Consult, thank you for the detailed solution process of this chemistry problem

Select B for this question].

The organic matter reacts with acetic acid to form an ester of acetate, and the reaction is as follows:

R-OH + CH3COOH---CH3COOR + H2O Let the molecular mass of the organic matter be X

x 59+x-17

=> x≈

So, the closest is 102

I wish you good luck in your studies

Because C has a hydroxyl group, 1mola and 1mol acetate esterification remove 1mol of water molecules, and the mass of a reaction can be seen from the question as grams, and the molar mass of a is xg mol

Then the amount of the reacted A substance is, the amount of acetic acid substance is, and the amount of H2O substance formed is the total mass of the reactant: plus 60

Total mass of product: plus 18

Reactant = product, plus 60 plus 18

The solution is the relative molecular mass of a, which is closest to 116, so I hope it will be helpful to you, and you can ask if you have any questions.

The A of the reaction explained by the title is that because this substance has only one hydroxyl group, it reacts 1:1 with acetic acid.

The mass of acetic acid is the mass of acetic acid by adding a water and subtracting a.

So (so the relative molecular mass of a is .

So choose B

Let the relative mass of a be x, and the relative mass of a certain ester of acetate is x+60-18, then there is x (, and the solution is x=102.

The reaction of a hydroxyl compound, the reaction ratio is 1:1, let the relative molecular mass of acetic acid nmol, a x*n=; (x-17)*n+45n=, two-way connection, find x=102

1) HCO3- +H2O=H2CO36+OH - this doesn't need to be explained, right?

2) Greater than. The hydrolysis of bicarbonate is the second hydrolysis of carbonate, so the degree of hydrolysis is much less than that of carbonate.

3) Greater than. If the pH changes when it is returned to the initial temperature, it proves that the substance has changed, then sodium bicarbonate is decomposed by heat to produce sodium carbonate.

4) B pairs. Since the pH increases after returning to room temperature than the pH of sodium bicarbonate at room temperature, it is correct to know that it is B that produces sodium carbonate.

HCO3-)+H2O==H2CO3+(OH-) is greater than (the greater the hydrolysis, the greater the alkalinity, so the degree of hydrolysis of Na2CO3 is greater than that of NaHCO3).

If Na2CO3 is generated, it will not change after cooling, and the degree of hydrolysis of Na2CO3 is greater than that of NaHCO3, so the pH will be larger than the original after Na2CO3 is produced).

Armor; Because the pH becomes smaller after cooling, it means that there is no Na2CO3 production, and B's assumption is incorrect. Heating accelerates the thermal movement of the molecule and increases the hydrolysis of HCO3, so the pH increases, and the assumption of A is correct.

As soon as you look at the questions, you know that you are still a student, and I can only tell you the idea of solving the problem, not the answer. 1. Methane + oxygen = = carbon dioxide + 2 water, one oxygen corresponds to one carbon dioxide, the volume remains the same, only the methane is reduced and the generation of water, and the water at room temperature and pressure is liquid and does not occupy the volume. Only methane has changed.

2. That is the total mass of carbon dioxide and water, and that is the mass of barium oxide consumed by carbon dioxide, which can be calculated by writing the equation! 3, halo, this question is the easiest, the carbon dioxide contains c, the water is h, this is not alkane contained, the rest will be solved by yourself!

The relative atomic mass of sodium is 23g mol, now it is sodium, according to n = m m m can calculate the amount of sodium substance n = , according to n = n * na (Avogadro constant), it can be seen that the amount of matter and the number of molecules are proportional, so the requirement of 10 water molecules to dissolve a sodium ion, is equivalent to the amount of water required is 1mol, and the mass of 1mol of water is easy to find, calculated 18 grams.

2na2o2+2h2o=4naoh+o2

The oxygen in sodium peroxide is -1 valence, the oxygen in water is -2 valence, the oxygen in sodium hydroxide is -2 valence, and the oxygen in oxygen is 0 valence. Because the redox anti-absolute theory should not be cross-changed, that is, the lowest price cannot be turned into the most ** and the most ** into the lowest price, but only the more ** into the most, and the lower price into the lowest. Therefore, it cannot be the oxygen in the water that becomes oxygen, but only the oxygen in the sodium peroxide that becomes oxygen.

Therefore, this is an auto-redox reaction, and both the oxidizing agent and the reducing agent are sodium peroxide. And two of the imitations of oxygen become -2 valence to sodium hydroxide, and the other two oxygen become 0 valence to oxygen, and the change valence state is the same. According to the conservation of electrons, the final answer can be obtained.

So the answer is 1:1

2Na2O2 +2H2O 4Na OH + O2 Bright.

4 oxygen of sodium peroxide, two Jinqiao were reduced, and two were violently oxidized by Xianghuai. Choose A

Solution: The KNO3 precipitated at 10 degrees (30 degrees) is that water can be dissolved at 30 degrees according to the title.

The solubility of Kno3 at 30 degrees is .

So the mass of the solution containing kno3 is:

So the mass of kno3 in the original solution is.

So the solubility at 40 degrees is:

Haha, why don't you have an answer!!

b, if you have any questions, you can send me a message.

The ratio of the number of particles The ratio of the amount of matter of the particles, so that the ratio of the number of k+ ions to the number of water molecules is 1 100 i.e.: n(k+): n(h2o) 1mol:

100mol 1 KCl can be ionized into 1 k+ 1 cl-, the amount of water is n(H2O), so the required KCl substance is 1mol, and the mass is 1mol