common names chemical formulas
diamond, graphite, C
ethanol, C2H5OH
hydrated lime, slaked lime, calcium hydroxide, Ca(OH)2
quicklime, calcium oxide, CaO
acetic acid (melting point 16.6℃, Solid state is called glacial acetic acid) acetic acid CH3COOH
wood alcohol, wood alcohol methanol CH3OH
dry ice solid CO2 CO2
verdigris, malachite basic copper carbonate Cu2(OH)2CO3
vitriol, blue vitriol copper sulfate crystal CuSO4 5h2o
hydrogen sulfide
H2SO4 3
salt. HCl
Mercury Hg
soda ash, soda, sodium carbonate Na2CO3
sodium carbonate crystal Na2CO3 1H2O
acid sodium carbonate, sodium bicarbonate NaHCO3
caustic soda, caustic soda, sodium hydroxide NaOH
toxic salt, Nitrate (industrial name) sodium nitrite NaNO2
ammonia water-ammonia hydrate NH3 H2O
2. Color and state of common substances
1. White solids: MgO, P2O5, CaO, NaOH, Ca(OH)2, KClO3, KCl, Na2CO3, NaCl and anhydrous CuSO4；; Iron and magnesium are silvery white (mercury is silvery white liquid)
2, black solid: graphite, carbon powder, iron powder, CuO, MnO2, Fe3O4, *KMnO4 is purplish black
3, red solid: Cu, Fe2O3, HgO, red phosphorus
4, and light yellow: sulfur.
5. Green: Cu2(OH)2CO3 is green
6. Color of solution: all solutions containing Cu2+ are blue; Any solution containing Fe2+ is light green; Any solution containing Fe3+ is brownish yellow, and other solutions are generally colorless. (Potassium permanganate solution is purplish red)
7. Precipitation (that is, salt and alkali insoluble in water): ① Salt: white ↓：CaCO3, BaCO3 (soluble in acid) AgCl, BaSO4 (insoluble in dilute HNO3), etc. ② Alkali: blue precipitation: Cu (OH) 2; Reddish-brown precipitate: Fe(OH)3, white precipitate: the rest alkali.
8. (1) Gases with irritant gases: NH3, SO2 and HCl (all colorless)
(2) COlorless and odorless gases: O2, H2, N2, CO2, CH4 and Co (highly toxic)
Note: liquids with irritant odor: hydrochloric acid, nitric acid and acetic acid. Alcohol is a liquid with special gas.
9. toxic gas: CO liquid: CH3OH solid: NaNO2, CuSO4 (can be used as bactericide, mixed with hydrated lime to make a blue sticky substance-bordeaux liquid).
III. Solubility of substances
1. Solubility of salts
All substances containing potassium, sodium, nitrate and ammonium are soluble in water
Only AgCl and HgCl are insoluble in water, while others are soluble in water;
only BaSO4, PbSO4 is insoluble in water, AgSO4 is slightly soluble in water, and others are soluble in water.
only kCO32－, Na2CO3 and (NH4)2CO3 are soluble in water, while others are insoluble in water.
2. Solubility of alkali
Alkalis soluble in water include barium hydroxide, potassium hydroxide, calcium hydroxide, sodium hydroxide and ammonia water, while others are insoluble in water. Fe(OH)3 is reddish brown precipitate, Cu(OH)2 is blue precipitate, and other insoluble bases are white. (including Fe(OH)2)
Note: AgCl and BaSO4 in the precipitate are insoluble in dilute nitric acid, while other precipitates are soluble in acid. Such as: mg (oh) 2co3 baco3.
3. Most acids and acidic oxides are soluble in water, while most basic oxides are insoluble in water, and some are soluble: barium oxide, potassium oxide, calcium oxide and sodium oxide (basic oxide+water → alkali). There is a formula that can help students remember these things: potassium, sodium, ammonium and nitrate are all soluble, and hydrochloric acid is insoluble in silver and mercury; Sulfate insoluble barium and lead and carbon phosphate are mostly insoluble; Most acids are soluble in alkali, but only potassium, sodium, ammonium and barium are soluble.
