Chemistry Questions, Urgent, Chemistry Questions, Urgent

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1) Fe + 2 HCl = FeCl2 + H2 (g) The amount of substances that produce H2 is n=v

The amount of Fe is n1=n=v

The amount concentration of the HCl substance is C1 = 2N

2) 2Al+2NaOH+2H2O=2Naalo2+3H2(g) The amount of substances that produce H2 is n'=3V

The amount of matter of Al is n2=2n'/3=v/

The amount concentration of NaOH is C2=2N'/

And in the title it is known that c2=2mol l

Therefore v i.e. v = is brought into the previously obtained equation, the quantity of the substance of fe is n1 = al and the quantity of the substance is n2 =

HCl concentration is C1 = 2mol L

The ratio of the quantity to concentration of a substance is 1:1

What about the topic? Kiss.

fe+2hcl==fecl2+h2

x y v/

v x is the mass of iron, and if you are the mass of aluminum, you can also write the equation and solve it in the same way.

y=2v/100ml=

c（hcl）=y/

Pasted from another buddy.,Hurry up and use it.,Use it up and find out to that buddy!!

In order to concentrate a 10% sodium hydroxide solution, how many grams of water are evaporated from each kilogram of this solution, and the resulting solution concentration is 40%?

2.The steel is cleaned in a 10% sulfuric acid solution in the factory. If a 10% sulfuric acid solution is used, what volume of 98% sulfuric acid is mixed with water? (10% sulfuric acid) =; (98% sulfuric acid) =

3.After a certain amount of sodium carbonate solution evaporates the gram of water, the remaining solution volume is 31 ml ( for, find the percentage concentration of the remaining solution.

4.If you have a 15% sodium nitrate solution, what are the ways to change its concentration to 30%?

None of the answers upstairs are completely correct, it's really a pity, 1, in the third cycle, the most active non-metallic element is (Cl, the chemical formula of its most ** oxide hydrate is (HCO4).

2, an element is located in the third period of the VIA group, the element symbol of the element is (S3, if M represents the IA group elements, the chemical formula of the hydrate of the most ** oxide is (MOH) 4, an element A and fluorine elements can form an ionic compound AF2, in which the electronic shell structure of anions and cations is the same, then the element symbol of element A is (mg) and the formation process of the compound is represented by the electronic formula: ().

It's hard to write electronically.

The electronic formula of the f atom.

mg atom electronic formula +

f atomic electronic formula.

The electronic formula of MGF2.

Among them, the two electrons of mg are represented by curved arrows.

Direction of electron transfer.

5. Potassium and aluminum are located in different periods and different main groups, but the metallicity of potassium and aluminum can be compared by another element as a reference, and this reference element is (Na).

k>na na

al can be concluded

caco3+2hcl=cacl2+h2o+co2↑100 73

x 60*10%

x=60*10%*100/73=

The quality of the calcium carbonate reflected in the participation is.

After fully reacting with sulfuric acid, the insoluble matter is obtained, so there is the insoluble substance in the insoluble matter in the sufficient amount of CuSO4 solution, and the gram is the mass of the reaction to form Cu.

Set the mass of iron powder to x grams.

fe+cuso4=feso4+cu

xg。。。56/xg=64/

x = iron powder mass in grams, sample mass in grams.

Calculate the latter reaction first.

cuso4+fe*****===cu+feso456 64xx=

That's how it should be.

Another pile of impurities is:

Copper Cu - Fe is generated

x64 56

x=raw iron powderm=(

Quality score.

In the end, there are two kinds of insoluble substances, one is copper that is replaced by iron, and the other is impurities that do not participate in the reaction. Therefore, the mass of copper is, knowing the quality of copper, you can find the mass of iron as. Therefore, you can find the quality of the iron powder in the sample, and remember to divide it into two parts.

Deke insoluble matter, it can be known that its impurities are grams, and because iron and copper sulfate are gram insoluble, it can be known that the reaction of grams of copper (grams are insoluble), so the reaction of molar iron, both gram iron.

The limestone of A and B is excessive, the dilute hydrochloric acid of Ding is excessive, and the calcium of C is just completely reacting.

caco3+2hcl=cacl2+h2o+co2x y

100/x=73/y=44/

x=15g y=

The mass fraction of calcium carbonate in limestone: 15g 20g * 100% = 75% The mass fraction of hydrochloric acid used is.

It is calculated by the excess hydrochloric acid of the D group and the complete reaction of calcium carbonate.

caco3+2hcl=cacl2+co2+h2ox

x=15w=75%

After the change, it just means that the reaction of group C is complete.

C, compared with D, it can be seen from the data that the quality of CO2 generated no longer increases with the increase of hydrochloric acid, so the hydrochloric acid added by student C happens to be completely reactive.

The mass fraction of CaCO3 in limestone is required here, so the CO2 generated by a set of data is determined by CaCO3, and only Group D matches the 4 groups. So it is necessary to use group D to calculate.

Write down the reaction.

CaCO3+2HCl=CaCl2+H2O+CO2 According to the reaction formula, CaCO3 should also be only.

And the mass of CaCO3 is 15g

Because the title says that it is evenly distributed, the mass of the total caCO3 should be 15g 4=60g

The quality score is out.

60g/80g ×100%=75%

C-D. The quality of the limestone sample and the quality of CO2 formation are the same, and the amount of hydrochloric acid added to C is less, so it is C.

According to C, CaCO3+2HCl=CaCl2+H2O+CO2You can get it.

c=12 h=1 c6h124 = 72+14=86 12co2=528

x = kilograms) kilograms) = 52800 grams.

Volume = mass Density = 52800 2 = 26400 (liters).