Combinatorial reaction: multivariable-decomposition reaction: multivariable
Displacement reaction: one-to-one displacement reaction: exchange ions
2. Valence of common elements (positive):
Univalent potassium, sodium, hydrogen, silver, bivalent calcium, magnesium, barium and zinc, trivalent metal element aluminum;
157 variable valence chlorine, 245 nitrogen, 46 sulfur, 35 phosphorus, 24 carbon;
One, two copper, two, three iron and two, four, six and seven manganese are special.
3, the steps of making oxygen in the laboratory:
"Tea (stop), tea (bag), tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea, tea,
Check the air tightness of the equipment "package" the medicine and connect the equipment.
The "fixed" test tube is fixed on the "point" of the iron frame, and the alcohol lamp is lit and heated.
"Collect" the collected gas and "leave" the conduit away from the water surface.
Turn off the alcohol lamp and stop heating.
4. Experimental steps of reducing copper oxide with CO:
"One pass, two points, three stops, four stops and five treatments":
"One pass" is filled with hydrogen first, and after "two points", the alcohol lamp is lit for heating; After the "three-stop" experiment is completed, the alcohol lamp should be turned off first, and then the hydrogen gas should be stopped at room temperature after the "four stops". "Five treatments" to control tail gas and prevent carbon monoxide from polluting the environment.
5, the experimental phenomenon of electrolytic water:
"oxygen positive hydrogen negative, oxygen one hydrogen two": the positive electrode releases oxygen and the negative electrode releases hydrogen; The volume ratio of oxygen to hydrogen is 1: 2.
6. Elements that make up the earth's crust: adopted sons (oxygen, silicon, aluminum).
7. Relationship between outermost atoms and ions and valence formation:
"Yang loss is positive, Yin gain is negative, and the value remains unchanged": the outermost layer of atoms loses electrons to form cations, and the valence of elements is positive; The outermost layer of atoms gains electrons to form anions, and the valence of elements is negative; Number of electrons gained or lost = number of charges = valence.
8, chemical experiment basic operation formula:
Solids need spoons or paper slots, one free, two vertical and three elastic; It is best to use a block or tweezers, one horizontal and two vertical.
The liquid should be put in a flask, labeled by hand, and then poured out. The reading should be flat with the section, with the head down low and the head down high.
The dropper drips with the glue head, and the vertical suspension is pollution-free, uneven and in good position. Don't forget to clean it after use.
The balance of the tray should be flat and the screw should be centered; Put things left and right, and clamp the tweezers first big and then small;
The test paper should be cut down first, and the glass rod is immersed in liquid for the best test effect. Wet the test paper first, stick it on a stick and lean against the air.
The outer flame of the heating wine lamp is two-thirds of the boundary. Sulfuric acid is stirred in water and injected slowly to prevent boiling and splashing.
In the experiment, the air tightness is checked first, and the cups and bottles are heated through the net. After drainage and gas collection, remove the conduit first, and then move the lamp.
9, metal activity sequence:
The order of metal activity from strong to weak is: KCaNaMgalZnFeSnPb (H) CuHgAgPtAu (listed in turn) K, Ca, Na, Mg, Al, Zn, Fe, Sn, Pb(H)Cu, Hg, Ag and Pt.
Metal activity sequence table:
(Junior high school) K, Ca, Na, Mg, Al, Zn, Fe, Sn, Pb, H, Cu, Hg, Ag and Pt. (senior high school) potassium, calcium, sodium, magnesium, aluminum, manganese, zinc, chromium, iron, nickel, tin, lead and hydrogen; Copper, mercury, silver and platinum.
10, "cross method" to write the formula of chemical formula:
"Positive price left negative price right, cross subtraction, write right to test right and wrong."
1 1, filtering operation formula:
The funnel angle of the glass rod and filter paper of the beaker of the bucket frame is the same; Let stand before filtering, don't forget to tilt three times and two times.