fourth, the most chemical
1. The most abundant metal element in the earth's crust is aluminum.
2. The most nonmetallic element in the earth's crust is oxygen.
3. Nitrogen is the most abundant substance in the air.
4. The hardest substance in nature is diamond.
5. The simplest organic matter is methane.
6. The most active metal in the metal activity sequence table is potassium.
7. The oxide with the smallest relative molecular mass is water.
8. The simplest organic compound CH4.
9. Under the same conditions, the gas with the lowest density is hydrogen.
1. The most conductive metal is silver.
11. The atom with the smallest relative atomic mass is hydrogen.
12. The metal with the lowest melting point is mercury.
13. The most abundant element in human body is oxygen.
14. The element that makes up the most kinds of compounds is carbon.
15. The most widely used metal in daily life is iron.
16. The only nonmetallic liquid simple substance is bromine;
17. China was the first to use natural gas;
18. The largest coal base in China is: Shanxi Province;
19. China was the first to use wet copper smelting (discovered in the Western Han Dynasty [Liu An's Huainan Wanbi Shu, "Zeng Qing turned iron into copper"] and applied in the Song Dynasty);
2, the earliest discovery of electrons is Thomson in Britain;
21. The earliest conclusion that air is composed of N2 and O2 was made by lavoisier.
five, "certain" and "not necessarily" in chemistry
1. There must be physical changes in chemical changes, and there may not be chemical changes in physical changes.
2. Metals are not always solid at room temperature (for example, Hg is liquid), and nonmetals are not always gas or solid (for example, Br2 is liquid). Note: Metals and nonmetals refer to simple substances and cannot be confused with material elements.
3. Atomic groups must be charged ions, but they are not necessarily acid groups (such as NH4+, OH- )；; Acid radical is not necessarily an atomic group (for example, Cl- is called hydrochloric acid radical).
4. Slow oxidation does not necessarily cause spontaneous combustion. Combustion must be a chemical change. The explosion is not necessarily a chemical change. (For example, pressure cooker explosion is a physical change. )
5. Neutrons are not always in the nucleus (for example, there are no neutrons in the H atom).
6. The atom is not necessarily smaller than the molecule (you can't say "the molecule is big and the atom is small"). The fundamental difference between molecules and atoms is that molecules can be separated and atoms cannot be separated in chemical reactions.
7. The substance composed of the same element is not necessarily a simple substance, but may be a mixture of several simple substances. Such as O2 and O3.
8. The particles with the outermost electron number of 8 are not necessarily atoms of rare gas elements, but may also be cations or anions.
9. The outermost electron number of atoms with stable structures is not necessarily 8, such as helium atoms. (The first layer is the outermost two electrons).
1. Particles with the same nuclear charge are not necessarily the same element. (Because particles include atoms, molecules and ions, while elements do not include molecules or atomic groups composed of multi-atoms) Only mononuclear particles (one atom and one nucleus) with the same nuclear charge number must belong to the same element.
11. (1) A concentrated solution is not necessarily a saturated solution; A dilute solution is not necessarily an unsaturated solution. (For different solutes) (2) The saturated solution of the same substance is not necessarily thicker than the unsaturated solution. (Because the temperature is uncertain, just like the temperature is certain) (3) The solution after crystal precipitation must be a saturated solution of something. Crystals do not necessarily precipitate after the saturated solution is cooled. (4) At a certain temperature, the solubility of any substance must be greater than the solute mass fraction of its saturated solution, that is, S must be greater than C..
12. A reaction involving simple substances and compounds is not necessarily a displacement reaction. But there must be a change in the valence of elements.
13. The valence of elements does not necessarily change in decomposition reaction and combination reaction; There must be a change in the valence of elements in the displacement reaction; There must be no change in the valence of elements in the metathesis reaction. (Note: there must be a change in the valence of elements in the redox reaction)
14. Simple substances must not undergo decomposition reaction.
15. The same element does not necessarily show a valence in the same compound. For example, NH4NO3 (the former N is -3 valence and the latter N is +5 valence)
16. There are not necessarily metal elements in the composition of the salt. For example, NH4+ is a cation, which has the properties of metal ions, but it is not a metal ion.
17. Cations are not necessarily metal ions. Such as H+ and NH4+.
18. Among compounds (oxides, acids, bases and salts), oxides and bases must contain oxygen; Acids and salts do not necessarily (possibly) contain oxygen elements; It is acids and bases that must contain hydrogen; It is salts and oxides that do not necessarily contain hydrogen; The composition of salt and alkali does not necessarily contain metal elements (such as NH4NO3, NH3, H2O); The acid composition may contain metal elements (for example, HMnO4 is called permanganate), but all the material compositions must contain nonmetallic elements.
19. The salt solution is not necessarily neutral. For example, Na2CO3 solution is alkaline.
2. The acid salt solution is not necessarily acidic (that is, the PH is not necessarily less than 7), such as the NaHCO3 solution is alkaline. However, the sodium bisulfate solution is acidic, so the substance that can ionize hydrogen ions is not necessarily acid.
