In a hurry, a high school chemistry problem will not be, and the master will enter 50

a. The pH value is 5

It is possible, but not necessarily, that the ionization of water is facilitated, but it may be that the hydrogen ions are bound by the weak acid anion, or the hydroxide ions are bound by the weak base cation. Equals 5 or 9 are possible. This question is about the ionization of water, which does not mean that there are so many hydrogen ions in the solution.

It can be ionized and then bound by a weak acid anion.

b. It must be an acid solution.

Impossible, the ionization of water in acid is inhibited!

c. Acid salt solution that may be a strong acid.

It is impossible, the acid salt of a strong acid also ionizes hydrogen ions, which is equivalent to a mixed solution of acid and salt, and the ionization of water in the acid is inhibited!

d. The pH value may be 9

Possibly, see option A for the reasons!

First, compare the concentration of hydrogen ions ionized by water in the solution with the concentration of hydrogen ions ionized by pure water, if it is greater than that, it means that it promotes water ionization and is a salt solution that can be hydrolyzed, if it is less than, it is an acid or alkali solution.

This question is greater than, so it must be a salt solution that can be hydrolyzed. There are two more cases: strong acid and weak alkali salt or strong alkali and weak salt are possible.

So the pH may be 5 or 9. The answer to this question is D

The concentration of hydrogen ions ionized by water in the aqueous solution is greater than that ionized by pure water, which means that the ionization of water is promoted, and it cannot be acid-base (because acid-base inhibits ionization, and acid-type salts are the same), so it may be caused by hydrolysis

Acid-base is impossible, because acid-base inhibits the ionization of water, this topic is to promote, it can only be hydrolyzed salts, strong alkali weak salts or strong acid and weak alkali salts are possible, hydrolysis reactions are to promote the ionization of water, so choose D

The ionization of water by C(H+) = 1 10 -5mol L has exceeded 1 10 -7mol L, so it must have promoted the ionization of water, and it should be a solution of strong acid and weak alkali salt.

Answer? Of course, if you don't choose A, you can't choose B and D, so C is left. C is completely possible, and the answer C also says that it is possible.

If the acid solution will inhibit the ionization of water, the C(H+) ionized by water must be less than 1 10 -7mol L, so B and C are not right, and the principle of D is the same. d is the base, under alkaline conditions, the ph is who ionizes c(h+), so d corresponds to the ionization c(h+) = 1 10 -9mol l

Since the hydrogen ions produced by water ionization are promoted, it is not possible to add acid or alkali, but it should be a salt that can be hydrolyzed, so a should be chosen

The water ionization equilibrium shifts to the right, and can only reduce the hydrolysis of hydroxide ions, such as strong acids and weak alkaline salts.

So 250 ml of this solution is exactly neutralized with the NaOH solution, because only HCl in the solution can react with NaOH.

Therefore, HCL can be obtained.

and H2+Cl2+=2HCl

So the consumed H2 is and the consumed Cl2 is.

Because the gas mixture altogether.

So a total of 5 224mol

So the total O2 consumed is 11 1120mol

Therefore, the total H2 reacted with O2 is 11 560mol, so the total consumption of H2 in the reaction is 9 280mol

So the volume of H2 consumed is, which is 720ml

So the answer is d

This question mainly examines the conservation of mass and the molar volume of a gas.

Because the mass of the gas produced is 15 times that of the same volume of H2. Therefore, it can be known that the molar mass of the gas mixture produced is 30g mol, and because v is inverse v = 2 (1 + 2 + 3) = 1 3

So mr(a) = 90g mol

If the mass of the generated gas is 15 times that of the same volume of hydrogen, the average molar mass of the produced gas is 30 g mol, and the molar mass of 2 times a is 30 from the reaction formula, then the answer is 15 g mol

90g per mole Consider the conservation of mass 2a = 6mol of gas on the right.

The landlord should be asking about the amount and concentration of the substance.

m(h2so4) =50 * 98% *=n(h2so4) = =

c(h2so4) = =

Question 1 When a hydrocarbon and a halogen undergo a substitution reaction, the first thing to do is to form an active halogen atom, which is an atom!

After that, it collides with the hydrogen in the hydrocarbon to form a substitution reaction

The halogen atoms formed are very reactive and cannot be formed in water, but must be present in the gaseous state

Therefore, bromine water cannot undergo substitution reactions with halogens.

Question 2 AB Question 3 D 1mol ethane CH3CH3 has six H, which can have a substitution reaction (complete substitution) with up to 6molCl2

Question 4: Select b: There is only one substitute for ethane monochloride, so it is excluded.

n-butane c-c-c-c

There are 2 kinds of monochlorogenates, which are in position 1 and 2.

Whereas, there are 6 types of dichlorides.

1.Two cl on one carbon, which is the same chlorinated substance.

2.Two cl on two carbons.

2.1 and a C are in the 1st position, then there are 3 and 3 and the other is in the 2 3 and 4 squares.

If one C is in the 2nd position, then there is only 1 and the other is in the 3rd position.

There are 2 kinds of isobutane monochlorine substitutes, and there are only three dichloroisobutane substitutes: 1,1-dichloroisobutane 1,2-dichloroisobutane 1,3-dichloroisobutane (the chemical formula is not written to compare the place).

Question 5. A has the largest amount of methane at the same mass, and one c needs one mole of oxygen, and two hydrogen need one mole of oxygen, so you can estimate the answer.