12, the law in the experiment:
(1) When solid is heated to produce gas, potassium permanganate oxygen generator (solid-solid heating type) is selected;
The device for preparing O2 from hydrogen peroxide (solid-liquid unheated type) is used to prepare gas by solid-liquid reaction without heating.
(2) When heating the test tube solid, it should be preheated first, and the test tube mouth is slightly inclined downward.
(3) Any generated gas that is insoluble in water (does not react with water) can be collected by drainage.
Any gas with higher density than air can be collected by exhausting upwards.
Any gas less dense than air can be collected by downward exhaust.
(4) When doing the gas experiment, first check the air tightness of the device, the rubber plug 1-2ml should be exposed on the catheter, and the iron clip should be clamped at the distance from the nozzle 1/3.
⑤ When making gas with a long-necked funnel, the nozzle at the end of the long-necked funnel should be inserted under the liquid surface.
⑥ When igniting combustible gas, you must first check its purity.
⑦ When doing experiments with toxic gases, the tail gas must be finally treated.
⑧ When reducing metal oxides with reducing gas, "one pass, two points, three extinguishes and four stops" must be achieved.
13, reaction law:
Displacement reaction: (1) simple metal+acid → salt+hydrogen.
(2) simple metal+salt (solution) → another metal+another salt
(3) metal oxide+charcoal or hydrogen → metal+carbon dioxide or water
Double decomposition reaction:
① Alkaline oxide+acid → salt+water ② Alkali+acid → salt+water
③ Acid+salt → new salt+new acid ④ salt 1+ salt 2→ new salt 1+ new salt 2.
⑤ salt+alkali → new salt+new alkali
14, metal+acid → salt +H2 =
(1) The order in which metals with the same mass react with enough acid to release hydrogen is al >；; Mg & gtFe & gt zinc
② Different acids with equal mass react with enough metals, and the smaller the relative molecular weight of the acid, the more hydrogen is released.
③ The same acid with the same mass reacts with enough different metals to release the same amount of hydrogen.
(4) After the reaction of metal+acid → salt +H2↑, the solution becomes heavier and the metal becomes lighter.
15, metal+salt solution → new metal+new salt:
(1) the relative atomic mass of metal >; When the relative atomic mass of the new metal is equal, the solution mass becomes heavier and the metal becomes lighter after the reaction.
② Relative atomic mass of metal
16, catalyst:
One constant and two constant (substances with constant chemical properties and mass are catalysts for changing the reaction rate of substances)
17, oxidant and reductant:
Oxygen gain and oxygen loss (the substance that takes oxygen is a reducing agent, and the substance that loses oxygen is an oxidant)
18. Impurity removal connector of gas washing cylinder: long inlet and short outlet.
Connection between drainage and gas collection and washing tank: short in and long out.
Connection between exhaust gas gathering and gas washing cylinder: low density means short inlet and outlet, while high density means long inlet and outlet.
19, experimental impurity removal principle: remove other things first, and then remove water vapor.
Experimental inspection principle: water first, then water.
20, oxygen production:
Manganese dioxide potassium chlorate; Stir well and heat. Oxygen plant has its own characteristics; The bottom is high and the mouth is slightly inclined.
2 1, gas gathering:
Exhaust method interacting with water; According to the density. Insoluble and slightly soluble drainage methods; The obtained gas has high purity.
22. Electrolyzing water: Positive oxygen contributes to combustion; Negative hydrogen will burn badly.
23, valence formula:
The main valence states of common elements: Fuwan iodine is negative; Silver monohydride and potassium sodium. Remember the negative two of oxygen first; Magnesium, calcium, barium and zinc were positive. Positive three is aluminum positive silicon; Let's change the price again. All metals are positive electrodes; One, two copper, two, three iron. Manganese is 24 and 67; Remember the second and fourth carbons. Non-metallic negative body is uneven; Chlorine is negative, positive and 157. Nitrogen and phosphorus are negative three and positive five; Different phosphorus, three nitrogen, two four. There are negative two positive four six; Remember, it's cooked after use.
