High school chemistry questions will not, please help analyze it, thank you!

Pick B. Isotopes refer to atoms with the same number of protons and an unequal number of neutrons, which become isotopes with each other. Ozone and oxygen are both substances that do not fit the concept of isotopes; Allotrope refers to two pure substances that are composed of the same element, but because the internal atomic or molecular structure is different, they are two substances.

Ozone and oxygen are allotropic forms of each other.

Compound: A pure substance composed of two or more elements. Ozone is only composed of one element, which is elemental.

One mole of oxygen contains 16 protons, and 1 mole of ozone contains 8*3=24 protons.

A is an allotrope and C is an elemental D2; 3

Personally, I think the answer is b, c, a, oxygen and ozone are all composed of aerobic atoms, so they are not isotopes, see the concept of isotopes.

d, an oxygen molecule contains 2 oxygen atoms, an ozone molecule contains 3 oxygen atoms, the number of protons of oxygen and ozone in the same amount of matter must be different, the ratio is 2:3

The answer is BA: Oxygen and ozone are allotropic forms of each other.

bThe interconversion of oxygen and ozone is a chemical change, because the formation of a new substance is a chemical change.

cOzone is an elemental substance made up of 3 oxygen atoms.

The amount of oxygen and ozone contains different protons.

Oxygen and ozone are allotropic forms, the mutual conversion of oxygen and ozone does not produce new substances so it is a physical change, ozone is made up of an oxygen molecule and an oxygen atom, therefore, the answer is d. I don't know if you understand?

The answer is bOxygen and ozone are not isotopes and are different substances; Ozone is a elemental substance, not a compound, so the C answer is wrong.

Obviously, the formation of ozone in b implies that there is a chemical reaction, and oxygen will become ozone when it is discharged.

Option b Oxygen and ozone are allotropic isotopes are elements with the same number of protons and different numbers of neutrons Ozone is also elemental oxygen and ozone contain different atomic numbers in the same amount of substance, and the number of protons is of course different.

Select BHPO42- in solution in two variations as:

Hydrolysis: hpo42- +h2o=reversible number=h2po4- +oh- ionization: hpo42- = reversible number=po43- +h+ can also be written as hpo42- +h2o=reversible number=po43-+h3o+

A: The solution itself is alkaline, the dilution alkalinity is weakened, and the C(H+) increases, which is not compliant.

B: All three specified ions can react with Ca(OH)2 (some are reactive with H+, such as OH-; Some are reacting with Ca2+, such as Po43-; Some are reacting with both, e.g., HPO42-). Therefore, the concentration of the three ions increases and decreases.

C: The degree of hydrolysis by heating is enhanced, the alkalinity is enhanced, and C(PO43-) will increase. Not true.

D: Add silver nitrate solid, it can form precipitate with PO43- and HPO42-, the alkalinity of the solution is weakened, and C(H+) increases. Not true.

a H+ increase.

Both CH+ and PO43- are increased.

d h+ increases.

b are all reduced.

When A adds water, the concentration of H+ increases, and B adds a small amount of slaked lime solid, due to precipitation reaction and neutralization reaction.

C(Hpo4 2-), C(H30+), and C(Po4 3-) decreased.

The thinner the water, the more ionized it is, and C(HPO4 2-) and C(Po43-) increase, but because the concentration is smaller, C(H30+) decreases. So a mistake.

The addition of slaked lime means the addition of alkali, C( H30+) definitely decreases, the base reacts with K2HPO4, C(HPO4 2-) decreases, and C(HPO4 2-) decreases, so the balance shifts to the left, and C( Po4 3-) also decreases. So B right.

