Two high school chemistry questions to help!!

1.The gaseous HCl itself is a covalent bond, and when dissolved in water, it forms a hydrochloric acid solution, containing H+, Cl- ions, which becomes an ionic bond.

The element gaseous hydride is NH3, the aqueous solution is alkaline, and the element 1-20 is located in the lower left of the periodic table, the stronger the element metal, the more alkaline the hydrate corresponding to the most ** oxide, so it is the K element, and the most ** oxide corresponds to the hydrate as KOH

Element 1-20 is located in the upper right of the periodic table, the stronger the element metal, the most ** oxide corresponding to it, the hydrate is also the strongest, (except for the noble gas element), so it is the cl element, and the most ** oxide corresponds to the hydrate is HCO4

Question 2: Because the hydride of the N gas station is ammonia, that is, NH3, NH3 is dissolved in water to produce NH4OH, which is alkaline. So it's n

The second question: the hydrate corresponding to the most ** oxide is the most alkaline, that is, the most metallic, and the most active metal is kThe hydrate corresponding to the most ** oxide is the most acidic, that is, the most non-metallic, and the strongest non-metallic is fluorine, but fluorine has no oxide, so the next one is chlorine.

The hydrate corresponding to the most ** oxide of chlorine is perchloric acid, which is also one of the six strong acids.

The first question is a bit uncertain: it seems that only the fourth of the four options is covalent, and the first three are not covalently bonded.

That's it, I hope it helps you.

1. The covalent bond of a:i2 is i-i, and it is still i2 after sublimation, and the covalent bond is not broken;

B: Similarly, br2 is still br2 when adsorbed from vapor

C: The covalent bond of ethanol exists between C, H, and O, and is still an ethanol molecule after being dissolved in water, and it is not destroyed;

D: The covalent bond of HCl is H-Cl, which is dissolved in water to form separate hydrogen ions and chloride ions, and obviously the covalent bond is broken (of course, there is a small number of HCl in the molecular state, but very little, generally not considered).

2. (1) NH3, soluble in water is ammonia, alkaline.

2) The strongest base in the first 20 elements is obviously the first main group 19 element potassium, koh; The strongest acid is HCO4 perchlorate. Something needs to be accumulated.

The first question option A does not break the covalent bonds, he just breaks the van der Waals force between the molecules.

Option B, option C, and even option A are physical changes that generally do not involve the destruction of covalent bonds (chemical bonds).

Question 2 The hydride of the first question n is ammonia dissolved in water for ammonia monohydrate, that is, at this time the solute becomes ammonia monohydrate, ammonia monohydrate ionizes in water as NH4+ and OH-, so the solution is alkaline.

The next question is actually asked about the reduction, that is, what is the strongest metallic, (the stronger the metallicity, the stronger the alkalinity of the hydrate) As for the last question, I don't know how to explain it, it forms HCO4 (perchloric acid), you just remember this, that's how I did it.

There's still a lot to remember about chemistry

1) Molecules that were originally covalently bonded become ions in water, and the bonds naturally change.

2) The only basic gas in high school chemistry is ammonia, so n.

According to the table of metal activity sequences, regardless of radioactive elements, K is the strongest metallic and Cl is the strongest non-metallic, so it corresponds to the strongest alkaline acidity.

1. The covalent bond is broken and an ionic bond is formed with water.

2、n---nh3,--nh3h2o;becomes +7 valence, yielding perchloric acid HCIO4

a The sublimation of iodine is a physical change, that is, before and after sublimation, the substance does not change, and it is all iodine molecules. The structure of i2 is not broken, so the covalent bond is not broken.

b Ibid., physical changes.

c Ibid., physical changes.

When dissolved in water, HCL ionizes H+ and Cl- ions, and the two atoms were originally held together by covalent bonds, but now they are separated, that is, the covalent bonds are broken.

The gaseous hydride of N is NH3, which is ammonia when dissolved in water. It is the only alkaline gas in middle and high school, and this is very commonly used, so keep in mind.

The alkalinity of the most ** oxide corresponding to the hydrate is an indicator of the metallicity of the element. That is, the question is asking, which element is the most metallic. We all know that the order of metallic strength is:

k ca na mg al...So it's k.

Again, the third problem corresponds to being the most non-metallic. Follow f cl br....It was supposed to be F, but F has no valence and no oxygenated acid, so it's Cl underneath it.

It is a physical change. HCl is ionized when dissolved in water and exists in the form of H+ and Cl-.

2。There is no easy way to do this, just memorize the periodic table and the periodic law.

HCl is dissolved in water for H+ and Cl-, the covalent bond is naturally broken, the second 1 is ammonia, 2 is KOH, 3 is perchloric acid (HCO4), 2, 3 items are the strongest metallic and non-metallic elements (aqueous solution of element F: 2 fluorine gas and 2 water to generate 4 hydrofluoric acid 1 oxygen).

1.Let the relative molecular mass of saturated chain hydrocarbon A be m, then the average relative molecular mass of the gas mixture formed by complete cracking under certain conditions is m 2, and because the ratio of relative density is the ratio of relative molecular weight, therefore.

m/2:2=

The solution is m=58

From the general formula of saturated chain hydrocarbons (cnh2n+2), it can be seen that 12n+2n+2=58 is solved to obtain n=4, so the molecular formula of saturated chain hydrocarbon a is c4h10

2.Let b be a CMH (2M+2) and M an integer.

Because C is an olefin, C contains at least 2 carbon atoms, so 0cmH(2M+2)+(3M+1) 2O2=MCO2+(M+1)H2O Because the amount of the substance that requires oxygen is an integer multiple of it, that is, (3M+1) 2 is an integer, so M=1, B is CH4, which can be known from the conservation of atoms, C is C3H6, so C is propylene. bar.

The average molar mass of the gas mixture is 29, and only methane is below 29 in the alkanes, so alkane b is methane, and then the molar mass of c is 42, so c is propylene, and a is ethylene.

Question 2 can be found without answering.

1.The answer is B

2.Because the degree of ionization of ammonia and acetic acid are equal at the same temperature and concentration, in the aqueous solution, CH3CoonH4 will not be hydrolyzed like ammonium chloride solution to produce H+, so that according to the actual phenomenon, we can judge who is wrong and who is right.

3.Since H+ is not produced by hydrolysis, it means that NH4+ reacts with OH-, not H+, so B's explanation is more reasonable. nh4+ +oh-=nh3•h2o

The root of the problem is whether the OH- ionized by Mg(OH)2 preferentially binds to NH4+ or to H+ hydrolyzed by NH4+.

Because B contains NH4+ and remains neutral, the interference of H+ hydrolyzed by NH4+ is excluded.

3.Second. nh4+ +oh- = nh3•h2o

(1)nb=a/。Note: The volume of the solution must be divided by the mass of the solution (the mass of the gas plus the mass of the water) by the density of the solution.

The volume of the solution should be changed to L. (2)d。There are too many words, so I won't hit it.

To explain to you, the same valence state is the same valence (after all, there are multiple valences of an element, and it is difficult to find when there are many), and the value of valence refers to how many valences it is. For example, O2- means that the valency value of oxygen is -2