A chemically important metal compound

1. Na2O2 light yellow solid can react with H2O or CO2 to form O2

2. NaHCO3 is commonly known as baking soda, and the solid is heated and decomposed to obtain Na2CO3

3. Na2CO3, soda ash, does not decompose when heated, and can react with CO2 and H2O to obtain NaHCO3

4. Al2O3, Al(OH)3 amphoteric reacts with acid to obtain Al3+, and reacts with alkali to obtain ALO2-

5. Fe2O3 red solid Fe3O4 black solid magnetic Feo black solid.

6. Fe(Oh)2 reacts with H2O O2 to obtain Fe(Oh)3 FeCl2+NaOH white precipitate, which quickly turns gray-green, and finally turns into reddish-brown precipitate.

7. Fe2+ encounters an oxidant and becomes Fe3+ Fe3+ reacts with Fe or Cu to obtain Fe2+

The above are the more important metal compounds.

Sodium: Na2O and Na2O2 Na2CO3 and NaHCO3 Aluminum: Al2O3 and Al(OH)3

Iron: FeO, Fe2O3 and Fe3O4 Fe(OH)2 and Fe(OH)3 Divalent iron salts and trivalent iron salts.

In addition, sodium metaaluminate and metaaluminate ions.

Homometallic compounds are mainly these, and their chemical equations are important.

I'm a chemistry major in college, and studying chemistry requires memorization of something, so don't be lazy, but not rote memorization. I didn't memorize equations when I was in high school, but you have to do the following. 1. Be sure to learn the properties of various chemical substances, physical and chemical properties must be remembered (for example, H2SO4, strong oxidation, dehydration, can be completely ionized, dilution of "acid into water"), in order to speculate the product (the same concentrated sulfuric acid encounters C, you suddenly reflect that C is oxidized, generating CO2, the concentrated sulfuric acid is reduced, generating SO2, and where does the H atom go, it becomes water, so you will have 2H2SO4 + C = = CO2 + 2H2O + 2SO2 , The ionic equation is a continuation of the chemical equation:

First ask yourself how many can be dismantled, and how many can be removed on both sides of the equation, only H2SO4 can be split into H+ and SO42-, so it is 4H++2SO42-+C==CO2 +2H2O+2SO2). 2. Learn to launch reaction products according to the relative content and conditions of the substance, such as the reaction of Na and O2, which is slowly oxidized into Na2O in the air, and violently burned to generate Na2O2, both of which are alkaline, water absorption, alkaline can react with acid or acidic oxide (you know that no matter you give me CO2 or H2SO4 or something, I will), and can also absorb water to generate alkali, and we also know that peroxide decomposition often has O2 generation (such as H2O2), So Na2O2 reacts with water and O2 is generated. 3. To launch a reaction with similar chemical properties according to a chemical element or compound, for example, Na and K are in the same main group, I know the properties of Na, I know that K also has similar properties, and K is more active than Na, the reaction is more violent, and the conditions are lower.

In fact, the study of metals is nothing more than that: the reaction with the acid finally yields salt and water (the metal before hydrogen) and the oxidizing acid side of the metal acts as a reducing agent.

One reaction with salt is displacement reaction, that is, redox reaction.

Amphoteric metals can react with alkalis and acids (such as aluminum, etc., the metals used for oxidation also have the same properties).

Electrolysis is actually a derivative of the displacement reaction, don't think about it as difficult, remember that the law of the reaction can be like the product.

Summarize similarities and differences.

The chapter on metals generally starts with metal elementals, then metal oxides, and then compounds. Focus on learning the properties of aluminum and iron. In particular, the thermite reaction and the oxidation reaction of ferrous hydroxide are particularly important.

You can try to dictate all the chemistry in this chapter yourself. Build your own knowledge network structure. From elemental to compound formation reactions, a framework diagram can be drawn.

Inductive summary form knowledge network.

Chemical equations and ion equations require you to memorize a few rules, first write the chemical equation, break it down into ionic forms in solution, eliminate the left and right equals, and mark the gas or precipitate on the right. In short, you have to practice diligently, I spent a month practicing equations, and finally found that it is actually very simple, you can read the book, and there is no big problem with the college entrance examination.

It's good to read the book with certification, read the notes, master the method, and don't crash.

Find the chemistry textbook for the third year of junior high school, read it again, and then learn it.

