Chemistry inference questions in the third year of junior high school If you are satisfied, you will

The only common alkaline gas is ammonia, assuming it is ammonia.

Insoluble acid-insoluble precipitates are generated, which may be AgCl, Ba(SO)4, MgCl2 are more common, in fact, such precipitates also include lead sulfide, cadmium sulfide, antimony sulfide, stannous sulfide, silver sulfide, copper sulfide, mercury sulfide ......

Finally, when it comes to the generation of water, it means that it is acid-base neutralization or ammonia gas.

To sum up, there should be OH-, NH4+, BA2+, SO42- in the raw materials, so BA(OH)2 and (NH4)2SO4

It can be seen that C becomes precipitated and has C with nitric acid, and B and C are an acid-base neutralization reaction, and C has NO3-, so B is BA(OH)2

B and C are to produce acid-soluble precipitates, and this precipitate has OH-, so it is Al(OH)3, so Cd is AL(OH)3, H2O

Compound A with solution B, when heated, produces an alkaline gas, an acid-insoluble precipitate and water.

Q: What are the substances a b?

There is an alkaline gas in the product, and there is only one alkaline gas in secondary school chemistry, NH3, so the alkaline gas is NH3.

To generate NH3 and water when heated, there must be OH- and NH4+ in A and B.

There is an acid-insoluble precipitate in the product, and the only precipitates that come into contact with in junior high school chemistry are AGCL and BaSO4. Because agoh cannot exist stably, one of a and b can be BA(OH)2, and because BASO4 is to be generated, then there must be SO42- in a and b, and the other can be (NH4)2SO4.

As for which is the solution, Ba(OH)2 or (NH4)2SO4, it doesn't matter.

Alkaline gas can only be ammonia, and there is also water formation, indicating that ammonia water (NH4OH) is generated. From this, it can be judged that compound A contains ammonium ions, and solution B is an alkaline solution. Based on the formation of an acid-insoluble precipitate, it can be inferred that it is barium sulfate.

In this way, compound A is ammonium sulfate, solution B barium hydroxide solution.

The alkaline gas mastered in middle school is only NH3, and the insoluble acids are generally BaSO4 and AGCL, if it is a displacement reaction, then one of the two substances has BA2+, and the other has SO4 2-, so it is not difficult to judge that it is BA(OH)2 and (NH4)2SO4.

The alkaline gas is ammonia.

So it can be (NH4)2CO3 + Ca(OH)2 = heating = CaCO3 precipitation + 2NH3 gas + 2H2O

Barium hydroxide and ammonia sulfate. C is carbon dioxide and D is barium nitrate.

Ammonium sulfate and barium hydroxide.

The reaction equation is:

NH4)2SO4 + BA(OH)2=BASO4 +NH3 +H2OBASO4: insoluble acid-insoluble precipitate.

NH3: Alkaline gas.

Generally, when you see alkaline gas, you have to think of NH3Insoluble acid-insoluble precipitates that will bring to mind baso4or agcl

So it is not difficult to infer that it is Ba(OH)2+(NH4)2SO4=

Ammonium sulfate and barium hydroxide.

NH4)2SO4 + BA(OH)2=BASO4 (precipitation) + NH3 (gas) + H2O

How did you learn it??? Stupid.

The first two answers must be correct.

The analysis is as follows, and the chemical formula and chemical equation can be written by yourself.

This question belongs to the inference problem I have talked about without breakthroughs, and this kind of problem generally starts with the type of reaction and the common acid roots. In this question, we can first look at the reaction between c and n to produce e, and c and e are both elemental. There are two types of reactions like this that we focus on in junior high school:

One is the displacement of metals and acids, and the other is the displacement of metals and salt solutions. So C must be an elemental metal, and E is hydrogen or another metal. If E is hydrogen, then X is oxygen and F is water.

