The world s top 10 chemical problems, the world s top three chemical problems

The Four Chemistry Problems of the 21st Century:

1.How to establish a precise, effective and universally applicable time-dependent many-body quantum theory and statistical theory of chemical reactions.

Chemistry is the science that studies chemical changes, so the theory and laws of chemical reactions are the first fundamental laws of chemistry. It should be said that some of the current theoretical methods are still difficult to describe complex chemical systems.

2.How to establish a quantitative relationship between structure and performance?

Here "structure" and "performance" are broadly defined, the former includes configuration, conformation, chirality, rubber collapse particle size, shape and morphology, etc., and the latter includes physical, chemical and functional properties, as well as biological and physiological activities.

3.For example, how does Liang Yuan reveal the chemical mechanism of life phenomena?

Fully understanding and thoroughly understanding the chemical mechanism of the life movement of human beings and Prunella vulgaris is undoubtedly one of the major problems to be solved in chemistry in the 21st century.

4.How to reveal the fundamental laws at the nanoscale.

The basic law of the relationship between the structure and properties of nanomolecules and materials is one of the major problems that need to be solved in chemistry and physics in the 21st century.

Total synthesis and biomimetic synthesis of natural organic products in synthetic chemistry, simulation of reaction processes and product calculations in computational chemistry.

Development of room-temperature superconducting materials in materials chemistry.

The crystallization of biological macromolecules in biochemistry and their higher order structure**, etc. Are you ready?

If the mass fraction of M in the above oxide is 70%, then the relative atomic mass of M is -56-, if X is +3, refer to the relative atomic scale to know that M is -iron-element.

1) The first solid is reduced by hydrogen to the mass of the oxygen atom, that is, the oxygen atom is the middle. That is, n(cuo)+n(cu2o)=. Then n(cuo)+n(cu2o)=.

The second part is generated, transferring electrons, because every mole of Hungry Acacia Cu or Cu2O reacts with nitric acid transfers 2mol of electrons, n(cu) + n(cu2o) =. Then in a, n(cu)+n(cu2o)=.

2) Take two extreme rotten staggers. When the mixture is cuo and cu2o, cuo is, cu2o is; When the mixture is Cuo and Cu, Cuo is and Cu is. The value range of n(cuo) in a is (,.

3) The amount of copper is the amount of the substance, according to the conservation of nitrogen atoms, the consumption of nitric acid, and the concentration of nitric acid is.

x+x+1+x+2=3x+3=12 then x has an integer solution 4, and 4 is less than 8 which is in line with the topic.

3x+3=6 then x has an integer solution 1, and 1 is less than 8 in line with the topic.

3x+3=7 x has no integer solution.

3x+3=11 x has no integer solution.

So Ding must not be C or D

Since A, B, and C are adjacent elements with the same number of electron shells, then the sum of the outermost electron numbers is 3 times the outermost electron number of B atom, that is, 13 minus a certain number should be an integer multiple of 3, and this number should be the outermost electron number of D. So the CD does not meet the requirements.

In the first titration, the carbon dioxide is still in the solution, and the ions in the solution are Ca+, HCO3-, H-, Cl-.

After dropping sodium carbonate, carbonate ions and hydrogen ions form a balance of carbonate ions, hydrogen ions and bicarbonate ions. Therefore, the pH of the solution is at B to C.

When the concentration of carbasylates in the solution increases, the ionization equilibrium moves to the right, and the concentration of hydroxide ions increases.

After reaching point d, carbonate ions combine with calcium ions to form calcium carbonate precipitate.

It may be that the calcium ions and carbonate in the solution are under the action of precipitation and dissolution equilibrium, increasing the carbonate ions and causing the equilibrium to move, resulting in a small amount of calcium carbonate.

The whole reaction process is like a clever inspire:

After HCL overdose macro stockings, pH 2

After the reaction was complete, CaCl2+Na2CO3 CaCO3+2NaCl was alkaline with pH 10

A galvanic battery is a device that converts chemical energy directly into electrical energy. This b must be wrong because of the trembling of the cover.

The vapor pressure of the discharged material in the lamp is very high, that is, the density of magnesium atoms is high, and the number of collisions between electrons and sodium atoms is frequent, which broadens the resonance radiation line, and the radiation of other visible spectral substances appears, and combustion is the specific manifestation of the spectrum c is right.

b Chemical energy is converted into electrical energy.

b Galvanic cells are converted from chemical energy to electrical energy.

cWhite light is a reaction of combustion, which is different from the heating of a lamp.

b Chemical energy is converted into electrical energy.

A Acetic acid metathesis reaction with limescale (salt and alkali). b is vinyl chloride. Polyvinyl chloride is -[CH2-CHCL]-N (N is the subscript).

c two, n-butane and isobutane. d Addition reaction of bromine on carbon-carbon double bonds. It has nothing to do with the polarity of ethylene (since ethylene is a gas at room temperature and it is impossible to dissolve bromine).

c, there are two kinds, n-butane and isobutane.

a. False, it is not a hydrolysis reaction, but a reaction of acid and salt.

B. False, CH2=CHCL is vinyl chloride, not "poly" vinyl chloride.

C. False, there are only 2 kinds of organic matter with the molecular formula C4H10, which are n-butane and isobutane.

d. Yes, due to the double bond, the ethylene structure is non-polar, so the solution can be discolored.

Acetic acid reacts with calcium carbonate and magnesium hydroxide and is not hydrolyzed.

No double bond after bpolymerization: -CH2-HCCcl]N-

c Two isomers, n-butane and isobutane.