One high 2 chemistry question, one high 2 chemistry question

Excess zinc reacts with sulphuric acid, and the addition of water does not affect the total amount of hydrogen released? Because Zn reacts with hydrogen ions in dilute sulfuric acid to generate hydrogen and zinc ions, after adding water, the amount of hydrogen ions does not change, although there are hydrogen ions in the added water, but the concentration is too low to react with Zn, so it can be ignored, that is, the concentration of hydrogen ions remains unchanged, so the total amount of hydrogen released will not change! However, when water is added, the contact opportunities between the hydrogen ions in the dilute sulfuric acid and Zn are reduced, so the reaction rate slows down, but does not affect the total amount of hydrogen produced.

Is Zn and water not reactive, or is it because the concentration of hydrogen ions in water is too low, much lower than that in acid, so water does not react with Zn.

The reaction between the metal and the dilute acid is an exothermic reaction because the total energy of the product is less than the total energy of the reactant, so it is exothermic.

No, zinc will not react with water even if there are conditions for the presence of sulfuric acid, if you say that zn reacts with sulfuric acid to release heat, then you mean to let zinc react with water and heat it?

Usually dilute sulfuric acid, waste with concentrated words.

Yes, depending on the amount of water you add, it is originally dilute sulfuric acid, add too much water, the acidity drops, the pH reaches 5-7, the zinc reaction is very slow, put it slowly, put it less!

It doesn't affect the total amount of hydrogen because zinc only reacts with hydrogen ions in sulfuric acid and not with water.

It is an exothermic reaction.

If H2O2 is considered a dibasic weak acid, write his ionization equation in water, H2O2=(reversible)Ho2(-).

h+,ho2-= (reversible) (o2)2-

h+_。In view of the weak acidity of H2O2, he can react with a strong base to form a normal salt, and then form an acid salt under certain conditions, and write the chemical equation of H2O2 and Ba(OH)2 to form a normal salt and an acid salt: H2O2+BA(OH)2=Bao2+2H2O, 2H2O2+BA(OH)2=BA(HO2)2+2H2O.

The equation for self-coupling ionization of H2O2 is 2H2O2 = (reversible) Ho2(-)H3O2(+) or H2O2 = (reversible) Ho2(-)Ho2(+).

No. Zn does not react with sulfuric acid.

No, it will only affect the rate at which hydrogen is produced. Zinc does not react with water.

It will not affect the total amount of hydrogen generated, zinc and water are not reacting, dilute sulfuric acid is a binary mixed solution of sulfuric acid and water, the main driving force of this reaction is the concentration of hydrogen ions and the activity of zinc, the reaction will be exothermic, but the concentration of hydrogen ions is not increased after adding water, so the reaction cannot occur, and it will not affect the total amount of hydrogen generated.

Aluminum can't react with water anymore, and zinc can't, it doesn't matter.

Suppose this olefin is CNH2N+3N2O2=NCo2+NH2O, then N=2 can be produced

So for ethylene.

Then assume alkyne q

cnhn+5n 4o2=nco2+n 2h2o subtract the left and right sides to get n 4-1》0 It is obvious that n should be greater than or equal to 4, landlord, we all know that when n is greater than 4, the alkyne at this time is liquid, not gaseous, so n can only be equal to 4, so q is butyne.

Because the volume in b increases, so the volume of butyne is determined, then the oxygen that reacts with butyne is also determined. But there may still be a surplus of oxygen, so it is only when there is no oxygen left that the r in b will have a maximum... So let's assume that r is xl, then the O2 and butyne of the reaction are ,。。

Then according to the chemical equation and the extra.

The calculation can find the volume of O2 and butyne is, so the answer is.

Landlord, think about it.

