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pet coke price is so cheap here: What is wrong with the following statement is () A. Atoms can directly form substance B. Molecules can be subdivided, atoms can't be subdivided into C. In a chemical reaction, the molecule changes but the atom does not, indicating that the molecule is in motion and the atom is at rest. Water molecules maintain the chemical properties of water solution: both molecules and atoms can directly constitute matter, molecules are composed of atoms, atoms can be divided into protons and neutrons. Molecules are the smallest particles that hold the chemical properties of a substance. Molecules and atoms all move irregularly. 2 Basic concepts: 1, chemical change: the change of other substances; 2, physical change: no change of other substances; 3, physical properties: no chemical change is required to show the nature (such as: color, state, density, odor, melting point, boiling point, hardness, water solubility, etc.) The properties of substances shown in chem...

chemicals wholesale  (1) The use of alcohol lamp should pay attention to the "three Nos" : ① Do not add alcohol to the burning alcohol lamp; ② Light the alcohol lamp from the side with a match, and do not use the burning alcohol lamp to directly light another alcohol lamp; ③ Put out the alcohol lamp should be put out by the lamp cap, do not blow out. (2) The amount of alcohol in the alcohol lamp shall not exceed 2/3 of the volume of the alcohol lamp and shall not be less than 1/4.  (3) The flame of the alcohol lamp is divided into three layers, external flame, internal flame and flame core. Heat objects with the outer flame of an alcohol lamp. (4) If the alcohol lamp is accidentally overturned when burning, when the alcohol is burning on the test bench, it should be covered with sand in time or put out the flame with a wet rag, and cannot be washed with water. (5) Clamp - iron clamp, tube clamp The position of the tube clamp should be nearly 1/3 of the tube mouth. The long ha...

Chemicals wholesale  common acid or ion: SO42-(sulfate), NO3-(nitrate), CO32-(carbonate), ClO3-(chloric acid), MnO4-(permanganate), MnO42-(manganate), PO43-(phosphate), Cl-(chloride), HCO3-(bicarbonate), HSO4-(hydrogen sulfate), HPO42-(hydrogen phosphate), H2PO4-(dihydrogen phosphate), OH-(hydroxide), HS-(hydrogen sulfide), S2-(sulfur ion), NH4+(ammonium or ammonium ion), K+(potassium ion), Ca2+(calcium ion), Na+(sodium ion), Mg2+(magnesium ion), Al3+(aluminum ion), Zn2+(zinc ion), Fe2+(ferrous ion), Fe3+(iron ion), Cu2+(copper ion), Ag+(silver ion), Ba2+(barium ion) 3, ① directly represented by the element symbol: a. Metallic elements. Such as: potassium K copper Cu silver Ag; b. Solid non-metal. Such as: carbon C sulfur S phosphorus P and so on c. Noble gases. Such as: helium (gas)He neon (gas)Ne argon (gas)Ar and so on ② Polyatomic composition of the molecule: its molecule is composed of several atoms of the same kind in the lower right corner of the element symbol to write seve...

 Blue solid basic copper carbonate (patina) : green solid Black solid: carbon powder, copper oxide, manganese dioxide, iron tetroxide White solid: anhydrous copper sulfate (CuSO4), potassium chlorate, potassium chloride, magnesium oxide, sodium chloride, calcium carbonate, sodium carbonate, zinc sulfate Purple black: potassium permanganate light green solution:  Ferrous sulfate (FeSO4) 32, to make combustibles burning conditions: combustibles in contact with oxygen, to make the temperature of the combustibles reach the ignition point. 33, gases composed of diatomic molecules: H2, O2, N2, Cl2, F2 34, the following is determined by which part of the atomic structure:  (1) The type of element is determined by the number of protons, (2) the classification of the element is determined by the number of outermost electrons, (3) the chemical properties of the element are determined by the number of outermost electrons, (4) the valence of the element is determined by the number of...

C hemical wiki : The ambient temperature of the metal coins can not be too high, and the metal coins are afraid of heat. Because the higher the temperature of the metal, the more chemically active it is. Experiments show that a copper wire placed at room temperature and placed on the flame of an alcohol lamp, the speed of chemical reaction with oxygen is very different. Fourth, metal coins of different materials should not be stored together, because their chemical activity is not the same. For example, some antique coin lovers, in order to maintain the "original ancient style" of the coin, are not willing to polish and remove rust, and the ancient coin may be accompanied by a layer of inorganic salt compounds containing crystal water, the most common is the patina on the copper coin. When metal coins of different materials are put together with such coins attached to a layer of crystalline compounds, displacement reactions and galvanic reactions are easy to form, resulting i...

Chemical wholesaler maleic acid boiling point is 202 °C (at 1 atmosphere), Powder form, purity 99% price 0.1 dollar /kg 1. Acid + metal oxide - → Salt + water Fe2O3+6HCl===2FeCl3+3H2OFe2O3+3H2SO4===Fe2(SO4)3+3H2OCuO+2HCl===CuCl2+H2OCuO+H2SO4===CuSO4+H2O2. Acid + base - → Salt + water NaOH+HCl===NaCl+H2O2NaOH+H2SO4===Na2SO4+2H2OCa(OH)2+H2SO4===CaSO4+2H2OAl(OH)3+3HCl===AlCl3+3H2OCu(OH)2+2HCl=== =Cu Cl2+2H2O Unit 1 Metals and metallic materials Common metallic materials and their chemical properties and applications 1.  Several important metals and alloys (1) Physical properties of metals: in addition to mercury (liquid) at room temperature are solid, metallic luster, most of them are excellent conductors of electricity and heat, ductility, high density, high melting point.  (2) The comparison of several common metals (see Table 8-18-1) : Table 8-18-1 Metal physical properties used iron Pure iron has a silver-white metallic luster, soft, good ductility, density 7.86g/cm3, meltin...