Senior 3 Chemistry, Seeking Answers, Senior 3 Chemistry Questions, Seeking Answers

a：fe2o3 b：al2o3 c：alo2- d：fe3+ e：fe2+

x：al y：fe z：h2

Reagent 1: OH- Reagent 2: H+ Reagent 3: Water.

1.Electrolysis (electrolysis of molten alumina to produce elemental aluminum).

High temperature) ==Fe3O4+4H2

2oh- +2h2o == 2alo2- +3h2↑4.(1) Add KSCN solution, if blood red is produced, there is Fe3+2)Fe3+ +3H2O (boiling) === Fe(OH)3(colloid) +3H+

The breaking point is in the sentence reddish-brown metal oxide.

Considering that it should be ferric oxide x elemental reaction with ferric oxide to form y elemental, typical replacement, the common natural is thermite reaction. That's the way it goes.

1.Electrolytic molten aluminum oxide.

2. 3fe + 4h2o = fe3o4 + 4h23. 2al + 2oh- +6h2o = 2[al(oh)4]- 3h2 ↑

4.The addition of KSCN produces blood red; fe + 3h2o = fe(oh)3 +3h+

a:fe2o3 b:al2o3 c:al(oh)3 d:fecl3 e:fecl2

x:al y:fe z:h2

That's pretty much it. You try it.

1.Sulfate, if the metal is all magnesium, if all aluminum, so it should be in between.

2. 2nacl~~~na2co3

The theoretical production of Na2CO3 is grams, and the actual production of 2NaHCO3 is Na2CO3 grams. So.

The first question uses the extreme value method, assuming that all metals are aluminum, to see what is the amount of substances that need metals, and then assuming that all metals are magnesium, what is the amount of substances that need metals, and find the median value.

In the second question, the theoretical yield of sodium carbonate is calculated according to the chemical equation by using the conservation of elements method, and then the actual yield of sodium carbonate is calculated, and the ratio of the two is the yield of sodium carbonate.

1.Let's analyze them one by one. First of all, look at b, when all dissolved, it does not necessarily contain +3 valence iron ions, because when the amount of nitric acid is not very large, that is, nitric acid cannot make all the copper into 2 valence by itself, and the 3-valent iron reacts with Cu to form 2-valent copper and 2-valent iron, and 3-valent iron is not necessarily there.

Needless to say, option C, as long as the amount of iron and copper meets certain requirements, it has nothing to do with how much B is equal to. d You don't need to look at it to know that it's wrong, you think, the iron and copper are all dissolved, is the more nitric acid, the better. As for a, doesn't it come out, give a specific one, when sulfuric acid is added again, it is actually adding hydrogen ions, you write out the reaction between nitric acid and iron and copper, and see if there is more nitrate, and the added hydrogen ions and the extra nitrate react with iron or copper.

Okay, send the Buddha to the west, do good things to the end, and then teach you the second question.

2.First of all, Al3+ and OH- generate Al(OH)4- understand, because OH - has, so AI3+ has, and then according to the valency to get the k+ of the meta solution, so the k+ after the reaction is (

The answer is C.

Assuming that the equilibrium does not move, the concentration of a becomes 50% of the original after doubling the volume

But at this time, the concentration of A becomes 60% of the original, so A is more, that is, the equilibrium moves in the opposite direction, so AC is wrong, B is right, because the pressure is reduced and the balance moves in the opposite direction, so A B, so D is wrong.

Stem: In a neutral or alkaline solution, Na2SO3 and S can be smoothly reacted to synthesize baking soda (Na2S2O3·5H2O); The reaction equation is as follows: Na2SO3+S+5H2O Na2S2O3·5H2O

At present, baking soda is synthesized with mixed solutions of Na2SO3 and Na2CO3, Na2SO3 solids, dilute sulfuric acid and other reagents, according to the following requirements: (you give less Na2S substance, otherwise only the substance on the stem will not be able to make baking soda).

1) The chemical equation for the preparation of SO2 is Na2SO3 + H2SO4 Na2SO4 + SO2 +H2O

2) During the reaction, the pH of the solution gradually decreases, and at the same time, there is sulfur generation and the chemical equation of the reaction is:

na2so3 + h2so4 ＝ na2so4 + so2↑+h2o ；

na2s + h2so4 ＝ h2s↑ +na2so4 ；

2h2s + so2 ＝3s↓ +2h2o 。

3) When synthesizing baking soda, the ratio of the most suitable amount of Na2S to Na2CO3 is:

From the above several equations Na2SO3 + H2SO4 NA2SO4 + SO2 +H2O ;

na2s + h2so4 ＝ h2s↑ +na2so4 ；

2h2s + so2 ＝3s↓ +2h2o

na2so3+s+5h2o＝na2s2o3·5h2o

It can be seen that Na2SO3 reacts with H2SO4 to form SO2, and Na2S+ and H2SO4 to form H2S, both of which have a 1:1 relationship. The ratio of H2S to SO2 reaction is 2:1. The ratio of Na2SO3 to S complete reaction is 1:

1；Then the ratio of the most suitable amount of Na2S and Na2CO3 is just a complete reaction between the two, and the ratio of the amount of the two substances is 1:2.

4) When the pH of the solution drops to about 7, under the condition of heating, the solution becomes colorless orange clear, the chemical equation of the reaction is to synthesize baking soda with a mixed solution of Na2SO3 and Na2CO3, Na2SO3 solid, dilute sulfuric acid and other reagents, according to the following requirements: 4Na2SO3 +2Na2S + 3H2SO4 + 12H2O 3Na2S2O3·5H2O + 3Na2SO4

1) Na2SO3 + H2SO4 = Na2SO4 + SO2 + H2O The question is wrong: a mixed solution of Na2SO3 and Na2CO3???