A couple of junior high school chemistry questions about the chemical properties of metals.

I miss it so much, I've done this book too. Since it's junior high school, let's make it simpler.

1.Zinc, iron and magnesium are all 2-valent, so the reaction formula is: X+H2SO4==XSO4+H2 So the smaller the relative molecular mass, the greater the hydrogen.

And magnesium "iron" zinc, so magnesium "iron" zinc.

Looking at the aluminum 2AL+3H2SO4==AL2(SO4)3+3H2 magnesium is the maximum, 12g of magnesium produces 1g of hydrogen, and the above calculation of 9g of aluminum gets one gram of hydrogen, aluminum "magnesium.

2.Since the amount of sulfuric acid is equal, the maximum amount of hydrogen that can be produced is equal.

So in the end, according to the table of metal activity sequence, magnesium "zinc" "iron", get the solution.

3.From above, the same mass of magnesium produces hydrogen gas greater than iron, so the magnesium side is light after the reaction.

4.If there is zinc left, there must be no ions in the solution that can react with zinc, Fe2+ will be replaced with zinc, A is not right, B is right, there is no zinc left, everything is possible, Cd is uncertain. So it's b

5.Note that there is a sufficient amount of hydrochloric acid, that is to say, there is no metal left that can react with acid, and only two of the 4 options A can react with acid, so it is impossible to leave two metals in A.

Take 1 gram of the substance to produce hydrogen.

Magnesium: 1 divided by 24 multiplied by 2 = one-twelfth mol

Aluminum: 1 in 9.

Iron: 1/28.

Zinc: 1 in 65.

Question 1: D Question 2: Which light point points to that side and points A

Question 3: A zinc can replace iron and copper.

Question 5: A Metal Activity Sequence Table Hydrogen can react with non-reducing acids before hydrogen, but not afterwards.

Aluminum, magnesium, iron, zinc. The teacher asked us to carry it!

Note: The words should be written well, and the learning attitude should be correct! Good luck with your studies!

According to the diagram, it is clear that the reaction rate of A is faster than that of B, so the rate of hydrogen production A is faster.

b two solutions with the same mass fraction, due to the large relative molecular mass of sulfuric acid, according to the calculation of the amount of hydrogen ions in the solution is small, to replace the amount of hydrogen of the same substance, the acid must be sufficient, then the metal must be consumed.

c displaces the amount of hydrogen of the same substance, then the amount of hydrochloric acid participating in the reaction is twice the amount of sulfuric acid substance, and the mass is obviously not the same.

D is a metal with the same positive bivalent, and in order to replace the same hydrogen, two metals with the same amount of substance are consumed, and the relative atomic mass of A is smaller than B, so the mass of the metal A participating in the reaction is smaller than B.

A and B are both positive bivalent, so one mole of metal must replace one mole of hydrogen, since the mass of hydrogen produced is the same, then the amount of substances to form hydrogen is also the same, and the amount of substances of the two metals participating in the reaction is also the same.

To generate the same hydrogen, there is one hydrogen ion in hydrochloric acid and two hydrogen ions in sulfuric acid, and the amount of hydrochloric acid consumed is twice that of sulfuric acid to replace the same hydrogen.

Because you have already been told in the question that the relative atomic mass of a is smaller than that of b.

As you can see from the figure, to produce hydrogen of the same mass, it takes less time for A to produce hydrogen, i.e., the rate of hydrogen production A>B option A is wrong.

In the reaction, A and B are both positive bivalent A+H2SO4===ASO4+H2 (gas) B+2HCl===BCL2+H2 (gas) From these 2 reaction equations, it can be seen that both metals are one atom can replace a hydrogen molecule, because the mass of hydrogen produced is equal, so the number of metal atoms consumed is equal, because ar(a) ar(b), so the mass of the metal participating in the reaction a Both metals are one atom can replace a hydrogen molecule, Since the mass of hydrogen produced is equal, from the point of view of particles, to take the least example, to produce 1 hydrogen molecule, 1 H2SO4 molecule is needed with a relative molecular mass of 98, while HCL requires 2 molecules with a relative molecular mass of 73, indicating that the mass of hydrogen of Changsheng and the same mass of sulfuric acid consumed is greater than the mass of hydrochloric acid (they have equal mass fraction) so C is correct.

For option B, if you don't understand it yet, you still need to work hard. Metals A and B can have surpluses, and both acids (containing an equal number of hydrogen ions) are all consumed; It is also possible that A has a surplus, B reacts all of them, and both acids (containing an equal number of hydrogen ions) are all consumed: both metals are one atom that can be replaced by a hydrogen molecule, and since the mass of hydrogen produced is equal, ar(a) ar(b), for question 1, the amount of matter, refers to the number of particles, which should be understood here as the number of metal atoms participating in the reaction is equal;

Question 2, or does it mean that the number of particles is 2:1, looking at the above chemical reaction equation, the formation of 1 molecule of hydrogen requires 1 molecule of sulfuric acid or 2 molecules of hydrochloric acid, so the ratio of the amount of hydrochloric acid and sulfuric acid substances participating in the reaction is 2:1

Question 3, your question is wrong, why is the amount of two metallic substances consumed (the number of particles) the same when producing hydrogen of equal mass, and the relative atomic mass of A is smaller than that of B? Explain as above, see for yourself.

(1) Because ab is both positive bivalent, the reaction equation is balanced to generate 1mol of hydrogen and consumes 1mol of a and b, because the mass of hydrogen is equal, and the mol of hydrogen generated by the two reaction formulas is also equal, so the amount of substances participating in the reaction of the two metals is equal, not equal in mass.

