One to the chemistry question

Option C: Na2O2 + SO2 = Na2SO4 in which sodium peroxide itself has strong oxidation, and the +4 valence S in SO2 can be oxidized to +6 valence to generate Na2SO4 and when sodium peroxide reacts with carbon dioxide, the C of carbon dioxide is already in the most ** position and cannot be continued to oxidize, so sodium peroxide can only disproportionate itself.

I found this equation on Wang Houxiong, which is oxidized to 6 valence.

Option B: When the aluminum is heated, a dense oxide is generated on the surface as alumina, and the melting point of the alumina is high, so the aluminum foil is heated on the alcohol lamp until it melts, and the molten aluminum does not drip down, so B is correct;

Happy New Year! Wish! Thank you.

A is wrong, Fe(OH)3 is colloidal, and the particle size is 10 (-9) to 10 (-7) m, and it cannot be filtered.

b correct. c, not true. Assuming that Na2SO3 and O2 are obtained, Na2SO3 will also be oxidized by O2 to Na2SO4:

2na2so3 o2 = 2na2so4。Correct reaction: Na2O2 SO2 = Na2SO4

d, incorrect. Acetic acid is a weak electrolyte and cannot be removed.

Because iron hydroxide is colloidal in A, not precipitated, iron hydroxide can not be obtained by filtration, because the chemical properties of aluminum are relatively active in B, it reacts with oxygen in the air at room temperature to form a dense film of alumina on the surface, and because sodium peroxide has strong oxidation, sodium sulfate should be generated, not sodium sulfite, in the equation, only the oxygen element is increased, but it is not reduced, so it is not right, acetic acid in D is a weak acid, So the ionization equation is not right.

If satisfied.

So Na2SO3 won't be generated, so C is wrong! ~

B: Yes, SO2 is 4-valent and Na2O2 is strongly oxidizing. Therefore, is it possible for the S in SO2 to increase to 6 valence?

What is the generation of copper sulfate solution when added to sodium hydroxide solution Copper hydroxide precipitate and sodium sulfate are generated.

Heating copper hydroxide solid, the color changes from what color to what color; The blue turns black (copper oxide).

Copper hydroxide precipitates and sodium sulfate are generated.

Equation: 2NaOH+Cu(SO4)2==Cu(OH)2+ Na2SO4

Heating copper hydroxide solids: blue turns black (copper oxide).

5t coal combustion produces n(SO2)=(

1molSO2 consumes 1molCa(OH)2

n(ca(oh)2)=n(so2)=(

m(ca(oh)2)=1000x(

It's a high school question. This should be perfect. Give points, o( o thank you.

(1) In industry, B can be prepared by chemical reaction, and a large amount of heat is released during the reaction, and B is commonly known as.

Hydrated lime, slaked lime

2) The mass of the solid of e will increase after being exposed in the air for a period of time, and the reason for this is:

Sodium hydroxide reacts with carbon dioxide in the air to form sodium carbonate and water. ．

3) Both H and G can react with solution F to form two salt solutions containing the metal element respectively, then the chemical equation for the reaction of solution G and solution F is Fe2O3 + 3H2SO4 = Fe2(SO4)3 + 3H2O (the answer is not unique).

4) Add a certain amount of D solution to solution B, take the filtrate after filtration, and drop into the excess F solution, if there is no obvious phenomenon, the solute in the filtrate is (write out all possible) Na2SO4, H2SO4 or Na2SO4, CASO4 and H2SO4

5) Knowing that the metal aluminum can react with solution E to form sodium metaaluminate (Naalo2) and one of the lightest gases, write the chemical equation of this reaction.

2al+2naoh+2h2o=3h2↑+2naalo2

6) A m: Among the nine substances, there are substances that can react with solution F.

A calcium oxide, B calcium hydroxide, C calcium carbonate, D sodium carbonate, E sodium hydroxide, G iron oxide, H iron.

Analysis: (1) B can be prepared by chemical reaction in industry, and a large amount of heat is released during the reaction, B is alkali, indicating that B is calcium hydroxide B, commonly known as hydrated lime and slaked lime, A is calcium oxide, C is calcium carbonate, 2) B can be converted into E, E is also alkali, and the mass of E solid will increase after being exposed in the air for a period of time, indicating that E is sodium hydroxide and D is sodium carbonate. Its mass increases because sodium hydroxide reacts with carbon dioxide in the air to produce sodium carbonate and water.

3) H and G can react with F solution to form two salt solutions containing the metal element, indicating that H is iron, G is iron oxide, and M is iron sulfate.

The decomposition of AKCo3 requires MNO2 as a catalyst, otherwise the rate is very slow. Whereas, KmNO4 does not require a catalyst for decomposition.

So a has only kclo3 and decomposes more slowly; There is KMNO4 in b and c, which decomposes quickly. Because there is MNO2 as a catalyst in D, it decomposes quickly.

Because the condition of this decomposition is heating and catalyst, both are indispensable!

Potassium chlorate is heated to melt to decompose oxygen (which can only be produced quickly when there is a catalyst), so oxygen cannot be produced quickly.

