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(1) Nature of chemicals:
1. Sulfuric acid: H2SO4-colorless oily liquid, 1.837 (1.84) at a specific gravity of 15 ° C. Smoke at 30-40 ° C; boil at 290 ° C. Concentrated sulfuric acid has strong water absorption, so it is an excellent desiccant.
2. Nitric acid: HNO3-colorless liquid, with a specific gravity of 1.526 at 15 ℃ and a boiling point of 86 ℃. Red fuming nitric acid is a reddish-brown, highly caustic, transparent liquid that fumes violently in the air and absorbs moisture.
3. Hydrochloric acid: HCl-colorless has a pungent odor, its specific gravity is 1.264 (for air) at 17 ℃. The boiling point is -85.2. Very soluble in water.
4. Gold chloride: red crystal, easy to deliquesce.
5. Silver nitrate: AgNO3-colorless rhombic flaky crystals, specific gravity 4.3551, 208.5 ℃, melting and burning decomposition. If there is no organic matter, seeing light will not work, otherwise it will turn black. Easily soluble in water and glycerin. Soluble in alcohol, methanol and isopropanol. Almost insoluble in nitric acid. poisonous!
6. Ammonium persulfate: (NH4) 2S2O8-light green flake crystals when colorless, soluble in water.
7. Stannous chloride: SnCl2 colorless translucent crystalline substance (diamond-shaped crystal system) specific gravity 3.95, melting at 241 ℃, boiling at 603.25 ℃. It is soluble in water, alcohol, ether, acetone, azabenzene and ethyl acetate. It is quite stable in the air.
8. Potassium dichromate: K2CrO7- orange-red anhydrous triclinic needle or plate crystal, specific gravity 2.7, soluble in water.
9. Aqua regia: a colorless liquid that quickly turns yellow, is extremely corrosive, and has a smell of chlorine. Preparation method: 3 volumes of hydrochloric acid with a specific gravity of 1.19 and 1 volume of nitric acid with a specific gravity of 1.38-1.40 are mixed.
10. Activated carbon: black fine grains (blocks) with many holes. The surface area of ​​1 gram of activated carbon is about 10 or 1000 square meters, which determines that activated carbon has a high degree of adsorption.
11. Sodium chloride: NaCl-white square crystal or fine crystalline powder, specific gravity 2. 1675, melting point 800 ℃, boiling point 1440 ℃. Soluble in water but not alcohol.
12. Sodium carbonate: Na2CO3 • 10H2O-colorless and transparent monoclinic crystal, specific gravity 1.5; soluble in water, with maximum solubility at 34 ℃.
13. Sodium hydroxide: NaOH-colorless crystalline substance, specific gravity 2.20, quickly absorbs carbon dioxide and moisture in the air. It becomes sodium carbonate after deliquescence. soluble in water.
14. Copper sulfate: blue crystals of CuSO4 • 5H2O-triclinic system, specific gravity 2.29. Above 100 ℃, it will start to lose crystal water. Anhydrous copper sulfate is formed at 220 ° C. It is a white powder with a specific gravity of 3.606. It easily absorbs water to form hydrates.
15. Boric acid: H3BO3- is a hexagonal triclinic white small phosphor plate with pearlescent, specific gravity is 1.44. It can be dissolved in water, alcohol (4%), glycerin and ether.
16. Potassium cyanide: KCN-colorless crystalline powder: specific gravity 1.52, easily soluble in water. poisonous!
17. Potassium permanganate: KnMO4- is easy to form light red purple near black diamond crystal, with metallic luster, specific gravity 2.71. It is soluble in water and has a deep purple color, a very strong oxidant.
18. Hydrogen peroxide: H2O2-colorless thick liquid, specific gravity 1.465 (at 0 ℃), with weak acid reaction.
19. Palladium chloride: PdCl2 • 2H2O-red brown diamond crystal, easy to lose water.
20. Hydrofluoric acid: HF-colorless liquid with easy flow and strong hygroscopicity, specific gravity of 0.9879 at 12.8 ℃. Smoke in the air. Its steam is extremely corrosive and toxic!