2) Because the amount of hydrochloric acid contains hydrogen ions of 1 and sulfuric acid contains hydrogen ions of 2 for the same substance, and the hydrogen gas generated is equal, the consumption of hydrochloric acid is 2 times.

3) Since the mass is equal to the amount of matter multiplied by the relative atomic mass, the amount of matter consumed is the same, and the relative atomic mass is so small that it must consume less mass.

The answer is c

Did you learn the concept of the quantity of matter in junior high school?

c Definitely yes, I dare to guarantee it.

The quantity of matter is synonymous with the number of molecules. The unit is mol, and the amount of the substance is 1mol, and the substance contains a particle.

After the reaction of iron and silver nitrate, the solution changes from colorless to light green, and the solution changes from colorless to blue after the reaction of copper and silver nitrate, so answer B can be.

9.⑴ag⑵mn

2HCI====mnci2+H2 (gas symbol) 10Aluminum alloy material is a mixture of metals composed of aluminum and other metals or non-metals.

Equation: 4al+3o2====2al2o3

A dense oxide film is formed.

al2o3+3

h2so4====al2(so4)3+3h2o;

2al+3h2so

4====al2(so4)3+

3h2 (gas symbol).

11.iron powder;

Filtration; fecuso4====cu+feso

412.Principle: Iron and copper sulfate react to form red copper and light green ferrous sulfate Fe+CuSo4====Cu+Feso

413.(1) Wetting the iron nail will oxidize it to form an iron oxide film (2) The rust increases the friction and makes the iron nail stronger on the wood product.

Actually, I don't understand the principle, I found it on the Internet.

Physical properties of metals: Most metals are silvery-white solids (mercury is liquid, copper is purplish-red, gold is yellow), has good electrical and thermal conductivity, is malleable, and has a high melting point (except for mercury).

Chemical properties of metals:1 Most metals can react with oxygen.

2. Active metals can react with dilute hydrochloric acid and dilute sulfuric acid.

3. Metals can react with certain salt solutions.

c Iron, copper, silver.

Dilute hydrochloric acid is dropped into the resulting solid, and bubbles are formed, indicating that there is iron powder in the solid, so copper and silver have been replaced, and there is a lot of iron.

After the end of the reaction, the metal residue can also react with hydrochloric acid, indicating that there is too much iron, then the copper ions and silver ions in the solution have been replaced, so all three metals are available.

Let's choose C. Because there must be iron powder in the formation of bubbles with hydrochloric acid, it proves that the iron powder is excessive, so copper and silver must have been replaced, and copper and silver do not react with dilute hydrochloric acid.

The correct answer is D

Because zinc is added to the mixed solution, it reacts with silver nitrate first, and the silver in the solution is replaced, and only after the silver is completely replaced can the copper be replaced, and at this time, dilute hydrochloric acid is added to the filtrate, and a white precipitate is generated, and the white precipitate is only AGCL, indicating that the silver nitrate is not completely reacted, so the copper nitrate is impossible to react, and the zinc nitrate is generated by reaction, so the solute in the solution is silver nitrate, copper nitrate, and zinc nitrate.

In this solution, there are AG, Cu2 and NO3 at the beginning, according to the metal activity order table, the farther the active metal is from the weakly active metal, the first replacement, or the easier it is to replace, at this time Zn is the farthest away from AG, so first replace with AG, after filtration, add HCl and still have white precipitate, that is, Zn and AgNO3 reaction is completely consumed, so the filtrate contains Zn2, and the remaining AG reacts with HCl to generate AGCL precipitation, which means that there is AG in the filtrate, However, Zn is consumed by AG and it is too late to replace it with Cu2, so there is unreacted Cu2 in the filtrate.

Choose B, first add zinc powder to replace the reaction, and then add dilute hydrochloric acid to generate a white precipitate, which means that there are silver ions, which will be combined with chloride ions to form silver chloride precipitate, since there are silver ions, it means that the zinc powder is not enough, because the replacement reaction is active to replace the inactive, now there are both silver ions and copper ions, then the zinc powder is the first to replace the more inactive silver ions, so there must be copper nitrate in the solution, of course, there is zinc nitrate.

Right, d. The second floor is the activity of the metal, that is, the strength of the reduction, so the oxidation of the cation is reversed, so the silver is replaced first

k ba ca na mg al zn fe sn pb (h) cu hg ag pt au, in this order, ag is first replaced by zn. According to the filtrate, if there is a white precipitate in HCl, only AGCL is a white precipitate, which means that the amount of Zn is not enough to replace all the AG, and there is AG+ remaining in the filtrate, then copper ions must exist, so there must be silver nitrate, copper nitrate, and zinc nitrate in the filtrate. Keep in mind the order of substitution above, and add a few more for high school applications.

Silver chloride is insoluble in water and is a white precipitate.

An example will you understand:

For example, magnesium: the relative atomic mass of the element is 24, and its valency is gram The mass of magnesium reacts with acid to produce hydrogen gas and is calculated as follows:

mg+2hcl=mgcl2+h2

24 21 xx = 2 24 = g).

It has a volume-to-price ratio of 12.

Iron: The relative atomic mass of the element is 56, and its valency is + grams of iron reacts with acid to produce hydrogen with a mass of:

fe+2hcl=fecl2+h2

56 21 xx = 2 56 = g).

It has a volume-to-price ratio of 28.

In this way, you can see that the larger the volume-price ratio, the smaller the amount of hydrogen produced; Conversely, the greater the amount of hydrogen produced.