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Less rigorous questions.

d is divided into two situations, the first is that when there is a surplus of hydrochloric acid, all the carbonate ions in the salt become carbon dioxide.

The molecular mass of a Na2CO3 is 28*23+12+16*3 (if I'm not mistaken).

The molecular mass of a NaHCO3 is 23+1+12+16*3

Obviously, a Na2CO3 is much heavier than a NaHCO3, so the number of molecules of the former is less than that of the latter for the same mass of Na2CO3 and NaHCO3, and when it reacts with hydrochloric acid, a NaHCO3 or Na2CO3 will release a CO2, so Na2CO3 emits less carbon dioxide, according to the conservation of mass, that is, there is more left.

In the second case, when the amount of hydrochloric acid is insufficient, it means that all the hydrogen ions in the hydrochloric acid have become hydrogen ions in the carbonic acid, and there are still two salts left. At this time, the amount of carbon dioxide produced is proportional to the amount of hydrochloric acid, and because there is the same amount of hydrochloric acid in the two containers, the amount of carbon dioxide produced is the same, and according to the conservation of mass, the remaining mass is the same.

Therefore, it may be that sodium carbonate is heavy on one side, or it may be the same, so D is chosen.

Let's see who's responding.

If it doesn't react, it's heavy.

Method 1: 1 part of Mg2+ (magnesium ion) and 3 parts of Cl- (chloride ion), then 1 part of Cl- (chloride ion) can be introduced, the same is true.

3 parts of K+ (potassium ion) and 1 part of Cl- (chloride ion) are, then 1 part of K+ (potassium ion) can be introduced, and the amount of substances of SO42- (sulfate ion) is summed up.

Method 2: Positive and negative charge balance, positive charge number: the amount of K+ (potassium ions) multiplied by the number of charges of K+ (potassium ions) + the amount of Mg2+ (magnesium ions) multiplied by the number of Mg2+ (magnesium ions);

Negative charge number: the amount of cl- (chloride ion) multiplied by the charge number of cl- (chloride ion) + the amount of SO42- (sulfate ion) multiplied by the charge number of SO42- (sulfate ion);

In summary, the amount of SO42- (sulfate ion) is .

The total amount of the total charge of the solution is 0

K+ is, 1molK+ is positively charged with 1mol, so it is positively charged.

Mg2+ is, and 1mol Mg2+ is positively charged with 2mol, so it is positively charged with 1mol.

So n (positively charged) =

Cl- is, 1molCl- is negatively charged with 1mol, so it is negatively charged.

Another 1mol SO42- with 2mol of negative charge, so n (negative charge) = n (positive charge) = so n (SO42-) =

The problem can be solved according to the power balance:

Cations: Mg2+, K+

Anions: Cl-, SO42-

Power Balance: So: N(SO42-) = mol

Analysis: Mg2+ (magnesium ion) is, then the Cl ion in MgCl2 is 1mol. then KCL is.

If the K ion in K2SO4 is 1mol, then the amount of SO42- (sulfate ion) is 1 2=

Let the three salts have x, y, and zmol, and the system of equations according to the meaning of the problem:

2x+y=2z+y=

x=so find x= y= z= mol

Therefore, the amount of SO42- (sulfate ion) is .

The sum of the anion and ion is 0, so K+ and Cl- cancel each other out, leaving Mg2+ and SO42+, they also cancel each other out, so SO42- is also.

Mg2+, then Cl- in MgCl2 is 1mol, so Cl- in KCl, K+ is, so K+ in K2SO4 is, and SO4- is 1mol2=

The amount of charge carried by the positive and negative ions of the solution should be equal. Moles.

According to the conservation of iron, the mass of iron in the oxide of iron and the mass of iron finally obtained are the same.

m(fe)＝ n(fe)＝

The mass of the oxide of iron minus the mass of iron is the mass of oxygen in the oxide.

m(o)＝24－ n(o)＝

The chemical formula of oxide can be obtained by the ratio of the number of atoms of iron and oxygen, which is also the ratio of the amount of matter, n(fe): n(o): 3

Chemical formula of oxide: Fe2O3

The mass of oxygen in the oxide of 24g of iron is.