Common root price formula
Monovalent ammonium nitrate; Hydrohalide hydroxide. Permanganate chlorate; Perchlorate acetate. Bivalent sulfate carbonate; Manganese bisulfate. Temporarily record ammonium as positive; Negative number three has phosphate.
24, valence formula 2:
Monovalent potassium sodium silver hydrogen chloride; Bivalent calcium, barium, magnesium, zinc, aluminum, silicon, nitrogen and phosphorus; Two, three, iron, two, four, carbon, two, four, six, sulfur; Cu2+is the most common.
25, salt solubility:
Potassium, sodium, ammonium and nitrate are all soluble, but hydrochloric acid is insoluble in silver and mercurous chloride. Sulfate insoluble barium, lead and carbon phosphate insoluble. Most acids are soluble in alkali, but only potassium, sodium, ammonium and barium are soluble.
Solubility formula
Potassium, sodium and ammonium salts can be dissolved in water quickly; ① sulfate can remove barium, lead and calcium. ② Chloride is insoluble in silver chloride, and nitrate solution is transparent. (3) There is no sinking place in the formula. ④ Note: ① Potassium, sodium and ammonium salts are all soluble in water; ② Only barium sulfate, lead sulfate and calcium sulfate are insoluble in sulfate; ③ Nitrates are all soluble in water; ④ All salts not involved in the formula are insoluble in water; Soluble molecular formula dipotassium, sodium, ammonium salt and nitrate; Removing silver and mercury by chloride; Removing barium and lead with sulfate; Carbonic acid, phosphate, only soluble in potassium, sodium and ammonium. Soluble formula: potassium, sodium, ammonium and nitrate are all soluble, but hydrochloric acid is insoluble in silver and mercurous chloride; Sulfate insoluble barium, lead and carbon phosphate insoluble. Most acids are soluble in alkali, but only potassium, sodium, ammonium and barium are soluble. Tetrapotassium, sodium and nitric acid are soluble, (potassium salt, sodium salt and nitrate are all soluble in water. Hydrochloric acid is soluble except silver (mercury). Besides sulfate, barium and lead are not allowed. (Insoluble in sulfate are barium sulfate and lead sulfate. Other kinds of salts (carbonate, sulfite, phosphate, silicate and sulfide) are only soluble in potassium, sodium and ammonium (only the corresponding potassium, sodium and ammonium salts are soluble). Finally, alkali, potassium, sodium, ammonium and barium are mentioned. (Potassium hydroxide, sodium hydroxide, barium hydroxide and ammonia water are soluble) There are several slightly soluble substances that can be remembered separately. Solubility Formula Ammonium pentapotassium sodium nitrate is not difficult to be completely dissolved. Mercurous chloride, silver chloride, barium sulfate and lead sulfate form precipitates. Mutual affinity hydrogen sulfate and basic phosphate nitrate are soluble. Only potassium sodium ammonium nitrate is soluble. Ammonium hexapotassium sodium nitrate is soluble. Strong solubility and weak insolubility. Molecular formula 7: Nitrate dissolved in potassium sodium ammonium salt water is dissolved in water. No chloride was removed. Mercury barium sulfate and lead sulfate are insoluble in water. Potassium sodium ammonium alkali soluble potassium calcium sodium barium ammonium special case: 6. 5438+0. The solubility of potassium perchlorate, rubidium and cesium is very small. 2. The solubility of silver perchlorate is very high, 5570 g/L 3 ... Silver fluoride is soluble in water, and the solubility is relatively high. 1800g/l
A, the nature of oxygen:
(1) Reaction of simple substance with oxygen: (combination reaction)