Answer: C Principle2 al +2naoh +2h2o =2naalo2 +3h2

Explanation: A b strong acid reacts with Fe while removing the aluminum plating on the surface of the iron, Fe+2HCl=FeCl2+H2

d and no one reacted.

c. Removing aluminium does not remove iron, and can only react with aluminum. So choose C

To learn any substance, we must start from both physical and chemical properties. The physical properties are mainly considered in eight points such as color taste, hard density, and dissolution and boiling (in order, color, state, odor, hardness, density, solubility, boiling point, and melting point), and for metals, its ductility and conductivity and other properties should be investigated. The chemical properties are mainly reactions.

For metal elements, you can organize the reactions according to the idea of learning sodium metal, mainly the reaction between metals and non-metal elements (oxygen, chlorine, sulfur, etc.), the reaction between metals and acids, and the preparation of metals (reduction of metal oxides or electrolysis of metal salts). Then we will learn the oxides corresponding to the metals, and the learning is still based on the ideas of physical properties and chemical properties. When studying, you must have conditioning, and remember to do it without duplication or omission!

It's about remembering the law that the lower left of the periodic table is the most metallic, and the upper right is the most non-metallic, and then memorize a few reaction formulas, and the valency questions will give you, and you don't have to memorize them.

Remember the order of activities, this is the most important, there are some special properties, as well as the special properties of some compounds, remember clearly, it is very helpful for the college entrance examination, and the first 20 elements are almost the same.

Analysis: A certain amount of iron, ferric oxide, copper oxide mixture into the sulfuric acid solution, after full reaction, the metal ions in the filtrate are only ferrous ions.

All 3 substances react with sulfuric acid, but Fe is more active than Cu and can be replaced with Cu from the solution, while Cu does not react with sulfuric acid, so the filter residue must contain copper.

Add 2 moles per liter of NaOH solution to the filtrate dropwise until 40 ml begins to precipitate, indicating that the sulfuric acid is excessive, the filter residue contains only copper, no Fe, and all Fe elements remain in the solution.

So, let the amount of sulfuric acid reacted with NaOH be x mol

h2so4 + 2naoh → na2so4 + 2h2o

x---2mol/l *

Solution: x =

The amount of ferrous sulfate is the same as the amount of sulfuric acid reacted with the mixture, let the amount of its substance be y mol

feso4 ～ h2so4

Solution: y = mol

So the amount concentration of FeSo4 substance = =

That's it].

It is better to do it according to the conservation of charge.

According to the sodium hydroxide added, after the reaction, the hydrogen ion in the solution = hydroxide ion = sulfuric acid after the full reaction The cation in the filtrate is ferrous ion and hydrogen ion Anion is sulfate ion, because the solution is acidic, so the hydroxide ion can be ignored.

According to the conservation of charge ferrous ions = sulfate ions[(hydrogen ions(0,08mol)]2

CFE=hehe, I haven't done chemistry for a long time, see if it's right.

Put a certain amount of iron, trioxane ferric oxide, and copper oxide mixture into the sulfuric acid solution, and wait until the full reaction, only ferrous ions are left in the filtrate.

All three substances react with sulfuric acid, but Fe is more active than Cu and can be displaced

This question can be understood by the concept of elements, the original magnesium element and aluminum element mass is a gram, and then the aluminum is dissolved in the alkali, and the remaining metal magnesium is heated in pure oxygen to form magnesium oxide, so it is magnesium and oxygen and a gram, so the mass of aluminum is the mass of oxygen in magnesium oxide, and the mass fraction of magnesium in magnesium oxide = 24 40 = 60%; Oxygen = 16 40 = 40%, so the mass fraction of aluminum in the metal mixture is also 40%.

In fact, the mass of H2 is equal to the mass of O2 reacting with magnesium, and let this mass be x

2al + 2naoh + 2h2o = 2naalo2 + 3h2↑

mal x2mg + o2 = 2mgo

mmgx

mal=9xmmg=Mass fraction of aluminum = 9x =

Wango, dear !!

First, the mixture was thrown into the NAOH, and the AL was all reacted. After that, magnesium reacts with oxygen to form magnesium oxide, which is also gram according to the quality of magnesium oxide. Therefore, the mass of oxygen in magnesium oxide is the mass of AL.

Therefore, al%=16 (16+24)=40%.