So the amount of iron contained in 24g oxide is:;

The amount of oxygen contained in the substance is:

The ratio of the amount of iron to oxygen is::3

So the chemical formula of this oxide is Fe2O3

The mass of oxygen in 24g of iron oxide is: It is also known that the atomic weight of iron is 56 and that of oxygen is 16.

So the molar ratio of iron to oxygen is (:(3. So the oxide of this iron is Fe2O3, ferric oxide.

The mass of oxygen in the oxide of 24g of iron is.

So the amount of iron contained in 24g oxide is:;

The amount of oxygen contained in the substance is:

The ratio of the amount of iron to oxygen is::3

So the chemical formula of this oxide is Fe2O3

Let the oxide of this iron be fexoy

then by the title. > fexoy+ co= x fe+ (y+1/2)co256x+16y 56x

24 lists proportional formulas.

24*56x

y=so the oxide of this iron is Fe2O3

Look at this is a high school question.

Molar ratio of ferrite to oxygen mass: 2

Hence fe2o3

The oxide of iron is reacted with 24g, and the iron is obtained, indicating that the mass of O in the oxide is 24 g

So the ratio of the number of Fe and O = : = : =2 : 3 so this oxide is Fe2O3

AD is a polar molecule made up of polar bonds. c is a non-polar molecule composed of polar bonds.

Magnesium burns in air and can react with both oxygen and nitrogen.

A will produce ammonium chloride, C will produce nitrogen dioxide, and D will produce sulfur element.

Others are easy to decompose when they see light.

White phosphorus is highly toxic, as mentioned in the book.

Passivation of the surface occurs. A dense oxide film forms on the surface, preventing the reaction from proceeding further.

A non-polar molecule made up of non-polar bonds.

A non-polar bond is the interaction force between atoms of the same kind, and a different kind is a polar bond.

It can react with O2 to get Mgo, or it can react with N2 to give Mg3N2 and HCl, and if it meets, it will produce white smoke.

and O2 to form NO2 reddish-brown gas.

O2 reacts to the formation of S, and an excess of it produces SO2

Nitrate is easy to decompose when exposed to light.

This is what the teacher said. In junior high school, I did experiments on the burning of red phosphorus, so I can be sure that red phosphorus is not poisonous.

Concentrated nitric acid and AL passivate to create a membrane.

Not reacting.

b All others are composed of polar bonds.

A B (A NH3 and HCl reaction C O2 and no reaction D O2 oxidation H2S).

b (ACD is easy to decompose, protect from light).

a (Red phosphorus is highly toxic.

a (concentrated sulfuric acid passivates aluminum at room temperature).

Moles of hydrochloric acid. Moles of hydrogen are released, moles of zinc ions and moles of chloride are released. Moles of zinc chloride can be obtained.

You can calculate it based on chemical equations.

m(co(nh2)2)=

Nitrogen content of urea:

More 100 million tons need to be produced.

Mass fraction of N in CO(NH2)2 = 28 60

One ton of grain needs to provide tons of nitrogen, 100 million tons of grain needs 100 million tons of nitrogen, and the mass of urea needs 100 million tons.

What 100 million tons of food needs is 100 million tons of nitrogen. In Co(NH2)2, it is solved proportionally according to the relative atomic weight. The atomic weight of nitrogen is 14, that of carbon is 12, that of oxygen is 16, and that of hydrogen is 1

The total molecular formula is 60, and what we need is 100 million tons of nitrogen, so how much urea do we need? Just follow this ratio.

14 60= Then solve for x= and divide by 2

This is the mass of the urea we want to be 100 million tons.

China wants to increase 100 million tons of grain every year, if the production of each ton of grain needs to provide tons of nitrogen, how many atoms are in a urea molecule? If all the nitrogen needed is provided by urea, how many tons of extra tons of urea will China need to produce?

According to the above calculations, how many more ammonia (NH3) plants with an annual output of 200,000 tons need to be built in order to increase the production of urea?