Potassium permanganate can quickly produce oxygen without direct heating of a catalyst.

Potassium permanganate, potassium chlorate mixture: potassium permanganate heating can decompose oxygen and produce manganese dioxide, which can act as a catalyst for potassium chlorate to accelerate the decomposition of potassium chlorate.

So the molecular formula of a is C4H8

There are only two methyl groups after the addition of a, which is ch3ch2ch2ch3, so a is ch3ch2ch=ch2

B is CH3CH2CH (CH3)cho

d is obviously an ester, (130-16*2) 14=7, so d is c7h12o2, x is ch3ch2ohd, ch3ch2ch(ch3), cooch2ch3e is ch3ch=c(ch3), cooch2ch3f is -[-ch---c-]n-

ch3 cooch2ch3

Write the equation yourself.

1. The reaction equation is 2kclo3=mNO2=2kCl+3O2, which means that MNO2 is a catalyst and does not participate in the reaction.

As the reflection stopped, the mass fraction of manganese dioxide in the remaining solids measured was 10%, while manganese dioxide remained unchanged.

So the community with solid mass is.

2. Conservation according to mass.

The mass reduced in the reaction is the mass of oxygen.

For kclo3=mno2=2kcl+3o2 the oxygen mass is, then the mass of kclo3 participating in the reaction is the mass of undecomposed kclo3 is.

(1) Because the mass fraction of manganese dioxide in the remaining solid is 10%, manganese dioxide is the catalyst, and the mass remains unchanged before and after the reaction, so the mass of the remaining solid is 20g.

2) The total solid mass before the reaction is 20g, and the solid mass after the reaction is 20g, and the mass of oxygen is reduced.

3) 2kclo3====2kcl+3o2 The mass of oxygen is known According to the chemical equation, the mass of the reacted potassium chlorate can be found as, then the mass of undecomposed potassium chlorate is.

1.Choose insoluble in water, CaCl2 soluble in water. The filtrate obtained by filtration is CaCl2, which evaporates and crystallizes to obtain a solid.

2.Both CaCl2 and CaCl2 are soluble in water, but the solubility of Kno3 varies greatly with temperature, and CaCl2 is basically unchanged, so the solid obtained by cooling crystallization and filtration is Kno3.

3.Choose C. The composition of the residue is mnO2 and soluble in water, Mno2 is insoluble in water, and the filter residue obtained by filtration is Mno2, and then washed.

(1) b, because calcium carbonate is insoluble in water, it is filtered out first, and then calcium chloride is evaporated and crystallized.

2) a, because potassium nitrate can be precipitated from water by cooling crystallization, it is precipitated first and then filtered out.

3) c, because manganese dioxide is insoluble in water, it can be filtered out of the solution first, and then its purity can be improved by washing.

Calcium carbonate is intolerable, calcium chloride is soluble, calcium carbonate precipitates after calcium chloride is dissolved, filtered, and evaporated and crystallized to obtain calcium chloride solid.

The solubility of potassium nitrate varies greatly under the influence of temperature, and it is washed out by cooling, and both are soluble.

Potassium chlorate is soluble, manganese dioxide is insoluble.

1.The standard for cleaning the inner wall of the glass instrument is (the water on the wall of the instrument is evenly distributed, neither gathering nor flowing down in strands).

2.The key to the success of the experiment (or **) is a rigorous scientific attitude, reasonable (experimental procedures and correct operation methods).

3.After the experiment (or **). To write a report, the report should first indicate the name of the reporter, collaborators, and dates.

The content of the report is: 1 ** Name of the activity. 2 **Purpose of the activity 3 Articles 4 Procedures and methods 5 Phenomena 6 Analysis 7 Conclusions 8 Questions and recommendations.

4.In the experiment, if the alcohol lamp is accidentally knocked over on the table, and the alcohol spilled on the table burns, the easiest and most effective way to extinguish it is (immediately cover it with a damp rag).

5.Science is one of the most important ways to learn chemistry. And experiments are scientific (important means).

1 The water of the inner wall is neither gathered in drops nor in strands.

and 5 this ......I guess the original words in the book, there is no knowledge, or turn the eight by yourself.

4 And take a tablecloth and cover it.

1. When inverted, the water droplets do not flow down in strands, and there are no stains on the test tube wall 2. Scheme and process.

3. Objective: Experimental design, instruments used, experimental process, recording phenomena, analyzing errors, and drawing conclusions.

4. Cover the flame with a damp rag.

5. Important ways to foundation.

Based on personal experience, most of them are true, and I hope it helps.

1 The water of the inner wall is neither gathered in drops nor in strands.

1.It can neither form droplets nor flow down in strands.

4.Cover with a damp rag.

I won't take the college entrance examination.

1.The water on the walls of the vessel is evenly distributed, neither gathering nor flowing down in strands2Experimental procedures and correct operation methods.

3.Purpose, instrument used, scope of application, method steps, data processing (raw data, calculation formula, calculation results),

Conclusions and precautions.

4.Immediately extinguish with a rag.

5.Important Ways Important Means.