Happy New Year, there are a few chemistry questions that I can t do, please help, thank you

Happy New Year, landlord! The one above is also ha!

A small addition to the first floor:

The answers of 1 and 3 are very correct, 1 is close to the concept, 3 in the trivalent iron and iron are centered, and copper ions and iron are replaced.

However, 2 and 4 are a bit of a problem on the first floor, 2 is not because nitric acid has strong oxidation - copper is bivalent, how can oxygen be returned? In fact, it is still acid-base neutralization, but copper hydroxide is precipitation, and the ion equation cannot be detached, it should be written as Cu(OH)2 + 2H+ == Cu2+ +2H2O; As for 4, it's a bit far-fetched to say that "CU is overdosed, and the generated NO2 part is reduced to NO" - why don't you all become NO? In fact, nitric acid reacts with copper to generate NO2, but NO2 can also react with water, and nitric oxide is generated, nitric acid is concentrated in the early stage, NO2 is difficult to react with water, and it is easy to generate NO2 in the later stage, so NO2 is generated in the early stage and NO2 is generated in the later stage, and the result is "NO2 and NO" - of course, it is best to explain it with the electrode potential, but that is a bit troublesome to say, as a solution, it is better to be simple!

60g/mol; c 60g;d Examine the meaning of units and Avogadro's constants.

Nitric acid has strong oxidation, the reaction is a redox reaction, and the product is not copper nitrate.

3.Excess iron powder Fe3+ was reduced to Fe2+; Cu2+ is reduced to Cu and precipitated, and there is only Fe2+ in the solution

4 cu is excessive, and the generated NO2 is partially restored to NO.

1 d2 fine sand, gauze.

3 Colloids. The filter paper is broken.

Pour too quickly. The liquid level in the funnel is too high.

4 edta

pH test strip pH meter.

5. Bring to a boil. 6. Cooling makes water vapor condense.

1.The chemical formula of the oxide with proton number Z=A-N, R3+ is R2O3, the relative molecular mass is X=2A+48, the molar mass is (2A+48)G mol, and the amount of Ngr2O3 is N(2A+48)And because the number of protons contained in 1molR2O3 is 2Z+24=2A-2N+24, the number of protons contained in Ngr2O3 is N(2A-2N+24) (2A+48)=

a-n+12

na+242.The electron shell structure of the four ions is the same, and it can be obtained: a-m=b-n=c+n=d+m

So choose the number of electrons of the M2O3 molecule = its number of protons, so the number of protons of M is (50-3*8) 2 = is Al

The relative molecular mass of M2O3 = 2*(13+x)+(8+8)*3=102

The number of neutrons in the nucleus of m is solved x = 14

4.From xh3, it can be judged that x is of the va group. Therefore, the most ** oxide is X2O5, which is composed of the mass fraction of oxygen element = 16*5 (2X+16*5)=

The mass of x is obtained x = 14 = a + n, and since a = n (the number of protons is equal to the number of neutrons), a = 7, so x is the nitrogen element.

5.Similar to question 2: a-2=b-1=c+3=d+1

Ionic radius: C3->D->B+>A2+ (when the ionic electron shell structure is the same, the larger the number of nuclear charges, the smaller the ionic radius).

The number of protons z=a-2The mass a=z+b=a+b-2, therefore.

The symbol for the r atom is.

a+b-2a-2

rA+B-2 on the top left and A-2 on the bottom left

7.Number of protons a=m-n=number of electrons. The number of electrons of x+ is m-n-1Again: The amount of a substance of wgx+ is w m, so the amount of a substance containing electrons of wgx+ is.

w(m-n-1)/mmol

1. Select D, first add hydrated white ash Ca(OH)2, and the reaction occurs: DumgCl2 + Ca(OH)2=mg(OH)2 +CaCl2

Then, the precipitate and filtrate were separated by filtration, hydrochloric acid was added to Mg(OH)2 to generate MgCl2, and then the crystallization was concentrated, and finally dehydrated and dried under certain conditions to remove the crystal water.

2. Decompose oxides, because the metal oxides behind h are easy to decompose.

3. D is correct, the melting point of most alloys is lower than any one of the components; b, the three major synthetic materials are: fiber' plastic rubber, not ceramics d, sodium hypochlorite is corrosive, so it cannot be used as an environmental disinfectant c. Grease is an important energy storage substance Not an important energy source in the body.

Add alkali to precipitate magnesium ions, filter, add acid to obtain magnesium chloride, concentrate crystals to obtain crystals with water, dehydrate and dry.

2.Electrolysis.

It is not safe, and the air must be isolated, otherwise it is easy to be oxidized, and it is not easy to operate.