21. Basic copper carbonate: CuC03 • Cu (OH) 2-amorphous powder with light green fine particles, specific gravity 3.36-4.03. Insoluble in water, but soluble in acid. It can also be dissolved in an aqueous solution of cyanide, ammonium salt and alkali metal carbonate to form a copper complex.
22. Ammonium dichromate: (NH4) Cr2O7-orange-red monoclinic crystal. Specific gravity 2.15. Easily soluble in water and alcohol.
23. Ammonia water: Ammonia water is a colorless liquid, lighter than water and has the unique smell of ammonia and strong alkaline reaction.
24. Potassium ferrocyanide (yellow blood salt): K4Fe (CN) 6 • 3H2O-light yellow square pieces or octahedral crystals, specific gravity 1.88. Stable in the air.
25. Potassium ferricyanide (red blood salt): K3Fe (CN) 6-dark red diamond crystal: specific gravity 1.845. It can dissolve in water, and the aqueous solution gradually decomposes when exposed to light to form K4Fe (CN) 6. It is a strong oxidant in alkaline media.
(2) Common test paper properties:
1. Iodine starch test paper: It turns blue (especially free halide) when it encounters oxidant, so you can check these substances.
2. Congo test paper: turns blue in acidic medium and red in alkaline medium (when PH = 2-3, it changes from blue to red.
3. Litmus test paper: light blue purple (blue) or purple rose (red) test paper, its color turns blue when it meets acidic medium and red when it meets alkaline medium. When PH = 6-7, the color changes.
4. Lead acetate test paper: it turns black when it meets hydrogen sulfide (lead sulfide is formed), and can be used to check trace amounts of hydrogen sulfide.
5. Phenolphthalein test paper: white phenolphthalein test paper turns dark red in alkaline medium.
6. Orange yellow I test paper: it changes to rosy red in acid medium, and the acid value is in the range of 1.3-3.2, then it changes from red to yellow.
1. Sulfuric acid: H2SO4-colorless oily liquid, 1.837 (1.84) at a specific gravity of 15 ° C. Smoke at 30-40 ° C; boil at 290 ° C. Concentrated sulfuric acid has strong water absorption, so it is an excellent desiccant.
2. Nitric acid: HNO3-colorless liquid, with a specific gravity of 1.526 at 15 ℃ and a boiling point of 86 ℃. Red fuming nitric acid is a reddish-brown, highly caustic, transparent liquid that fumes violently in the air and absorbs moisture.
3. Hydrochloric acid: HCl-colorless has a pungent odor, its specific gravity is 1.264 (for air) at 17 ℃. The boiling point is -85.2. Very soluble in water.
4. Gold chloride: red crystal, easy to deliquesce.
5. Silver nitrate: AgNO3-colorless rhombic flaky crystals, specific gravity 4.3551, 208.5 ℃, melting and burning decomposition. If there is no organic matter, seeing light will not work, otherwise it will turn black. Easily soluble in water and glycerin. Soluble in alcohol, methanol and isopropanol. Almost insoluble in nitric acid. poisonous!
6. Ammonium persulfate: (NH4) 2S2O8-light green flake crystals when colorless, soluble in water.
7. Stannous chloride: SnCl2 colorless translucent crystalline substance (diamond-shaped crystal system) specific gravity 3.95, melting at 241 ℃, boiling at 603.25 ℃. It is soluble in water, alcohol, ether, acetone, azabenzene and ethyl acetate. It is quite stable in the air.
8. Potassium dichromate: K2CrO7- orange-red anhydrous triclinic needle or plate crystal, specific gravity 2.7, soluble in water.
9. Aqua regia: a colorless liquid that quickly turns yellow, is extremely corrosive, and has a smell of chlorine. Preparation method: 3 volumes of hydrochloric acid with a specific gravity of 1.19 and 1 volume of nitric acid with a specific gravity of 1.38-1.40 are mixed.