If E is a metal, then X is oxygen and F is a metal oxide. However, the title indicates that f can also be obtained by the reaction of compound d and compound n, and the reaction of compound oxide has not been learned in junior high school, so f should be water and e is hydrogen. Compound A and compound Y can react to obtain metal, we should be able to think of the smelting principle of iron, so A and Y are one of carbon monoxide and iron oxide, and because A can also react with oxygen, A is carbon monoxide, Y is iron oxide, C is iron, N is dilute hydrochloric acid or dilute sulfuric acid, and B is carbon dioxide.

There are three types of substances that can react with carbon dioxide: water, alkalis, and carbonates. Since D can react with the acid N to obtain water, D is carbonate and M is sodium hydroxide or calcium hydroxide.

One more point.

Looking at the reaction between c and n to produce e, both c and e are elemental. That c could be c, h, metal. Therefore, it is difficult to judge. Therefore, it should be started from.

E—x breakthrough, e, x are elemental, in junior high chemistry, the reaction between elemental substances is only hydrogen and oxygen. In this way, E is determined to be hydrogen, C is metal, (E is not oxygen because oxygen has not been seen in the displacement reaction) and N is acid. And because there is no oxygen in b and m, d is not a metal oxide; anhydrous, so d is not a base.

So d is carbonate. So M is a base, B is carbon dioxide, A is carbon monoxide, and Y is a metal oxide.

Summary: e—x is the breakthrough.

(1) The common name of G is (baking soda) The chemical formula of X is NaOH (2) Mars shines and emits heat, and black molten matter splashes on the bottom of the bottle (3Fe + 2O2 = ignition = Fe3O4).

3) The conditions of the b reaction are (heating).

4）③fe+h2so4=feso4+h2↑④co2+ca(oh)2=caco3↓+h2o

5) increase the conformance (NaOH will deliquescent, and react with CO2 in the air) (6) Conclusion: Carbonate can react with acid to form CO2

I can't see the diagram clearly, so please make the diagram clearer.

1. G is baking soda; x is naoh; 2. The combustion phenomenon in oxygen is sparks, emitting a large amount of heat, and black solids are generated;

c: carbon dioxide; g: is sodium bicarbonate: f: is sodium carbonate 3, b The condition for the reaction to occur is heating;

4、fe+h2so4=h2+feso4；co2+ca(oh)2=caco3+h2o

5. Enlargement; Compliance with conservation of mass; 6. It is a metathesis reaction to generate carbon dioxide and water.

AB must be like this: A and B are H2 and O2, which cannot be determined;

C must be H2O (everyone knows this).

Here's the point: the solid in step 2 should be CA

Whereas D is Ca(OH)2 (Reaction Equation: Ca + 2H2O == Ca(OH)2 + H2 because the chemical properties of Ca are too reactive to react with water. This is also the reason why the order of chemical properties of k, ca, and na is not compared in the third year of junior high school).

f should be h2.

Because reaction 4 is often used in laboratories to make f gas, so e is zn As for reaction 3, I estimate that it should be something like this: d reacts to produce c(h2o) and g, so g should be caco3

Here's my analysis of this experiment.

Again, the solid in step 2 should be CA

I can't see the picture clearly... Type the small print on Reaction 2 and take a look.

I don't say exactly what the problem is, but it is known that the following is true:

A and B are H2 and O2, which cannot be determined;

C is H2O, D can be Ba(OH)2, E can be CaCO3, F is CO2, and G is BaCO3

A and b are H2 and O2, which correspond to one at random;

C is H2O, D can be Ba(OH)2, E can be CaCO3, F is CO2, and G is BaCO3

A and B are H2 and O2

c：h2od：ca（oh）2

e：na2co3

f：co2g：caco3

The solids in step 2 are: cao

Carbon dioxide.

Copper magnesium, sodium carbonate, sodium sulfate, copper oxide.

Sodium ion Ca(OH)2 + CO2 = CaCO3 + H2Ops The filter residue may be magnesium reducing copper ions to copper.

