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Anonymous users2024-02-11It is indeed difficult to calculate the unit cell, to have spatial three-dimensional thinking, geometric knowledge, you can summarize several unit cells together, such as face-centered cube, body-centered cube, etc., after summarizing together, find out the common points and differences, and compare them to learn, so that it will get twice the result with half the effort, I remember that there is a summary of this aspect on the textbook help, you can take a look at it specifically.
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Anonymous users2024-02-10Be three-dimensionally conscious. Calculations about cubic unit cells. Remember, the apex is one-eighth and the face is one-half. A quarter of the ridge is on the edge. One in the body. Find the density.
Formula p=nm (v na).
p is the crystal density, m is the molar mass of the generalized crystal, n is the number of molecules in the unit cell, na is the Avogadro constant, and V is the unit cell volume.
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Anonymous users2024-02-09That's actually quite simple, first grasp the basic formula. Density is equal to mass divided by volume, then mass is equal to molar mass multiplied by the amount of matter, and the amount of matter is equal to the number of particles divided by na, after the above substitution, it can be obtained.
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Anonymous users2024-02-08First of all, we must know the type of crystal, and then calculate the number of particles in the unit cell according to the proportion of particles in the unit cell, and then bring in the formula of the unit cell density, and pay attention to the conversion between units.
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Anonymous users2024-02-07If you memorize the unit cell model, memorize the formulas, memorize the rules, and do a class of problems, there will be basically no problem. You can also try the recommended formula methods and tutorials downstairs.
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Anonymous users2024-02-06Memorize the density formula, and then think about the volume of an atom in 1 unit cell, what is the volume of the unit cell, you can refer to the textbook Help Matter Structure and Properties book, which has various unit cell calculations.
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Anonymous users2024-02-05Summary. The writing of the chemical formula is smooth "before gold hydrogen, not after gold; oxide, oxygen in the after; Three elements, in order; Metallic, non-oxygen, last. The number of atoms cannot be leaked.
It means that the metal or hydrogen is in the front, the non-metal is in the back, and the compound composed of the three elements is metal, non-metal, and oxygen element.
And in the salts, it is the metal ion in the front, the acid in the back, you should write barium leadate, barium in the front, leadate in the back, barium ba leadate bao3 so the chemical formula is baPBO3. For organic matter, the order in which it is written is carbon, hydrogen, oxygen, and other elements.
High School Chemistry Elective Three Substances Structure and Properties Elective Questions, Is the order of unit cell chemical formula written incorrectly to give points.
Hello, no points.
In high school, it's better to write in strict order to make sure you can score.
What is the order in which the chemical formula is written, given three unfamiliar elements, I can't tell who to write first.
I'll help you figure it out later.
The state segment of the chemical formula is written smoothly "before gold and hydrogen, not after gold; oxide, oxygen in the after; Three elements, in order; Metallic, non-oxygen, last. The number of atoms cannot be leaked. It means that the metal or hydrogen is in the front, the non-metal is in the back, and the compound composed of the three elements is metal, non-metal, and oxygen element.
And in the salts, it is the metal ion in the front, the acid state root in the back, you should write barium leadate, barium in the front, leadate in the back, barium ba leadate bao3 so the chemical formula is bapbo3. For the first occlusion of organic matter, the order in which it is written is carbon, hydrogen, oxygen, and other elements.
You can arrange the order according to this slip of the tongue.
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Anonymous users2024-02-04B: For example, copper sulfate crystals, the s-o of sulfate is a covalent bond C: there is a hydrogen bond in the ice, and the ferrocene molecule contains an iron ion, and there is an ionic bond (ferrocene is two cyclopentadiene with an iron sandwiched between them).
In d:c, ferrocene contains a cation and no anion. There is also chlorophyll that contains only magnesium ions.
A: Crystals with a spatial network structure formed by strong covalent bonds between adjacent atoms are called atomic crystals.
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Anonymous users2024-02-03B error NaOH is an ionic compound but has a covalent bond, C error , CO2 has a covalent bond in addition to the intermolecular force; dFalse: Metals are composed of metal cations and free electrons, and there are no anions.
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Anonymous users2024-02-021) You've written that it's carbon, but it's not right that carbon is diamond, which is an elemental crystal, and it's an atomic crystal, and his other elemental carbon60 is a molecular crystal, and nitrogen60 is (2) b is oxygen, and its hydride is water, and the electronic formula of water is that it's a polar molecule.
The hydrogen water compound of carbon dioxide is carbonic acid D is chlorine C is aluminum (3) Is it a and B If yes, the substance is carbon dioxide It is a linear shape The latter question belongs to the unclear It is a non-polar molecule (4) A is carbon B is oxygen The corresponding substance of the ACD he asked is carbonic acid Metaaluminic acid Perchloric acid The acidity is greater than that of carbonic acid (5) The substance formed by C and D is aluminum chloride Add potassium hydroxide to excess The phenomenon is precipitation and then precipitation dissolves The ion equation is.
Just look at the equation of excess, and you need to disassemble the soluble salts of strong acids and alkalis, and just take it apart, and tell you these things first, and then ask if you know how to do it.
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Anonymous users2024-02-011 Stability depends on the bonds inside the molecule, and the boiling point depends on the intermolecular forces (norm force or hydrogen bonds).
Atomic Crystals" Ionic Crystals = Metal Dissipation Crystals "Hydrogen Bonds" Fan Li.
No, the higher the stability, the higher the boiling point. One is intramolecular and the other is intermolecular.
2 Molecular crystals will exhibit a specific pendulum splitting pattern due to intermolecular forces, because crystal wrappers are required to study crystals.
7. Diamond contains covalent bonds, and there are intermolecular forces between molecular crystals.
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Anonymous users2024-01-311 Not necessarily, for example, noble gases are stable and high, but the melting and boiling point is very low. There is no direct connection between the two.
2 A crystal is a macroscopic substance, which cannot be composed of a single sub-molecule, and requires several molecules to form a repeating unit.
4 1mol carbon is not equivalent to 2mol diamond, diamond does not have the concept of moles, it is an atomic crystal. 1mol is not legally available.
5 Benzene: 6 Acetylene: 2 Polystyrene: Not fixed Therefore the 3 together are not fixed.
6 Dry ice is a molecular crystal made up of CO2 molecules.
7 Diamond Qingweizi has covalent bonds, a lot. There is only intermolecular interaction in molecular crystals.
8 These atoms are all in the unit cell, and they belong to the unit cell.
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In this reaction, there is only the electron gain and loss of nitrogen element, the valency has risen and decreased, so C is wrong, the increase of nitrogen in metadimethylhydrazine is oxidized, it is a reducing agent, so a is wrong, the reaction is the recombination of atoms, so there is an endothermic and exothermic process, C is wrong, D is left, of course, there are eight electrons transferred from two N2O4 to N2 D is correct.