Choose 10 to 13 questions in chemistry for junior high school! 80 points for the reason for the spee

First, it is clear that the maximum number of electrons in the electron shell such as k, l, m, and n is 2, 8, and 18 ,..The 2n option m layer has a maximum of 8 electrons and is saturated with the noble gas element neon, which is neon atom. c option, the number of nuclear charges is 10, but the number of protons in the nucleus is 8, so it has two units of negative charge, which is an oxygen ion, that is, o (2-).

Remember that the maximum atomic number of the element in the third period is 18, then it is clear that the element of option d is a nonmetal. So use the elimination method to get a as the correct option.

First of all, we know that the number of protons of the particle is 12, the electron configuration of the outer nucleus is 1s 2 2s 2 sp 6 3s 2, and the number of outermost electrons is 2, which is the metal element magnesium.

The atom does not show electricity, the protons are positively charged, and the electrons are negatively charged, so the number of electrons outside the nucleus is equal to the number of protons inside the nucleus, which is 25

The first sentence is correct, some substances are made up of ions, such as metal elementals, which are made up of metal cations plus free electrons. In the second sentence, particles can be used to hit the target nucleus with an accelerator to physically create new atoms. The third sentence can be explained by the decay of the atom itself.

First of all, after high temperature heating, gas is generated, which can make the clarified lime water turbid, of course, CO2, and the residue Z is added with hydrochloric acid, which is completely dissolved, and hydrogen (the lightest gas) is produced, indicating that there is no CuO, and only Fe can replace hydrogen in the above substances and their constituent elements, so there must be FEO, how does FEO come about? It must have been reduced, and the first part was reflected in the mixture heated at high temperature, and the calcium carbonate could only produce CO2, and it was impossible to reduce FeO, so there must be carbon.

c.①②

The lightest gas is hydrogen, carbon and iron oxide at high temperature to produce iron and carbon dioxide, iron and hydrochloric acid react to form hydrogen, so there is iron oxide and carbon.

Calcium carbonate pyrolysis also produces carbon dioxide.

Choose CCACO CA + CO Heating calcium carbonate to 900 at one atmosphere will decompose into calcium oxide and carbon dioxide.

Carbon dioxide is a white precipitate of clarified lime water.

CA + 3C = High Temperature = CaC2 + CO Fe2O3 + 3Co = 2Fe + 3Co2 (High Temperature) 2Fe2O3 + 3C = (High Temperature) 4Fe + 3Co2 Fe + 2HCL FeCl2 + H2

c Gas x is carbon dioxide so there is calcium carbonate.

The most hydrogen gas is hydrogen, which reacts with hydrochloric acid to have iron element, so there is iron oxide, carbon and iron oxide at high temperature to form iron element.

1.Choose B, because 2 sodium hydroxide can react with one sulfuric acid, and the two solutions are of equal quality, purple litmus turns red when acidified.

2.No. and D cannot be dried with sodium hydroxide, because their aqueous solution is acid, and B is an alkali that cannot be dried with sulfuric acid, choose C

4.Select C, A neutralization reaction must have precipitation, gas and water, B normal rainwater pH less than 7, D life experience.

5.Choose d, a dilute sulfuric acid does not react with air, b your salt does not deteriorate in the air, c calcium carbonate is solid, stable, d there is water and carbon dioxide in the air, cao + h2o = ca(oh)2

ca(oh)2+co2=caco3+h2o

6.Option D, dilute hydrochloric acid does not react with copper, but can react with zinc.

7.Choose C, the same quality.

NaOH and KOH, the relative atomic mass of sodium is 23 potassium is 39, and the hydroxide of NaOH is more than that of KOH, so there is still sulfuric acid left after the reaction, so the pH is less than 7

8.As in the first question, choose C

Purely typed out word by word!! I only have a score out of 50 in chemistry

This question examines the properties of common elemental substances.

According to "A burns in the air and emits a dazzling white light, forming a white solid C", it can be judged that A is a mg element, and C is MGO. According to "A+B--C", B is O2 elemental.

According to "A+H--F+I (i is a gas)", it can be associated with the reaction of mg with acid to form hydrogen, so i is an element of H2; It is then judged that H is an acid, and F is a salt formed by Mg and H.

According to the analysis of "C+H--F+E", C is MGO, H is acid, F is salt, then E must be H2O.

In this way, "b+i--e" and "e--b+i" are verified.

The key is the condition of "G+H--F+E+D (D is a gas)", G contains Mg, and reacts with H (an acid) to form F (a salt of Mg), E (H2O) and a certain gas D (excluding H2), it can be seen that G itself contains a weak acid group, which reacts with H to form a colorless and odorless gas anhydride, which is easy to determine that this is carbonate (colorless and odorless excludes SO2). Therefore, d is CO2. Then depending on the presence of water in the product, then g is the basic carbonate.

Answer: (1) The chemical formula of substance A is: mg

2) Write the chemical formula of another substance with the same composition elements as the E substance: H2O2

3) Write the chemical equation for d to be converted to b under certain circumstances:

Did you copy the wrong question? ）

4) A and D can undergo displacement reactions under high temperature conditions, and the chemical equation of the reaction is written

2mg+CO2 = (high temperature) = 2mgo+c

I'm sure you've copied the wrong question, because B is a elemental substance, and D is definitely a compound ("A and D can be replaced at high temperatures, how can they be replaced if they are not compounds?"). So d can't be converted to b. But the ideas are clear to you, just understand!

Damn, I won't graduate from engineering,, I still got a full score in chemistry in the high school entrance examination that year, hey.