1. Magnesium burns in air: 2Mg+O2 ignites 2MgO.
2. Iron burns in oxygen: 3Fe+2O2 ignites Fe3O4.
3. Copper heating in air: 2Cu+O2 heating 2CuO.
4. Aluminum burns in air: 4Al+3O2 ignites 2Al2O3.
5. Combustion in hydrogen and air: 2H2+O2 ignites 2H2O.
6. Red phosphorus burns in air (experiment to study air composition): 4P+5O2 ignites 2P2O5.
7. Sulfur powder burns in air: S+O2 ignites SO2.
8. Complete combustion of carbon in oxygen: C+O2 ignites CO2.
9. Incomplete combustion of carbon in oxygen: 2C+O2 ignites 2CO.
(2) the reaction of compounds with oxygen:
10. Carbon monoxide burns in oxygen: 2CO+O2 ignites 2CO2.
1 1. Methane burns in air: CH4+2O2 ignites CO2+2H2O.
12. Alcohol burns in air: C2H5OH+3O2 ignites 2CO2+3H2O.
(3) Oxygen source:
13. Boyle studies the composition of air experiment 2HgO heating Hg+O2 =
14. heating potassium permanganate: 2KMnO4 heating k2mno4+MnO2+O2 = (principle of oxygen production in laboratory 1)
15. decomposition reaction of hydrogen peroxide with manganese dioxide as catalyst: H2O2, MnO2, 2h2o+O2 = (principle of oxygen production in laboratory 2)
Second, the water in nature:
16. Decomposition of water under the action of direct current (experimental study on composition of water): 2H2O electrified 2H2 =+O2 =
17. quicklime is soluble in water: CaO+H2O == Ca(OH)2.
18. Carbon dioxide is soluble in water: H2O+CO2==H2CO3.
Third, the law of conservation of mass:
19. Magnesium burns in air: 2Mg+O2 ignites 2MgO.
20. The reaction between iron and copper sulfate solution: Fe+CuSO4 = = FeSO4+Cu.
2 1. Reduction of copper oxide by hydrogen: H2+ copper oxide heats copper +H2O.
22. Magnesium reduces copper oxide: magnesium+copper oxide heats copper+magnesium oxide.
Four, carbon and carbon oxides:
Chemical properties of (1) carbon
23. Carbon burns completely in oxygen: C+O2 ignites CO2.
24. Reduction of copper oxide with charcoal: 2Cu, high temperature 2Cu+CO2↑ =
25. Reduction of iron oxide by coke: 3C+ 2Fe2O3, high temperature 4Fe+3CO2↑ =
(2) Three reactions in coal furnace: (several combined reactions)
26. Bottom of coal stove: C+O2 ignites CO2.
27. Middle layer of coal furnace: CO2+C high temperature 2CO.
28. Blue flame in the upper part of coal stove: 2CO+O2 ignites 2CO2.
(3) Preparation and properties of carbon dioxide:
29. Marble reacts with dilute hydrochloric acid (carbon dioxide made in the laboratory):
CaCO3 + 2HCl == CaCl2 + H2O + CO2
30. Carbonic acid is unstable and decomposed: H2CO3 == H2O+CO2↑ =
3 1. Carbon dioxide dissolved in water: H2O+CO2== H2CO3
32. Calcined limestone at high temperature (industrial carbon dioxide production): CaCO3, high temperature CaO+CO2↑ =
33. Lime water and carbon dioxide reaction (carbon dioxide identification):
Calcium hydroxide+carbon dioxide = = calcium carbonate ↓+ H2O
(4) Properties of carbon monoxide:
34. Reduction of copper oxide by carbon monoxide: CO+ CuO heats Cu+CO2.
35. Combustibility of carbon monoxide: 2CO+O2 ignites 2CO2.
Other reactions:
36. Sodium carbonate reacts with dilute hydrochloric acid (the principle of fire extinguisher):
Na2CO3 + 2HCl == 2NaCl + H2O + CO2
Verb (abbreviation of verb) fuel and its utilization:
37. Methane burns in air: CH4+2O2 ignites CO2+2H2O.
38. Alcohol burns in the air: C2H5OH+3O2 ignites 2CO2+3H2O.
39. Burning in hydrogen and air: 2H2+O2 ignites 2H2O.
Six, metal
(1) the reaction of metal with oxygen;
40. Magnesium burns in air: 2Mg+O2 ignites 2MgO.
4 1. Iron burns in oxygen: 3Fe+2O2 ignites Fe3O4.