1.The gas produced b is: CO2 2Filter residue c is:

3.In mixture A, the substances that are definitely present are: Na2CO3, Na2SO4

4.In filtrate D, the metal cation that is definitely present is: Na+

5.Write the chemical equation for the chemical reaction that occurs during the experiment

co2+ca（oh)2==caco3↓+h2o___

These substances are soluble in hydrochloric acid, there is no filter residue, if you have any questions, you can ask me, unless the hydrochloric acid is not enough, otherwise Shenma is a floating cloud.

1.Carbon dioxide.

2.No. 4.Sodium ions.

One of the most important things I do when I do the inference questions is to analyze the questions first. For example, according to the reaction, we can know that there must be carbonate in A, so there must be Na2CO3 in A. According to the reaction, the filtrate is known to be Na2SO4

To do the inference problem with drawings, it is best to use a pen and draw a flowchart or MG on paper. Ion.

Ca(OH)2 == CaCO3 H2O must be clear about the displacement reaction, metathesis reaction conditions, and which salts are soluble. This is the premise and important condition for making acid and alkali salts.

If there is anything inappropriate, please criticize.

Gas carbon dioxide.

The filter residue is copper carbonate.

There are definitely sodium carbonate, copper oxide, sodium sulfate.

Sodium ion CO2 + Ca(OH)2 = CaCO3 + H2O

`1.Hydrochloric acid. Analysis:

Hydrochloric acid and other qualities, magnesium and iron are also equal in quality, which are also balanced after the reaction. The amount of hydrogen produced is also the same, indicating that the amount of hydrochloric acid consumed is the same, and the amount of iron and magnesium substances consumed is the same. If there is an excess of hydrochloric acid, the amount of iron and magnesium is not the same, and the hydrogen produced is not the same.

If hydrochloric acid is insufficient, it is only enough iron to react completely, and magnesium is not reactive, and the hydrogen produced is not the same. If hydrochloric acid does not completely react with either iron or magnesium, then the hydrochloric acid reaction is complete and the hydrogen produced is the same.

Analysis: If pure iron is 5 grams, it will produce 5 56 grams of hydrogen, less than. Therefore, the impurities contained are more hydrogen than iron of the same mass of metal. There is only magnesium among the options.

1.If the hydrochloric acid is excessive, the H2 produced is of unequal quality and does not match the title. If there is too much magnesium in the beaker with magnesium, the hydrochloric acid in the beaker will be completely reactive, and the hydrochloric acid in the beaker with iron should also be completely reacted (the mass of H2 generated is equal), and the iron may or may not be left (iron and hydrochloric acid happen to react completely).

If there is too much iron in the beaker with iron, the hydrochloric acid in the beaker should be completely reactive, and the hydrochloric acid in the beaker with magnesium should also be completely reflected (the mass of H2 generated is equal), at this time, there must be a surplus of magnesium.

So there must be no remaining substance in the beaker is hydrochloric acid, and there must be a remaining substance in the beaker is magnesium.

There can be many answers to this question.

A is definitely O2, B is carbon dioxide, C is water, D is calcium carbonate, E is calcium hydroxide, and F is sodium hydroxide.

1) The chemical formula of a is O2

The basic type of reaction is reaction: decomposition reaction.

2) Write the chemical equations of reaction and reaction respectively;

Let's talk about the reactants: water electrolysis to produce hydrogen and oxygen, calcium hydroxide and carbon dioxide to produce calcium carbonate and water, sodium hydroxide and hydrochloric acid to produce sodium chloride and water.

There should be multiple answers.

This is a: a Oxygen O2

b Copper oxide. c. Water d Copper hydroxide.

e Sodium hydroxide.

f Sodium carbonate.

A oxygen b is carbon dioxide.

C is water and D is calcium carbonate.

E is calcium hydroxide.

f is sodium hydroxide.

Brother,Give it extra points.,It took a lot of brain cells.。。

A is O2 B is CO2 C is H2O D is CaCO3 E is Cao F is Ca(OH)2 I can't see your target number, but give it to you and you should know.

a. Oxygen, b, carbon dioxide, c, water, d. calcium carbonate, e. calcium hydroxide, f. sodium hydroxide.