1) Since the volume of A does not change after combustion, we can know from C2H4 + 3O2 = 2Co2 + 2H2O that the olefin R is C2H4

2) The alkyne is gaseous, so it can only be C2H2, C3H4, C4H62C2H2+5O2=4CO2+2H2O; C3H4+4O2=3CO2+2H2OSo if it is C2H2, the volume of C3H4 will not become larger after combustion, 2C4H6+11O2=8CO2+6H2O, so the alkyne is only established when it is C4H6, that is, the alkyne is C4H6

3) From the above molecular formula, it can be concluded that the volume of alkynes in b is liters, the sum of the volumes of oxygen and alkynes used to react with alkynes is liters, and the maximum allowable volume of alkenes, that is, the alkenes can be completely opposite to oxygen.

should, for (

The volume of gaseous hydrocarbons does not change after combustion, indicating that the number of h is 4

then the olefin is ethylene.

The gaseous state of the alkyne is only ethylene propylene, but the volume becomes larger, then the number of h is greater than 4, which is butyne.

The volume of B increases after the reaction, and the equation 2C4H6 + 11O2 = 8CO2 + 6H2O, the difference between the left and right sides is "1", indicating that there is liters of butyne (difference method) in B, and the oxygen that reacts with butyne is liters, and the rest is ethylene plus oxygen.

Ethylene reacts completely with oxygen at its maximum.

It is listed by the equation C2H4 + 3O2 = 2CO2 + 2H2O with a ratio of ethylene to oxygen 1:3 (

1. Use valence to rise and fall and conserve the problem.

The increase in valency is Fe2+, to Fe3+

The valency decreases first of cl2, from 0 to -1, and then x in x2o7 2-, from +6 to +n

n=3 i.e. b2, is your data wrong, 2mol l?

Analysis: Hydrochloric acid and sulfuric acid are of equal concentration, equal volume, i.e., equal moles.

If the amount of Fe added is sufficient, hydrochloric acid is a monobasic acid, sulfuric acid is a dibasic acid, and the generation of H2 should be 1:2 Now, it is 2:3

It is indicated that FE is in excess in hydrochloric acid and insufficient in sulfuric acid.

First, use hydrochloric acid to find the gas volume.

Sulfuric acid produces H2 that is twice that of hydrochloric acid.

That is, to find the quality of FE.

1. The so-called "mixed anhydride" is a mixture of anhydrides of several acids, so the definition of anhydride must still be observed, that is, "reaction with H2O to form acid" or "reaction with alkali to form salt and H2O".

2. Because there is still solid (Fe) remaining, the salt in the solution can only be Fe(NO3)2, and HNO3 has no remaining. Fe involved in the reaction is, i.e., so Fe(No3)2 is, then No3- is.

According to the conservation of n elements there are Hno3 No, Hno3 No2, so the sum of the quantities of the None and No2 substances is the amount of the reduced MnO3 substances, i.e.

The sum of the above two parts of Hno3 is the amount of Hno3 in the original solution, that is, the concentration of the substance is 7mol L.

Because (1) reacts with H2O to form acid (the definition of anhydride).

2) React with alkali to produce salts and H2O (definition of anhydride) (3) Describe a mixture of one mole of NO2 and one mole of NO, which is the anhydride of nitrite...

2.Iron powder remains, nitric acid must be completely reacted and the product is Fe(NO3)2, conserved by N element, after the reaction, part of N element exists in the mixed gas of NO2 and NO, and the other part exists in Fe(NO3)2, N(Fe)=(, so C(HNO3)=( molol-1

Answer: c

Analysis: (1) The reason why NO2 is called mixed anhydride is because NO2 can produce nitrate (salt) and nitrite with water or alkali by disproportionation reaction (both high and low by itself).

2NO2 + 2NaOH = nano3 + nano2 + H2O (correct, it is a disproportionation reaction, and it is both high and low on its own).

2NO2 + H2O = HNO3 + HNO2 (correct, it is a disproportionation reaction, which increases and decreases by itself).

3Hno2 = Hno3 + 2No + H2O (False, this reaction has nothing to do with No2).

NO2+NO+2NaOH = 2nano2+H2O (false, this is the centering reaction, and the disproportionation reaction is the reverse reaction, so it cannot be proven).

All things considered, if you consider that it is correct, there is a reaction that can be proved to be correct.

So choose D

Analysis: (2).

Iron powder was put into 40 ml of a certain Hno3 solution, and the remaining solids were left after full reaction.