42. Copper is heated in air: 2Cu+O2 heats 2CuO.
43. Aluminum forms an oxide film in air: 4Al+3O2 = 2Al2O3.
(2) Simple metal+acid salt+hydrogen (displacement reaction)
44. Zinc and dilute sulfuric acid Zn+H2SO4 = ZnSO4+H2 Write
45. Iron and dilute sulfuric acid Fe+H2SO4 = FeSO4+H2 Write
46. Magnesium and dilute sulfuric acid Mg+H2SO4 = MgSO4+H2 Write
47. Aluminum and dilute sulfuric acid 2al+3H2SO4 = Al2 (SO4) 3+3H2 Write
48. Zinc and dilute hydrochloric acid Zn+2HCl = = ZnCl2+H2 Write
49. Iron and dilute hydrochloric acid Fe+2 HCl = = FeCl 2+H2 Write
50. Magnesium and dilute hydrochloric acid Mg Mg+ 2HCl == MgCl2+H2↑ =
5 1. aluminum and dilute hydrochloric acid 2Al+6HCl = = 2AlCl3+3H2 =
(3) Simple metal+salt (solution)-new metal+new salt
52. The reaction between iron and copper sulfate solution: Fe+CuSO4 == FeSO4+Cu.
53. The reaction between zinc and copper sulfate solution: Zn+CuSO4 ==ZnSO4+Cu.
54. The reaction between copper and mercury nitrate solution: Cu+Hg(NO3)2 == Cu(NO3)2+Hg.
(3) The refining principle of metallic iron:
55.3CO+ 2Fe2O3 high temperature 4Fe+3CO2↑ =
Seven, acid, alkali, salt
1, chemical properties of acid
(1) acid+metal salt+hydrogen (see above)
(2) Acid+metal oxide-salt+water
56. Reaction of iron oxide with dilute hydrochloric acid: Fe2O3+6HCl ==2FeCl3+3H2O.
57. The reaction of iron oxide with dilute sulfuric acid: Fe2O3+3H2SO4 == Fe2(SO4)3+3H2O.
58. The reaction of copper oxide with dilute hydrochloric acid: CuO+2HCl ==CuCl2+H2O.
59. The reaction between copper oxide and dilute sulfuric acid: CuO+H2SO4 == CuSO4+H2O.
(3) acid+alkali-salt+water (neutralization reaction)
60. Reaction between hydrochloric acid and caustic soda: HCl+NaOH == NaCl +H2O.
6 1. The reaction between hydrochloric acid and calcium hydroxide: 2HCl+Ca(OH)2 == CaCl2+2H2O.
62. Aluminum hydroxide drugs treat hyperacidity: 3HCl+Al(OH)3 == AlCl3+3H2O.
63. Reaction between sulfuric acid and caustic soda: H2SO4+2NaOH == Na2SO4+2H2O.
(4) acid+salt-another acid+another salt
64. marble reacts with dilute hydrochloric acid: CaCO3+2hcl = = CaCl2+H2O+CO2 =
65. Reaction of sodium carbonate with dilute hydrochloric acid: Na2CO3+2HCl = = 2NaCl+H2O+CO2 =
66. Sodium bicarbonate reacts with dilute hydrochloric acid: nahco3+HCl = = NaCl+H2O+CO2 =
67. The reaction between sulfuric acid and barium chloride solution: H2SO4+BaCl2 == BaSO4 ↓+ 2HCl.
2. Chemical properties of alkali
(1) alkali+nonmetallic oxide-salt+water
68. Caustic sodium will deteriorate when exposed to air: 2NaOH+CO2 == Na2CO3+H2O.
69. Caustic sodium absorbs sulfur dioxide gas: 2NaOH+SO2 == Na2SO3+H2O.
70. Caustic sodium absorbs sulfur trioxide gas: 2NaOH+SO3 == Na2SO4+H2O.
7 1. The slaked lime deteriorates in air: Ca(OH)2+CO2 == CaCO3 ↓+ H2O.