10. Activated carbon: black fine grains (blocks) with many holes. The surface area of ​​1 gram of activated carbon is about 10 or 1000 square meters, which determines that activated carbon has a high degree of adsorption.
11. Sodium chloride: NaCl-white square crystal or fine crystalline powder, specific gravity 2. 1675, melting point 800 ℃, boiling point 1440 ℃. Soluble in water but not alcohol.
12. Sodium carbonate: Na2CO3 • 10H2O-colorless and transparent monoclinic crystal, specific gravity 1.5; soluble in water, with maximum solubility at 34 ℃.
13. Sodium hydroxide: NaOH-colorless crystalline substance, specific gravity 2.20, quickly absorbs carbon dioxide and moisture in the air. It becomes sodium carbonate after deliquescence. soluble in water.
14. Copper sulfate: blue crystals of CuSO4 • 5H2O-triclinic system, specific gravity 2.29. Above 100 ℃, it will start to lose crystal water. Anhydrous copper sulfate is formed at 220 ° C. It is a white powder with a specific gravity of 3.606. It easily absorbs water to form hydrates.
15. Boric acid: H3BO3- is a hexagonal triclinic white small phosphor plate with pearlescent, specific gravity is 1.44. It can be dissolved in water, alcohol (4%), glycerin and ether.
16. Potassium cyanide: KCN-colorless crystalline powder: specific gravity 1.52, easily soluble in water. poisonous!
17. Potassium permanganate: KnMO4- is easy to form light red purple near black diamond crystal, with metallic luster, specific gravity 2.71. It is soluble in water and has a deep purple color, a very strong oxidant.
18. Hydrogen peroxide: H2O2-colorless thick liquid, specific gravity 1.465 (at 0 ℃), with weak acid reaction.
19. Palladium chloride: PdCl2 • 2H2O-red brown diamond crystal, easy to lose water.
20. Hydrofluoric acid: HF-colorless liquid with easy flow and strong hygroscopicity, specific gravity of 0.9879 at 12.8 ℃. Smoke in the air. Its steam is extremely corrosive and toxic!
21. Basic copper carbonate: CuC03 • Cu (OH) 2-amorphous powder with light green fine particles, specific gravity 3.36-4.03. Insoluble in water, but soluble in acid. It can also be dissolved in an aqueous solution of cyanide, ammonium salt and alkali metal carbonate to form a copper complex.
22. Ammonium dichromate: (NH4) Cr2O7-orange-red monoclinic crystal. Specific gravity 2.15. Easily soluble in water and alcohol.
23. Ammonia water: Ammonia water is a colorless liquid, lighter than water and has the unique smell of ammonia and strong alkaline reaction.
24. Potassium ferrocyanide (yellow blood salt): K4Fe (CN) 6 • 3H2O-light yellow square pieces or octahedral crystals, specific gravity 1.88. Stable in the air.
25. Potassium ferricyanide (red blood salt): K3Fe (CN) 6-dark red diamond crystal: specific gravity 1.845. It can dissolve in water, and the aqueous solution gradually decomposes when exposed to light to form K4Fe (CN) 6. It is a strong oxidant in alkaline media.
(2) Common test paper properties:
1. Iodine starch test paper: It turns blue (especially free halide) when it encounters oxidant, so you can check these substances.
2. Congo test paper: turns blue in acidic medium and red in alkaline medium (when PH = 2-3, it changes from blue to red.
3. Litmus test paper: light blue purple (blue) or purple rose (red) test paper, its color turns blue when it meets acidic medium and red when it meets alkaline medium. When PH = 6-7, the color changes.
4. Lead acetate test paper: it turns black when it meets hydrogen sulfide (lead sulfide is formed), and can be used to check trace amounts of hydrogen sulfide.
5. Phenolphthalein test paper: white phenolphthalein test paper turns dark red in alkaline medium.
6. Orange yellow I test paper: it changes to rosy red in acid medium, and the acid value is in the range of 1.3-3.2, then it changes from red to yellow.
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