It indicates that there is an excess of Fe, so Fe(NO3)2 will inevitably be formed after the reaction

Because there is a reaction: 2Fe3+ + Fe 3Fe2+

Reacted Fe mass = - =

The amount of the substance = 56g mol =

The ratio of Fe to No3- in Fe(No3)2 = 1:2

So the amount of nitric acid species that act acidically = *2 =

The mixed gas mol of NO2 and NO, all the N elements in the gas are ** in HNO3

Fe reacts with concentrated nitric acid to produce NO2 and dilute nitric acid to produce NO

The amount of matter NOx:Hno3=1:1

So the amount of nitric acid substances that act as oxidizing =

So the amount of nitric acid substance = + = before the reaction

The amount concentration of the nitric acid substance = = 7mol l

So choose C

Because the third one is wrong, it is impossible to determine whether NO2 is a mixed anhydride because of the NOs involved in the reaction, so only the D pair is excluded.

2.3 reactions occur.

Fe+4Hno3=Fe(NO3)3+NO+2H2OFE+6HNO3=Fe(NO3)3+3NO+3H2O2FE(NO3)3+FE=3FE(NO3)2Please indicate the gas symbol yourself, I can't hit it.

The iron that is reacted by the question, i.e., Fe(No3)2, loses electrons in total, so that the mass of No2 is X, and No2 is.

The equation is obtained from the problem and the law of conservation of electrons.

x+3 (the solution is x=, so the mass of the no object is.

According to the material relationship obtained from the first two equations listed at the beginning, we can know that n(hno3)=4n(no)+2(no2)=c=

n(n2)=1120/

n(h2)=3360/

The gas before the reaction is 200mol, and the gas after the reaction is 150mol, which is reduced by 50molN2+3H2==2NH3 N

50mol…50mol

50molNH3 was generated, and the osmotic mass = 50mol*17g mol=850g=

The volume of 10L water quality cluster section is 10kg

Mass fraction of ammonia =

It should be the mass fraction, such as the amount and concentration of the substance in the silver chain fruit and the ammonia density obtained.

Question 1 is A.

4NO2 + O2 + 2H2O = 4HNO3 in A, leaving 3 8 gases.

Cl2 + SO2 + 2H2O = 2HCl + H2SO4 in B, leaving no gas.

4NO + 3O2 + 2H2O = 4HNO3 in C, leaving 1 8 gases.

There is no reaction in d, ammonia is very soluble in water, leaving 1 2 gas.

Question 2 (1) No3 Because the presence of reddish-brown gas indicates the presence of n

2) CO3 or SO4

3) CO3 does not have SO4 and Cl because BaSO4, AGCL precipitates regardless of acid or base.

4) CO3 and NO3

NO2 + O2 + 2H2O = 4HNO3, so A tube will leave 3 8 tubes of gas.

Cl2 + SO2 + 2H2O = 2HCl + H2SO4, so the gas left inside tube B is 0.

4NO + 3O2 + 2H2O = 4HNO3, so the C tube will leave 1 8 tubes of gas.

Only ammonia in the D test tube is very soluble in water, so the volume becomes half of the original. So d>a>c>b

1d2oh- no3-

oh- co3- so4-

co3- cl- so4-

oh- no3- co3-

I didn't study chemistry in high school, so it's not necessarily right, so I used it as a reference.

Question 1 is chosen D. There are two molecular formulas, the first is C6H12 and the second can be considered C2H4 (H2O).So carbon accounts for 72%, because the hydrocarbon mass ratio before water is 6:

1, so hydrogen accounts for 12%. In this way, water accounts for 16%, and oxygen in water accounts for eight-ninths of the mass, so oxygen accounts for it.

Question 2: Choice B. Because methanol can be written as (co)(H2)2, and the molecular formula can be written as H2 Co(Co)m(H2)N, the mass absorbed by sodium peroxide after full combustion is equal to its own mass.

Question 1 D Question 2 Question A

It is OK by the elimination method

The first question CH ratio is greater than 1:2 If 1:2 is exactly 12%, the result should be c, but it is greater than 1:2, so it is smaller than 16.

The second question adds the mass of h, which is sure that Xiaoyu 16 is so it is a