72. The slaked lime absorbs sulfur dioxide: Ca(OH)2+SO2 == CaSO3 ↓+ H2O.
(2) Alkali+acid-salt+water (neutralization reaction, see above).
(3) alkali+salt-another alkali+another salt
73. Calcium hydroxide and sodium carbonate: Ca(OH)2+Na2CO3 == CaCO3↓+ 2NaOH.
3. Chemical properties of salt
(1) salt (solution)+simple metal-another metal+another salt
74. The reaction between iron and copper sulfate solution: Fe+CuSO4 == FeSO4+Cu.
(2) salt+acid-another acid+another salt
75. Sodium carbonate reacts with dilute hydrochloric acid: Na2CO3+2HCl = = 2NaCl+H2O+CO2 =
Sodium bicarbonate reacts with dilute hydrochloric acid: nahco3+HCl = = NaCl+H2O+CO2 =
(3) salt+alkali-another alkali+another salt
76. Calcium hydroxide and sodium carbonate: Ca(OH)2+Na2CO3 == CaCO3↓+ 2NaOH.
(4) salt+salt-two new salts
77. Sodium chloride solution and silver nitrate solution: NaCl+AgNO3 == AgCl↓+NaNO3.
78. Sodium sulfate and barium chloride: Na2SO4+BaCl2 == BaSO4↓+2NaCl.
Ordinary acid hydrochloric acid sulfuric acid nitric acid phosphoric acid
1, commonality of acids
(1) acidic solution can react with acid-base indicator. Purple litmus test solution turns red in acid, and colorless phenolphthalein test solution does not change color in acid. Note that the chromogenic substance is an indicator.
(2) Acids can react with various active metals, usually producing salts and hydrogen. Only the metal in front of hydrogen in the metal active sequence table can react with dilute acids (HCl, H2SO4) to generate hydrogen. The metal behind hydrogen can not react with dilute acids (HCl, H2SO4), but can react with concentrated sulfuric acid and concentrated nitric acid.
For example: ① Cu+2H2SO4 (concentrated) CuSO4+SO2 =+2H2O.
② 3cu+8HNO3 (dilute) = 3cu (NO3) 2+2no =+4h2o.
It can be seen that the reaction of metal with concentrated sulfuric acid and nitric acid does not produce hydrogen, which is why the laboratory cannot produce hydrogen with concentrated sulfuric acid and nitric acid and zinc.
(3) Acid can react with basic oxides to form salt and water: H2SO4+CaO == CaSO4+H2O.
(4) Acids can react with some salts to generate new acids and salts: H2SO4+bacl2 = = baso4 ↓+2hcl.
(5) Acid reacts with alkali to produce salt and water: H2SO4+Ba (OH) 2 = = baso4 (white precipitate) +2H2O.
Common acids are hydrochloric acid, sulfuric acid and nitric acid, although they have the above five commonalities (because ionized cations are all H+). But each has different physical and chemical properties.
(1) hydrochloric acid is an aqueous solution of hydrogen chloride, which is a mixture. Pure hydrochloric acid is a colorless liquid with a pungent smell. Industrial concentrated hydrochloric acid is yellow because it contains impurities (Fe3++). Concentrated hydrochloric acid is volatile. When the bottle cap of concentrated hydrochloric acid is opened, white acid mist will be produced at the bottle mouth immediately. This is because the hydrogen chloride gas volatilized from concentrated hydrochloric acid contacts with water vapor in the air, forming hydrochloric acid droplets dispersed in the air and forming acid mist.
