Sophomore Chemistry, Why D Right? How to look at the sophomore chemistry D

A The two C's connected by a carbon-carbon double bond are in a straight line, and the other four atoms connected to the two C's are coplanar with it, but at an angle.

b is incorrect, all the atoms in the ethylene molecule are in the same plane, while the three carbon atoms in the propylene molecule are in the same plane, and the 3 hydrogen atoms on the methyl group in propylene are not in the same plane.

C is correct, and HCL addition is in line with the Marhalanobis rule, that is, H in HCL is added to the double-bonded carbon with more hydrogen in the propylene molecule, and Cl is added to the double-bonded carbon with less hydrogen However, high school chemistry may not be taught, so··· Estimate the reason.

dCorrect, the general polymerization reaction of olefins: under certain conditions, the bonds of olefins are broken, and the molecules are added to each other one after another to become a reaction of polymer compounds with huge relative molecular mass.

d correct. Propylene CH2=CHCH3, containing unsaturated CC double bonds, can undergo polyaddition reaction.

ABC is wrong because the configuration of C=C carbon-carbon double bonds is a planar regular triangle, and the atoms directly connected to it are all in the same plane. However, the hydrogen on the substituent methyl group is a spatial tetrahedral structure and cannot be in the same plane.

C is wrong because Cl is attached to C that is attached to a methyl group and C that is not attached to a methyl group, and the product is different.

You can draw the structure yourself and it will be clear.

First of all, propylene is also an olefin. The single bond is a three-dimensional structure, and the double bond is a planar structure, and it is clear that the answers of A and B are incorrect. Olefins can undergo addition reactions, and propylene ch3ch=ch2 can also undergo addition reactions.

But propylene has three carbon atoms, and an addition reaction occurs, the double bond is broken, and the H and Cl atoms join at different positions. Generate ch3-chcl-ch3 or ch3-ch2-ch2cl. Obviously, these are two different substances.

So the C answer is also incorrect. All olefins are subject to polymerization. Therefore d is correct.

In option A, propylene has only one carbon-carbon double bond, the two C's are collinear, and the other C is not.

Because there is a methyl group in option b, all atoms are not coplanar as long as the methyl group is present.

Because it is a CC double bond in the C option, there is only one product of HCL addition, and the stem says that all the errors may be.

Option d is correct, and the unsaturated bond can undergo a polyaddition reaction.

The structure of ethylene is that all atoms are in a plane again, and the conclusion is that ch2=ch2 is in the same plane, and it cannot be concluded that ch2=ch2=ch2 in c is in the same plane b is wrong.

The structure of ethylene The hydrogen atom has a tension angle with the carbon atom so propylene ch2=ch-ch3 "ch3" substitution is the position of ethylene h so the three carbon atoms are not in a line a wrong.

The structure of ethylene is symmetrical, so there is no difference between 1 and 2 digits when additive, but if it is propylene, there is a change in 12 digits of bonus, so c is wrong.

d to polyaddition reaction is a property of alkene.

A: The carbon atoms in ethylene have two single bonds in addition to the initial double bonds, and the bond angle of the double bond is a degree, and the bond angle between the single bonds is a degree, and the three carbon atoms after connecting the methyl group cannot be in a straight line.

B: If you say that the left and right carbon atoms in propylene may be on one plane, this option is correct, but it says that all atoms is wrong. The hybrid mode of carbon in methyl group is sp3 hybridization, that is to say, the spatial configuration is a regular tetrahedral type, and only two hydrogen atoms connected to class A may be in the plane where the three carbon atoms of propylene are located, and the remaining one cannot be in the plane.

c: With the addition of double bonds, the chlorine atom may be attached to the double-bonded carbon at the end of the chain, or to another double-bonded carbon linked to the methyl group. So the product is not unique. But the yield is different.

d: This option is correct. The unsaturated carbon-carbon double bond in propylene can undergo a polyaddition reaction.

First of all, the two options A and B are completely unreliable, ethylene is only two C, and the straight line is understandable, but the three Cs are not sure how it is arranged.

C option, propylene has three C atoms, CH3-CH=CH2, and the Cl addition in HCL can be on top of the second or third, so there are two products.

d, olefins can undergo polyaddition.

Ethylene has two carbons and one double bond. Acrylic three. , a double bond, so the remaining methyl group will be at an angle of 105 degrees to the double bond carbon. All olefins are subject to polymerization. Therefore d is correct.

Propylene can be regarded as a methyl group that replaces a hydrogen atom in the ethylene molecule, and does not change the properties of ethylene, so propylene can undergo a polyaddition reaction, and the polyaddition reaction is also a universal property of olefins.

Because ethylene speculates on propylene, it is necessary to find out what ethylene and propylene have in common. What they have in common is that they are both olefins with carbon-carbon double bonds, and the properties of carbon-carbon double bonds include polyaddition.