Question 6. a Methane is a tetrahedron. Carbon is located in the center of the tetrahedron, and four hydrogens are located at the fixed point of the tetrahedron, which is a perfectly symmetrical structure, difluorodichloromethane can be seen as two hydrogens in methane are replaced by fluorine, and two more hydrogens are replaced by chlorine.

b b d b a a

If you don't understand which one, please ask.

Let the valency of a be x, and the chemical formula of the most ** oxide is a2ox, then 2a (2a+16x)=40%; If the chemical formula of hydride is h(8-x)a, then a(8-x+a)=. The solution is a=28.

The molar mass of b = 28*.

a28 2=14, three periods and four main families; b12 2 = No. 6, two cycles of four main families.

A: sulfur, third cycle VIA group, B: nitrogen, second cycle VA group.

a is s (sulfur).b is c (carbon) and a is in the sixth main group b. in the third cycleIn the second cycle the fourth main family.

The element a--s, the third period of the sixth main group, and the element b--o, the second period of the sixth main group.

8GA can react exactly completely with 32GB to produce 22GC and a certain amount of DD with a mass of 8+32-22=18g.

Therefore, 8GA can react exactly completely with 32GB, which can produce 18 grams of D, and now the mixture of 16GA and 70GB is fully reacted.

At this time, B is excessive, and A reacts all, so 16GA reacts all and can produce 36 grams of D

The amount of substance d is 2mol

So the molar mass of d is 18g mol

8GA can be completely reacted with 32GB to generate 22GC and a certain amount of D, so that the mass ratio in the reaction is A:B:

c:d=8:32:

22: After the mixture of 1816GA and 70GB is fully reacted to generate 2 molar D and a certain amount of C16GA can completely react with 64GB to generate 44Gc and 36Gd, so the molar mass of D is: 36g 2mol = 18g mol

According to the law of conservation of mass: when 8GA can react exactly exactly with 32GB, the mass of D generated is 8+32-22=18. Because 8GA can react exactly completely with 32GB, when the mixture of 16GA and 70GB is fully reacted, all A reacts and B 64G reacts, resulting in 2 moles of D that is twice as much as 8G reaction.

So the molar mass of d is 9g mol.

Aluminum sodium carbonate and NaOH reaction 2Al+2NaOH====2NaAlO2+3H2

That's great, you can try it.

cㄥyp㊣⊙

By the conservation of mass 8GA completely reacted with 32GB, 18GD is generated, according to the ratio 16GA should be completely reacted with 64GB, i.e. B is excessive, A is completely reacted, let D molar mass be M, by mass ratio.

So 8 16 18 2m, m=18g mol, from the above we can see this equation ch4+2o2=CO2+2H2O

The molar mass of d should be 18.

a. Bluestone asbestos is a flammable product and soluble in water.

There is no carbon equation inorganic and non-flammable.

b. The chemical composition of bluestone asbestos can be expressed in the form of oxide as: Na2O FeO 2Fe2O3 8SiO2 H2O

If oxygen is not conserved, it is necessary to consume at least 6l3mol LHNO3 solution if Na2O 3Feo Fe2O3 8SiO2 H2OC and 1mol Na2Fe5Si8O22(OH)2 react with sufficient nitric acid.

According to the nitric acid consumed by Na2O 3FeO Fe2O3 8SiO2 H2O is 3FeO Fe2O3 is 15 + 3=18Mold of ferrous oxide, 1mol Na2Fe5Si8O22(OH)2 and sufficient hydrofluoric acid, at least the solution needs to be consumed.

The substance can be expressed as Na2O 3FeO Fe2O3 8SiO2 H2O, where Na2O does not consume nitric acid and reacts directly with water. FeO consumes 12mol of nitric acid and Fe2O3 consumes 6mol of nitric acid. SO2 does not react with nitric acid.

A total of 18mol of nitric acid is consumed.

If it's good, give it points.

Because the treatment with nitric acid produces NO, and a redox reaction occurs, there must be divalent iron, and then the oxide combination form is introduced according to the amount of oxygen

A is clearly wrong, and B is also incorrect as above.

When treated with nitric acid, it is divided into two parts: 1. The solute in the final solution is nano3 [2mol], Fe(NO3)3 [5mol] and the nitric acid that plays an acidic role is 17mol; 2. There are 3Fe2 3E-NO3-, and 3mol of divalent iron, so 1mol of nitric acid as an oxidant. There are a total of 18mol, c pairs.

d is judged to be wrong according to the atomic equilibrium.

It can be written to see.

3feO+10Hno3 (dilute) ==3Fe(No3)3+No +5H2ofe2O3+6Hno3===2Fe(NO3)3+3H2ONa2O+2H2O=2NaOH+H2 (gas symbol) 2NaOH+2HNO3=2nano3+2H2O

As above, 10+6+2=18mol

Crocidotile can be expressed as Na2O consumption of 2mol, Fe2O3 consumption of 6mol, and 3FeO consumption of 10mol, so a total of 18mol, C is correct. D is due to the fact that hydrofluoric acid and FeO do not undergo redox reaction, so a total of 2+6+6=12molHF is consumed. Hope it helps!

Answer: The oxide form is expressed as:

Therefore, 2mol of Hno3 is required to form nano3 and 15 mol of Hno3 to form Fe(NO3)3, and 1 mol of Hno3 is needed to oxidize ferrous iron to form no at the same time, so a total of 18 mol is required.