② Sulfuric acid is an oxyacid, and the corresponding anhydride is SO3(SO3+H2O==H2SO4). Pure sulfuric acid is a colorless, viscous and oily liquid, which is not volatile. The mass fraction of H2SO4 in commonly used concentrated sulfuric acid is 98%, and its density is 1.84g/cm3. Dilute H2SO4 has the generality of acid. In addition to the commonness of acids, concentrated sulfuric acid has three characteristics:
A, water absorption: concentrated H2SO4 absorbs water to form hydrated sulfuric acid molecules (H2SO4? NH2O) and releases a lot of heat, so concentrated sulfuric acid is usually used as a desiccant.
B dehydrating agent: concentrated sulfuric acid can extract hydrogen atoms and oxygen atoms from organic compounds according to the composition of water molecules (h: o = 2: 1) to dehydrate and carbonize organic compounds. Paper, firewood, clothes, etc. When it meets concentrated sulfuric acid, it turns black, which is because concentrated sulfuric acid is dehydrated and carbonized.
C, strong oxidation: H2SO4 molecules exist in concentrated sulfuric acid solution rather than H+, and H2SO4 molecules have strong oxidation. Concentrated sulfuric acid can dissolve some metals behind hydrogen in metal active sequence and oxidize nonmetallic elements such as C and S, while concentrated sulfuric acid itself is reduced to SO2. However, cold concentrated sulfuric acid cannot react with the more active metals iron and aluminum. The reason is that concentrated sulfuric acid can form a dense oxide film on the surface of iron and aluminum, preventing the metal inside from continuing to react with concentrated sulfuric acid. This phenomenon is chemically called passivation.
Because concentrated sulfuric acid has dehydration and strong oxidation, we drop concentrated sulfuric acid on sucrose, and we will see that sucrose turns black and expands in volume. Chemical equation of the reaction:
c 12h 22 o 1 1 12C+ 1 1H2O
C+2 H2SO4=CO2↑+2SO2↑+2 H2O
The generated CO2 and SO2 gases expand the volume of sucrose.
Because concentrated sulfuric acid has water absorption and concentrated hydrochloric acid is volatile, dropping concentrated sulfuric acid into concentrated hydrochloric acid will produce a lot of acid mist, and hydrogen chloride gas can be obtained by this method.
③ Nitric acid is also an oxyacid, and the corresponding anhydride is N2O5, not NO2.
Pure nitric acid is a colorless liquid with pungent smell and can be volatilized. Open the bottle cap of concentrated nitric acid, and the bottle mouth will produce white acid mist. Concentrated nitric acid is usually yellow, and the thicker the nitric acid, the darker the color. This is because nitric acid is unstable. When it is illuminated or heated, it decomposes to produce reddish-brown NO2 gas, which dissolves in nitric acid solution and turns yellow. Therefore, nitric acid should be stored in a dark and low temperature place with brown (dark) glass reagent bottle in the laboratory. Nitric acid is very corrosive, so reagent bottle containing nitric acid can only use glass plugs, not rubber plugs.
In addition to the commonness of acids, both dilute nitric acid and concentrated nitric acid have strong oxidizability. Nitric acid can dissolve all metals except gold and platinum. When a metal reacts with nitric acid, it is oxidized into high-valent nitrate, concentrated nitric acid is reduced to NO2, and dilute nitric acid is reduced to NO, but no hydrogen is produced when it reacts with metal, whether it is dilute nitric acid or concentrated nitric acid. The more active metallic iron and aluminum can be passivated in cold concentrated nitric acid, and can also be transported and stored by aluminum tanker and tin tanker. Nitric acid can oxidize not only metals, but also nonmetals, such as carbon, sulfur and phosphorus. Chemical equation of nitric acid reacting with copper and carbon;
Cu+4hNO3 (concentrated) = Cu (NO3) 2+2no2 ↑+2h2o
3cu+8HNO3 (diluted) = 3cu (NO3) 2+2no =+4h2o.
C+4HNO3 (concentrated) CO2 =+4NO2 =+2H2O
④ Phosphoric acid is a medium-strength ternary acid, which can form one normal salt and two acid salts.