The double bond can be polyadded, and the propylene has a methyl group, which is sp2 hybridized, so all the elements cannot be in the same plane, and the three carbons may be in the same straight line, because the double bond is a straight line, and the single bond can turn.

ch2==ch—ch3,a: there is a single key that can be rotated.

B: where — ch3 so there are hydrogen atoms that are not in one plane.

C: Because ch2==ch—ch3, the double bond in ch2==ch can become ch3--chcl--ch3 or ch2cl--ch2--ch3

D: Polypolymerization can be done with double bonds.

Molecules are all in a spatial structure, so ab is wrong. c, chloride ions can be added to two carbon atoms with double bonds, respectively, as two products.

In the question, the structure or properties of propylene are inferred from ethylene, and ethylene can be polyadded. The common feature of both substances is that there is a carbon-carbon double bond.

Olefins have at least one carbon-carbon double bond that can be added to the poly.

The carbon-carbon double bond is in a plane, but the other groups (atoms) attached to it are not in the same plane as them, and the double bond is rotatable, but the unsaturated bond such as the double bond can undergo addition reactions. Take a look at the chemistry textbooks.

All olefins can undergo addition reactions, and polymerization reactions occur after polymerization, so the answer is d.

There are only two carbon atoms in a straight line.

At least one hydrogen atom in b is not in a plane.

There are two bonus directions for hcly in c, which can be added to the side with more h and the side with less h.

d Right.

Absolutely, unsaturated carbon atoms can generally be polyadded (limited to double-bonded carbon or formaldehyde, etc.).

Olefins have carbon-carbon double bonds, which can undergo a polyaddition reaction.

Because propylene also has a carbon-carbon double bond.

They both have double bonds, which is the most straightforward speculation.

Olefins can undergo polyaddition.

The mass of CO2 generated =

Solution: The mass of Na2CO3 in the original mixture is X, and the mass of sodium chloride generated is YN2CO3+2HCl==2NaCl+H2O+CO2 106 117 44

x y106/x=117/y=44/

x= y=mass fraction of solute in the solution obtained after the reaction =(

co2：

na2co3 --co2 --2nacl

m1 m2m1= m2=

After the reaction of NaCl altogether:

The solute in the solution obtained after the reaction is NaCl, and the mass fraction is 30g 200g *100% = 15%.

Melting and boiling point:

Diamond, quartz, silicon carbide, crystalline silicon.

Comparison and regularity of melting and boiling points of substances.

1) Different types of crystals, generally speaking, the melting and boiling point is atomic crystals, ion crystals, and molecular crystals.

2) In the atomic crystal formed by covalent bonds, the smaller the atomic radius, the shorter the bond length, the greater the bond energy, and the higher the melting and boiling points of the crystal. Such as melting point: diamond, quartz, silicon carbide, crystalline silicon.

3) The strength of the ionic bond is compared with the ionic crystal. Generally speaking, the more the charge number of anions and cations, and the smaller the ionic radius, the stronger the interaction between ions, and the higher the melting and boiling point of their ionic crystals, such as melting point: mgo>mgCl2>NaCl>csCl

4) Molecular crystals: substances with similar composition and structure, the larger the relative molecular mass, the higher the melting and boiling point; Such as CL222For substances with dissimilar composition and structure, the greater the molecular polarity, the higher its melting and boiling point, such as melting and boiling point: CO>N2

Crystalline silicon and diamond are both atomic crystals, not molecular crystals. Both of them have covalent bonds between their atoms, forming a spatial network structure.

Because the carbon-carbon bond length is shorter than the silicon-silicon bond length and the bond energy is greater, diamond has a higher melting and boiling point than crystalline silicon.

Wow, this question is a bit of a pit, I was stunned for a long time in my senior year of high school. . . N(Cu2+) = in CuSO4 solution, the number of electrons transferred when completely consumed is, mol E- flowing through the wire, indicating that water is also involved in the total reaction of electrolytic electrolysis of CuSO4 2Cu2++2H2O=2Cu+O2 +4H+ The reduction in the solution is 2Cu and O2 (equivalent to 2CuO), which needs to be supplemented, and the total reaction of electrolyzed water is 2H2O=2H2 +O2, and the number of transferred electrons is, so the consumed H2O Cu2(OH)2CO3 can be written as 2CuO?h2o?

CO2 is so added that the CuSO4 solution can restore its original composition.

The effect of pressure on equilibrium is caused by the change of concentration, so the effect of concentration is taken into account when increasing pressure and moving the equilibrium forward.

Moreover, the increase of pressure is the increase of the concentration of each component to the same degree, and the equilibrium positive movement C(Co) decreases, so the percentage of Co decreases.

The stem acidity indicates that it contains hydrogen ions, S2- in A will combine with hydrogen ions but cannot coexist, SO32- in B it will combine with hydrogen ions but cannot coexist, and HCO3- in C will combine with hydrogen ions but cannot coexist, so D is selected

There will be no reaction or precipitation.