High School Chemistry To explain in detail, High School Chemistry Please explain in detail

The density of the mixed gas is the same as that of N2 under the same t,p, that is, the average relative molecular weight of the mixed gas is the same as that of N2, which is 28, and the relative molecular weight of Co is 28, so it is sufficient to make the average relative molecular weight of CO2 and H2 28. Let n(CO2)=x, n(h2)=1-x

44x+2(1-x)=28 x:(1-x)=13:8, so the volume ratio of CO2, H2 and CO may be 13:8:k (any positive value), select "C, D".

High School Chemistry to be explained in detail.

It's very rude to ask for advice like this!!

CO doesn't have to think about the molecular weight of his door is 28, so I don't need to talk about the rest.

c d at the same temperature and pressure, with the same density and the same average relative molecular weight, then the average relative molecular mass of the gas mixture is 28 and the relative molecular mass of CO is 28, so CO can be arbitrary.

CO2 and H2 need to average 28, and the minimum integer ratio of CO2 and H2 is 13:8 according to the cross method

So c d is all in line.

Criss-cross method: 44 26

where 44 is the molecular weight of CO2 and 28 is the molecular weight of H2 on average. Cross-subtract ratio...

Cl2+2Nabr==br2+2NaCl δm solid.

x -4g x=

There is a problem, the balance of rent -4G on the vertical omen Ying Qing Oak -89

x corresponds to 117

Indicates the absence of ferric ions.

Let's look at this gas first, it is colorless and turns reddish-brown when exposed to air. In secondary school, reddish-brown gas is NO2.

Therefore, the emitted gas is NO, and it reacts with the air to form NO2, so it is judged to have nitrate.

The nitrate group becomes no from +5 valence electrons, so there must be a reducing agent to lose electrons to him, and the only one that can be oxidized by nitrate is Fe2+

There is also information that after the addition of hydrochloric acid, the anion type does not change, and if there are no chloride ions in itself, the anion type will change when hydrochloric acid (containing chloride ions) is added. Therefore, judging that the analysis of the building was very good, there was a small mistake here, hehe. Expressing regret.

Now the identified ones are Fe2+, NO3-, Cl-Now there are 5 ions, and 3 ions have been identified.

According to the conservation of charge, 1 mol of ferrous ions, followed by 1 mol of nitrate and 1 mol of chloride. It happens that the positive and negative charges are equal.

So the problem is changed here to this: the remaining two ions must be one yin and one yang. And the two charges are positive and negative.

Ferrous ions and OH- cannot coexist, so OH- is excluded, and the remaining alternatives are: CO3 2-, SO4 2-, sodium ions, aluminum ions, magnesium ions.

It is known that each ion is 1mol, and aluminum ions can be directly excluded. Sodium ions.

Because both carbonate and sulfate are -2 valent, they should be combined with the amount of other substances to form a compound, and the charge is equal to positive and negative. There must be a +2 valence cation. +3, +1 price of aluminum, sodium can not be satisfied.

So this cation is magnesium ion, then the anion must be sulfate. Why? Why, you ask? Magnesium carbonate is precipitation! Although the title says that hydrolysis is not considered, it does not say that precipitation is not considered.

At this point in the analysis, there is nothing to say. The hardest thing is the first empty. The second empty writes by yourself.

Thirdly, a sufficient amount of sodium hydroxide is added to form a precipitation of ferrous hydroxide and magnesium hydroxide. What is obtained after burning is not ferrous oxide! Here's another pit!

That's the way chemistry is the problem, you didn't negotiate the pit. Ferrous hydroxide is present in solution for a while and is oxidized to iron hydroxide. Coupled with the process of evaporative heating, it will be converted into iron hydroxide.

According to the law of conservation of mass, the final result is ferric oxide, and 1mol of magnesium oxide.

(1) CaCl2 +H2O2 +2NH3 +8H2O== precipitation) +2NH4Cl

2) Take an appropriate amount of the last washing solution, add nitric acid acidified silver nitrate solution, if there is a white precipitate, it proves that it is not clean; Otherwise, it is qualified.

3) At this temperature, the reaction of generating calcium peroxide octahydrate is prone to occur At low temperature, the generated calcium peroxide octahydrate is stable and not easy to decompose.

4) Relational:

n is obtained by n=, so m=, then the mass fraction is low.

4) Acetate becomes CO2. Oxygenation and dehydrogenation are oxidation reactions that lose electrons. In galvanic cells, one of the electrons lost is negative.