Such as: disodium hydrogen phosphate (Na2HPO4), sodium dihydrogen phosphate (NaH2 PO4), ammonium dihydrogen phosphate [NH4H2PO4], diammonium hydrogen phosphate [(NH4)2HPO4], calcium dihydrogen phosphate [Ca(H2PO4)2] (soluble in water).
★★★★ Common alkali sodium hydroxide, calcium hydroxide and ammonia water.
(1) alkali solution can react with acid-base indicator, purple litmus solution turns blue and colorless phenolphthalein solution turns red. Insoluble alkali, if it cannot change the color of acid-base indicator.
(2) Alkali can react with acid oxides to produce salt and water.
(3) Alkali can react with acid to produce salt and water.
(4) Alkali can react with some salts to generate new alkali and new salt.
Common alkalis are NaOH, KOH, Ca(OH)2, ammonia water, etc. They each have some characteristics.
(1) sodium hydroxide (NaOH) common name caustic soda, caustic soda, caustic soda, this is because it is highly corrosive. NaOH is a soluble strong base. White solid, easily soluble in water and deliquescent in air, can be used as a desiccant for alkaline gases (such as NH3) or neutral gases (such as H2, O2 and CO). ). NaOH easily reacts with CO2 in the air to generate Na2CO3 solid. NaOH solution will corrode glass, and reagent bottle with NaOH solution can only use rubber plugs instead of frosted glass plugs.
② Calcium hydroxide [Ca(OH)2] is a white powder, slightly soluble in water, commonly known as hydrated lime or hydrated lime, and its aqueous solution is called limewater. Ca(OH)2 also has corrosive effect. Ca(OH)2 reacts with CO2 to produce white precipitated CaCO3, which is usually used to test CO2.
Calcium hydroxide+carbon dioxide = calcium carbonate ↓+H2O
Ca(OH)2 can react with Na2CO3 to generate NaOH, which can be used to prepare NaOH. The reaction equation is:
Ca(OH)2+Na2CO3=CaCO3↓+2NaOH
(3) ammonia (NH3? H2O) is a soluble weak base, and NH3 can be dissolved in water to obtain ammonia water. Have a pungent smell, have
Volatility. Ammonia gas generates nitrogen, water and copper through a glass tube filled with copper oxide, and the reaction equation is:
2NH3+3CuO 3Cu+N2↑+3H2O, which shows that ammonia can be reduced.
In addition, KOH and Ba(OH)2 are also common soluble strong bases. Insoluble bases are mostly weak bases, such as Fe(OH)3 and Cu(OH)2. Their similarity is that they have poor thermal stability and are easily decomposed into corresponding metal oxides and water when heated.
★★★★★ Salt NaCl Na2CO3 NaHCO3 CuSO4 ammonium salt KMnO4
(1) salt reacts with some metals to form new metals and new salts. For example:
(1) zinc+copper sulfate = = zinc sulfate+copper.
②Cu+Hg(NO3)2 === Cu(NO3)2+Hg
Only the metal in front of the metal active sequence table can replace the metal in the back from its salt solution.
(2) Salt reacts with acid to generate new acid and new salt. For example:
bacl 2+h2so 4 = baso 4↓+2 HCl；
(3) Salt reacts with alkali to generate new salt and alkali. For example:
①mgso 4+2 NaOH = Mg(OH)2↓+na2so 4；
②mgso 4+Ba(OH)2 = = baso 4↓+Mg(OH)2↓
(4) Salt reacts with another salt to generate two new salts, such as:
2AgNO3+Na2CO3 === Ag2CO3↓+2NaNO3
There are exceptions, such as: Al2 (SO4) 3+6 nahco3 = = 2al (OH) 3 ↓+6co2 ↑+3a2so4.
(5) Insoluble carbonate can be decomposed at high temperature to generate corresponding metal oxide and carbon dioxide gas.
①CaCO3 CaO + CO2↑, ②BaCO3 BaO + CO2↑;
②Cu2(OH)2CO3 (green) 2cuo+H2O+CO2 =