Simple chemistry questions, a simple chemistry questions

You can press"Strong acid + strong base === weak acid + weak base"to analyze the law.

Al(OH)3 can be written as acid H3alo3 or HALo2+H2O, and if reacted with, the reaction is as follows:

halo2+

Since NH4+ is more acidic than HALo2, it violates the above law. So do not react.

Of course, high school can be illustrated by balancing moves. That is, the oh- produced by ionization causes the following equilibrium to move without noticeable movement:

halo2=== (reversible) ===h+ +alo2-

Although aluminum hydroxide is amphoterical, it is more alkaline, so it can react with weak acids but is difficult to react with weak alkalis;

In addition, aluminum ions are hard alkali, and the ligand ions formed with ammonia are unstable, so they cannot form ligands to shift the equilibrium in the direction of dissolution.

Aluminum hydroxide is only soluble in strong acids and bases.

It's not okay for ammonia to be too weak alkaline!!

Al(OH)3 is a 2-sex compound, he can ionize both H and OH, if it encounters a strong base, it will promote the ionization of Al(OH)3 in the direction of H+, because NH4·H2O ionized Oh- is very good, can only have a weak effect.

The alkalinity is too weak to dissolve aluminum hydroxide.

Aluminium hydroxide only reacts with strong acids and bases.

Ammonia is a weak base.

So can't react.

Remember that Al(OH)3 only reacts with strong bases. The reason for this is that when it comes to hydrolytic equilibrium and a deep understanding of the structural properties of Al(OH)3, I may not be able to explain it clearly.

Hello, magnesium is very active and can be burned even in CO2 to produce magnesium oxide and elemental carbon, the reaction equation is:

2mg+co2==2mgo+c

1、 ，44kg。

Solution: Dilute 98% concentrated sulfuric acid, and the quality of the solute will not change. So the mass of H2SO4 is 5*. Since the mass of the solute before and after dilution remains unchanged, the total mass after dilution is, so the amount of water that needs to be added is 49kg-5kg=44kg

kg or still apply the law of dilution: the mass of the solute does not change before and after dilution.

The principle of application is the same as the topic.

50g*4, yes, is it 10kg or 10g? Calculated as 10g. ZN is 65% and CU is 35%.

Because Cu does not react with dilute sulfuric acid, the H2 produced is Zn and H2SO4 reactions.

With a fairly relational formula: zn h2so4

Yes, then the reaction of zn is then the mass of zn is.

Then the mass fraction of zn is 65%, and cu is.

5. If it happens to be a complete response, it is 49%.

Fe28g then FE is.

fe~h2so4

Then the mass of H2SO4 is.

Then the mass fraction of H2SO4 is 49 100=

The mass of HCl used in the reaction is:

caco3~~2hcl

x then x = 2g, so the mass of caCO3 in the mixture is 2g

Then the mass fraction of caCO3 is 2

7. B Any chemical reaction obeys the law of conservation of mass, A right.

Substance x y z q

Mass before reaction g 4 10 1 25

The mass after the reaction g was not measured 21 10 9

It can be seen that the mass of q decreases, so it is an oxidation reaction, d pair.

The mass before the reaction is 40g, and the mass before the reaction is 40gAccording to the law of conservation of energy, the total mass after the reaction should be the same as the total mass before the reaction of 40g, regardless of whether there are other products. So x=right.

As can be seen from this table, x,q decreases and y,z increases, which is not a decomposition reaction. So b wrong.

.9kg；44kg

2. g or kg?1250kg

kg or 10g? According to 10g, zinc accounts for 65%, copper accounts for 35%5, I don't know if it happens to be a complete reaction can not be calculated. If it happens to be completely reacted, the sulfuric acid mass fraction is 49%7, c

1.Carbonated drinks are carbon dioxide that gets into the bottle.

2.When preparing CO2 in the laboratory, why do we not use concentrated hydrochloric acid or concentrated sulfuric acid because concentrated hydrochloric acid volatilizes quickly, and the calcium sulfate produced by the reaction of concentrated sulfuric acid is slightly soluble in water.

3.The upward exhaust air method collects a denser gas than air.

The downward exhaust air method collects less dense gases than air.

1: Carbon dioxide is pressed into purified drinking water.

2: Concentrated hydrochloric acid is easy to volatile, and the gas mixed with CO2 is impure. As for concentrated sulfuric acid, I'll correct ...... first"Concentrated sulfuric acid" generally refers to a solution of 98% sulfuric acid, and there is no "slightly soluble" = =.

Concentrated sulfuric acid is not used because concentrated sulfuric acid exists in the form of molecules in water, and the reaction is very slow or does not react. If dilute sulfuric acid is used to react with calcium carbonate, calcium sulfate will be formed, which will be coated with calcium carbonate to prevent the reaction from continuing.

3. I don't understand what you're asking......If the gas is non-toxic and harmless, and the relative molecular mass is greater than 29 (the average relative molecular weight of the air), the upward air exhaust method can be used; If it is less than 29, you can use the downward exhaust air method.