5) Looking at the figure, at the A pole (positive pole), after the reaction of p-chlorophenol, it becomes cl- and phenol. It is equivalent to breaking off the chlorine atom and connecting the fracture with an H. The title says that under acidic conditions, that is to say, there is a large amount of H+, and now the material of H atoms is enough, and there is still a shortage of electrons, electrons**?

It is given by the acetate of the B pole.

6) According to the reaction of 5, it can be seen that 2 electrons consume one h+. I'm surprised, there's something wrong with this question! A polar region consumes H+, and the pH is going to rise, how can it be reduced from 4 to 1. It is estimated that it is reversed, and it is almost the same from 1 to 4.

H+= consumed. Then the electron obtained is.

How many electrons can I lose by breaking down an acetate? According to the hydrogen-oxygen price method, the o is -4 valence, and there is a negative charge -1 valence. 3 Hs is +1 valence.

Now the negative valence is -4, the positive valence is +3, and it also carries a negative charge.

So, the 2 C's are 0 prices. It becomes CO2 and is +4 valence. Lose 4e.

2 C's lose 8e.

So the decomposition of acetate:. Then sodium acetate is also so much.

Convert to mass. The molecular weight of sodium acetate is 82

Then the mass of sodium acetate is 82

Reaction 1 is to dissolve Al and Al2O3 and then filter, there are Al3+ and Na+, Oh- in the solution

The purpose of reaction 2 is to remove Na+ and OH- by filtrate. And leave Al in the precipitate, i.e. aluminum hydroxide.

Reaction 3 is the formation of aluminum nitrate with dilute nitric acid.

In this way, the amount of dilute nitric acid should be controlled in reaction 2, and if the dilute nitric acid is excessive, the aluminum hydroxide precipitate will dissolve into the solution and be removed along with Na+ and OH-.

Excessive carbon dioxide was used to reduce the pH value of the filtrate after reaction 1, so that it was close to 7, and the solubility product of aluminum hydroxide in neutral and weak alkaline environments was very small.

Vacuum evaporation is also to be heated, but the boiling point is reduced under pressure. The aluminum nitrate solution is heated, and the heating promotes hydrolysis.

The hydrolysate has nitric acid, but nitric acid is a volatile acid, and part of the nitric acid will overflow the reaction system in the form of gas during the evaporation process.

The hydrolysis reaction proceeds in the forward direction, Al(NO3)3+H2O=reversible=Al(OH)3+Hno3 gas.

Al(NO3)3 is heated to generate 2 gases, the valency of AL does not change, the thermal decomposition regularity of solid metal nitrate (NO3-), NO3- self-redox reaction, and there must be oxygen generation, and the other is an oxide of N.

4:1 volume, say O2 is 1 volume, O-2 valence, 2 O-2 valence - 2 O0 valence is to lose 2x2 = 4 electrons, 4 volume is N oxide to get 4 electrons (electron gain and loss is conserved) that is, No2 (4 N + 5 - 4 N + 4).

5. The temperature of water vapor is high, so the introduction of water vapor must make the reaction system warm up and accelerate the reaction.

In addition, the introduced gas has a disturbing effect on the reaction system, so that the product is effectively separated from the surface of the reactant and the reaction rate is accelerated.

2Al+2OH—+2H2O 2ALO2—+3H2 (or Al2O3 + 2OH— 2ALO2— +H2O).

How to control the end point of the reaction (or the amount of nitric acid) Replace the addition of dilute nitric acid with the introduction of excess CO2 to prevent the hydrolysis of aluminum nitrate.

4Al(NO3)3 2AL2O3 12NO2 3O2 Increase the temperature and stir to accelerate the reaction rate.

1 solution: according to the title a can react with strong acid, and can react with strong alkali, and is a normal salt, this substance can only be ammonium sulfide, a, when a is ammonium sulfide, it ,-- sulfuric acid, so a is correct;

B. When A is ammonium sulfide, ammonium sulfide --- nitric acid, so B is correct;

c. The reaction of hydrogen sulfide or ammonia and chlorine is a displacement reaction, which must be a redox reaction, so C is correct;

D. When X is a strong acid, C is a sulfur element, and it is a solid state at room temperature, so D is wrong, so the solvent selected by D 2 A is a very small solubility of impurities.

b correct. c The catheter should be removed from the liquid level first, and then the heating should be stopped to avoid causing suction.

d No need for a catheter to reach into the bottom of the cylinder.

The density of a common gas is right, no, it's too big. g l Yes,