Urgent! I ve definitely seen chemistry problems, but I ve never understood them

ge bibi4ge3o12

Bi4O6 loses 5 electrons and is of course harder than it gets 3 electrons.

The +3 valence ratio of Bi is stable to +5 valence, which is called the inert electron pair effect (that is, the electrons left in the outermost shell), and this phenomenon is present in both TL and PB.

6s2 inert electron pair effect... You can search for it on the Internet, and I will only give a brief introduction here.

In the 6S orbital, the two electrons in the orbital are not easily lost, so Pb is not only stable at 4 oxidation number, but also at 2 oxidation number. To this day, the explanation for this phenomenon is still debated. I have now found some reasons for the controversy from the encyclopedia, please refer to it.

In addition, in the fourth edition of Inorganic Chemistry (Part II), I collected some information. p693

Drager explained the stability of TL, Pb and Bi in the low oxidation state of compounds from the relevant thermodynamic data and valence bond theory, and believed that the reasons for the weak bonding ability of the heavy element 6S2 electron pairs were: (1) the atomic radius is large and the electron cloud overlap is poor; (2) The number of inner shell electrons is large, and the repulsion force between these inner shell electrons and the electrons between the inner shell of the bonding atom is larger.

If you are a high school student, you only need to understand the inert electron pair effect, but the college entrance examination does not require it. If you want to do a competition, you must understand it thoroughly. Chemistry is actually very interesting, and I'm also doing a chemistry contest to join us.

8h+ +3cu + 2no3- = 3cu2+ +2no + 4h2o

Because the concentration of 1L of a mixture of dilute H2SO4 and dilute HNO3 is and that is, C(H+)=, and C(NO3-)=, respectively

So n(cu)=n(no3-)*

So m(cu)=

This kind of problem is very simple, use the equation 8h+ +3cu +2no3- =3cu2+ +2no +4h2o.

n（h+）= n（no3-）=

So n(cu2+)=

m(cu)=

The mass of MSO4 is (5G+45G)*30%=15GMO+H2SO4= MSO4+H2OX+16 98 x+96

5g y 15g

x=24 y=

The relative atomic mass of a metal is 24

Mass fraction of solutes in dilute sulfuric acid.

The answer is d.

The mistake of option A is that it answers the question as if the conclusion were a phenomenon. When we describe the burning of iron, we can only say that it is sparkling, with black solids generated. It cannot be said that it produces ferric tetroxide, because what it produces is not visible to the naked eye.

The mistake with option b is that phosphorus combustion only produces a large amount of white smoke, and there is no fog. Smoke refers to small particles of solid, whereas fog refers to small particles of liquid. Phosphorus pentoxide is a solid.

The mistake with option c is that sulfur emits a blue-purple flame only when burned in oxygen, and light blue when burned in air.

DA is selected to generate iron oxide, which is iron oxide.

b. I kind of forgot what the specific phenomenon was.

cSulfur produces a pale blue flame.

Right:

b produces a large amount of white smoke, not fog.

c。Sulfur burns in the air and emits a blue-purple flame. in oxygen.

First of all, the radius of Mg is the smallest and the most charged, so the ionic bond is the strongest to exclude AD, and then comparing K and Ca, it is obvious that the charge of Ca is multi-radius and small. Therefore, choose B.

When the mass ratio of 1Na2CO3 to NaHCO3 is 106:84, the ratio of the amount of matter in the two = (106 106):(84 84) = 1:1

So the hydrochloric acid volume ratio consumed by the reaction of Na2CO3 with NaHCO3 with the same concentration of hydrochloric acid = 2:1

The intensity of the reaction was that NAHC3 was more violent.

22hcl~na2co3 hcl~nahco3

When hydrochloric acid containing the same mass of HCl reacts, the ratio of the amount of substances consuming Na2CO3 to NaHCO3 = 1:2

So the mass ratio of consumed Na2CO3 to NaHCO3 = (106):(84*2) = 53:84

The volume ratio of the resulting gas under the same conditions is 1:2

3 The ratio of the amount of matter of Na2CO3 to NaHCO3 of the same mass = 84:106 = 42:53

Therefore, the volume ratio of CO2 produced by sufficient hydrochloric acid reaction is 42:53

When the mass ratio to NaHCO3 is 106:84, the volume ratio of hydrochloric acid consumed by the reaction of Na2CO3 with the same concentration of NaHCO3 is 2:1, and the intensity of the reaction is that sodium bicarbonate is more intense.

2.When two parts of hydrochloric acid containing the same mass of HCl reacted with a sufficient amount of Na2CO3 and NaHCO3, respectively, the mass ratio of Na2CO3 to NaHCO3 was 53:84;The volume ratio of the resulting gas under the same conditions is 1:2

3.The volume ratio of CO2 produced by the same mass of Na2CO3 and NaHCO3 was 84:106 respectively, and the volume ratio of CO2 produced was 84:106

As a result, simplify it yourself.

This is simple, 1) 2:1, naHCO3 is more intense.

2) 84:106, the second question itself is not rigorous, because HCL and Na2CO3 react, first all NaHCO3 is generated, and then NaHCO3 and HCl react to produce CO2, that is to say, when two parts of hydrochloric acid containing the same mass of HCl react with a sufficient amount of Na2CO3 and NaHCO3 respectively, they may not produce anything else with Na2CO3, but only NaHCO3