21. The acid solution must be an acid solution, but it is not necessarily an acid solution. For example, H2SO4 and NaHSO4 are all acidic, and NaHSO4 is a salt. (An acid solution is an acid aqueous solution, and an acid solution is a solution containing H+).
22. The alkaline solution must be an alkaline solution, but the alkaline solution is not necessarily an alkaline solution. For example, NaOH, Na2CO3 and NaHCO3 solutions are all alkaline, while Na2CO3 and NaHCO3 are salts. An alkaline solution is an aqueous solution of alkali, and an alkaline solution is a solution containing OH-).
23. The basic oxide must be a metal oxide, and the metal oxide is not necessarily a basic oxide. (For example, Mn2O7 is a metal oxide, but it is an acid oxide, and its corresponding acid is permanganate, that is, HMnO4 )；; Remember: only K2O, Na2O, BaO and CaO in basic oxides can be dissolved in water and react with water to form alkali.
24. acidic oxides are NOt necessarily nonmetallic oxides (such as Mn2O7), and nonmetallic oxides are not necessarily acidic oxides (such as H2O, CO and no). ★ Common acid oxides: CO2, SO2, SO3, P2O5, SiO2, etc. Most acid oxides can be dissolved in water and react with water to generate corresponding acids. Remember that silica (SiO2) is insoluble in water.
25. The reaction of producing salt and water is not necessarily a neutralization reaction.
26. All chemical reactions do not necessarily belong to basic reaction types, and those that do not belong to basic reactions are: ① the reaction between CO and metal oxides; (2) the reaction between acid oxide and alkali; ③ Combustion of organic matter.
27. In any substitution reaction (reaction of iron with acid and salt) in which elemental iron participates, iron will definitely show a valence of +2 after the reaction (i.e. ferrous salt will be generated).
28. whenever there is a displacement reaction between a metal and an acid, the quality of the solution will definitely increase after the reaction. When a metal reacts with a salt solution, we can judge the mass change of the solution before and after the reaction only by looking at the relative atomic mass of the metal participating in the reaction and the relative atomic mass of the metal generated. "Big for small weight gain, small for big weight loss".
29. When metals with the same mass and valence react with acids, the greater the relative atomic mass, the less the hydrogen produced.
3. Any metal (such as K, Ca, Na) that can react with water at room temperature must not react with salt solution; But their reaction with acid is that most intense. If Na is added to CuSO4 solution, the reaction will be: 2Na+2H2O = 2NaOH+H2 ↑; 2NaOH+CuSO4 =Cu(OH)2 ↓+Na2SO4 。
31. In all air exhausting methods (upward or downward), the airway must be extended to the bottom of the gas container.
32. The gas generator must be checked for air tightness before filling drugs. Be sure to check the purity before igniting or heating the combustible gas.
33. When writing the chemical formula, the positive valence elements are not always written on the left. For example, NH3, CH4.
34, 5g of a substance is put into 95g of water, and the solute mass fraction of the obtained solution is not necessarily equal to 5%.
may be equal to 5%, such as NaCl, KNO3, etc. It may also be greater than 5%, such as K2O, Na2O, BaO, SO3, etc. It may also be less than 5%, such as crystalline hydrate and Ca(OH)2, CaO, etc.
◆ Under the same conditions, the solute mass fraction of the solution obtained by dissolving CaO or Ca(OH)2 in water is the smallest
VI. "Three" in junior middle school chemistry
1.
2. Three reductants commonly used for reducing copper oxide are hydrogen, carbon monoxide and carbon.
3. As a fuel, hydrogen has three advantages: rich resources, high calorific value, and the product of combustion is water that does not pollute the environment.
4. There are generally three kinds of particles that make up atoms: protons, neutrons and electrons.
5. There are only three kinds of ferrous metals: iron, manganese and chromium.
6. The elements that make up a substance can be divided into three categories, namely (1) metallic elements, (2) nonmetallic elements and (3) rare gas elements.
7, there are three kinds of iron oxides, and their chemical formulas are (1)FeO, (2)Fe2O3 and (3) Fe3O4.
8. The solution has three characteristics: (1) homogeneity; (2) stability; (3) mixture.
9. The chemical equation has three meanings: (1) It indicates what substances participate in the reaction and what substances are generated as a result; (2) The particle number ratio of molecules or atoms between reactants and products; (3) Represents the mass ratio of each reactant and product. Chemical equations have two principles: based on objective facts; Follow the law of conservation of mass.
1. Pig iron is generally divided into three types: white iron, gray iron and ductile iron.
11. Carbon steel can be divided into three types: high carbon steel, medium carbon steel and low carbon steel.
12. There are three kinds of iron ore commonly used in ironmaking: (1) Hematite (mainly composed of Fe2O)