High school chemistry about the combustion of Mg, high school about all chemical equations about Mg

In fact, this question does not need to be calculated, and the answer will be known at a glance, because mg is completely burned in the air and generates mgo

The MG produced after complete combustion of 12GMG in the air contains 12G, we know that the atomic mass of MG is 24, the relative atomic mass of O is 16, and the relative molecular mass of MG is 40, so the mass ratio of MG in MG is 24 40, so the mass mass of MG after complete combustion is equal to 20G.

However, MG cannot be completely burned in the air, that is to say, there is still a part of MG that does not participate in the reaction, so the mass of this part of MG remains unchanged, and the mass of the reaction with oxygen does not increase, so the final total mass is less than 20g.

The answer is B

The final products of the combustion of MG in air are two solids, MGO and MG3N2.

If it is all MGO, it is equal to 20 g, but because some of it generates Mg3N2, the mass of the solid is less than 20 g

If all mg3n2 then the solid mass is.

So the range of values for solids is.

In addition to the reaction of Mg with O2 in air, it also reacts with CO2 and N2, mainly with N2.

2mg + O2 = ignition = 2mgo

3mg+n2=ignition=mg3n2

will react with N2.

So less than 20g

In air, it is mainly N2 (78%) and O2 (21%) that react separately

2mg+ o2 =2mgo

12g ?So? =20g

3mg +n2 = mg3n2

Less than 20 so the sum will be less than 20

If it is less than 20g, if the total generation MGO is 20g

All are mg3n2.

Therefore, the value between the two is less than 20g

Magnesium and its compounds.

1. The properties of magnesium.

1) Physical properties.

Magnesium is a silvery-white metal, soft, density, light metal, and small hardness.

2) Chemical properties.

Magnesium is the more reactive metal.

Reaction with non-metal: 2mg + O2 ==2mgo, mg + Cl2 ==mgCl2, 3mg + 3N2 ==mg3N2, etc.

Reaction with boiling water: mg + 2H2O (boiling water) = = mg (OH)2 + H2

Reaction with acid: reaction with non-strong oxidizing acid: H+ in acid reacts with mg, and H2 is released.

Reaction with strong oxidizing acids: such as concentrated H2SO4 and HNO3, the reaction is more complicated, but no H2 is released.

Reaction with some salt solutions: such as CuSO4 solution, FeCl2 solution, FeCl3 solution, etc.

mg + 2fecl3 ==2fecl2 + mgcl2,mg + fecl2 ==fe + mgcl2.

2. Magnesium is extracted.

Seawater contains a large amount of MgCl2, so MgCl2 is mainly extracted from seawater with isolated NaCl

Process: Add CaO or Ca(OH)2 mg(OH)2 precipitation, filter, wash and precipitate in seawater, dissolve MgCl2 solution with dilute HCl, evaporate crystallized MgCl2 6H2O crystals, heat MgCl2 solid in HCL gas Kaibi body environment, and electrolyze molten MgCl2 mg + Cl2

Main reactions: MgCl2 + Ca(OH)2 ==Mg(OH)2 + CaCl2, Mg(OH)2 + 2HCl ==MGCL2 + 2H2O, MgCl2 6H2O MgCl2 + 6H2O, MgCl2 (melted) MG+Cl2

3. The use of magnesium.

Magnesium is mainly widely used in the manufacture of alloys. The alloys manufactured are both harder and stronger. Hence the magnesium alloy.

It is widely used in rockets, missiles, airplanes, and other manufacturing industries.

4. Magnesium oxide (MGO).

White solid, high melting point (2800), is a high-quality high temperature resistant material (refractory material).It is an alkaline oxide.

mgo + h2o ==mg(oh)2,mgo + 2hcl ==mgcl2 + h2o .

Pay attention to the writing of ionic equations in the following cases:

1）n(mg(hco3)2):n(naoh)＝1:4：mg2+ +2hco3- +4oh- =mg(oh)2↓+ 2co32- +2h2o；

2)n(mg(hco3)2):n(naoh)=1:2：mg2+ +2hco3- +2oh- =mgco3↓+ co32- +2h2o；

3)n(mg(hco3)2):n(naoh)=1:1：mg2+ +hco3- +oh- =mgco3↓+h2o

Can react with water (heating), oxygen, acid.

Let's not talk about the simple ones.

Focus, 2mg+CO2=ignition=2mgo+c, derivation 2mg+SO2=ignition=2mgo+s

3mg+n2=ignition=mg3n2

mg + 2H2O = Heating = mg (OH) 2 + H2 high one is all that.