Heating, promote hydrolysis, the natural equilibrium shifts to the left, C(Hpo42-) increases, C(H30+), C(Po43-) decreases. So C is wrong D doesn't understand.

a Because hydrolysis is greater than ionization, the solution is alkaline. Adding water will dilute the solution, the concentration of hydroxide ions will decrease, and the ionization equilibrium constant of water will not change, so the concentration of hydrogen ions will increase, so a can not.

c Heating will increase the degree of hydrolysis and ionization, so the concentration of hydrogen ions will increase, and phosphate ions (PO4 3-) will increase

The concentration increases, so C is impossible.

d The solution is alkaline, add silver nitrate, silver ions and hydroxide ions to react, so that the concentration of hydroxide ions decreases, so the concentration of hydrogen ions increases, so d can not.

b Slaked lime is calcium hydroxide [Ca(OH)2], calcium phosphate is a precipitate, adding a small amount of [Ca(OH)2] will reduce the concentration of PO4 3-; The slaked lime is alkaline, and the alkalinity of the solution is enhanced after addition, and the concentration of H3O+ of hydronium hydride ions decreases. When the concentration of (PO4 3-) decreases, the Hpo4 2- +H2O <*****====> H3O+ +PO4 3- equilibrium shifts in the positive direction, and the HPO4 2- concentration decreases.

First of all, device A is a constant pressure anti-clogging device.

Its function is to make the separating funnel and the flask in the air pressure the same, to ensure the smooth flow of liquid in the funnel in the fifth question stem of the check of the constant pressure anti-clogging device air tightness method is wrong, correct inspection method:

Check whether the separating funnel is leaking, after confirming that the water is not leaking, connect the device and then insert the A end into the water, use a hot towel to slightly heat the flask, if there are bubbles at the catheter mouth in the water, take the hot towel away for a period of time, and form a water column in the catheter, indicating that the device does not leak.

There is a loophole in the inspection method of the question stem, that is, the air tightness of the device is not tested when the C clamp goes to the left to the liquid level of the separating funnel, and if this section of air leaks, the water will not flow down, so this device can be both good and leaky, that is, device A can be both airtight and leaky.

1,2NaHCO3=δ=Na2CO3+CO2+H2O2,m2 m4 Mass fraction of sodium carbonate: (84m4-31m1-53m2) (31m2-31m1).

3,n(nahco3)=n(hcl)=

m(nahco3)=

m(na2co3)=

na2co3)=

4. Looking down at the burette, the numerical reading is small, and the amount of NaHCO3 is small, and (Na2CO3) is large.

The rest of the part, no diagram, can't be answered.

The galvanic cell must first be a spontaneous redox reaction, where Si can undergo redox reaction with NaOH, so Si is the negative electrode, and loses electrons Then the negative electrode Si-4E + 6OH - ==SiO3 2- +3H2O

Positive electrode: 2H2O +2E=2oh- +H2

Total reaction si + 2oh- +h2o =siO32- +2H2

Do sodium hydroxide and magnesium react???

Don't worry, just a few numbers confuse you? What does "100 tons of pyrite with 75% purity" mean? That is, how much pyrite there is; What does it mean to "lose 2% of sulfur"?

That is, how much ...... is leftThat's all four numbers multiplied (not the last 98%).

Known: 4 FeS2 + 11 O2 = 2 Fe03 + 8 SO2

I made a mistake on it.

4 fes2+11o2=2fe203+8so2，2so2+o2= 2so3，so3+h2o=h2so4。 fes2——2so2——2so3——2h2so4

100t*75%*（1-2%）*90% x*96%120 ：196=100*75%*（1-2%）*90% ：x*96%，x=

Answer: 100 tons of pyrite with a purity of 75% are produced by this method to produce sulfuric acid, and 98% tons of concentrated sulfuric acid can be obtained.

It is easier to understand by substituting special values.

Suppose after the reaction:

n(fe3+) = 2mol

n(fe2+) = 3mol

Write the ionic reaction equation:

2fe3+ +cu = cu2+ +2fe2+

x 3 is easy to get: n(cu2+) =

Then, n(cu2+) n(fe3+) = :2 = 3:4

The following reaction occurred: Cu+2FeCl3=CuCl2+2FeCl2, the ion equation is: Cu+2Fe(3+)==Cu(2+)+2Fe(2+), and the concentration ratio of ferric iron and ferric iron formed after the reaction is 2:

3, it can be considered that the ratio of the amount of their matter is 2:3, because the conversion from ferric iron to ferric iron to obtain an electron, according to the law of conservation of electrons, the amount of bivalent iron to form a substance of 3mol requires copper3 2=, so now the amount of copper ions in the solution of the substance is, the ratio of the amount of matter is: 2=3:4