Those who are excellent in middle and high school chemistry will know how to enter high school chemi

1.Oxygen production:

2kclo3 catalyst 2kCl+3O2 2kmNO4 heats K2mNO4+mNO2+O2 2H2O2Mno2 2H2O+O2

Industrial: 2H2O electrolysis 2 H2 + O2

Oxygen should be generated

Decomposition reaction: KCLO3, KMno4, H2O Hno3 or light 2H2O + 4NO2 + O2, hypochlorous acid decomposition, sulfur trioxide decomposition, nitrate decomposition,

1-valent and -2-valent are oxidized: 5H2O2 + 3H2SO4 + 2kmNO4 = 2MnSO4 + K2SO4 + 8H2O + 5O2, F2 + H2O,

Electrolysis: H2O electrolysis, 2Al2O3 (melting) electrolysis 1000 4Al3O2, copper sulfate solution.

Non-redox: 2O3 = 3O2,

Disproportionation: Na2O2+H2O, Na2O2+CO2, Na2O2+H2So4H2 + O2 = 2H2O burns and emits a blue flame.

S + O2 = SO2 burns and emits a blue flame.

A chemical compound with elemental participation must be a redox reaction.

3naoh = fe(oh)3↓ +3nacl+ 2ag+ = fe2+ +2ag

Aren't all these things in chemistry textbooks?

1) 2H2O2=MNO2=2H2O+O2 2KMno4= =K2Mno4+Mno2+O2 2KCLO3=MNO2 =2KCl+3O2 2)2H2+O2=Ignite=2H2O, the flame is light blue.

3)3naoh+fecl3=fe(oh)3↓+3nacl4)2ag+ +fe=2ag+fe2+

1 :d The first question is very simple First of all, you see that the number of protons of an element is equal to the number of electrons, and the ammonium root has a positive charge, so you must choose a positive ion, if you remember the number of protons, you can test it Of course, the answer to the question should be speed 2: d Ammonium water is not a weak electrolyte, but ammonium water will electrolyze ammonium gas, ammonium water, and ammonium in the water Only according to the conservation of elements to answer this question, the nitrogen element does not change, and it is always one mole 3:

c First know what is a non-polar bond? Non-polar bonds are not necessarily the same as the covalent compounds in a by a common electron, such as water, carbon monoxide, nitric oxide, etc., they show a certain polarity b; There must be ionic bonds in ionic compounds, but there are also covalent bonds. Since there are ionic bonds, are ionic bonds polar bonds?

No, so b is wrong c is non-polar between non-metallic elements through the pairing of common electron pairs d looks correct, in fact, it is not, there are non-polar bonds in it, but there may also be polar bonds For example, there are many in organic matter For example, acetylene carbon is a non-polar bond between the carbon element, but the carbon element and the hydrogen element are not, but a polar bond.

Number of protons: 7+1*4=11, number of electrons: 11-1=10 Number of protons Number of electrons A 1*2+16=18 18b 1*2+8=10 10C 9 9+1=10d 11 11-1=10, so it is selected, because NH3 is dissolved in water and forms NH3·H2O, a very small amount is ionized into NH4+ ions, and a small amount of NH3 gas, such as the covalent compound H-Cl in A, is not a non-polar bond, and there is no polarity problem in the ionic bond in B, In C, because there is no electronegativity difference between the two atoms, the positive and negative charge centers coincide, and there is no polarity, in D, the non-polar molecules are not necessarily non-polar bonds, and there can be polar bonds in non-polar molecules, for example, CS2 is a non-polar molecule, but the C=S bond in S=C=S is a polar bond (C and S are different in electronegativity, and the positive and negative charge centers do not coincide), but the molecule as a whole is non-polar.

1d, ammonia ions have 11 protons, the same as sodium 2d, the material is conserved, the total ammonia sum is 1mol3c A is a polar bond, B, the hydroxide ion in sodium hydroxide is a polar bond, D methane is a non-polar molecule, but a polar bond.

Question 1: B Question 2: C Question 4: C

The first question should be selected in D, B iron and iodine will be redox.

Question 2: Under b H+, nitric acid and carbonic acid are redox.

Under the third question A H+, the sulfur in the bisulfite group will be disproportionated, and the first question selected Fe3+ will oxidize I- and cannot coexist. Ca2+ and CO32+ in C produce calcium carbonate and cannot coexist. d may.

The second question is A. Sodium carbonate is relatively alkaline, and phenolphthalein can turn red.

Select D for the third question.

In the first question, Fe3+ will oxidize I- and cannot coexist. Ca2+ and CO32+ in C produce calcium carbonate and cannot coexist. d may.

The second question is A. Sodium carbonate is relatively alkaline, and phenolphthalein can turn red.

The third question is colorless, which does not indicate acidity and alkalinity, and sulfites may not exist. bCarbonate should not be present in large quantities. cEthanol is not an electrolyte.

Options B and D can be excluded by choosing a colorless solution of C, because Fe2+ is light green and Fe3+ is yellow.

pH = 1, option A can be ruled out, because pH = 1 is strongly acidic and reacts with CO32- and cannot coexist in large quantities!

Select BA ions and carbonate in CA to form precipitates.

b Ferrous ions do not coexist with hydroxides.

Because the solution pH=1 in D, there is a large amount of H+, and AlO2- reacts with H+ to form Al3+

ph=1

On behalf of the acidic solution, H+ reacts with CO32-OH—and ALO2 to generate CO2, H2O, and Al3+, respectively

Therefore, choose C for adoption.

The order of metal activity adopted by domestic middle schools is actually the order of metal replacement, so it is also called the order of metal replacement: potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, lead, hydrogen, copper, mercury, silver, platinum, gold. In addition, we generally do not distinguish between the order of metallic activity and the difference between metallic activity and metallic activity at the middle school level, and often think that a strong metallic activity is a strong activity.

Metal activity is actually a property of metal elements, which refers to the tendency of metal elements to form hydrated cations in aqueous solutions.

In fact, there is a difference between metal activity and elemental metallicity. So, college chemistry emphasizes the metallicity of the elements. That is, the energy required for the gaseous element atom to lose electrons to become a cation, that is, the amount of ionization energy, is used to judge the strength of the element's metalness.

The order obtained by ionization energy is potassium, sodium, aluminum, calcium, chromium, tin, lead, manganese, nickel, magnesium, silver, copper, iron, platinum, gold, mercury, hydrogen. It can be seen that there is a big difference with the order of activity of metals.

In the United States, the junior high school science textbook "The Nature of Matter" uses the change in temperature before and after the reaction between metals and acids to infer the strength of metal activity. Here's how:

Add 5 ml of hydrochloric acid solution to the test tube, determine the temperature, add 2 scoops of metal shavings, and measure the temperature again after a few minutes. Hunger is recorded. After several metals have been made, the more the temperature rises, the more mobile it is.

This approach is also theoretically desirable. (See Tao Yaqi and Dongkong Ma Hongjia of the Institute of Chemistry of Southern Normal University, "Correct Understanding and ** Metal Activity Sequence" article).

Therefore, it can be said that the difference in order is caused by different perspectives. Each has its own truth and scope of application, and it cannot be said which is absolutely good and which is absolutely bad.