 34, three k
29、inds of water heating substances: concentrated sulfuric acid, sodium hydroxide, lime 35, filter two times filtrate still muddy reason: filter paper damage, the instrument is not clean, the liquid level is higher than the filter edge 36, the three principles of drug use: can not touch the drug by han
30、d, do not put your nose to the mouth of the container, smell the medicine, and do not taste any medicine Three, meaning 37 metal activity series: (1) the metal position is in the front, it is easy to become lost in the aqueous solution and electron ion, its activity is strong; (2) in front of the me
31、tal hydrogen replacement of acid hydrogen in hydrogen behind the metal can not be replaced acid hydrogen; (3) the row in front of the metal can be put at the back of the metal is displaced from the salt solution in their. Effect of temperature on the solubility of solids, 38 (1): the solubility of m
32、ost solid material increases with the increase of temperature, the solubility of a solid substance (2) affected by temperature changes (3) the solubility of a handful of solid material decreases with increasing temperature. 39, the factors affecting the dissolution rate: (1) temperature, (2) whether
33、 stirring (3) the size of solid particles 40. The three substances that make iron rusty: iron, water, oxygen. 41. The three states of the solute: solid, liquid, and gas. 42. Three factors affecting solubility: the nature of the solute, the nature of the solvent, and the temperature. Six. Important i
34、ngredients of common chemical compounds in junior high school 1, air: nitrogen (N2) and oxygen (O2) 2, water gas: carbon monoxide (CO) and hydrogen (H2) 3 gas: carbon monoxide (CO) 4. Natural gas: methane (CH4) 5, limestone / marble: (CaCO3) 6, pig iron / steel: (Fe) 7, charcoal / coke / carbon blac
35、k / activated carbon: (C) 8 rust: (Fe2O3) Seven, the elimination of impurities 1, CO2 (CO): pass the gas through the glowing copper oxide, 2, CO (CO2): by adequate sodium hydroxide solution 3, H2 (steam): through concentrated sulfuric acid / solid through sodium hydroxide 4, CuO (C): burning mixture
36、 in air (in oxygen stream) 5, Cu (Fe): add sufficient dilute sulfuric acid 6, Cu (CuO): add sufficient dilute sulfuric acid 7, FeSO4 (CuSO4): add enough iron powder 8, NaCl (Na2CO3): add sufficient hydrochloric acid 9, NaCl (Na2SO4): add sufficient barium chloride solution 10, NaCl (NaOH): add suffi
37、cient hydrochloric acid 11, NaOH (Na2CO3): add a sufficient amount of calcium hydroxide solution 12, NaCl (CuSO4): add sufficient barium hydroxide solution 13, NaNO3 (NaCl): add a full amount of silver nitrate solution 14, NaCl (KNO3): evaporating solvent 15, KNO3 (NaCl): cooling, heat saturated sol
38、ution. 16, CO2 (steam): through concentrated sulfuric acid. Eight, chemistry of the most 1. The best fuel for the future is H2. 2. The simplest organic substance is CH4. 3. The least dense gas is H2. 4, the relative molecular mass of the smallest material is H2. 5, the relative molecular mass of the
39、 smallest oxide is H2O. 6. The smallest particle in chemical change is an atom. 7, PH=0, the strongest acidity, alkaline weakest. At PH=14, alkaline is the strongest and acidity is weakest. 8, the most scarce in the soil are N, K, P three elements, the highest fertilizer nitrogen is urea. 9, the nat
40、ural existence of the hardest material is diamond. 10. The earliest country to use natural gas is china. 经过同一直线上的三点不能作圆.11. The most abundant element in the earths crust is oxygen. 12. The most abundant metallic element in the earths crust is aluminum. 函数的取值范围是全体实数；13. The most abundant gas in the a
41、ir is nitrogen. 14. The element with the highest content in the air is nitrogen. 8、加强作业指导、抓质量。15. The three most important fossil fuels in the world today are coal, oil, and natural gas. 16. Forming the most diverse element of the compound: carbon. Nine, about the difference 156.46.10总复习4 P84-901, d
42、iamond and graphite have different physical properties: because of the different arrangement of carbon atoms. 2, pig iron and steel performance is different: Because carbon content is different. (5)直角三角形的内切圆半径3 carbon monoxide and carbon dioxide have different chemical properties: because the molecu
43、les are different. 4.坡度：如图2，坡面与水平面的夹角叫做坡角坡角的正切称为坡度 (或坡比)。用字母i表示，即(oxygen and ozone differ in their chemical properties because the molecules are different; the chemical properties of water and hydrogen peroxide are different because of the different molecular composition) 4, the element type is diff
44、erent: because the proton number is different. （3）圆内接四边形：若四边形的四个顶点都在同一个圆上,这个四边形叫做圆内接四边形.5, because of different valence elements: the outermost electron number. 点在圆外 dr.6, the chemical properties of sodium and sodium are different: because the outermost electron number is different. 周 次日 期教 学 内 容Ten: toxic substances 1, toxic solids: sodium nitrite (NaNO2), lead acetate, etc. 5.方位角：从某点的指北方向按顺时针转到目标方向的水平角，叫做方位角。如图3，OA、OB、OC的方位角分别为45、135、225。2, toxic liquid: Mercury, copper sulfate solution, methanol, Ba2+ containing solution (except BaSO4). 3, toxic gases: CO, nitrogen oxides, sulfur oxides